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How BAM differs from traditional business intelligence The Oracle SOA Suite stores the state of all processes in a database in documented schemas so why do we need yet another reporting tool to provide insight into our processes and services? In other words how does BAM differ from traditional BI (Business Intelligence)? In traditional BI, reports are generated and delivered either on a scheduled basis or in response to a user request. Any changes to the information will not be reflected until the next scheduled run or until a user requests the report to be rerun. BAM is an event-driven reporting tool that generates alerts and reports in real time, based on a continuously changing data stream, some of whose data may not be in the database. As events occur in the Services and Processes, the business has defined they are captured by BAM and reports and views are updated in real time. Where necessary these updated reports are delivered to users. This delivery to users can take several forms. The best known is the dashboard on users' desktops that will automatically update without any need for the user to refresh the screen. There are also other means to deliver reports to the end user, including sending them via a text message or an email. Traditional reporting tools such as Oracle Reports and Oracle Discoverer as well as Oracles latest Business Intelligence Suite can be used to provide some real-time reporting needs but they do not provide the event driven reporting that gives the business a continuously updating view of the current business situation. Event Driven Architecture Event Driven Architecture (EDA) is about building business solutions around responsiveness to events. Events may be simple triggers such as a stock out event or they may be more complex triggers such as the calculations to realize that a stock out will occur in three days. An Event Driven Architecture will often take a number of simple events and then combine them through a complex event processing sequence to generate complex events that could not have been raised without aggregation of several simpler events. Oracle BAM scenarios Oracle Business Activity Monitoring is typically used to monitor two distinct types of real-time data. Firstly it may be used to monitor the overall state of processes in the business. For example it may be used to track how many auctions are currently running, how many have bids on them, and how many have completed in the last 24 hours (or other time periods). Secondly it may be used to track in real-time Key Performance Indicators or KPIS. For example it may be used to provide a real-time updating dashboard to a seller to show the current total value of all the sellers' auctions and to track this against an expected target. In the first case, we are interested in how business processes are progressing and are using BAM to identify bottlenecks and failure points within those processes. Bottlenecks can be identified by too much time being spent on given steps in the process. BAM allows us to compute the time taken between two points in a process, such as the time between order placement and shipping, and provide real-time feedback on those times. Similarly BAM can be used to track the percentage drop-out rate between steps in a sales process, allowing the business to take appropriate action. In the second case, our interest is on some aggregate number, such as our total liabilities should we win all the auctions we are bidding on. This requires us to aggregate results from many events, possibly performing some kind of calculation on them to provide us with a single KPI that gives an indication to the business of how things are going. BAM allows us to continuously update this number in real on a dashboard without the need for continued polling. It also allows us to trigger alerts, perhaps through email or SMS, to notify an individual, when a threshold is breached. In both cases reports delivered can be customized based on the individual receiving the report. BAM architecture It may seem odd to have a section on architecture in the middle of a article about how to effectively use BAM, but key to successful utilization of BAM is an understanding of how the different tiers relate to each other. Logical view The following diagram represents a logical view of how BAM operates. Events are acquired from one or more sources through event acquisition and then normalized, correlated, and stored in event storage (generally a memory area in BAM that is backed up to disc). The report cache generates reports based on events in storage and then delivers those reports, together with real-time updates through the report delivery layer. Event processing is also performed on events in storage, and when defined conditions are met, alerts will be delivered through the alert delivery service. Physical view To better understand the physical view of the architecture of BAM, we have divided this section into four parts. Let us discuss these in detail. Capture This logical view maps onto the physical BAM components shown in the following diagram. Data acquisition in the SOA Suite is handled by sensors in BPEL and ESB. BAM can also receive events from JMS message queues and access data in databases (useful for historical comparison). For complex data formats or for other data sources then Oracle Data Integrator (ODI is a separate product to the SOA Suite) is recommended by Oracle. Although potentially less efficient and more work than running ODI, it is also possible to use adapters to acquire data from multiple sources and feed it into BAM through ESB or BPEL. At the data capture level we need to think of the data items that we can provide to feed the reports and alerts that we desire to generate. We must consider the sources of that data and the best way to load it into BAM. Store Once the data is captured, it is then stored in a normalized form in the Active Data Cache (ADC). This storage facility has the ability to do simple correlation based on fields within the data, and multiple data items received from the acquisition layer may update just a single object in the data cache. For example the state of a given BPEL process instance may be represented by a single object in the ADC and all updates to that process state will just update that single data item rather than creating multiple data items. Process Reports are run based on user demand. Once a report is run it will update the user's screen on a real time basis. Where multiple users are accessing the same report only one instance of the report is maintained by the report server. As events are captured and stored in real time the report engine will continuously monitor them for any changes that need to be made to those reports which are currently active. When changes are detected that impact active reports, then the appropriate report will be updated in memory and the updates sent to the user screen. In addition to the event processing required to correctly insert and update items in the ADC, there is also a requirement to monitor items in the ADC for events that require some sort of action to be taken. This is the job of the event processor. This will monitor data in the ADC to see if registered thresholds on values have been exceeded or if certain time-outs have expired. The event processor will often need to perform calculations across multiple data items to do this. Deliver Delivery of reports takes place in two ways. First, users request reports to be delivered to their desktop by selecting views within BAM. These reports are delivered as HTML pages within a browser and are updated whenever the underlying data used in the report changes. The second approach is that reports are sent out as a result of events being triggered by the Event Processing Engine. In the latter case, the report may be delivered by email, SMS, or voice messaging using the notifications service. A final option available for these event generated reports is to invoke a web service to take some sort of automated action. Closing the loop While monitoring what is happening is all very laudable, it is only of benefit if we actually do something about what we are monitoring. BAM provides the real-time monitoring ability very well but it also provides the facility to invoke other services to respond to undesirable events such as stock outs. The ability to invoke external services is crucial to the concept of a closed loop control environment where as a result of monitoring we are able to reach back into the processes and either alter their execution or start new ones. For example when a stock out or low stock event is raised then the message centre could invoke a web service requesting a supplier to send more stock to replenish inventory. Placing this kind of feedback mechanism in BAM allows us to trigger events across multiple applications and locations in a way that may not be possible within a single application or process. For example, in response to a stock out, instead of requesting our supplier to provide more stock, we may be monitoring stock levels in independent systems and, based on stock levels elsewhere, may redirect stock from one location to another. BAM platform anomaly In 10g SOA Suite, BAM runs only as a Windows application. Unlike the rest of SOA Suite, it does not run on a JEE Application Server and it can only run on the Windows platform. In the next release, 11g, BAM will be provided as a JEE application that can run on a number of application servers and operating systems. User interface Development in Oracle BAM is done through a web-based user interface. This user interface gives access to four different applications that allow you to interact with different parts of BAM. These are: Active Viewer for giving access to reports; this relates to the deliver stage for user requested reports. Active Studio for building reports; this relates to the 'process' stage for creating reports. Architect for setting up both inbound and outbound events. Data elements are defined here as data sources. Alerts are also configured here. This covers setting up, acquire and store stages as well as the deliver stage for alerts. Administrator for managing users and roles as well as defining the types of message sources. We will not examine the applications individually but will take a task-focused look at how to use them as part of providing some specific reports. Monitoring process state Now that we have examined how BAM is constructed, let us use this knowledge to construct some simple dashboards that track the state of a business process. We will instrument a simple version of an auction process. The process is shown in the following figure: An auction is started and then bids are placed until the time runs out at which point the auction is completed. This is modelled in BPEL. This process has three distinct states: Started Bid received Completed We are interested in the number of auctions in each state as well as the total value of auctions in progress. One needs to follow these steps to build the dashboard: Define our data within the Active Data Cache Create sensors in BPEL and map to data in the ADC Create suitable reports Run the reports Defining data objects Data in BAM is stored in data objects. Individual data objects contain the information that is reported in BAM dashboards and may be updated by multiple events. Generally BAM will report against aggregations of objects, but there is also the ability for reports to drill down into individual data objects. Before defining our data objects let's group them into an Auction folder so they are easy to find. To do this we use the BAM Architect application and select Data Objects which gives us the following screen: We select Create subfolder to create the folder and give it a name Auction. We then select Create folder to actually create the folder and we get a confirmation message to tell us that the folder was created. Notice that once created, the folder also appears in the Folders window on the left-hand side of the screen. Now we have our folder we can create a data object. Again we select Data Objects from the drop-down menu. To define the data objects that are to be stored in our Active Data Cache, we open the Auction folder if it is not already open and selectCreate Data Object. If we don't select the Auction folder then we pick it later when filling in the details of the data object. We need to give our object a unique name within the folder and optionally provide it with a tip text that helps explain what the object does when the mouse is moved over it in object listings. Having named our object we can now create the data fields by selecting Add a field. When adding fields we need to provide a name and type as well as indicating if they must contain data; the default Nullable does not require a field to be populated. We may also optionally indicate if a field should be public "available for display" and what if any tool tip text it should have. Once all the data fields have been defined then we can click Create Data Object to actually create the object as we have defined it. We are then presented with a confirmation screen that the object has been created. Grouping data into hierarchies When creating a data object it is possible to specify Dimensions for the object. A dimension is based on one or more fields within the object. A given field can only participate in one dimension. This gives the ability to group the object by the fields in the given dimension. If multiple fields are selected for a single dimension then they can be layered into a hierarchy, for example to allow analysis by country, region, and city. In this case all three elements would be selected into a single dimension, perhaps called geography. Within geography a hierarchy could be set up with country at the top, region next, and finally city at the bottom, allowing drill down to occur in views. Just as a data object can have multiple dimensions, a dimension can also have multiple hierarchies. A digression on populating data object fields In the previous discussion, we mentioned the Nullable attribute that can be attached to fields. This is very important as we do not expect to populate all or even most of the fields in a data object at one moment in time. Do not confuse data objects with the low level events that are used to populate them. Data objects in BAM do not have a one-to-one correspondence with the low level events that populate them. In our auction example there will be just one auction object for every auction. However there will be at least two and usually more messages for every auction; one message for the auction starting, another for the auction completing, and additional messages for each bid received. These messages will all populate or in some cases overwrite different parts of the auction data object. The table shows how the three messages populate different parts of the data object. Message Auction ID State Highest bid Reserve Expires Seller Highest bidder Auction Started Inserted Inserted Inserted Inserted Inserted Inserted   Bid Received   Updated Updated       Updated Auction Finished   Updated           Summary In this article we have explored how Business Activity Monitoring differs from and is complementary to more traditional Business Intelligence solutions such as Oracle Reports and Business Objects. We have explored how BAM can allow the business to monitor the state of business targets and Key Performance Indicators, such as the current most popular products in a retail environment or the current time taken to serve customers in a service environment.

Here we are! programming in a powerful language specially designed for the Web and using an IDE that promises to help us with many of the mechanical tasks involved in the coding. If you have been already programming with Rails, you probably know that if we take advantage of scaffolding we can have a simple web application for table maintenance in a matter of minutes (yes/no typo here, it really takes just a few minutes). And we are even talking about the database table creation process. If we wanted to add validations, a nice design, and some more complexity we would be talking about a few hours. Still pretty impressive, depending from which programming language (or framework) you are coming. The truth is, creating the wireframe of your application in Rails is quick and easy enough even from the command line, but we'll be learning in this article how to do it a bit more comfortably by using RadRails for creating your models, controllers, database migrations, and for starting your server and test your application. Basic Views Most of the time when working with our IDE we will be using the Editor Area. Apart from that, two of the views we will be working with more frequently are the Ruby Explorer—the enhanced equivalent of the Rails Navigator, if you were using RadRails Classic—and the Console. Both of these views are fairly easy to use, but since they will be present at almost every point of the development process, it's interesting to get familiar with them from the beginning. The Ruby Explorer View If you have already opened the Rails perspective, then you should be seeing the Ruby Explorer at the left of your workbench. This view looks like a file-tree pane. At the root level, you will find a folder for each of the projects in your workspace. By clicking on the icon to the left of the project name, you will unfold its files and folders. The Ruby files can be expanded too, displaying the modules, classes, variables, and methods defined in the selected file. By clicking on any of these elements you will be taken directly to the line in which it is defined. Before navigating through the contents of a project, we have to open it. Just right-click on its name and choose Open Project. When opening a project, Eclipse will ask you if you want to open the referenced projects. By default, your projects don't have any references and that's the most common scenario when working with a Rails application. If you want, you can include references to other projects on the workspace so you can open and close them together. To view and change the project references, you can right-click on the project name, then select Properties. Notice you can also get here from the Project menu by selecting Properties. In the properties dialog, you have to select Project References. Here you will see a list of all the available projects in the workspace. Just check or uncheck all the projects you want to reference. Once your project is open, the mechanism for navigating the contents is pretty straightforward. You can open or close any sub-folders and you can right-click on any item to get a context menu. From this menu you can perform common file operations like creating, renaming, or deleting a file. We will see more details about creating new files when talking about the Editor Area. There is also a Properties option from where you can change the encoding for a particular file, or the file attributes (read only, for example). The Properties option is also available at the project level. Also in the context menu, you can see there is a Tail option. This will work like the tail command in UNIX, displaying the contents of a file as it's changing. This option is especially useful for a quick monitoring of the log files of your application. You can also find in the context menu two options with the names Compare With and Replace With. If you select either of them, you will see a new menu in which there is an option named Local history. This functionality is really interesting. You can compare your current version against an older version of the same file, or you could replace the contents with a previous one. This can be a life-saver because when using it on a folder the local history will contain copies even of deleted files. Comparing a file against another copy is a powerful tool, which can also be used when working with repositories or to compare different files between them. Let's try it and see how it works. Open any of the files in your project tree by double-clicking on the file name. Now go to the Editor Area and add some lines with Mumbo-Jumbo text. After you are done, click on the save icon of the toolbar or select Save in the File menu. Now let's go back to the Ruby Explorer, double-click on the file name and select Compare With | Local History. You will see there are some entries here, one for each time we saved the file. If this was the first time you worked with the file, then there will be only two versions, the original and the one you just saved. Double-click on the oldest local version you have. Now a new editor will be opened. The editor is divided into three panes, the top one displaying structural differences, the bottom-left one with the code of the current version, and the bottom-right one with the old version of the code. At the top pane, you will see the structural differences between the versions being compared. For every added or deleted method or variable—at instance or class level, you will see the name of the element with an icon displaying a plus or a minus sign. If a method exists in both versions, but its content was changed, the name will be displayed without any additional icons. When reviewing the differences/changes you will see the editors at both sides are linked with a line representing the parts that are not equal between the files. When you are on a given change/difference you can select the icon for 'copying current change from right to left' (or the other way round, depending in which of the files the change is), which will override the contents of the left editor with those of the right. You can also just manually edit or copy/paste in your editor as usual. There is an interesting icon labeled 'Copy all non-conflicting changes from right to left' that will do exactly as it promises. Any changes that can be automatically merged, will be incorporated to your editor. Depending on the differences between the files, the icon could be the contrary 'Copy all non-conflicting changes from left to right'. When you finish comparing or modifying your current editor, remember to save the contents of the editor in order to keep your changes. If you just wanted to review the changes without any modifications, you can directly scroll down the editors, use the 'Previous' or 'Next' icons, or use the quick marks by the right margin. You can also compare two files instead of comparing a file against an older version. Go to the Ruby Explorer and select one of the files, then hold down the control key and select another one. With both files selected, you right-click and select Compare With and then Each Other. Once opened, the compare editor works exactly the same as when comparing with an old version of the same file.

  Loading external XML documents You can use the URLLoader class to load external data from a URL. The URLLoader class downloads data from a URL as text or binary data. In this section, we will see how to use the URLLoader class for loading external XML data into your application. You can create a URLLoader class instance and call the load() method by passing URLRequest as a parameter and register for its complete event to handle loaded data. The following code snippet shows how exactly this works: private var xmlUrl:String = "http://www.foo.com/rssdata.xml";private var request:URLRequest = new URLRequest(xmlUrl);private var loader:URLLoader = new URLLoader(;private var rssData:XML;loader.addEventListener(Event.COMPLETE, completeHandler);loader.load(request);private function completeHandler(event:Event):void { rssData = XML(loader.data); trace(rssData);} Let's see one quick complete sample of loading RSS data from the Internet: <?xml version="1.0" encoding="utf-8"?><mx:Application creationComplete="loadData();"> <mx:Script> <![CDATA[ import mx.collections.XMLListCollection; private var xmlUrl:String = "http://sessions.adobe.com/360FlexSJ2008/feed.xml"; private var request:URLRequest = new URLRequest(xmlUrl); private var loader:URLLoader = new URLLoader(request); [Bindable] private var rssData:XML; private function loadData():void { loader.addEventListener(Event.COMPLETE, completeHandler); loader.load(request); } private function completeHandler(event:Event):void { rssData = new XML(loader.data); } ]]></mx:Script><mx:Panel title="RSS Feed Reader" width="100%" height="100%"> <mx:DataGrid id="dgGrid" dataProvider="{rssData.channel.item}" height="100%" width="100%"> <mx:columns> <mx:DataGridColumn headerText="Title" dataField="title"/> <mx:DataGridColumn headerText="Link" dataField="link"/> <mx:DataGridColumn headerText="pubDate" dataField="pubDate"/> <mx:DataGridColumn headerText="Description" dataField="description"/> </mx:columns></mx:DataGrid><mx:TextArea width="100%" height="80" text="{dgGrid.selectedItem.description}"/></mx:Panel></mx:Application> In the code above, we are loading RSS feed from an external URL and displaying it in DataGrid by using data binding. Output: An example: Building a book explorer In this section, we will build something more complicated and interesting by using many features, including custom components, events, data binding, E4X, loading external XML data, and so on. We will build a sample books explorer, which will load a books catalog from an external XML file and allow the users to explore and view details of books. We will also build a simple shopping cart component, which will list books that a user would add to cart by clicking on the Add to cart button. Create a new Flex project using Flex Builder. Once the project is created, create an assetsimages folder under its src folder. This folder will be used to store images used in this application. Now start creating the following source files into its source folder. Let's start by creating a simple book catalog XML file as follows: bookscatalog.xml:<books> <book ISBN="184719530X"> <title>Building Websites with Joomla! 1.5</title> <author> <lastName>Hagen</lastName> <firstName>Graf</firstName> </author> <image>../assets/images/184719530X.png</image> <pageCount>363</pageCount> <price>Rs.1,247.40</price> <description>The best-selling Joomla! tutorial guide updated for the latest 1.5 release </description> </book> <book ISBN="1847196160"> <title>Drupal 6 JavaScript and jQuery</title> <author> <lastName>Matt</lastName> <firstName>Butcher</firstName> </author> <image>../assets/images/1847196160.png</image> <pageCount>250</pageCount> <price>Rs.1,108.80</price> <description>Putting jQuery, AJAX, and JavaScript effects into your Drupal 6 modules and themes</description> </book> <book ISBN="184719494X"> <title>Expert Python Programming</title> <author> <lastName>Tarek</lastName> <firstName>Ziadé</firstName> </author> <image>../assets/images/184719494X.png</image> <pageCount>350</pageCount> <price>Rs.1,247.4</price> <description>Best practices for designing, coding, and distributing your Python software</description> </book> <book ISBN="1847194885"> <title>Joomla! Web Security</title> <author> <lastName>Tom</lastName> <firstName>Canavan</firstName> </author> <image>../assets/images/1847194885.png</image> <pageCount>248</pageCount> <price>Rs.1,108.80</price> <description>Secure your Joomla! website from common security threats with this easy-to-use guide</description> </book></books> The above XML file contains details of individual books in an XML form. You can also deploy this file on your web server and specify its URL into URLRequest while loading it. Next, we will create a custom event which we will be dispatching from our custom component. Make sure you create an events package under your src folder in Flex Builder called events, and place this file in it. AddToCartEvent.as:package events{ import flash.events.Event; public class AddToCartEvent extends Event { public static const ADD_TO_CART:String = "addToCart"; public var book:Object; public function AddToCartEvent(type:String, bubbles_Boolean=false, cancelable_Boolean=false) { super(type, bubbles, cancelable); } }} This is a simple custom event created by inheriting the flash.events.Event class. This class defines the ADD_TO_CART string constant, which will be used as the name of the event in the addEventListener() method. You will see this in the BooksExplorer.mxml code. We have also defined an object to hold the reference of the book which the user can add into the shopping cart. In short, this object will hold the XML node of a selected book. Next, we will create the MXML custom component called BookDetailItemRenderer.mxml. Make sure that you create a package under your src folder in Flex Builder called components, and place this file in it and copy the following code in it: <?xml version="1.0" encoding="utf-8"?><mx:HBox cornerRadius="8" paddingBottom="2" paddingLeft="2"paddingRight="2" paddingTop="2"><mx:Metadata>[Event(name="addToCart", type="flash.events.Event")]</mx:Metadata><mx:Script><![CDATA[import events.AddToCartEvent;import mx.controls.Alert;[Bindable][Embed(source="../assets/images/cart.gif")]public var cartImage:Class;private function addToCardEventDispatcher():void {var addToCartEvent:AddToCartEvent = new AddToCartEvent("addToCart", true, true);addtoCartEvent.book = data;dispatchEvent(addtoCartEvent);}]]></mx:Script><mx:HBox width="100%" verticalAlign="middle" paddingBottom="2"paddingLeft="2" paddingRight="2" paddingTop="2" height="100%"borderStyle="solid" borderThickness="2" borderColor="#6E6B6B"cornerRadius="4"><mx:Image id="bookImage" source="{data.image}" height="109"width="78" maintainAspectRatio="false"/><mx:VBox height="100%" width="100%" verticalGap="2"paddingBottom="0" paddingLeft="0" paddingRight="0"paddingTop="0" verticalAlign="middle"><mx:Label id="bookTitle" text="{data.title}"fontSize="12" fontWeight="bold"/><mx:Label id="bookAuthor" text="By: {data.author.lastName},{data.author.firstName}" fontWeight="bold"/><mx:Label id="coverPrice" text="Price: {data.price}"fontWeight="bold"/><mx:Label id="pageCount" text="Pages: {data.pageCount}"fontWeight="bold"/><mx:HBox width="100%" backgroundColor="#3A478D"horizontalAlign="right" paddingBottom="0" paddingLeft="0"paddingRight="5" paddingTop="0" height="22"verticalAlign="middle"><mx:Label text="Add to cart " color="#FFFFFF"fontWeight="bold"/><mx:Button icon="{cartImage}" height="20" width="20"click="addToCardEventDispatcher();"/></mx:HBox></mx:VBox></mx:HBox></mx:HBox>

Using Spring Faces Module The following section shows you how to use the Spring Faces module. Overview of all tags of the Spring Faces tag library The Spring Faces module comes with a set of components, which are provided through a tag library. If you want more detailed information about the tag library, look at the following files inside the Spring Faces source distribution: spring-faces/src/main/resources/META-INF/spring-faces.tld spring-faces/src/main/resources/META-INF/springfaces.taglib.xml spring-faces/src/main/resources/META-INF/faces-config.xml If you want to see the source code of a specific tag, refer to faces-config.xml and springfaces.taglib.xml to get the name of the class of the component. The spring-faces.tld file can be used for documentation issues. The following table should give you a short description about the available tags from the Spring Faces component library: Name of the tag Description includeStyles The includeStyles tag renders the necessary CSS stylesheets which are essential for the components from Spring Faces. The usage of this tag in the head section is recommended for performance optimization. If the tag isn't included, the necessary stylesheets are rendered on the first usage of the tag. If you are using a template for your pages, it's a good pattern to include the tag in the header of that template. For more information about performance optimization, refer to the Yahoo performance guidelines, which are available at the following URL: http://developer.yahoo.com/performance. Some tags (includeStyles, resource, and resourceGroup) of the Spring Faces tag library are implementing patterns to optimize the performance on client side. resource The resource tag loads and renders a resource with ResourceServlet. You should prefer this tag instead of directly including a CSS stylesheet or a JavaScript file because ResourceServlet sets the proper response headers for caching the resource file. resourceGroup With the resourceGroup tag, it is possible to combine all resources which are inside the tag. It is important that all resources are the same type. The tag uses ResourceServlet with the appended parameter to create one resource file which is sent to the client. clientTextValidator With the clientTextValidator tag, you can validate a child inputText element. For the validation, you have an attribute called regExp where you can provide a regular expression. The validation is done on client side. clientNumberValidator With the clientNumberValidator tag, you can validate a child inputText element. With the provided validation methods, you can check whether the text is a number and check some properties for the number, e.g. range. The validation is done on client side. clientCurrencyValidator With the clientCurrencyValidator tag, you can validate a child inputText element. This tag should be used if you want to validate a currency. The validation is done on client side. clientDateValidator With the clientDateValidator tag, you can validate a child inputText element. The tag should be used to validate a date. The field displays a pop-up calendar. The validation is done on client side. validateAllOnClick With the validateAllOnClick tag, you can execute all client-side validation on the click of a specific element. That can be useful for a submit button. commandButton With the commandButton tag, it is possible to execute an arbitrary method on an instance. The method itself has to be a public method with no parameters and a java.lang.Object instance as the return value. commandLink The commandLink tag renders an AJAX link. With the processIds attribute, you can provide the ids of components which should be processed through the process. ajaxEvent The ajaxEvent tag creates a JavaScript event listener. This tag should only be used if you can ensure that the client has JavaScript enabled. A complete example After we have shown the main configuration elements and described the Spring Faces components, the following section shows a complete example in order to get a good understanding about how to work with the Spring Faces module in your own web application. The following diagram shows the screen of the sample application. With the shown screen, it is possible to create a new issue and save it to the bug database. It is not part of this example to describe the bug database or to describe how to work with databases in general. The sample uses the model classes. The diagram has three required fields. These fields are: Name: The name of the issue Description: A short description for the issue Fix until: The fixing date for the issue Additionally, there are the following two buttons: store: With a click on the store button, the system tries to create a new issue that includes the provided information cancel: With a click on the cancel button, the system ignores the data which is entered and navigates to the overview page. Now, the first step is to create the implementation of that input page. That implementation and its description are shown in the section below. Creating the input page As we described above, we use Facelets as a view handler technology. Therefore, the pages have to be defined with XHTML, with .xhtml as the file extension. The name for the input page will be add.xhtml. For the description, we separate the page into the following five parts: Header Name Description Fix until The Buttons This separation is shown in the diagram below: The Header part The first step in the header is to define that we have an XHTML page. This is done through the definition of the correct doctype. <!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> An XHTML page is described as an XML page. If you want to use special tags inside the XML page, you have to define a namespace for that. For a page with Facelets and Spring Faces, we have to define more than one namespace. The following table describes those namespaces: Namespace Description http://www.w3.org/1999/xhtml The namespace for XHTML itself. http://java.sun.com/jsf/facelets The Facelet defines some components (tags). These components are available under this namespace. http://java.sun.com/jsf/html The user interface components of JSF are available under this namespace. http://java.sun.com/jsf/core The core tags of JSF, for example converter, can be accessed under this namespace. http://www.springframework.org/tags/faces The namespace for the Spring Faces component library. For the header definition, we use the composition component of the Facelets components. With that component, it is possible to define a template for the layout. This is very similar to the previously mentioned Tiles framework. The following code snippet shows you the second part (after the doctype) of the header definition: A description and overview of the JSF tags is available at: http://developers.sun.com/jscreator/archive/learning/bookshelf/pearson/corejsf/standard_jsf_tags.pdf. <ui:composition template="/WEB-INF/layouts/standard.xhtml"> With the help of the template attribute, we refer to the used layout template. In our example, we refer to /WEB-INF/layouts/standard.xhtml. The following code shows the complete layout file standard.xhtml. This layout file is also described with the Facelets technology. Therefore, it is possible to use Facelets components inside that page, too. Additionally, we use Spring Faces components inside that layout page. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html > <f:view contentType="text/html"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>flow.tracR</title> <sf:includeStyles/> <sf:resourceGroup> <sf:resource path="/css-framework/css/tools.css"/> <sf:resource path="/css-framework/css/typo.css"/> <sf:resource path="/css-framework/css/forms.css"/> <sf:resource path="/css-framework/css/layout-navtop-localleft. css"/> <sf:resource path="/css-framework/css/layout.css"/> </sf:resourceGroup> <sf:resource path="/css/issue.css"/> <ui:insert name="headIncludes"/> </head> <body class="tundra spring"> <div id="page"> <div id="content"> <div id="main"> <ui:insert name="content"/> </div> </div> </div> </body> </f:view> </html> The Name part The first element in the input page is the section for the input of the name. For the description of that section, we use elements from the JSF component library. We access this library with h as the prefix, which we have defined in the header section. For the general layout, we use standard HTML elements, such as the div element. The definition is shown below. <div class="field"> <div class="label"> <h:outputLabel for="name">Name:</h:outputLabel> </div> <div class="input"> <h:inputText id="name" value="#{issue.name}" /> </div> </div> The Description part The next element in the page is the Description element. The definition is very similar to the Name part. Instead of the definition of the Name part, we use the element description inside the h:inputText element—the required attribute with true as its value. This attribute tells the JSF system that the issue.description value is mandatory. If the user does not enter a value, the validation fails. <div class="field"> <div class="label"> <h:outputLabel for="description">Description:</h:outputLabel> </div> <div class="input"> <h:inputText id="description" value="#{issue.description}" required="true"/> </div> </div> The Fix until part The last input section is the Fix until part. This field is a very common field in web applications, because there is often the need to input a date. Internally, a date is often represented through an instance of the java.util.Date class. The text which is entered by the user has to be validated and converted in order to get a valid instance. To help the user with the input, a calendar for the input is often used. The Spring Faces library offers a component which shows a calendar and adds client-side validation. The complete definition of the Fix until part is shown below. The name of the component is clientDateValidator. The clientDateValidator component is used with sf as the prefix. This prefix is defined in the namespace definition in the shown header of the add.xhtml page. <div class="field"> <div class="label"> <h:outputLabel for="checkinDate">Fix until:</h:outputLabel> </div> <div class="input"> <sf:clientDateValidator required="true" invalidMessage="pleaseinsert a correct fixing date. format: dd.MM.yyyy"promptMessage="Format: dd.MM.yyyy, example: 01.01.2020"> <h:inputText id="checkinDate" value="#{issue.fixingDate}" required="true"> <f:convertDateTime pattern="dd.MM.yyyy" timeZone="GMT"/> </h:inputText> </sf:clientDateValidator> </div> </div> In the example above, we use the promptMessage attribute to help the user with the format. The message is shown when the user sets the cursor on the input element. If the validation fails, the message of the invalidMessage attribute is used to show the user that a wrong formatted input has been entered. The Buttons part The last element in the page are the buttons. For these buttons, the commandButton component from Spring Faces is used. The definition is shown below: <div class="buttonGroup"> <sf:commandButton id="store" action="store" processIds="*" value="store"/> <sf:commandButton id="cancel" action="cancel" processIds="*" value="cancel"/> </div> It is worth mentioning that JavaServer Faces binds an action to the action method of a backing bean. Spring Web Flow binds the action to events. Handling of errors It's possible to have validation on the client side or on the server side. For the Fix until element, we use the previously mentioned clientDateValidator component of the Spring Faces library. The following figure shows how this component shows the error message to the user: Reflecting the actions of the buttons into the flow definition file Clicking the buttons executes an action that has a transition as the result. The name of the action is expressed in the action attribute of the button component which is implemented as commandButton from the Spring Faces component library. If you click on the store button, the validation is executed first. If you want to prevent that validation, you have to use the bind attribute and set it to false. This feature is used for the cancel button, because in this state it is necessary to ignore the inputs. <view-state id="add" model="issue"> <transition on="store" to="issueStore" > <evaluate expression="persistenceContext.persist(issue)"/> </transition> <transition on="cancel" to="cancelInput" bind="false"> </transition> </view-state> Showing the results To test the implemented feature, we implement an overview page. We have the choice to implement the page as a flow with one view state or implement it as a simple JSF view. Independent from that choice, we will use Facelets to implement that overview page, because Facelets does not depend on the Spring Web Flow Framework as it is a feature of JSF. The example uses a table to show the entered issues. If no issue is entered, a message is shown to the user. The figure below shows this table with one row of data. The Id is a URL. If you click on this link, the input page is shown with the data of that issue. With data, we execute an update. The indicator for that is the valid ID of the issue. If your data is available, the No issues in database message is shown to the user. This is done with a condition on the outputText component. See the code snippet below: <h:outputText id="noIssuesText" value="No Issues in the database" rendered="#{empty issueList}"/> For the table, we use the dataTable component. <h:dataTable id="issues" value="#{issueList}" var="issue"rendered="#{not empty issueList}" border="1"> <h:column> <f:facet name="header">Id</f:facet> <a href="add?id=#{issue.id}">#{issue.id}</a> </h:column> <h:column> <f:facet name="header">Name</f:facet> #{issue.name} </h:column> <h:column> <f:facet name="header">fix until</f:facet> #{issue.fixingDate} </h:column> <h:column> <f:facet name="header">creation date</f:facet> #{issue.creationDate} </h:column> <h:column> <f:facet name="header">last modified</f:facet> #{issue.lastModified} </h:column> </h:dataTable>

Problem There are many aspects to building relationships in any community—real or virtual. First and foremost is initiating contact with the people whom you will eventually call your friends. We will do this in a few ways. First, we will provide a way for our users to search the site for friends who are also members. Second, we will create a form that allows you to enter your friends' email IDs and invite them directly. Third, we will create a form that allows you to import all of your contacts from Outlook. All of these methods of inviting a friend into the system would of course generate an email invite. The user would have the ability to then follow the link into the system and either sign up or log in to accept the request. The preceding screenshot shows a sample email that the user would receive in their inbox. And following is the message that would be seen: Once the user has clicked on the link in their email, he/she will be taken to a page displaying the request. Once we have a way for our users to attach friends to their profile, we need to start integrating the concept of friends into the fabric of our site. We will need a way for our users to view all of their friends. We will also need a way for our users to remove the relationships (for those users who are no longer friends!). Then we will need to add friends to our user's public profile. While this is a good first pass at integrating the concept of friends into our site, there are a couple more steps for true integration. We need to add friend request and friend confirm alerts. We also need to modify the alert system so that when users modify their profile, change their avatar, or any other alert that is triggered by users of our system, all of their friends are notified on The Filter. Once this is done we have one final topic to cover—which sort of fits in the realm of friends—the concept of Status Updates. This is a form of a micro blog. It allows users to post something about: What they are currently doing Where they are or What they are thinking about This is then added to their profile and sent out to their friends' filters. The box in the preceding screenshot is where the user can enter his/herStatus Updates. Each of these updates will also be shown on the updates view and in their filter views. This really helps to keep The Filter busy and helps people feel involved with their friends. Design Now let's talk about the design of these features. Friends This article is an attempt to throw light on the infrastructure needs and more heavily focused on the UI side for creating and managing relationships. That being said, there is always some form of groundwork that has to be in place prior to adding new features. In this case we need to add the concept of a friend prior to having the ability to create friendships. This concept is a relatively simple one as it is really only defining a relationship between two accounts. We have the account that requested the relationship and the account that accepted the relationship. This allows an account to be linked to as many other accounts as they wish. Finding friends Like in life, it is very difficult to create friends without first locating and meeting people. For that reason the various ways to locate and invite someone to be your friend is our first topic. Searching for a friend The easiest way to locate friends who might be interested in the same site that you are is to search through the existing user base. For that reason we will need to create a simple keyword search box that is accessible from any page on the site. This search feature should take a look at several fields of data pertaining to an account and return all possible users. From the search results page we should be able to initiate a friend request. Inviting a friend The next best thing to locating friends who are already members of the site is to invite people who you know out of the site. The quickest way to implement this is to allow a user to manually enter an email address or many email addresses, type a message, and then submit. This would be implemented with a simple form that generates a quick email to the recipient list. In the body of the email will be a link that allows the recipients to come in to our site. Importing friends from external sources An obvious extension of the last topic is to somehow automate the importing process of contacts from an email management tool. We will create a toolset that allows the user to export their contacts from Outlook and import them via a web form. The user should then be able to select the contacts that they want to invite. Sending an invitation With all the three of the above methods we will end up sending out an invitation email. We could simply send out an email with a link to the site. However, we need to maintain: Who has been invited Who initiated the invitation and When this occurred Then in the email, rather than just invite people in, we want to assign the user a key so that we can easily identify them on their way in. We will use a system-generated GUID to do this. In the case of inviting an existing user, we will allow him/her to log in to acknowledge the new friendship. In the case of a non-member user who was invited, we will allow him/her to create a new account. In both cases we will populate the invitation with the invited user's Account ID so that we have some history about the relationship. Adding friend alerts to the filter Once we have the framework in place for inviting and accepting friendship requests, we need to extend our existing system with alerts. These alerts should show up on existing user's Filters to show that they sent an invitation. We should also have alerts showing that a user has been invited. Once a user has accepted a friendship we should also have an alert. Interacting with your friends Now let's discuss some of the features that we need to interact with our friends. Viewing your friends Friends are only good if a user can interact with them. The first stop along this train of thought is to provide a page that allows a user to see all the friends he/she has. This is a jumping off point for a user to view the profile of friends. Also, as the concept of a user's profile grows, more data can be shown about each friend in an at-a-glance format. In addition to an all Friends page, we can add friends' views to a user's public profile so that other users can see the relationships. Managing your friends Now that we can see into all the relationships, we can finally provide the users with the ability to remove a relationship. In our initial pass this will be a permanent deletion of the relationship. Following your friends Now, we can extend the alert system so that when alerts are generated for a common user, such as updating their profile information, uploading a new photo, or any other user specific task, all the user's friends are automatically notified via their Filter. Providing status updates to your friends Somewhat related to friend-oriented relationships and The Filter is the concept of micro blogs. We need to add a way for a user to send a quick blurb about what they are doing, what they are thinking, and so on. This would also show up on the Filters of all the user's friends. This feature creates a lot of dynamic content on an end user's homepage, which keeps things interesting. Solution Now let's take a look at our solution. Implementing the database Let's look at the tables that are needed to support these new features. The Friends Table As the concept of friends is our base discussion for this article, we will immediately dive in and start creating the tables around this subject. As you have seen previously this is very straightforward table structure that simply links one account to the other. Friend Invitations This table is responsible for keeping track of who has been invited to the site, by whom, and when. It also holds the key (GUID) that is sent to the friends so that they can get back into the system under the appropriate invitation. Once a friend has accepted the relationship, their AccountID is stored here too, so that we can see how relationships were created in the past. Status Updates Status Updates allow a user to tell their friends what they are doing at that time. This is a micro blog so to speak. A micro blog allows a user to write small blurbs about anything. Examples of this are Twitter and Yammer. For more information take a look here: http://en.wikipedia.org/wiki/Micro-blogging The table needed for this is also simple. It tracks who said what, what was said, and when. Creating the Relationships Here are the relationships that we need for the tables we just discussed: Friends and Accounts via the owning account Friends and Accounts via the friends account FriendInvitations and Accounts StatusUpdates and Accounts Setting up the data access layer Let's extend the data access layer now to handle these new tables. Open your Fisharoo.dbml file and drag in these three new tables. We are not allowing LINQ to manage these relationships for us. So go ahead and remove the relationships from the surrounding tables. Once you hit Save we should have three new classes to work with! Building repositories As always, with these new tables will come new repositories. The following repositories will be created: FriendRepository FriendInvitationRepository StatusUpdateRepository In addition to the creation of the above repositories, we will also need to modify the AccountRepository. FriendRepository Most of our repositories will always follow the same design. They provide a way to get at one record, many records by a parent ID, save a record, and delete a record. This repository differs slightly from the norm when it is time to retrieve a list of friends in that it has two sides of the relationship to look at—on one side where it is the owning Account of the Friend relationship and on the other side where the relationship is owned by another account. Here is that method: public List<Friend> GetFriendsByAccountID(Int32 AccountID){ List<Friend> result = new List<Friend>(); using(FisharooDataContext dc = conn.GetContext()) { //Get my friends direct relationship IEnumerable<Friend> friends = (from f in dc.Friends where f.AccountID == AccountID && f.MyFriendsAccountID AccountID select f).Distinct(); result = friends.ToList(); //Getmy friends indirect relationship var friends2 = (from f in dc.Friends where f.MyFriendsAccountID == AccountID && f.AccountID != AccountID select new { FriendID = f.FriendID, AccountID = f.MyFriendsAccountID, MyFriendsAccountID = f.AccountID, CreateDate = f.CreateDate, Timestamp = f.Timestamp }).Distinct(); foreach (object o in friends2) { Friend friend = o as Friend; if(friend != null) result.Add(friend); } } return result;} This method queries for all friends that are owned by this account. It then queries for the reverse relationship where this account is owned by another account. Then it adds the second query to the first and returns that result. Here is the method that gets the Accounts of our Friends: public List<Account> GetFriendsAccountsByAccountID(Int32 AccountID){ List<Friend> friends = GetFriendsByAccountID(AccountID); List<int> accountIDs = new List<int>(); foreach (Friend friend in friends) { accountIDs.Add(friend.MyFriendsAccountID); } List<Account> result = new List<Account>(); using(FisharooDataContext dc = conn.GetContext()) { IEnumerable<Account> accounts = from a in dc.Accounts where accountIDs.Contains(a.AccountID) select a; result = accounts.ToList(); } return result;} This method first gathers all the friends (via the first method we discussed) and then queries for all the related accounts. It then returns the result. FriendInvitationRepository Like the other repositories this one has the standard methods. In addition to those we also need to be able to retrieve an invitation by GUID or the invitation key that was sent to the friend. public FriendInvitation GetFriendInvitationByGUID(Guid guid){ FriendInvitation friendInvitation; using(FisharooDataContext dc = conn.GetContext()) { friendInvitation = dc.FriendInvitations.Where(fi => fi.GUID == guid).FirstOrDefault(); } return friendInvitation;} This is a very straightforward query matching the GUID values. In addition to the above method we will also need a way for invitations to be cleaned up. For this reason we will also have a method named CleanUpFriendInvitations(). public void CleanUpFriendInvitationsForThisEmail(FriendInvitation friendInvitation){ using (FisharooDataContext dc = conn.GetContext()) { IEnumerable<FriendInvitation> friendInvitations = from fi in dc.FriendInvitations where fi.Email == friendInvitation.Email && fi.BecameAccountID == 0 && fi.AccountID == friendInvitation.AccountID select fi; foreach (FriendInvitation invitation in friendInvitations) { dc.FriendInvitations.DeleteOnSubmit(invitation); } dc.SubmitChanges(); }} This method is responsible for clearing out any invitations in the system that are sent from account A to account B and have not been activated (account B never did anything with the invite). Rather than checking if the invitation already exists when it is created, we will allow them to be created time and again (checking each invite during the import process of 500 contacts could really slow things down!). When account B finally accepts one of the invitations all of the others will be cleared. Also, in case account B never does anything with the invites, we will need a database process that periodically cleans out old invitations. StatusUpdateRepository Other than the norm, this repository has a method that gets topN StatusUpdates for use on the profile page. public List<StatusUpdate> GetTopNStatusUpdatesByAccountID(Int32 AccountID, Int32 Number){ List<StatusUpdate> result = new List<StatusUpdate>(); using (FisharooDataContext dc = conn.GetContext()) { IEnumerable<StatusUpdate> statusUpdates = (from su in dc.StatusUpdates where su.AccountID == AccountID orderby su.CreateDate descending select su).Take(Number); result = statusUpdates.ToList(); } return result;} This is done with a standard query with the addition of the Take() method, which translates into a TOP statement in the resulting SQL. AccountRepository With the addition of our search capabilities we will require a new method in our AccountRepository. This method will be the key for searching accounts. public List<Account> SearchAccounts(string SearchText){ List<Account> result = new List<Account>(); using (FisharooDataContext dc = conn.GetContext()) { IEnumerable<Account> accounts = from a in dc.Accounts where(a.FirstName + " " + a.LastName).Contains(SearchText) || a.Email.Contains(SearchText) || a.Username.Contains(SearchText) select a; result = accounts.ToList(); } return result;} This method currently searches through a user's first name, last name, email address, and username. This could of course be extended to their profile data and many other data points (all in good time!). Implementing the services/application layer Now that we have the repositories in place, we can begin to create the services that sit on top of those repositories. We will be creating the following services: FriendService In addition to that we will also be extending these services: AlertService PrivacyService FriendService The FriendService currently has a couple of duties. We will need it to tell us whether or not a user is a Friend, so that we can extend the PrivacyService to consider friends (recall that we currently only understand public and private settings!). In addition to that we need our FriendService to be able to handle creating Friends from a FriendInvitation. public bool IsFriend(Account account, Account accountBeingViewed){ if(account == null) return false; if(accountBeingViewed == null) return false; if(account.AccountID == accountBeingViewed.AccountID) return true; else { Friend friend = _friendRepository.GetFriendsByAccountID (accountBeingViewed.AccountID). Where(f => f.MyFriendsAccountID == account.AccountID).FirstOrDefault(); if(friend != null) return true; } return false;} This method needs to know who is making the request as well as who it is making the request about. It then verifies that both accounts are not null so that we can use them down the road and returns false if either of them are null. We then check to see if the user that is doing the viewing is the same user as is being viewed. If so we can safely return true. Then comes the fun part—currently we are using the GetFriendsByAccountID method found in the FriendRepository. We iterate through that list to see if our friend is there in the list or not. If we locate it, we return true. Otherwise the whole method has failed to locate a result and returns false. Keep in mind that this way of doing things could quickly become a major performance issue. If you are checking security around several data points frequently in the same page, this is a large query and moves a lot of data around. If someone had 500 friends this would not be acceptable. As our goal is for people to have lots of friends, we generally would not want to follow this way. Your best bet then is to create a LINQ query in the FriendsRepository to handle this logic directly only returning true or false. Now comes our CreateFriendFromFriendInvitation method, which as the name suggests, creates a friend from a friend invitation! public void CreateFriendFromFriendInvitation(Guid InvitationKey, Account InvitationTo){ //update friend invitation request FriendInvitation friendInvitation = _friendInvitationRepository. GetFriendInvitationByGUID(InvitationKey); friendInvitation.BecameAccountID = InvitationTo.AccountID; _friendInvitationRepository.SaveFriendInvitation(friendInvitation); _friendInvitationRepository.CleanUpFriendInvitationsForThisEmail(frie ndInvitation); //create friendship Friend friend = new Friend(); friend.AccountID = friendInvitation.AccountID; friend.MyFriendsAccountID = InvitationTo.AccountID; _friendRepository.SaveFriend(friend); Account InvitationFrom = _accountRepository.GetAccountByID (friendInvitation.AccountID); _alertService.AddFriendAddedAlert(InvitationFrom, InvitationTo); //TODO: MESSAGING - Add message to inbox regarding new friendship!} This method expects the InvitationKey (in the form of a system generated GUID) and the Account that is wishing to create the relationship. It then gets the FriendInvitation and updates the BecameAccountID property of the new friend. We then make a call to flush any other friend invites between these two users. Once we have everything cleaned up, we add a new alert to the system letting the account that initiated this invitation know that the invitation was accepted. AlertService The alert service is essentially a wrapper to post an alert to the user's profile on The Filter. Go through the following methods. They do not need much explanation! public void AddStatusUpdateAlert(StatusUpdate statusUpdate){ alert = new Alert(); alert.CreateDate = DateTime.Now; alert.AccountID = _userSession.CurrentUser.AccountID; alert.AlertTypeID = (int)AlertType.AlertTypes.StatusUpdate; alertMessage = "<div class="AlertHeader">" + GetProfileImage(_userSession.CurrentUser.AccountID) + GetProfileUrl(_userSession.CurrentUser.Username) + " " + statusUpdate.Status + "</div>"; alert.Message = alertMessage; SaveAlert(alert); SendAlertToFriends(alert);}public void AddFriendRequestAlert(Account FriendRequestFrom, Account FriendRequestTo, Guid requestGuid, string Message){ alert = new Alert(); alert.CreateDate = DateTime.Now; alert.AccountID = FriendRequestTo.AccountID; alertMessage = "<div class="AlertHeader">" + GetProfileImage(FriendRequestFrom.AccountID) + GetProfileUrl(FriendRequestFrom.Username) + " would like to be friends!</div>"; alertMessage += "<div class="AlertRow">"; alertMessage += FriendRequestFrom.FirstName + " " + FriendRequestFrom.LastName + " would like to be friends with you! Click this link to add this user as a friend: "; alertMessage += "<a href="" + _configuration.RootURL + "Friends/ConfirmFriendshipRequest.aspx?InvitationKey=" + requestGuid.ToString() + "">" + _configuration.RootURL + "Friends/ConfirmFriendshipRequest.aspx?InvitationKey=" + requestGuid.ToString() + "</a><HR>" + Message + "</div>"; alert.Message = alertMessage; alert.AlertTypeID = (int) AlertType.AlertTypes.FriendRequest; SaveAlert(alert);}public void AddFriendAddedAlert(Account FriendRequestFrom, Account FriendRequestTo){ alert = new Alert(); alert.CreateDate = DateTime.Now; alert.AccountID = FriendRequestFrom.AccountID; alertMessage = "<div class="AlertHeader">" + GetProfileImage(FriendRequestTo.AccountID) + GetProfileUrl(FriendRequestTo.Username) + " is now your friend!</div>"; alertMessage += "<div class="AlertRow">" + GetSendMessageUrl(FriendRequestTo.AccountID) + "</div>"; alert.Message = alertMessage; alert.AlertTypeID = (int)AlertType.AlertTypes.FriendAdded; SaveAlert(alert); alert = new Alert(); alert.CreateDate = DateTime.Now; alert.AccountID = FriendRequestTo.AccountID; alertMessage = "<div class="AlertHeader">" + GetProfileImage(FriendRequestFrom.AccountID) + GetProfileUrl(FriendRequestFrom.Username) + " is now your friend!</div>"; alertMessage += "<div class="AlertRow">" + GetSendMessageUrl(FriendRequestFrom.AccountID) + "</div>"; alert.Message = alertMessage; alert.AlertTypeID = (int)AlertType.AlertTypes.FriendAdded; SaveAlert(alert); alert = new Alert(); alert.CreateDate = DateTime.Now; alert.AlertTypeID = (int) AlertType.AlertTypes.FriendAdded; alertMessage = "<div class="AlertHeader">" + GetProfileUrl(FriendRequestFrom.Username) + " and " + GetProfileUrl(FriendRequestTo.Username) + " are now friends!</div>"; alert.Message = alertMessage; alert.AccountID = FriendRequestFrom.AccountID; SendAlertToFriends(alert); alert.AccountID = FriendRequestTo.AccountID; SendAlertToFriends(alert);} PrivacyService Now that we have a method to check if two people are friends or not, we can finally extend our PrivacyService to account for friends. Up to this point we are only interrogating whether something is marked as private or public. Friends is marked false by default! public bool ShouldShow(Int32 PrivacyFlagTypeID, Account AccountBeingViewed, Account Account, List<PrivacyFlag> Flags){ bool result; bool isFriend = _friendService.IsFriend(Account,AccountBeingViewed); //flag marked as private test if(Flags.Where(f => f.PrivacyFlagTypeID == PrivacyFlagTypeID && f.VisibilityLevelID == (int)VisibilityLevel.VisibilityLevels.Private) .FirstOrDefault() != null) result = false; //flag marked as friends only test else if (Flags.Where(f => f.PrivacyFlagTypeID == PrivacyFlagTypeID && f.VisibilityLevelID == (int)VisibilityLevel.VisibilityLevels.Friends) .FirstOrDefault() != null && isFriend) result = true; else if (Flags.Where(f => f.PrivacyFlagTypeID == PrivacyFlagTypeID && f.VisibilityLevelID == (int)VisibilityLevel.VisibilityLevels.Public) .FirstOrDefault() != null) result = true; else result = false; return result;} Summary The article started with the thought process of how we can apply the concept of Friends to our community site. We tried to figure out what we need to do to implement the concept, we then finalized our requirements, and finally we began implementing the features. In the next part of this article we will continue with the implementation process.  

Downloading FreeNAS Before you can install the FreeNAS server, you will need to download the latest version from the FreeNAS website (http://www.freenas.org). Go to the download section and find the latest "LiveCD" version. The LiveCD version is what is known as an ISO image file and will have the .iso file extension. An ISO image is an exact copy of the structure and data for a CD or DVD disk. Using a CD burning program, you can create a FreeNAS bootable CD. We will look at this in more detail later on. What Hardware Do I Need? In this tutorial, we will start exploring FreeNAS, so you will need a machine on which to install the FreeNAS software. At this point in time, it doesn't have to be the final machine you are going to use as the FreeNAS server. You can use a "test" machine now and having learnt all about FreeNAS, you can build, install, and deploy a production machine (or machines) later. So, what we need now is a PC with at least 96Mb of RAM (but 128Mb or more is recommended), a bootable CD-ROM drive, a network card, one or more hard disks, and either a floppy disk drive (and a blank formatted disk) or a USB flash disk (MS-DOS formatted and empty). The hard disk will be for the data that you want to store and the floppy disk or USB flash disk will be for storing the configuration information. For the installation and initialization stages, you will also need a monitor and keyboard (but not mouse) attached to the PC. You can remove the monitor later, once FreeNAS is up and running. Warning FreeNAS boots as a LiveCD, which means that it does not use the disks on the host machine during boot up. However, when you start to configure storage on the FreeNAS server (specifically, when you format drives) all the data on the disk will be LOST. Do NOT use a machine that contains important data or an operating system that you will need afterwards. Virtualization  & VMWare The average PC runs just one operating system and inside that operating system, you would run your applications like word processing and email. There is a technology (called virtualization), which allows PCs to run more than one operating system, or to be more precise, to allow a guest virtual PC to run inside your actual PC. This virtual PC is an independent software box that can run its own OS and applications as if it were a physical computer. A virtual PC behaves exactly like a physical PC and has its own virtual CPU, RAM, hard disk, and network interface card (NIC). You can install FreeNAS on a virtual PC and FreeNAS can't tell the difference between the virtual PC and any other physical machine, also, it appears on the network just as a real PC would, running FreeNAS. There are lots of virtualization products available for Windows, Linux, and Apple OS X today. You can learn more at Wikipedia http://en.wikipedia.org/wiki/Virtualization. A very popular virtualization solution is from VMWare (http://www.vmware.com). VMWare have both commercial and freeware offerings and there are pre-configured FreeNAS images available for the VMWare range of products. This makes it an ideal environment for testing the FreeNAS server. Quick Start Guide For the Impatient If you are comfortable with burning ISO images to CDs, setting your computer's BIOS to boot from CDROM, disk partitions, and TCP/IP networking then this little guide should help you get a simple version of the FreeNAS server up and running in just a few minutes. If, however, some of these things sound daunting, then skip this section and go on to the next one where we shall go through the installation process one step at a time. For this example, we will use a USB flash disk to store the configuration information. You can use a floppy but be careful that during the boot process, the PC doesn't try to boot from the floppy before it boots from the CDROM. Burning and Booting Once you have downloaded the ISO image file from the FreeNAS website, you need to burn it to a CD. Having done that, put the CD into the PC as well as the flash disk and switch it on. Make sure that the BIOS is set to boot from CD. If it isn't, you need to enter into the BIOS and configure it to boot from CD. On many modern PCs, it is possible to select the boot device at start-up by pressing a special key (which is often either F8 or F12) to show a boot device menu. You can then select the CD as the boot device. The boot process is in four distinct parts: First, the PC will go through its POST (Power On Self Test) sequence. Here, the PC will check the amount of memory installed (which you can often see being counted on the screen) and which devices are connected (like hard drives and CDROMs). It should then start to boot from the CD. Here, FreeBSD (the underlying OS of FreeNAS) will start to boot, this is recognizable by the simple spinning wheel (made up of simple text characters like | - / and , which are animated to give the appearance of spinning). The third step is the FreeNAS boot menu. This will appear for just a few seconds and you should just let it boot normally, which is the default. The final stage is when the FreeNAS logo appears and the system will boot as FreeNAS server. You can tell when the system is fully loaded because the PC speaker will make some short but melodious beeps. To enable access to the web interface, the network of the FreeNAS server must be configured. Press the SPACE bar on the keyboard and the FreeNAS logo will disappear and a simple text menu will appear.       There are two aspects to configuring the network, first, you need to choose which network card to use and second, you need to assign it an address. If you have only one network card in your machine, then the FreeNAS server should have found it and automatically assigned it to be the LAN (Local Area Network) interface. What If My Network Card Isn't Found?This probably means that the network card in your machine isn't supported by FreeNAS or more specifically, by FreeBSD. You will need to replace the card with one supported by FreeBSD. Check the FreeBSD hardware compatibility page for more information: http://www.freebsd.org/releases/6.2R/hardware-i386.html If you see something like this: then the network has been recognized and assigned automatically by FreeNAS. The default IPv4 address for FreeNAS is 192.168.1.250, if this is good for your network, then you can just leave it unchanged. However, if you need to change it then press 2 followed by ENTER. If you want the machine to get its address from DHCP (Dynamic Host Configuration Protocol), answer yes (y) to the IPv4 DHCP question, otherwise answer no (n). If you are not using DHCP, you can now enter the desired IP address. Next, you need to enter the subnet mask. For 255.255.255.0, enter 24, for 255.255.0.0 enter 16, and for 255.0.0.0, enter 8. At this point, you can now skip the default gateway and DNS questions (by just pressing ENTER). If you do want to enter a default gateway and DNS server at this point, they will usually be the IP address of your Internet router. We won't be using IPv6 so the simplest thing to do now is just answer yes to the "Do you want to use AutoConfiguration for IPv6?" question. This will cause a small delay while FreeNAS tries (and probably fails) to get the IPv6 address but it is simpler than trying to enter the IPv6 address manually! You are now ready to access the web interface. The FreeNAS web interface can be accessed from any machine on the network with a web browser (including Windows, Linux, and OS X machines). On this client machine, type the address of the FreeNAS server with http:// in front of it into your web browser. For example: http://192.168.1.250 Configuring The first time you access the FreeNAS web interface, you will be asked for the username and password. The default username is admin and the default password is freenas. You should now be in the web interface. To configure some storage space, you need to work with "Disks". The logical order of working is that disks must be added, then formatted (if need be), then mounted. Finally, access is given to the various mounted disks by configuring different system services like CIFS and FTP.     So, to add a disk, go to Disks: Management. There is a + sign in a circle on the right-hand-side of the page (it can be easy to miss first time), click on it to add a disk. On the next page, select the disk you want to add. If you click on the drop-down menu, you should see the hard disks of the machines, the CDROM, and the USB flash disk. Dis'k Names in FreeBSD'The disk naming convention in FreeBSD is:/dev/ad0: Is the IDE/ATA Primary Master /dev/ad1 : Is the IDE/ATA Primary Slave/dev/ad2 : Is the IDE/ATA Secondary Master/dev/ad3 : Is the IDE/ATA Secondary Slave/dev/acd0 : Is the first ATA CD/DVD drive detected/dev/da0: Is the first SCSI hard drive, /dev/da1 the second and so on.USB flash disks are controlled using the SCSI driver, so they will appear as /dev/daN drives as well. Make sure ad0 is selected (which it should be by default). The rest of the page you can leave alone. Click Add to add the disk to the system. You then need to click Apply in order for the changes to take effect. You will now have a table showing you the disk you have added, including its size and a description. ApplyIn FreeNAS, the majority of steps need to be applied (which saves the configuration file to disk) by clicking the Apply button. It is normally found near the top of the page before any tables or configuration information is given. If you do not apply the changes, the interface will, on the whole, remember your changes but they will not be enacted in the system. After a reboot, unapplied changes will disappear. It is possible on some pages to make multiple operations and apply them all at the end. Next, the disk needs to be formatted. In Disks: Format, select the disk ad0 (which you just added above). Leave everything else unchanged and click Format disk. The disk will then be formatted. The low level output of the format command will be displayed in a box. It should end with Done!. Now the disk needs to be mounted. Go to Disks: Mount Point. Click on the + in the circle (which I shall refer to as the "add circle" from now on). Leave the Type as Disk and select the disk ad0 again. You need to type in a name, store is as good a name as any, but feel free to use which ever descriptive name you want to. Be DescriptiveIn setting up and configuring your FreeNAS server, you will be called upon to invent various names for mount points and share names etc. Try to be as descriptive as you can without being long winded. Temp, scratch, blob, and even zob are OK for testing, but try more meaningful names like storeage1, storage60gb or backupstorage etc. Don't use spaces in the names, instead use underline and in general, the names should be no longer than 15 characters. Although filling-in the description isn't mandatory in the web interface, it is worth using. Once you have completed the form click Add and then apply the changes. Sharing with Windows Machines Now that the disk has been added, formatted, and mounted, it is time to share it on the network and give other users the ability to read and write to it. FreeNAS supports many different types of access protocol, for this start guide, we will only look at Microsoft's CIFS protocol that primarily allows Windows machines (but also Apple OS X and Linux machines) to access the storage. In Services: CIFS/SMB, tick the enable box (in the title of the configuration data table). At this point, you can just about leave everything else as is with the exception of the workgroup name. We will be leaving the authentication method as "Anonymous" here as this is the easiest to get working and provides unrestricted read/write access to everyone. To make sure that the Windows machines are able to find the shared storage, we need to set the workgroup name, on the FreeNAS server, to be the same as the workgroup name of the Windows PC that will access the share. The default workgroup name for Windows Vista is WORKGROUP but note that the default for Window XP Home Edition was MSHOME. Now click Save and Restart. This will save the changes you have made and restart the CIFS service. Go to the Shares tab and click on add circle. Enter a name for the share. Repeating the name of the mount point is probably the safest policy, so in this case, store and also add a comment. Then click ... in the Path section. This will bring up a simple file system browser. The files you are seeing are on the FreeNAS server and NOT on your local PC. Click store and /mnt/store/ will appear in the little edit box at the click. OK it and you will be taken back to the shares page. Now /mnt/store/ has been added as the path. Leave everything else as it is and click Add and then apply the changes. So now the first hard disk of the computer is formatted, mounted, and shared to the rest of the network. Now, we will access the share from a Windows Vista machine. Testing the Share You can perform this test from any machine that supports the CIFS protocol including Windows 95/98/ME, Windows 2000/XP, Apple OS X, and Linux. Here, we are going to use Windows Vista. Open the Network and Sharing Center by clicking Network on the Start menu. When the window appears, Vista will automatically scan the network for any shared network resources. When it has finished, you will see the available machines on the network including FREENAS.     Open up the FREENAS computer and you will see store, the storage area that you configured. Double click on that and you now "inside" the FreeNAS server from within your Windows machine. Try dragging and dropping a few files in to the store area. Then try deleting them again. To access the FreeNAS server without using the Network and Sharing Center, click Start, and type freenas and then press Enter. This will bring up the shares available on the FreeNAS server directly:     Detailed Overview of Installation It is time to get your hands on a working FreeNAS server and to do that, we need to boot it up onto a PC. There are several steps to this. First, you must burn a CD of the ISO image file you have downloaded. Then, you need to boot the PC from the CD; this may involve changing your computers BIOS to make it boot from the optical drive. Then, you can configure the FreeNAS server to make some storage space available on the network. When using the LiveCD to boot FreeNAS, there are two types of storage on FreeNAS: data and configuration information. The data will be held on the hard drive of the PC, but the configuration needs to be held on a floppy disk or a USB flash disk. For this example, we will use a USB flash disk to store the configuration information. Making the FreeNAS CD To boot the PC into FreeNAS, you need a CD. The ISO image file you have downloaded contains all the information needed for the CD, but it needs to be written onto a physical CD. This process is often known as burning the CD as the laser writes to the disk by heating it and marking or scorching the surface layer. You need to use a PC with a CD-RW drive and a blank CD-R disk (I recommend using a good brand name CD-R for best results). Download the FreeNAS ISO image on to that machine. The PC with the CD writer should have some CD writing software on it (for example Roxio Easy CD or Nero). If you are familiar with the CD writing software, go ahead and burn the ISO file to the CD-R disk. If you aren't familiar with the CD writing software or it doesn't have any CD writing software, then I recommend ISO Recorder. You can download it from http://isorecorder.alexfeinman.com/isorecorder.htm.     Booting from CD Put your newly made FreeNAS CD into the CD drive of the machine on which you want to install FreeNAS, and also put the USB flash disk into a USB port. The flash disk will be used to store the configuration data. (You can also use a floppy disk. If you have both a USB flash disk and a floppy inserted, FreeNAS will save the configuration on the USB device). Now, you need to switch on the PC. When a PC starts, it goes through what is known as the Power On Self Test sequence. Here, the PC will check the amount of memory installed in the PC and find the installed hard drives. After the checks, the PC will try and boot from one of the hard drives, the CDROM, the floppy disk or even a USB flash disk. Which device the PC chooses first as its boot device can be changed by a built-in setup program. The setup program lets you modify basic system configuration settings. These settings are stored in a special battery-backed area of the computer's memory that retains the settings even when the power is switched off. During the POST sequence, there is normally a message telling you how to enter into the built-in setup program. It is normally either the DEL key or F2, on some systems it is also F10. You need to enter into the setup to check and/or change the first boot device to be the CDROM so that the computer will boot into FreeNAS. Each PC has a slightly different setup program, so you will need to search around until you find what you need. The three most popular types of setup programs (also known as BIOS Basic Input Output Program) are the Phoenix setup program, the Phoenix-Award setup program, and the AMI setup program. There are many types of BIOS setup programs and each PC manufacturer modifies the setup program for their own use. The information below is really only a "rough guide" to help you feel your way around. Your BIOS setup program may be significantly different from the examples below. The best source of information is the manual that came with your PC or your motherboard. If you don't have one, most PC manufacturers have them available for download on their websites. Phoenix BIOS If your machine has a Phoenix BIOS, then normally you need to press F2 to enter the setup program. The top of the setup program has a menu that you can navigate with the left and right arrow keys, you need to select the Boot menu.     On the Boot menu page, you can move up and down the available boot devices using the up and down arrow keys. You can expand and collapse sections with the + or signs using the ENTER key. To change the boot order, you use the + and keys. You want to make sure that the CDROM is the first device in the list. After you have changed the boot order list, you need to go to the Exit menu (by pressing the right arrow key) and select Exit Saving Changes. The PC will then reboot and after the POST, it will start to boot from the FreeNAS CD.     Phoenix-Award BIOS If your PC has a Phoenix-Award BIOS, then normally, you need to press DEL to enter the setup program. Once inside, you can the up, down, left, and right keys to navigate around the menus. Go in to Advanced BIOS Features and set the First Boot Device to be CDROM by using the + and keys. You now need to save your changes and exit. Pressing ESC will bring you back to the main menu, then select Save & Exit Setup. Often, pressing F10 will have the same effect. The PC will then reboot and if you have made the changes correctly, it will boot from the FreeNAS CD. AMI BIOS The American Megatrends, Inc (AMI) BIOS normally displays a message telling you to Hit <DEL> if you want to run setup. Once inside, it is quite different to that of the setup programs for Phoenix or Award. Here, the Tab key is used to navigate and the arrow keys are used to change values. To go from one page to the next, press the ALT+P keys. This information should also be printed at the bottom of the BIOS setup page. You need to find the variable Boot Sequence and make sure that it is set to boot from the CDROM first. First Look at FreeNAS The boot process is in 4 distinct parts. First, the PC will go through its POST (Power On Self Test) sequence. Here, the PC will check the amount of memory installed (which you can often see being counted on the screen) and which devices are connected (like hard drives and CDROMs). It should then start to boot from the CD. Here, FreeBSD (the underlying OS of FreeNAS) will start to boot, this is recognizable by the simple spinning wheel (made up of simple text characters like | - / and which are animated to give the appearance of spinning). The third step is the FreeNAS boot menu. This will appear for just five seconds and you should just let it boot normally which is the default. The final stage is when the FreeNAS logo appears and the system will boot as a FreeNAS server. You can tell when the system is fully loaded because the PC speaker will make some short but melodious beeps. Configuring the Network The majority of the configuration for FreeNAS is done via a web interface, but before you can use the web interface, the FreeNAS server needs to be configured for your network. This is done via a simple text menu system using the keyboard and monitor attached to the PC with FreeNAS running on it. You probably only need to do this once, and after that this new network information will be saved on the USB flash disk (or floppy disk) and the server will boot into this configuration every time. If you press the SPACE bar on FreeNAS machine, the FreeNAS logo will disappear and a simple menu will appear.     Here, you have a number of options including options to reboot or power off the system. The first two options are about configuring the network and they reflect the two parts to configuring the network, first you need to choose which network card to use (option 1) and second you need to assign it an address (option 2). If you have only one network card in your machine then the FreeNAS server should have found it and automatically assigned it to be the LAN (Local Area Network) interface. What If My Network Card Isn't Found?This probably means that the network card in your machine isn't supported by FreeNAS or more specifically by FreeBSD. You will need to replace the card with one supported by FreeBSD. Check the FreeBSD hardware compatibility page for more information: http://www.freebsd.org/releases/6.2R/hardware-i386.html If you see something like the following screenshot:     then the network has been recognised and assigned automatically by FreeNAS. What is a LAN IP Address? IP stands for Internet Protocol and it is the basic low level language that computers use to talk to each other on the Internet. It is also used on private networks (in the office or at home) to connect different PCs and even printers to each other. An IPv4 address is made up of 4 sets of number (0 to 255) and is expressed in what is known as dot notation (meaning that each number has a dot between it). So 192.168.1.250 is an IP address, it also happens to be the default IP address for the FreeNAS server. Like email, the postal service and telephone, each destination (email account, mailbox or handset) needs a unique way of being identified. This is what IP addresses do; they allow each piece of equipment on the network to have a unique identifier so that messages can be addressed to the right place on the network. Pronouncing IP AddressesIf you need to speak to someone about an IP address, the simplest way is to speak about each digit separately, so 192.168.1.250 isn't "one hundred and ninety two dot" but rather "one nine two dot one six eight dot one dot two five zero". There are two ways in which you can obtain an IP address for the FreeNAS server. The first is to have the address assigned automatically via the DHCP service (Dynamic Host Configuration Protocol), and the second is to assign it manually. What is DHCP?The Dynamic Host Configuration Protocol (DHCP) automates the assignment of IP addresses and other IP parameters (like subnet masks and default gateway). A computer that needs an IP address will send a request to the DHCP server and the server will reply with an IP address from a pool of addresses that have been set aside for this purpose. A DHCP server can be a PC or server (running Windows, OS X or Linux) as well as small devices like modern DSL modems and firewalls. The advantage of the DHCP method is that the IP address assignment, all happens in the background and you don't need to worry about setting it yourself. The disadvantages are that first you need to have an already configured and running DHCP server on your network; and second, DHCP assigns addresses from a pool of available addresses. This means that every time the FreeNAS server boots, it is not guaranteed to have the same address as it had previously. This isn't a problem when using the CIFS protocol, however, for accessing the web interface or using protocols like FTP, it is desirable to have a stable IP address to refer to. However, for testing the FreeNAS server and learning about how it works using a DHCP assigned address could be acceptable for now. It is actually possible to assign fixed, permanent IP address to certain pieces of hardware, including a FreeNAS server over DHCP, but that requires extra advanced configuration changes in the DHCP server that cannot be covered in this tutorial. So opting for the manual IP address, you now need to obtain two pieces of information. The first is the actual IP address for the FreeNAS and the second is what is known as the subnet mask. The subnet mask will also be expressed in the dot notation and is normally something like 255.255.255.0. If you are in an office environment, you need to speak to the network administrator and he/she will be able to give you the information you need. If you are administering your own network, you need to choose an IP that isn't currently allocated to any other machine on your network (and also, isn't part of the address pool of any DHCP server on your network). Having obtained the IP address and subnet mask, you can now configure the FreeNAS server for your network. Select option 2 on the console menu. If you have chosen to have DHCP assign the address, answer yes (y) to the first question about using DHCP for IPv4. Otherwise answer no (n). If you are setting the address manually, you can now enter the address in dot notation, i.e. 192.168.1.240. Next, comes the subnet mask. If your subnet mask is 255.255.255.0: enter 24, for 255.255.0.0: enter 16, and for 255.0.0.0: enter 8. At this point, you can now skip the default gateway and DNS questions (by just pressing ENTER). We won't be using IPv6 so the simplest thing to do now is just answer yes to the "Do you want to use AutoConfiguration for IPv6?" question. This will cause a small delay while FreeNAS tries (and probably fails) to get the IPv6 address but it is simpler than trying to enter the IPv6 address manually! After you have successful set the IP address, there will be a small message on the screen inviting you to access the web interface by opening the listed URL in your web browser. If you have used DHCP, note down the URL listed. If you set the IP address manually, check that the URL listed is the same as the IP address you set with [http:// http://] in front of it. You are now ready to access the web interface. What is IPv4 and IPv6?The Internet Protocol has been around since the mid 1980's and when it was designed, the popularity of the Internet was not envisaged. The number of computers connected to the Internet is quickly growing beyond the addressing capabilities of the original protocol. As an answer to this, a new version of the IP protocol has been designed and has been given the name IP version 6 or IPv6 for short and the older version has taken the name IP version 4 or IPv4 for short. FreeNAS supports both versions of the Internet Protocol. In this tutorial, we will concentrate just on IPv4 as it still remains the most popular of the two protocols. Basic Configuration With your FreeNAS server now being up and running, it is time to access the web interface. Open a web browser on a computer on the same network as the FreeNAS server. Enter in the URL of the FreeNAS server. This should be the same as the IP address of the server with [http:// http://] in the front. The default URL is http://192.168.1.250     The first time you access the FreeNAS web interface, you will be asked for the username and password. The default username is admin and the default password is freenas. FreeNAS Web Interface You should now have the web interface in your browser. The interface is split into two main sections. Down the left-hand-side are the menus, and the right-hand-side contains the pages for configuration. The menus are split into various sections: System, Interfaces, Disks, Services, Access, Status, Diagnostics, and Advanced.     When talking about a particular menu item, we shall use the notation Subsection: Menu Item to help you find the right menu option easily. So, the Management option, which is in the Disks subsection, will be referred to as Disks: Management. System This section is for system level configuration and operations, here for example you can change the username and password, backup and restore the configuration data, and shutdown or reboot the server. Interfaces Here, you can configure the network of the FreeNAS server much like you did via the console menu. You can change the network card that is used for the web interface and assign permanent or automatic IP addresses. Be careful when you change things here as some changes won't take effect until you reboot. If you have changed any of the addressing, you will need to access the web interface with the IP address. Disks This section of the menu is for administering the disks on the server. Here, you can set up disk redundancy (RAID), control encryption, format disks, and mount the disks on the server. Services The various access protocols like CIFS, NFS, and FTP are controlled from here. Each service is administered individually and by default NONE of the services are enabled, so before you can access files stored on the FreeNAS server, you need to enable at least one of these services. Access Most of the services offered by FreeNAS use some form of list of users to control who has access and who does not. This section is for defining these users and the groups they belong to as well as connecting the FreeNAS server to other directory services. Status The status menu has several reporting tools for you to see the current state of your FreeNAS server including a general overview, memory usage, disk usage, and network usage. You can also configure emails to be sent periodically about the status of the server. Diagnostics The diagnostics menu contains different tools to help diagnose any problem with the FreeNAS server, including logs of all the important services and diagnostic information from the hard disks and other system modules. Advanced The advanced section provides some simple tools for executing commands at the operating system level and should not be used by those unfamiliar with FreeBSD.    

Installing Elgg In addition to its impressive feature list, Elgg is an admin's dolly. In this tutorial by Mayank Sharma, we will see how Elgg can be installed in popular Linux web application rollout stack of Linux, Apache, MySQL, and PHP, fondly referred to as LAMP. As MySQL and PHP can run under Windows operating system as well, you can set up Elgg to serve your purpose for such an environment. Setting Up LAMP Let's look at setting up the Linux, Apache, MySQL, PHP web server environment. There are several reasons for the LAMP stack's popularity. While most people enjoy the freedom offered by these Open Source software, small business and non-profits will also be impressed by its procurement cost—$0. Step 1: Install Linux The critical difference between setting up Elgg under Windows or Linux is installing the operating system. The Linux distribution I'm using to set up Elgg is Ubuntu Linux ( http://www.ubuntu.com/ ).It's available as a free download and has a huge and active global community, should you run into any problems. Covering step-by-step installation of Ubuntu Linux is too much of a digression for this tutorial. Despite the fact that Ubuntu isn't too difficult to install, because of its popularity there are tons of installation and usage documentation available all over the Web. Linux.com has a set of videos that detail the procedure of installing Ubuntu ( http://www.linux.com/articles/114152 ).Ubuntu has a dedicated help section ( https://help.ubuntu.com/ ) for introduction and general usage of the distribution. Step 2: Install Apache Apache is the most popular web server used on the Internet. Reams and reams of documents have been written on installing Apache under Linux. Apache's documentation sub-project ( http://httpd.apache.org/docs-project/ ) has information on installing various versions of Apache under Linux. Ubuntu, based on another popular Linux distribution, Debian, uses a very powerful and user-friendly packaging system. It's called apt-get and can install an Apache server within minutes. All you have to do is open a terminal and write this command telling apt-get what to install: apt-get install apache2 apache2-common apache2-doc apache2-mpm-prefork apache2-utils libapr0 libexpat1 ssl-cert This will download Apache and its most essential libraries. Next, you need to enable some of Apache's most critical modules: a2enmod ssla2enmod rewritea2enmod include The rewrite module is critical to Elgg, so make sure it's enabled, else Elgg wouldn't work properly. That's it. Now, just restart Apache with: /etc/init.d/apache2 restart. Step 3: MySQL Installing MySQL isn't too much of an issue either. Again, like Ubuntu and Apache, MySQL can also boast of a strong and dedicated community. This means there's no dearth of MySQL installation or usage related documentation ( http://www.mysql.org/doc/ ). If you're using MySQL under Ubuntu, like me, installation is just a matter of giving apt-get a set of packages to install: apt-get install mysql-server mysql-client libmysqlclient12-dev Finally, set up a password for MySQL with: mysqladmin -h yourserver.example.com -u root password yourrootmysqlpassword Step 4: Install PHP Support You might think I am exaggerating things a little bit here, but I am not, PHP is one of the most popular and easy to learn languages for writing web applications. Why do you think we are setting up out Linux web server environment to execute PHP? It's because Elgg itself is written in PHP! And so are hundreds and thousands of other web applications. So I'm sure you've guessed by now that PHP has a good deal of documentation ( http://www.php.net/docs.php )as well. You've also guessed it's now time to call upon Ubuntu's apt-get package manager to set up PHP:  apt-get install libapache2-mod-php5 php5 php5-common php5-gd php5-mysql php5-mysqli As you can see, in addition to PHP, we are also installing packages that'll hook up PHP with the MySQL database and the Apache web server. That's all there is to setting up the LAMP architecture to power your Elgg network. Setting Up WAMP If you are used to Microsoft's Windows operating system or want to avoid the extra minor learning curve involved with setting up the web server on a Linux distribution, especially, if you haven't done it before, you can easily replicate the Apache, MySQL, PHP web server on a Windows machine. Cost wise, all server components the Apache web server, MySQL database, and the PHP development language have freely available Windows versions as well. But the base component of this stack, the operating system —Microsoft Windows, isn't. Versions of Apache, MySQL, and PHP for Windows are all available on the same websites mentioned above. As Windows doesn't have an apt-get kind of utility, you'll have to download and install all three components from their respective websites, but you have an easier way to set up a WAMP server. There are several pre-packaged Apache, MySQL, and PHP software bundles available for Windows(http://en.wikipedia.org/wiki/Comparison_of_WAMPs).I've successfully run Elgg on the WAMP5 bundle (http://www.en.wampserver.com/). The developer updates the bundle, time and again, to make sure it's running the latest versions of all server components included in the bundle. Note - While WAMP5 requires no configuration, make sure you have Apache's rewrite_module and PHP's php_gd2 extension enabled. They will have a bullet next to their name if they are enabled. If the bullet is missing, click on the respective entries under the Apache and PHP sub-categories and restart WAMP5. Installing Elgg Now that we have a platform ready for Elgg, let's move on to the most important step of setting up Elgg. Download the latest version of Elgg from its website. At the time of writing this tutorial, the latest version of Elgg was Elgg-0.8. Elgg is distributed as a zipped file. To uncompress under Linux: Move this zipped file to /tmp and uncompress it with the following command: $ unzip /tmp/elgg-0.8.zip To uncompress under Windows: Right-click on the ZIP file and select the Extract here option. After uncompressing the ZIP file, you should have a directory called Elgg-<version-number>, in my case, elgg-0.8/. This directory contains several sub directories and files. The INSTALL file contains detailed installation instructions. The first step is to move this uncompressed directory to your web server. Note: You can set up Elgg on your local web server that sits on the Internet or on a paid web server in a data center anywhere on the planet. The only difference between the two setups is that if you don't have access to the local web server, you'll have to contact the web service provider and ask him about the transfer options available to you. Most probably, you'll have FTP access to your web server, and you'll have to use one of the dozens of FTP clients, available for free, to transfer Elgg's files from your computer to the remote web server. Optionally, if you have "shell" access on the web server, you might want to save time by transferring just the zipped file and unzipping it on the web server itself. Contact your web server provider for this information. The web server's directory where you need to copy the contents of the Elgg directory depends upon your Apache installation and operating system. In Ubuntu Linux, the default web server directory is /var/www/. In Windows, WAMP5 asks where it should create this directory during installation. By default, it's the www directory and is created within the directory you installed WAMP5 under. Note: Another important decision you need to make while installing Elgg is how do you want your users to access your network. If you're setting up the network to be part of your existing web infrastructure, you'll need to install Elgg inside a directory. If, on the other hand, you are setting up a new site just for the Elgg-powered social network, copy the contents of the Elgg directory inside the www directory itself and not within a subdirectory. Once you have the Elgg directory within your web server's www directory, it's time to set things in motion. Start by renaming the config-dist.php file to config.php and the htaccess-dist to .htaccess. Simply right-click on the file and give it a new name or use the mv command in this format: $ mv <original-file-name> <new-file-name> Note : To rename htacces-dist to .htaccess in Windows, you'll have to open the htaccess-dist file in notepad and then go to File | Save As and specify the name as .htaccess with the quotes. Editing config.php Believe it or not, we've completed the "installation" bit of setting up Elgg. But we still need to configure it before throwing the doors open to visitors. Not surprisingly, all this involves is creating a database and editing the config.php file to our liking. Creating a Database Making an empty database in MySQL isn't difficult at all. Just enter the MySQL interactive shell using your username, password, and hostname you specified while installing MySQL. $ mysql -u root -h localhost -pEnter password: Welcome to the MySQL monitor. Commands end with ; or g.Your MySQL connection id is 9 to server version: 5.0.22-Debian_0ubuntu6.06.3-logType 'help;' or 'h' for help. Type 'c' to clear the buffer.mysql> CREATE DATABASE elgg; You can also create a MySQL database using a graphical front-end manager like PHPMyAdmin, which comes with WAMP5. Just look for a database field, enter a new name (Elgg), and hit the Create button to create an empty Elgg database. Initial Configuration Elgg has a front-end interface to set up config.php, but there are a couple of things you need to do before you can use that interface: Create a data directory outside your web server root. As described in the configuration file, this is a special directory where uploaded files will go. It's also advisable to create this directory outside your main Elgg install. This is because this directory will be writable by everyone accessing the Elgg site and having such a "world-accessible" directory under your Elgg installation is a security risk. If you call the directory Elgg-data, make it world-readable with the following command: $ chmod 777 elgg-data Setup admin username and password. Before you can access Elgg's configuration web front-end, you need an admin user and a password. For that open the config.php file in your favorite text editor and scroll down to the following variables: $CFG->adminuser = "";$CFG->adminpassword = ""; Specify your chosen admin username and password between the quotes, so that it looks something like this: $CFG->adminuser = "admin";$CFG->adminpassword = "765thyr3"; Make sure you don't forget the username and password of the admin user. Important Settings When you have created the data directory and specified an admin username and password, it's time to go ahead with the rest of the configuration. Open a web browser and point to http://<your-web-server>/<Elgg-installation>/elggadmin/ This will open up a simple web page with lots of fields. All fields have a title and a brief description of the kind of information you need to fill in that field. There are some drop-down lists as well, from which you have to select one of the listed options. Here are all the options and their descriptions: Administration panel username: Username to log in to this admin panel, in future, to change your settings. Admin password: Password to log in to this admin panel in future. Site name: Enter the name of your site here (e.g. Elgg, Apcala, University of Bogton's Social Network, etc.). Tagline: A tagline for your site (e.g. Social network for Bogton). Web root: External URL to the site (e.g. http://elgg.bogton.edu/). Elgg install root: Physical path to the files (e.g./home/Elggserver/httpdocs/). Elgg data root: This is a special directory where uploaded files will go. If possible, this should live outside your main Elgg installation? (you'll need to create it by hand). It must have world writable permissions set, and have a final slash at the end. Note: Even in Windows, where we use back slashes () to separate directories, use Unix's forward slashes (/) to specify the path to the install root, data root, and other path names. For example, if you have Elgg files under WAMP's default directory in your C drive, use this path: C:/wamp/www/elgg/. Database type: Acceptable values are mysql and postgres - MySQL is highly recommended. System administrator email: The email address your site will send emails from(e.g. elgg-admin@bogton.edu). News account initial password: The initial password for the 'news' account. This will be the first administrator user within your system, and you should change the password immediately after the first time you log in. Default locale: Country code to set language to if you have gettext installed. Public registration: Can general members of the public register for this system? Public invitations: Can users of this system invite other users? Maximum users: The maximum number of users in your system. If you set this to 0, you will have an unlimited number of users. Maximum disk space: The maximum disk space taken up by all uploaded files. Disable public comments: Set the following to true to force users to log in before they can post comments, overriding the per-user option. This is a handy sledgehammer-to-crack-a-nut tactic to protect against comment spam (although an Akismet plug-in is available from elgg.org). Email filter: Anything you enter here must be present in the email address of anyone who registers; e.g. @mycompany.com will only allow email address from mycompany.com to register. Default access: The default access level for all new items in the system. Disable user templates: If this is set, users can only choose from available templates rather than defining their own. Persistent connections: Should Elgg use persistent database connections? Debug: Set this to 2047 to get ADOdb error handling. RSS posts maximum age: Number of days for which to keep incoming RSS feed entries before deleting them. Set this to 0 if you don't want RSS posts to be removed. Community create flag: Set this to admin if you would like to restrict the ability to create communities to admin users. cURL path: Set this to the cURL executable if cURL is installed; otherwise leave blank. Note : According to Wikipedia, cURL is a command line tool for transferring files with URL syntax, supporting FTP, FTPS, HTTP, HTTPS, TFTP, SCP,SFTP, Telnet, DICT, FILE, and LDAP. The main purpose and use for cURL is to automate unattended file transfers or sequences of operations. For example, it is a good tool for simulating a user's actions at a web browser. Under Ubuntu Linux, you can install curl using the following command: apt-get install curl Templates location: The full path of your Default_Template directory. Profile location: The full path to your profile configuration file (usually, it's best to leave this in mod/profile/). Finally, when you're done, click on the Save button to save the settings. Note : The next version of Elgg, Elgg 0.9, will further simplify installation. Already an early release candidate of this version (elgg-0.9rc1) is a lot more straightforward to install and configure, for initial use. First Log In Now, it's time to let Elgg use these settings and set things up for you. Just point your browser to your main Elgg installation (http://<your-web-servergt;/<Elgg-installation>). It'll connect to the MySQL database and create some tables, then upload some basic data, before taking you to the main page. On the main page, you can use the news account and the password you specified for this account during configuration to log in to your Elgg installation.

Obtaining the SDK If you are running the Enterprise network, it is likely that the SDK has been provided to you as a binary. Alternatively, you can check out the Enterprise source code and build it yourself. In the Enterprise SVN repository, specific releases are tagged. So if you wanted 2.2.0, for example, you'd check out V2.2.0-ENTERPRISE-FINAL. The Enterprise SVN repository for the Enterprise network is password-protected. Consult your Alfresco representative for the URL, port, and credentials that are needed to obtain the Enterprise source code. Labs network users can either download the SDK as a binary from SourceForge (https://sourceforge.net/project/showfiles.php?group_id=143373&package_id=189441) or check out the Labs source code and build it. The SVN URL for the Labs source code is svn://svn.alfresco.com. In the Labs repository, nothing is tagged. You must check out HEAD. Step-by-Step: Building Alfresco from Source Regardless of whether you are using Enterprise or Labs, if you've decided to build from the source it is very easy to do it. At a high level, you simply check out the source and then run Ant. If you've opted to use the pre-compiled binaries, skip to the next section. Otherwise, let's use Ant to create the same ZIP/TAR file that is available on the download page. To do that, follow these steps: Check out the source from the appropriate SVN repository, as mentioned earlier. Set the TOMCAT_HOME environment variable to the root of your Apache Tomcat install directory. Navigate to the root of the source directory, then run the default Ant target: ant build.xml ant build.xml It will take a few minutes to build everything. When it is done, run the distribute task like this: ant -f continuous.xml distribute Again, it may take several minutes for this to run. When it is done, you should see several archives in the build|dist directory. For example, running this Ant task for Alfresco 3.0 Labs produces several archives. The subset relevant to the article includes: alfresco-labs-sdk-*.tar.gz alfresco-labs-sdk-*.zip alfresco-labs-tomcat-*.tar.gz alfresco-labs-tomcat-*.zip alfresco-labs-war-*.tar.gz alfresco-labs-war-*.zip alfresco-labs-wcm-*.tar.gz alfresco-labs-wcm-*.zip You should extract the SDK archive somewhere handy. The next step will be to import the SDK into Eclipse. Setting up the SDK in Eclipse Nothing about Alfresco requires you to use Eclipse or any other IDE. But Eclipse is very widely used and the Alfresco SDK distribution includes Eclipse projects that can easily be imported into Eclipse, so that's what these instructions will cover. In addition to the Alfresco JARs, dependent JARs, Javadocs, and source code, the SDK bundle has several Eclipse projects. Most of the Eclipse projects are sample projects showing how to write code for a particular area of Alfresco. Two are special, however. The SDK AlfrescoEmbedded project and the SDK AlfrescoRemote project reference all of the JARs needed for the Java API and the Web Services API respectively. The easiest way to make sure your own Eclipse project has everything it needs to compile is to import the projects bundled with the SDK into your Eclipse workspace, and then add the appropriate SDK projects to your project's build path. Step-by-Step: Importing the SDK into Eclipse Every developer has his or her own favorite way of configuring tools. If you are going to work with multiple versions of Alfresco, you should use version-specific Eclipse workspaces. For example, you might want to have a workspace-alfresco-2.2 workspace as well as a workspace-alfresco-3.0 workspace, each with the corresponding Alfresco SDK projects imported. Then, if you need to test customizations against a different version of the Alfresco SDK, all you have to do is switch your workspace, import your customization project if it isn't in the workspace already, and build it. Let's go ahead and set this up. Follow these steps: In Eclipse, select File|Switch Workspace or specify a new workspace location. This will be your workspace for a specific version of the Alfresco SDK so use a name such as workspace-alfresco-3.0. Eclipse will restart with an empty workspace. Make sure the Java compiler compliance level preference is set to 5.0 (Window|Preferences|Java|Compiler). If you forget to do that, Eclipse won't be able to build the projects after they are imported. Select File|Import|Existing Projects into Workspace. For the root directory, specify the directory where the SDK was uncompressed. For the root directory, specify the directory where the SDK was uncompressed. You want the root SDK directory, not the Samples directory. Select all of the projects that are listed and click Import. After the import, Eclipse should be able to build all projects cleanly. If not, double-check the compiler compliance level. If that is set but there are still errors, make sure you imported all SDK projects including SDK AlfrescoEmbedded and SDK AlfrescoRemote. Now that the files are in the workspace, take a look at the Embedded project. That's quite a list of dependent JAR files! The Alfresco-specific JARs all start with alfresco-. It depends on what you are doing, of course, but the JAR that is referenced most often is likely to be alfresco-repository.jar because that's where the bulk of the API resides. The SDK comes with zipped source code and Javadocs, which are both useful references (although the Javadocs are pretty sparse). It's a good idea to tell Eclipse where those files are, so you can drill in to the Alfresco source when debugging. To do that, right-click on the Alfresco JAR, and then select Properties. You'll see panels for Java Source Attachment and Javadoc Location that you can use to associate the JAR with the appropriate source and Javadoc archives. The following image shows the Java Source Attachment for alfresco-repository.jar: The following image shows the Javadoc Location panel for alfresco-repository.jar. Source and Javadoc are provided for each of the Alfresco JARs, as shown in the following table. Note that source and Javadoc for everything is available. This is open source software after all, not just all bundled with the SDK: Alfresco JAR Source archive Javadoc archive alfresco-core.jar Src|core-src.zip Doc|api|core-doc.zip alfresco-remote-api.jar Src|remote-api-src.zip Doc|api|remote-api-doc.zip alfresco-web-client.jar src|web-client-src.zip doc|api|web-client-doc.zip alfresco-repository.jar src|repository-src.zip doc|api|repository-doc.zip    

PHx in action Let us learn our need of PHx by building a new functionality for our site that lets us add profiles of our family members and friends. We will add a new page called 'Family and Friends' that will show the list of all the individuals that we add. Once the user clicks on an individual, it will show certain details such as name, relationship to you, occupation, web site. This is easy to implement; all we have to do is create the template variables for each of the fields, and create a template that uses these template variables. So, to display the Occupation, the template will have a code similar to the following: Occupation: [*occupation*] Though this might appear to work initially, it has a small glitch in it. When we are entering the personal details of an individual, we may not want to enter all of the values for every individual. In the case of not having a value for the variable, it looks cleaner to not show the label at all instead of leaving it blank. In our case—if we have no value for occupation—it will look cleaner to not show the label Occupation. So here comes a need for displaying certain text only if the template variable—in this case, occupation—has a value. We can do this using PHx without having to write a snippet. Installing PHx To download PHx, use the following steps: Download PHx from http://MODxcms.com/PHx-1006.html. Extract the contents of the downloaded file. Create a directory called phx in the assets/plugins folder of your MODx installation. Copy all the files within the extracted folder to the assets/plugins/phx folder. Create a new plug-in using the MODx Manager interface: Click on the Manage Resources menu item in the Resources menu Click on the Plugins tab Click on the New Plugin link Fill it with the following details: Field Name Field Value Plugin Name PHx Plugin Code Contents of the file phx.plugin.txt in the extracted folder System Events | OnParseDocument Checked      6.Click on Save. Adding Family and Friends documents Let us create a page that lists all the members from the Family or Friends group. This document will be a container that will have a document for each member that you would like to add. Hence, just as you have learned earlier, a call to the Ditto snippet can get you all the documents that a container holds. Create a page with the following details: Field Name Field Value Title Family and Friends Uses template Learning MODx default template Modify the page created in the previous step to have the following code. (Note that we need to know the ID of the created page for the code and hence, we are modifying it after creating it.) <ul> [!Ditto? &parents=`65` &tpl=`familyandfriendslist`!]</ul> Here, 65 is the ID of the created document. We give the ID of this document here as we will be adding the other documents as child documents of this document. In the above Ditto call, we have indicated that we are using a custom chunk to control the appearance of the listing. Create a chunk with the following details, to show a neat list of the documents that represent a member with the title and a link to the document. Field Name Field Value Chunk name familyandfriendslist Existing Category Learning MODx Chunk Code <li> <h3><a href="[~[+id+]~]">[+title+]</a></h3> </li>  

Public key infrastructure Public Key Infrastructure (PKI) is a framework that enables integration of various services that are related to cryptography. The aim of PKI is to provide confidentiality, integrity, access control, authentication, and most importantly, non-repudiation. Non-repudiation is a concept, or a way, to ensure that the sender or receiver of a message cannot deny either sending or receiving such a message in future. One of the important audit checks for non-repudiation is a time stamp. The time stamp is an audit trail that provides information of the time the message is sent by the sender and the time the message is received by the receiver. Encryption and decryption, digital signature, and key exchange are the three primary functions of a PKI. RSS and elliptic curve algorithms provide all of the three primary functions: encryption and decryption, digital signatures, and key exchanges. Diffie-Hellmen algorithm supports key exchanges, while Digital Signature Standard (DSS) is used in digital signatures. Public Key Encryption is the encryption methodology used in PKI and was initially proposed by Diffie and Hellman in 1976. The algorithm is based on mathematical functions and uses asymmetric cryptography, that is, uses a pair of keys. The image above represents a simple document-signing function. In PKI, every user will have two keys known as "pair of keys". One key is known as a private key and the other is known as a public key. The private key is never revealed and is kept with the owner, and the public key is accessible by every one and is stored in a key repository. A key can be used to encrypt as well as to decrypt a message. Most importantly, a message that is encrypted with a private key can only be decrypted with a corresponding public key. Similarly, a message that is encrypted with a public key can only be decrypted with the corresponding private key. In the example image above, Bob wants to send a confidential document to Alice electronically. Bob has four issues to address before this electronic transmission can occur: Ensuring the contents of the document are encrypted such that the document is kept confidential. Ensuring the document is not altered during transmission. Since Alice does not know Bob, he has to somehow prove that the document is indeed sent by him. Ensuring Alice receives the document and that she cannot deny receiving it in future. PKI supports all the above four requirements with methods such as secure messaging, message digests, digital signatures, and non-repudiation services. Secure messaging To ensure that the document is protected from eavesdropping and not altered during the transmission, Bob will first encrypt the document using Alice's public key. This ensures two things: one, that the document is encrypted, and two, only Alice can open it as the document requires the private key of Alice to open it. To summarize, encryption is accomplished using the public key of the receiver and the receiver decrypts with his or her private key. In this method, Bob could ensure that the document is encrypted and only the intended receiver (Alice) can open it. However, Bob cannot ensure whether the contents are altered (Integrity) during transmission by document encryption alone. Message digest In order to ensure that the document is not altered during transmission, Bob performs a hash function on the document. The hash value is a computational value based on the contents of the document. This hash value is known as the message digest. By performing the same hash function on the decrypted document the message, the digest can be obtained by Alice and she can compare it with the one sent by Bob to ensure that the contents are not altered. This process will ensure the integrity requirement. Digital signature In order to prove that the document is sent by Bob to Alice, Bob needs to use a digital signature. Using a digital signature means applying the sender's private key to the message, or document, or to the message digest. This process is known as as signing. Only by using the sender's public key can the message be decrypted. Bob will encrypt the message digest with his private key to create a digital signature. In the scenario illustrated in the image above, Bob will encrypt the document using Alice's public key and sign it using his digital signature. This ensures that Alice can verify that the document is sent by Bob, by verifying the digital signature (Bob's private key) using Bob's public key. Remember a private key and the corresponding public key are linked, albeit mathematically. Alice can also verify that the document is not altered by validating the message digest, and also can open the encrypted document using her private key. Message authentication is an authenticity verification procedure that facilitates the verification of the integrity of the message as well as the authenticity of the source from which the message is received. Digital certificate By digitally signing the document, Bob has assured that the document is sent by him to Alice. However, he has not yet proved that he is Bob. To prove this, Bob needs to use a digital certificate. A digital certificate is an electronic identity issued to a person, system, or an organization by a competent authority after verifying the credentials of the entity. A digital certificate is a public key that is unique for each entity. A certification authority issues digital certificates. In PKI, digital certificates are used for authenticity verification of an entity. An entity can be an individual, system, or an organization. An organization that is involved in issuing, distributing, and revoking digital certificates is known as a Certification Authority (CA). A CA acts as a notary by verifying an entity's identity. One of the important PKI standards pertaining to digital certificates is X.509. It is a standard published by the International Telecommunication Union (ITU) that specifies the standard format for digital certificates. PKI also provides key exchange functionality that facilitates the secure exchange of public keys such that the authenticity of the parties can be verified. Key management procedures Key management consists of four essential procedures concerning public and private keys. They are as follows: Secure generation of keys—Ensures that private and public keys are generated in a secure manner. Secure storage of keys—Ensures that keys are stored securely. Secure distribution of keys—Ensures that keys are not lost or modified during distribution. Secure destruction of keys—Ensures that keys are destroyed completely once the useful life of the key is over. Type of keys NIST Special Publication 800-57 titled Recommendation for Key Management - Part 1: General specifies the following nineteen types of keys: Private signature key—It is a private key of public key pairs and is used to generate digital signatures. It is also used to provide authentication, integrity, and non-repudiation. Public signature verification key—It is the public key of the asymmetric (public) key pair. It is used to verify the digital signature. Symmetric authentication key—It is used with symmetric key algorithms to provide assurance of the integrity and source of the messages. Private authentication key—It is the private key of the asymmetric (public) key pair. It is used to provide assurance of the integrity of information. Public authentication key—Public key of an asymmetric (public) pair that is used to determine the integrity of information and to authenticate the identity of entities. Symmetric data encryption key—It is used to apply confidentiality protection to information. Symmetric key wrapping key—It is a key-encryptin key that is used to encrypt the other symmetric keys. Symmetric and asymmetric random number generation keys—They are used to generate random numbers. Symmetric master key—It is a master key that is used to derive other symmetric keys. Private key transport key—They are the private keys of asymmetric (public) key pairs, which are used to decrypt keys that have been encrypted with the associated public key. Public key transport key—They are the public keys of asymmetric (public) key pairs that are used to decrypt keys that have been encrypted with the associated public key. Symmetric agreement key—It is used to establish keys such as key wrapping keys and data encryption keys using a symmetric key agreement algorithm. Private static key agreement key—It is a private key of asymmetric (public) key pairs that is used to establish keys such as key wrapping keys and data encryption keys. Public static key agreement key— It is a public key of asymmetric (public) key pairs that is used to establish keys such as key wrapping keys and data encryption keys. Private ephemeral key agreement key—It is a private key of asymmetric (public) key pairs used only once to establish one or more keys such as key wrapping keys and data encryption keys. Public ephemeral key agreement key—It is a public key of asymmetric (public) key pairs that is used in a single key establishment transaction to establish one or more keys. Symmetric authorization key—This key is used to provide privileges to an entity using symmetric cryptographic method. Private authorization key—It is a private key of an asymmetric (public) key pair that is used to provide privileges to an entity. Public authorization key—It is a public key of an asymmetric (public) key pair that is used to verify privileges for an entity that knows the associated private authorization key.   Key management best practices Key Usage refers to using a key for a cryptographic process, and should be limited to using a single key for only one cryptographic process. This is to ensure that the strength of the security provided by the key is not weakened. When a specific key is authorized for use by legitimate entities for a period of time, or the effect of a specific key for a given system is for a specific period, then the time span is known as a cryptoperiod. The purpose of defining a cryptoperiod is to limit a successful cryptanalysis by a malicious entity. Cryptanalysis is the science of analyzing and deciphering code and ciphers. The following assurance requirements are part of the key management process: Integrity protection—Assuring the source and format of the keying material by verification Domain parameter validity—Assuring parameters used by some public key algorithms during the generation of key pairs and digital signatures, and the generation of shared secrets that are subsequently used to derive keying material Public key validity—Assuring that the public key is arithmetically correct Private key possession—Assuring that the possession of the private key is obtained before using the public key Cryptographic algorithm and key size selection are the two important key management parameters that provide adequate protection to the system and the data throughout their expected lifetime. Key states A cryptographic key goes through different states from its generation to destruction. These states are defined as key states. The movement of a cryptographic key from one state to another is known as a key transition. NIST SP800-57 defines the following six key states: Pre-activation state—The key has been generated, but not yet authorized for use Active state—The key may used to cryptographically protect information Deactivated state—The cryptoperiod of the key is expired, but the key is still needed to perform cryptographic operations Destroyed state—The key is destroyed Compromised state—The key is released or determined by an unauthorized entity Destroyed compromised state—The key is destroyed after a compromise or the comprise is found after the key is destroyed

Adding new events to the calendar Good Eatin' Goal: Create an event that will be displayed on the calendar. Additional modules needed: Event (http://drupal.org/project/event). Basic steps In order to add an event, you must first install and activate the Event module in the Module manager as shown in the following screenshot: Activating the Event module will a create a new Event content type. There are also several settings that control how events are displayed and how time zones are handled. To modify the time zone settings, select Site configuration, then Events, and finally Timezone handling, from the Administer menu. Drupal will display a page similar to the following: You will want to customize these settings according to where the majority of your users live, and the types of events that you are holding. For example, if most of your users are in the U.S., 12 hour notation is probably appropriate, but if most of you users are in Europe, 24 hour notation is better. If the events are held online with a mix of users in different time zones, it would make sense to have the events displayed in the user's time zone. However, if the event is being held at a single site, it would make sense to use the local time of the event. For the Good Eatin' site, we will use the site's time zone for events, display the events in the event time zone, and use the 12 hour time notification. Before we can create an event, we must set the default time zone for the site. This is done by selecting Site configuration and then Date and time, from the Administer menu. The Good Eatin' restaurant is located in Colorado, so we will set the time zone to US/Mountain. Click Save configuration to save your changes. To add an event, select Create content and then Event, from the main Navigation menu. Enter a title and a description for the event, as shown in the following screenshot, and then set the start time and optionally the end time for the event. Click Save when you are happy with the event settings. Displaying events Good Eatin' Goal: Display events on the site in various formats including a block of upcoming events, a table of events, and a calendar of events. Additional modules needed: Event (http://drupal.org/project/event). Basic steps The Event module provides several methods for allowing customers to view events. We will explore each of these in turn. The easiest way to allow visitors to browse events is by using the event page, which is accessed by at http://yoursite.com/event. The page appears as follows: If you want the user to be able to access this page without knowing the URL in advance, you can create a menu item for the page. Open the Menu Manager by selecting on Site building and then menus, from the Administer menu. Select the menu that you want to add to the menu item and then click the Add item tab. Enter the information about the new menu item, as shown in the following screenshot, and then click Save when you are satisfied. The second method of presenting events to users is by using the upcoming events block. To add this, open the Blocks Manager by selecting Site building and then Blocks, from the Administer menu. Set the region for the List of upcoming events to Right sidebar. The new block will appear as follows: The final method of displaying calendar entries is a block showing upcoming events in a calendar view. To add this block, open the Block Manager by selecting Site building and then Blocks, from the Administer menu. Set the region for Calendar to browse events to Right sidebar. The display for the calendar will appear as follows: You can decide which of these methods to use for your own site, based on how the user will work with your site. Adding other content types to the event calendar Good Eatin' Goal: Discuss how to add custom content types to the event calendar. Additional modules needed: Event (http://drupal.org/project/event). An easy way of adding additional content types to your existing event calendar is by modifying the content type and then setting the Event calendar options. Open the Content Manager by selecting Content management and thenContent types, from the Administer menu. Edit the type that you want to add to the event calendar. Open the Event calendar section and modify the options, as shown here: If you prefer to have a calendar just for the type, you can use the Only in views for this type option. Save the changes to your content type, and the event calendar will be automatically updated. Creating events using CCK Good Eatin' Goal: Build events using the CCK module and the Date module, rather than the Event module, thereby giving additional control over the events. Additional modules needed: CCK (http://drupal.org/project/cck), Date (http://drupal.org/project/date). Basic steps Depending on your site, it may be more convenient to use CCK and the Date API to build dates. This strategy also gives you additional control over what information is included in the event and in the display. In addition, all required modules should be updated more quickly after each new Drupal release. However, you will need to carry out more initial setup for events and displays if you use this strategy. Install and activate the CCK and Date modules if you have not done so already. Open the Content Type Manager by selecting Content management and then Content types, from the Administer menu. Click Add content type to begin creating your new event type. We will call this type Event CCK to avoid conflicts with the Event module, as shown below: After you are satisfied with the information for the new content type, click Save Content Type to create the new event type. We now need to add fields to store the date and the time of the event. Click on the Add field link to begin the process. We will call the field event_time_cck and make the type a Datetime field so that we can enter both the day on which the event occurs and the time of day at which it starts, as shown in the following screenshot: Click Continue to save the new field. You will now need to select the display widget for the field. Text field with jQuery pop-up calendar is appropriate. Click Continue to complete the field definition. You can optionally modify various settings related to how the field is displayed. You should make the time Required. If you want to define end dates or times for the event, you should modify the To Date to Optional or Required. You can now create CCK-based events using the same techniques that we used to create other content—just select Create content and then Event CCK, from the main Navigation menu. Enter the information for the event, as shown in the following screenshot: When you are satisfied with the event, click Save to add the new event to the site's calendar.   Good Eatin' Goal: Display a calendar that gives more details than a block view on a page. Additional modules needed: Calendar (http://drupal.org/project/calendar), Views(http://drupal.org/project/views), Date API (http://drupal.org/ project/date). Basic steps Now that we can create events using CCK, we need to display them on the site. We will begin by creating a page where visitors can browse all of the upcoming events using a convenient calendar. Begin by installing and activating the Views and Calendar modules if you have not done so already. Note that, some versions of Calendar released prior to June 28, 2008 require you to activate both Calendar and iCal at the same time. If you experience an error when installing the Calendar module, either upgrade to the latest development module or install both modules at the same time. The easiest way to build new views using the calendar is to clone the default calendar view and customize it to meet your needs. Go to the Views Manager by selecting Site building and then Views, from the Administer menu. Drupal will display a list of all of the views that have currently been established on the site. If you scroll the list, you will see the Default Node view: calendar as shown in the following screenshot: Temporarily enable the default view by clicking on the Enable link. After the view has been activated, a new set of links will appear, labeled: Edit, Export, Clone, and Disable. Click on the Clone link to make a copy of the calendar. Drupal will allow you to change the name and description of the view. Change the name to event_calendar and then click next to edit the view. The default settings for the view are shown in the following screenshot. We will edit several settings for our purposes. The first change we need to make is to create a new Filter by clicking on the + symbol next to the Filters label. Select the Node: Type filter, as shown in the following screenshot: In most cases, you should also select the Node: published or admin filter to prevent unauthorized access to private information. Click the Add button and set the allowable types to Event CCK. The next change we will need to make is to modify the fields by selecting Node: Updated date. Click Remove to remove this field from the view. Click the + next to the Fields label to add a new field. Select Content: Event Time for the new field to be added, as shown in the following screenshot: Click Add to save the changes. You will now need to configure the display of the field. In most cases, including this one, the defaults are acceptable. So we will just click Update to continue. You will also need to update the settings for the end time (value 2), as described above. The final change we need to make to the view is in the Arguments. Select the Date:Date link in the Arguments section. Drupal will display a list of parameters that you can use to customize the arguments. We will need to change this to use our Content Event time fields, and then click Update to save the changes. Now that all of the required changes have been made, click Save to finish building the View. We can now return to the list of all views by clicking on the List link, and disable the default calendar view by selecting the Disable link for the default calendar view. Now that our view has been completely set up, we can use it to browse our events. The calendar view, which we used as a starting point, provides several methods of displaying the content as shown below: You may use any of these views, or you can add more views according to your site's needs. If you do not want to use a display type, you can delete it. If you click on the Calendar Page display type and review the Page settings, you will see that a Page is provided, which can be accessed using the path http://yoursite.com/calendar. No menu is provided. You can either add a menu link here, or use the Menu Manager if desired. If you open the calendar page, the display appears as follows: The calendar view also provides several block displays that can be activated and added to your site via the Block Manager. These blocks include a Calendar block that is similar to the display provided by the event block, and a Legend block that can be used to allow visitors to understand the information in the calendar more easily. Summary Congratulations! You have now added calendar and events to your sites. These will provide valuable ways of communicating with your customers to ensure that they keep coming back to your web site and, more importantly, to your business.  

Basic Security and Firewalls An administrator installing a Scalix server in a productive environment must make some considerations before setting up his system: Is the server accessible from the Internet? Is the server accessible to untrusted users? Who must access Scalix? Who must access administration? Who must be prevented from gaining access? Which services must be accessible from where? Though this may sound theoretical, such thoughts always play an important role when you are planning any productive server. In most cases, there are only three different setups for a groupware server: There are only local users in the company's network and the server is located in the company. There are local users and remote users connecting to the Scalix server located in the company. There are both local and remote users connecting to the Scalix server located on the Internet. While the installation leaves a perfectly configured system that is stable, there are several possible precautions that should be taken when your Scalix server is accessible from the Internet — the access should be controlled by a firewall, connections should be encrypted, and users must be forced to use strong authentication mechanisms. As always, there are several ways to achieve this. Before we start, here is a list of services that have to be available for Scalix users accessing the server remotely:- SSH: TCP port 22, the standard remote administration for the admin. SMTP: TCP port 25 — Sending mail. IMAP: TCP port 143 — Retrieving mail with the IMAP protocol. POP: TCP port 110 —  Retrieving mail with the POP protocol. HTTP: TCP port 80: Accessing the Web interface. Scalix UAL uses port 5287 And as of 11.3, secure UAL connects over 5767 Linux Firewall Terminology Basically speaking, a firewall is a piece of software that controls internet connections to and from a server. SUSE's Linux systems come with a built-in firewall named SUSEfirewall that can easily be configured with YaST. On Red Hat Linux systems, there is Bastille and firewall GUIs like Shorewall, which are all good choices for any Linux system. All common Linux firewalls are based on iptables or its predecessor ipchains. Its concept is pretty simple: the administrator defines a chain of rules that are worked through by the operating system one after another for every incoming or outgoing connection or package. So-called targets define what to do with packages matching the rule specified. Targets may be, for example, Accept, Reject, Drop or Log. Furthermore, there are policies that define the default behavior for connections where no rule matches. The Linux program iptables controls these rules. A little glance on this tool may help understanding how a Linux firewall works. iptables—the Standard Linux Firewall Tool iptables (http://www.netfilter.org) is a simple command-line tool that controls the kernels' IP tables. In these tables, rules that define how network packets are treated on this system can be stored. As always, the simple commands offer the best solutions when they are combined with an abundance of options. There is a vast amount of options and extensions for iptables, so this short description is far from perfect and far from complete. The iptables syntax is very simple: iptables <rule command> <chain> <matching extensions><target> A typical rule command is A, which means Add the following rule. Since iptables use different chains (by default, INPUT, FORWARD, OUTPUT), we must declare a chain where this rule is to be added to. The following table shows three examples: Iptables Command Function: iptables -A INPUT <rule> Adds a rule to the INPUT chain, which affects all incoming packets heading for the firewall itself. iptables -A OUTPUT <rule> Adds a rule to the FORWARD chain, which affects all packets that are supposed to be forwarded by the firewall. iptables -A FORWARD <rule> Adds a rule to the OUTPUT chain, which affects all outgoing packets originating from the firewall. Another typical command is -P that sets the default policy for a chain. This should always be set to DROP, because then all packets arriving in this chain are dropped if not specified explicitly by another rule. This is the only way to make sure that only the traffic allowed by us is handled and any unspecified traffic is dropped. A typical example for this is: scalixbook:~ # iptables -P FORWARD DROPscalixbook:~ # This would prevent your system from forwarding any traffic, unless specified otherwise, later on. Then there are iptables' targets. A target can be either DROP, REJECT or ACCEPT (among others) and is invoked by the switch — j. Furthermore, so-called "matching extensions" are like a filter specifying exactly which packet is meant. Thus a rule like iptables -A INPUT <matching extension> -j DROP  means: Drop every packet that is headed for my firewall and matches the <matching extension>. Matching Extension Meaning -i <interface> The incoming interface of the datagram -o <interface> The outgoing interface of the datagram -p <protocol> The IP protocol of the datagram --dport <destination port> The destination port of the datagram --sport <source port> The source port of the datagram -s <source IP> The source IP of the sender -d <destination IP> The destination IP of the recipient There are many other matching extensions, but these here should be sufficient to understand the basics of iptables. Have a look at these lines: #!/bin/bashiptables -P INPUT DROPiptables -P OUTPUT DROPiptables -P FORWARD DROPiptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPTiptables -A INPUT -i eth0 -p tcp --dport 25 -j ACCEPTiptables -A INPUT -i eth0 -p tcp --dport 143 -j ACCEPTiptables -A OUTPUT -o eth0 -p tcp --sport 22 -j ACCEPTiptables -A OUTPUT -o eth0 -p tcp --dport 25 -j ACCEPTiptables -A OUTPUT -o eth0 -p tcp --dport 143 -j ACCEPT(...) Do you already understand them? If you do, congratulations; if not, don't worry, it's easy. These lines represent a shell script that can be used to start a very simple firewall example. iptables is a command-line tool and therefore is simply called from a script with parameters like the following: Command Meaning iptables -P INPUT DROP Drop all incoming packets that are not specified by any other rule iptables -P OUTPUT DROP Drop all outgoing packets that are not specified by any other rule iptables -P FORWARD DROP Do not forward any packets that are not specified by any other rule iptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPT Accept TCP connections for port 22 (SSH) coming in on network interface eth0 iptables -A INPUT -i eth0 -p tcp --dport 25 -j ACCEPT Accept TCP connections for port 25 (SMTP) coming in on network interface eth0 iptables -A INPUT -i eth0 -p tcp --dport 143 -j ACCEPT Accept TCP connections for port 143 (IMAP) coming in on network interface eth0 iptables -A OUTPUT -o eth0 -p tcp --sport 22 -j ACCEPT Accept outgoing TCP connections for port 22 going out on network interface eth0 iptables -A OUTPUT -o eth0 -p tcp --dport 25 -j ACCEPT Accept outgoing TCP connections for port 25 going out on network interface eth0 iptables -A OUTPUT -o eth0 -p tcp --dport 143 -j ACCEPT Accept outgoing TCP connections for port 143 going out on network interface eth0

Sidebar gadget A sidebar gadget is a simple single-tasked tool that sits in the sidebar on Windows Vista. If you don't have Windows Vista, you're out of luck and won't be able to run this sample. You can explore the free gadgets available for download at http://gallery.live.com/. Typical gadgets include: RSS Feed Readers News Readers Weather Reports Clocks Performance Monitoring Tools Mini Notepads Photo Slideshows Hopefully you get the idea. We're going to create a sidebar gadget that will use the Web service capabilities of Dynamics NAV 2009 to display a cue (a stack of documents similar to those shown in the RoleTailored client), based upon the document approvals features that have been available since NAV 5.0. We want to display a document stack that represents the number of documents requiring approval from the current user and will allow the user to select the type of document as a configuration setting. In our example, clicking the document stack will show a list of documents and clicking an individual document will launch the RoleTailored client. There's no reason why you can't take this example and extend it to include the ability to display the actual documents and carry out the approval, all from the comfort of your Windows Vista desktop. Design time When we start to de sign NAV solutions, we use our knowledge of the standard application to create a solution that fits nicely within the NAV paradigm. We try to emulate the way the standard application solves common business problems and use the components that are used by the product team in a consistent manner. Designing applications for .NET, or in this case for a sidebar gadget, follows the same conventions. First of all we need to understand a little bit about what makes a sidebar gadget so that we can know the constraints of our design. What are little gadgets made of? There is an excellent tutorial on MSDN Magazine's web site by Donavon West that tells you how to build a sidebar gadget for displaying MSDN Magazine articles in a news-ticker format with the ability to click an article to see more details and click another link to read the full article on the Web. We're going to use that article and the gadget provided for download as the basis for exploring what a gadget is, which will in turn help us to design our own gadget. You can read Donavon West's MSDN Magazine article at: http://msdn.microsoft.com/en-nz/magazine/cc163370(en-us).aspx You can download the Gadget from: http://gallery.live.com/liveItemDetail.aspx?li=b21af41e-b846-46d9-a873-ac12a3c65ab3 Essentially a gadget is little more than a mini web page (HTML file with some supporting resources such as images and JavaScript) and an XML definition file called gadget.xml. When we're writing a sidebar gadget for Windows Vista, the HTML page is rendered in Microsoft Internet Explorer 7, so there is no need to worry about cross-browser support. Which is nice. If you download the gadget and save it somewhere instead of installing it, you will see an icon for the gadget like this: Before we can use this gadget there is a little problem that needs to be fixed—unfortunately it is pointing to an RSS Feed URL that is not valid and therefore the gadget doesn't work correctly. Donavon explains that a sidebar gadget is simply a collection of files that are stored in a ZIP or CAB file with a .gadget extension, so we can rename the file with a .zip extension and we should be able to open it as a folder. If you open the compressed folder, or extract it, you will see the following files: There is a file called local.js that we will need to edit in order to fix the problem. Gadgets support multi-language capabilities and if your language matches the folder names shown, you are going to need to open that folder and edit the local.js thatit contains. The languages supported by this gadget are as follows:   Folder Name Language de German (Standard) es Spanish (Spain) fr French (Standard) it Italian (Standard) ja Japanese kr I don't think this is a valid language code, so we'll just ignore this. pt Portuguese (Portugal) ru Russian zh-CN Chinese (PRC) zh-TW Chinese (Taiwan) You can get a full list of language codes at http://msdn.microsoft.com/en-us/library/ms533052(VS.85).aspx According to the tutorial, whenever the sidebar tries to load a file, it searches for the file in folders in the following order: Full locale (en-us, es-us, ja-jp) Language portion of the locale (en, es, ja) Gadget root folder So what does this mean? If your locale has a language component that is one of the folders listed in the table, you are going to need to edit the local.js within that folder in order for the gadget to work correctly. When you edit the local.js file (any text editor will do), you will see the following: If you copy the feedUrl string and paste it into a web browser address bar, you will see a runtime error telling you this is not a valid address. A little bit of digging soon reveals an address that we can use for the gadget: http://msdn.microsoft.com/en-nz/magazine/rss/default(en-us).aspx?issue=1 You need to replace the old URL with the new one so that your line in the fi le looks like the following: LOCAL.feedUrl = 'http://msdn.microsoft.com/en-nz/magazine/rss/ default(en-us).aspx?issue=1'; Now we can rename the file back to a .gadget extension and install it. This is to help us examine the main components of a sidebar gadget so we can consider how we will design our own gadget. The gadget The most obvious part of a gadget is the gadget itself. This is the gadget's main HTML page that is provided in the base src property of our gadget.xml file. For us, we want this to show a single document cue that represents the number of approval entries that are awaiting action for the current user. We want the main docked gadget to look something like this: The image is meant to look like a cue from an Activities Part in a Role Center. The pencil sketch is there to give you an idea. Since the 22 approval actions could be for multiple different document types, we will have some text underneath the stack of documents that tells us how many of each of the different document types there are. It could either fade in and out, or scroll horizontal like a marquee. That takes care of the docked state of the gadget. When we undock it, we can get a larger area to play with, so it would be nice if the undocked state showed one stack of documents for each of the approval document types with the name of the document type shown underneath. This may be a little time-consuming, so maybe we'll add that to version 2. For now the undocked image will be the same as the docked image. There are a couple of other pages that need to be considered: Flyouts and Options dialog. Flyouts When you click on a part of gadget, you can activate a flyout, which is basically a web page that gets displayed at the side of the gadget. The flyout file is specified by setting System.Gadget.Flyout.file to the name of the flyout HTML file. In the case of our MSDN Ticker gadget, the flyout looks like the following: For our flyout, we are going to show a list of approval entries with the ability to click a hyperlink to open the approval entries screen. An obvious next extension to this gadget is to provide the ability to approve, reject, or delegate the approval entry directly from the gadget without needing to open the RoleTailored client. For now, we'll concentrate on making this work with our NAV Web service. After taking a quick look at the fields available on the approval entry screen, our flyout will look something like the following: It's a simple table showing the documents with a document type and number, the ID of the sender and the amount that the document is for. Options There is one more part of the gadget to consider for our design and that is the options dialog page. Let's take a look at that for the MSDN Magazine Ticker sample gadget. When I hover my mouse over the gadget, a mini tool bar appears allowing me to close the gadget, show the options, and drag the gadget to a different position. Click the spanner to show the options page. As you can see it's just another little web page with some options on it. You need to instruct the gadget to enable the options icon by setting System.Gadget.settingsUI to the name of the options HTML file, generally in the gadget initialization area of our script. Donavon's article explains how this is done, and provides sample code for how to set up a callback function for when the options dialog closes (so your gadget can read the new user preferences). For our gadget we are going to need a place where we can enter the URL for our Web service. For more advanced options, we could possibly provide the ability to specify how often the gadget will call the Web service. Our options page will look something like this: These pencil sketches are just there to convey the intended layout of the pages; it's a lot quicker to scribble something on a piece of paper (for us) than to start playing around with graphics programs and although they're a little rough, if you squint at them, you can sort of work out what's intended in the final solution. Remember it's important to get an understanding of the design at this stage but it doesn't need to look great; form follows function. The tricky bits Now that we' ve done the high-level design for our sidebar gadget, and we know that a sidebar gadget is just a series of HTML pages, we can start to look at the technical design. There are a couple of tricky bits to take care of: how are we going to call our Web service from within what is essentially a web page, and how are we going to take our list of documents requiring approval and convert them into the table and graphics we want to display. The great thing about sidebar gadgets and the way they are constructed is that you can simply rename the file and take a look at how they are doing what they do (and, of course, you can borrow ideas and code). If you search on the Web, you'll find quite a few examples of sidebar gadgets that call Web services, so there're plenty of examples to look at. Let's pick an example from Microsoft that uses the Exchange 2007 Web service to display email, calendar, and task information. You can download it from: http://www.microsoft.com/downloads/details.aspx?FamilyID=F9A0D33CC894-4EA1-AD20-4E418C715175&displaylang=en A quick search for Exchange Web services Gadget will help you locate it. Actually finding this gadget was a stroke of luck because it does pretty much everything we are after: It has a setup page with a time interval on it. It calls a Web service to find how many items there are in a folder and shows a summary. It displays a flyout with a more detailed view of the folder contents. Finding good examples on the Internet and learning from them is a key skill for doing this kind of development. Just a little bit of SOAP Calling a NAV Web service from within a Visual Studio.NET project is dead easy as we've already seen. We just add our Web service as a web reference and Visual Studio does all the hard work for us. It creates a proxy class that allows us to call the member functions and access the properties of the service as though it was a piece of code that we had written ourselves and not just some black box at the end of a URL. But how do we do this when we don't have Visual Studio? Essentially a Web service is just some text sent over the Internet that generates a response (which is also text). It just so happens that the text being sent and received is formatted as XML which is handy because there is lots of support for reading XML text. Web services typically use a protocol called Simple Object Access Protocol (or SOAP) to allow any system that can post a request to a URL (and read a response message) to call to a function exposed by the Web service. In order to do this for our sidebar gadget, we need two things: we need to know how to send and receive our request, and we need to know what the SOAP request should look like. Figuring out the HTTP call and response handling isn't too hard and you can do this by looking at the Exchange Web service gadget source code or, once again, searching the Internet. Looking at how Microsoft did it in their Exchange Web service gadget shows us we can use the native Microsoft.XMLHTTP object provided by Internet Explorer (remember that a sidebar gadget runs in Internet Explorer only, so we don't need to worry about cross-browser support) to make an HTTP post to our Web service and read the response. Finding the XML for the SOAP request that is needed to invoke a NAV Web service is going to be a little trickier. If we do a Web search for 'how to view a soap request in Visual Studio?', it doesn't take much to find a link to a freeware product called Fiddler that will allow me to inspect messages to and from my web server. Here is the URL: http://www.fiddler2.com/fiddler2/ If we use this tool on the simple example we started the chapter with, we can see the SOAP request is: And the response is: We can guess we could have worked out this request and response format by reading the WSDL (pronounced 'wiz-dal'), that we get when we type the URL to the Codeunit in our web browser; however, we can think that using Visual Studio to test calling our Web service is by far the easiest way, and using the Fiddler tool to be able to inspect and copy the SOAP Envelope XML has got to be better than thinking. Now before we get too carried away trying to create a series of Web service calls to allow us to pull data from a page type Web service, we're going to create a simple proof-of-concept web page that will make a JavaScript call to this NAV Web service with our ConvertStrToUpperCase function. An HTML page that calls a NAV Codeunit This next script is 72 lines of text. The point of the exercise is to show how easy it is to do things in the .NET world even when you don't know what you're doing. Here is the code in full; we'll go through it in detail later: <HTML> <HEAD> <TITLE>Hello NAV 2009 With JavaScript</TITLE> </HEAD> <BODY> <b>Input: </b>hello nav2009!<br/> <div id="resultContainer"><b>Output: </b></div> <FORM Name="Form1" ACTION=""> <INPUT TYPE=BUTTON VALUE="Call NAV" NAME="BtnHello" OnClick="Hello NAV2009()"> </FORM> <SCRIPT LANGUAGE="JavaScript"> <!-- function HelloNAV2009 () { var data = ""; data += '<?xml version="1.0" encoding="utf-8"?>'; data += '<soap:Envelope '; data += ' '; data += ' >'; data += ' <soap:Body>'; data += ' <ConvertStrToUpperCase '; data += ' >'; data += ' <p_Str>hello nav2009!</p_Str>'; data += ' </ConvertStrToUpperCase>'; data += ' </soap:Body>'; data += '</soap:Envelope>'; var xmlHttpRequest = new ActiveXObject("Microsoft.XMLHTTP"); var url = 'http://ds-srv-01:7047/DynamicsNAV/ws/CRONUS_ International_Ltd/Codeunit/NAV_Codeunit'; xmlHttpRequest.open("POST", url, false); xmlHttpRequest.SetRequestHeader("Content-Type", "text/xml"); xmlHttpRequest.SetRequestHeader("SOAPAction", "urn:microsoftdynamics- schemas/codeunit/NAV_Codeunit:ConvertStrToUpperCase"); xmlHttpRequest.onreadystatechange = readResponse; xmlHttpRequest.send(data); function readResponse() { if (xmlHttpRequest.readyState == 4) { var xmlDoc = new ActiveXObject("Microsoft.XMLDOM"); xmlDoc.loadXML(xmlHttpRequest.responseText); resultText = xmlDoc.getElementsByTagName("return_value")[0]. childNodes[0].nodeValue; xmlDoc = null; resultContainerElement = document.getElementById("resultContaine r"); if (resultContainerElement != null) { resultContainerElement.innerHTML = "<b>Output: </b>" + resultText; } xmlHttpRequest = null; } } } //--> </SCRIPT> </BODY> </HTML> You can download the HelloNAV2009.html file from www.teachmenav.com (or http://www.packtpub.com/support). You may need to edit the file on the line where the url variable is assigned to point to the Web service URL available on your computer. When you open the file in your browser, you will need to allow the blocked content in order for the example to run. When you click the Call NAV button, the screen updates to show the following: Wooohooo! It works! OK, let's take a look at what's going on in the code. First of all we assign our variable called data to the XML for the SOAP request body (this is found by using the Fiddler application earlier). That block of code is not included for analysis, so let's move on. This next block of code creates an instance of the Microsoft.XMLHTTP object that we are going to use to make the HTTP post and read the response. var xmlHttpRequest = new ActiveXObject("Microsoft.XMLHTTP"); var url = 'http://ds-srv-01:7047/DynamicsNAV/ws/CRONUS_International_ Ltd/Codeunit/NAV_Codeunit'; xmlHttpRequest.open("POST", url, false); xmlHttpRequest.SetRequestHeader("Content-Type", "text/xml"); xmlHttpRequest.SetRequestHeader("SOAPAction", "urn:microsoft-dynamicsschemas/Codeunit/NAV_Codeunit:ConvertStrToUpperCase"); The highlighted text in the code caused a good deal of grief. Without the SOAPAction request header, the response always contained the WSDL definition of the Web service (the XML document that is shown when you type the Web service URL into the address bar on your browser). Once again this was the missing bit if we look at the results of the Fiddler application trace of .NET application we wrote at the start of this chapter. The following code will hookup the readResponse function to the xmlHttpRequest so that the response can be read when the call is finished. I borrowed this code from the Exchange Web service gadget (although I had to wade up to my armpits in functions in order to find the code that actually did the business). xmlHttpRequest.onreadystatechange = readResponse; xmlHttpRequest.send(data); function readResponse() { if (xmlHttpRequest.readyState == 4) { var xmlDoc = new ActiveXObject("Microsoft.XMLDOM"); xmlDoc.loadXML(xmlHttpRequest.responseText); This next bit of code assigns the resultText variable to the contents of the SOAP response and it took a while to figure out. This example has been taken from the W3 schools site by searching for Microsoft.XMLDOM (http://www.w3schools.com/Xml/xml_dom.asp). resultText = xmlDoc.getElementsByTagName("return_value") [0].childNodes[0].nodeValue; The code is reading the text result from the SOAP envelope. A real example will have to do a lot more with this XML document but for now, this does the job. Finally, we dispose of some objects and then inject the result text in to the body of our HTML page using the innerHTML property for our resultContainer div class. xmlDoc = null; resultContainerElement = document.getElementById("resultContainer"); if (resultContainerElement != null) { resultContainerElement.innerHTML = "<b>Output: </b>" + resultText; } xmlHttpRequest = null; I now know that we've broken the back of the problem. We have successfully called a NAV Web service from a web page (which is essentially all a sidebar gadget is). The next tricky bit is to see how to use a page Web service to get the records back that match our documents requiring approval. We'll use the same approach of first writing the code in .NET as a console application and then after we have this working the easy way, we'll convert the code into JavaScript. After that, it's just a case of tidying everything up and making it look pretty. Hey, Good Lookin' If there's one thing you need for a sidebar gadget, it's nice graphics. Vista is a beautiful operating system and, to be honest, if a gadget doesn't look good, we don't want it on our desktop. The idea is to use a single image and position the images on top of each other and create the image by taking a document and flipping it and applying perspective. Here are the document stacks. The images were created using Photoshop (and a lot of professional skill), and the original image that the stack is built from actually has the Microsoft Dynamics NAV logo at the top (how's that for attention to detail?) Here's the image of the document: HTML is used to render these documents as a stack with the number floating over the top, and the HTML to produce the previous image can be found on the www.teachmenav.com site under the Simple Document Stack sample for this article. We would generate the HTML dynamically based upon the number of documents requiring approval. The HTML used to generate the previous image is manipulated to give 12 document stacks that will be used by the application. The largest stack is 10 images high but this would be used to represent 31 or more documents. The question mark on the final empty stack shown in the following image will be used when the gadget gets no response from the Web service or has not been properly configured. Now we have nearly everything we need to be able to put together the sidebar gadget. There's just one piece of the puzzle missing; we need to be able to call a Web service to tell us how many documents we have for approval and also return the details of those documents, the rest is just applying more of what we know and writing a lot of code. We've covered calling a page Web service in an earlier example, so I won't go into details here but we do need to know what we are calling. As you know Web services from NAV can be based on either Codeunits or Pages, so which should we use? The temptation may be to use a Page Web service as this will allow us to bring back the Approval Entry records for the current user, but we need to do far more than read the records. Our first interaction will be to get a count of the records for approval so we can display the gadget; we don't want the gadget to have a lot of work to do in order to draw its initial state, so ideally we want a quick call that will return just the number of documents and maybe the document name. If you remember from the beginning, our gadgets are meant to be simple, single-tasked applications, so we want a single document approval gadget to work for any one document type. This way our users can have multiple gadgets on their desktop if they want to be notified on multiple document types. We can achieve this by using a Codeunit type Web service and have one of the parameters an identifier of the type of document we are interested in. The following is an overview of the functions we will need.

The main focus of the Spring Web Flow Framework is to deliver the infrastructure to describe the page flow of a web application. The flow itself is a very important element of a web application, because it describes its structure, particularly the structure of the implemented business use cases. But besides the flow which is only in the background, the user of your application is interested in the Graphical User Interface (GUI). Therefore, we need a solution of how to provide a rich user interface to the users. One framework which offers components is JavaServer Faces (JSF). With the release of Spring Web Flow 2, an integration module to connect these two technologies, called Spring Faces has been introduced. This article is no introduction to the JavaServer Faces technology. It is only a description about the integration of Spring Web Flow 2 with JSF. If you have never previously worked with JSF, please refer to the JSF reference to gain knowledge about the essential concepts of JavaServer Faces. JavaServer Faces (JSF)—a brief introductionThe JavaServer Faces (JSF) technology is a web application framework with the goal to make the development of user interfaces for a web application (based on Java EE) easier. JSF uses a component-based approach with an own lifecycle model, instead of a request-driven approach used by traditional MVC web frameworks. The version 1.0 of JSF is specified inside JSR (Java Specification Request) 127 (http://jcp.org/en/jsr/detail?id=127). To use the Spring Faces module, you have to add some configuration to your application. The diagram below depicts the single configuration blocks. These blocks are described in this article. The first step in the configuration is to configure the JSF framework itself. That is done in the deployment descriptor of the web application—web.xml. The servlet has to be loaded at the startup of the application. This is done with the <load-on-startup>1</load-on-startup> element. <!-- Initialization of the JSF implementation. The Servlet is not used at runtime --> <servlet> <servlet-name>Faces Servlet</servlet-name> <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.faces</url-pattern> </servlet-mapping> For the work with the JavaServer Faces, there are two important classes. These are the javax.faces.webapp.FacesServlet and the javax.faces.context.FacesContext classes.You can think of FacesServlet as the core base of each JSF application. Sometimes that servlet is called an infrastructure servlet. It is important to mention that each JSF application in one web container has its own instance of the FacesServlet class. This means that an infrastructure servlet cannot be shared between many web applications on the same JEE web container.FacesContext is the data container which encapsulates all information that is necessary around the current request.For the usage of Spring Faces, it is important to know that FacesServlet is only used to instantiate the framework. A further usage inside Spring Faces is not done. To be able to use the components from Spring Faces library, it's required to use Facelets instead of JSP. Therefore, we have to configure that mechanism. If you are interested in reading more about the Facelets technology, visit the Facelets homepage from java.net with the following URL: https://facelets.dev.java.net. A good introduction inside the Facelets technology is the http://www.ibm.com/developerworks/java/library/j-facelets/ article, too. The configuration process is done inside the deployment descriptor of your web application—web.xml. The following sample shows the configuration inside the mentioned file. <context-param> <param-name>javax.faces.DEFAULT_SUFFIX</param-name> <param-value>.xhtml</param-value></context-param> As you can see in the above code, the configuration parameter is done with a context parameter. The name of the parameter is javax.faces.DEFAULT_SUFFIX. The value for that context parameter is .xhtml. Inside the Facelets technology To present the separate views inside a JSF context, you need a specific view handler technology. One of those technologies is the well-known JavaServer Pages (JSP) technology. Facelets are an alternative for the JSP inside the JSF context. Instead, to define the views in JSP syntax, you will use XML. The pages are created using XHTML. The Facelets technology offers the following features: A template mechanism, similar to the mechanism which is known from the Tiles framework The composition of components based on other components Custom logic tags Expression functions With the Facelets technology, it's possible to use HTML for your pages. Therefore, it's easy to create the pages and view them directly in a browser, because you don't need an application server between the processes of designing a page The possibility to create libraries of your components The following sample shows a sample XHTML page which uses the component aliasing mechanism of the Facelets technology. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html > <body> <form jsfc="h:form"> <span jsfc="h:outputText" value="Welcome to our page: #{user.name}" disabled="#{empty user}" /> <input type="text" jsfc="h:inputText" value="#{bean.theProperty}" /> <input type="submit" jsfc="h:commandButton" value="OK" action="#{bean.doIt}" /> </form> </body></html> The sample code snippet above uses the mentioned expression language (for example, the #{user.name} expression accesses the name property from the user instance) of the JSF technology to access the data. What is component aliasingOne of the mentioned features of the Facelets technology is that it is possible to view a page directly in a browser without that the page is running inside a JEE container environment. This is possible through the component aliasing feature. With this feature, you can use normal HTML elements, for example an input element. Additionally, you can refer to the component which is used behind the scenes with the jsfc attribute. An example for that is <input type="text" jsfc="h:inputText" value="#{bean.theProperty}" /> . If you open this inside a browser, the normal input element is used. If you use it inside your application, the h:inputText element of the component library is used     The ResourceServlet One main part of the JSF framework are the components for the GUI. These components often consist of many files besides the class files. If you use many of these components, the problem of handling these files arises. To solve this problem, the files such as JavaScript and CSS (Cascading Style Sheets) can be delivered inside the JAR archive of the component. If you deliver the file inside the JAR file, you can organize the components in one file and therefore it is easier for the deployment and maintenance of your component library. Regardless of the framework you use, the result is HTML. The resources inside the HTML pages are required as URLs. For that, we need a way to access these resources inside the archive with the HTTP protocol. To solve that problem, there is a servlet with the name ResourceServlet (package org.springframework.js.resource). The servlet can deliver the following resources: Resources which are available inside the web application (for example, CSS files) Resources inside a JAR archive The configuration of the servlet inside web.xml is shown below: <servlet> <servlet-name>Resource Servlet</servlet-name> <servlet-class>org.springframework.js.resource.ResourceServlet</servlet-class> <load-on-startup>0</load-on-startup></servlet> <servlet-mapping> <servlet-name>Resource Servlet</servlet-name> <url-pattern>/resources/*</url-pattern></servlet-mapping> It is important that you use the correct url-pattern inside servlet-mapping. As you can see in the sample above, you have to use /resources/*. If a component does not work (from the Spring Faces components), first check if you have the correct mapping for the servlet. All resources in the context of Spring Faces should be retrieved through this Servlet. The base URL is /resources. Internals of the ResourceServlet ResourceServlet can only be accessed via a GET request. The ResourceServlet servlet implements only the GET method. Therefore, it's not possible to serve POST requests. Before we describe the separate steps, we want to show you the complete process, illustrated in the diagram below: For a better understanding, we choose an example for the explanation of the mechanism which is shown in the previous diagram. Let us assume that we have registered the ResourcesServlet as mentioned before and we request a resource by the following sample URL: http://localhost:8080/ flowtrac-web-jsf/resources/css/test1.css. How to request more than one resource with one requestFirst, you can specify the appended parameter. The value of the parameter is the path to the resource you want to retrieve. An example for that is the following URL: http://localhost:8080/ flowtracweb-jsf/resources/css/test1.css?appended=/css/test2.css. If you want to specify more than one resource, you can use the delimiter comma inside the value for the appended parameter. A simple example for that mechanism is the following URL: http://localhost:8080/ flowtrac-web-jsf/resources/css/test1.css?appended=/css/test2.css, http://localhost:8080/flowtrac-web-jsf/resources/css/test1.css?appended=/css/test3.css. Additionally, it is possible to use the comma delimiter inside the PathInfo. For example: http://localhost:8080/flowtrac-web-jsf/resources/css/test1.css,/css/test2.css. It is important to mention that if one resource of the requested resources is not available, none of the requested resources is delivered. This mechanism can be used to deliver more than one CSS in one request. From the view of development, it can make sense to modularize your CSS files to get more maintainable CSS files. With that concept, the client gets one CSS, instead of many CSS files. From the view of performance optimization, it is better to have as few requests for rendering a page as possible. Therefore, it makes sense to combine the CSS files of a page. Internally, the files are written in the same sequence as they are requested. To understand how a resource is addressed, we separate the sample URL into the specific parts. The example URL is a URL on a local servlet container which has an HTTP connector at port 8080. See the following diagram for the mentioned separation: The table below describes the five sections of the URL that are shown in the previous diagram:

Transport layer The transport layer in the TCP/IP model does two things: it packages the data given out by applications to a format that is suitable for transport over the network, and it unpacks the data received from the network to a format suitable for applications. The process of packaging the data packets received from the applications is known as encapsulation. The output of such a process is known as datagram. Similarly, the process of unpacking the datagram received from the network is known as abstraction A transport section in a protocol stack carries the information that is in the form of datagrams, Frames and Bits. Transport layer protocols There are many transport layer protocols that carry the transport layer functions. The most important ones are: Transmission Control Protocol (TCP): It is a core Internet protocol that provides reliable delivery mechanisms over the Internet. TCP is a connection-oriented protocol. User Datagram Protocol (UDP): This protocol is similar to TCP, but is connectionless. A connection-oriented protocol is a protocol that guarantees delivery of datagram (packets) to the destination application by way of a suitable mechanism. For example, a three-way handshake syn, syn-ack, ack in TCP. The reliability of datagram delivery of such protocol is high. A protocol that does not guarantee the delivery of datagram, or packets, to the destination is known as connectionless protocol. These protocols use only one-way communication. The speed of the datagram's delivery by such protocols is high. Other transport layer protocols are as follows: Sequenced Packet eXchange (SPX): SPX is a part of the IPX/SPX protocol suit and used in Novell NetWare operating system. While Internetwork Packet eXchange (IPX) is a network layer protocol, SPX is a transport layer protocol. Stream Control Transmission Protocol (SCTP): It is a connection-oriented protocol similar to TCP, but provides facilities such as multi-streaming and multi-homing for better performance and redundancy. It is used in Unix-like operating systems. Appletalk Transaction Protocol (ATP): It is a proprietary protocol developed for Apple Macintosh computers. Datagram Congestion Control Protocol (DCCP): As the name implies, it is a transport layer protocol used for congestion control. Applications include Internet telephony and video or audio streaming over the network. Fiber Channel Protocol (FCP): This protocol is used in high-speed networking such as Gigabit networking. One of its prominent applications is Storage Area Network (SAN). SAN is network architecture that's used for attaching remote storage devices such as tape drives, disk arrays, and so on to the local server. This facilitates the use of storage devices as if they were local devices. In the following sections we'll review the most important protocols—TCP and UDP. Transmission Control Protocol (TCP) TCP is a connection-oriented protocol that is widely used in Internet communications. As the name implies, a protocol has two primary functions. The primary function of TCP is the transmission of datagram between applications, while the secondary function is related to controls that are necessary for ensuring reliable transmissions. Protocol / Service Transmission Control Protocol (TCP) Layer(s) TCP works in the transport layer of the TCP/IP model Applications Applications where the delivery needs to be assured such as email, World Wide Web (WWW), file transfer, and so on use TCP for transmission Threats Service disruption Vulnerabilities Half-open connections Attacks Denial-of- service attacks such as TCP SYN attacks Connection hijacking such as IP Spoofing attacks Countermeasures Syn cookies Cryptographic solutions   A half-open connection is a vulnerability in TCP implementation. TCP uses a three-way handshake to establish or terminate connections. Refer to the following illustration: In a three-way handshake, first the client (workstation) sends a request to the server (www.some_website.com). This is known as an SYN request. The server acknowledges the request by sending SYN-ACK and, in the process, creates a buffer for that connection. The client does a final acknowledgement by sending ACK. TCP requires this setup because the protocol needs to ensure the reliability of packet delivery. If the client does not send the final ACK, then the connection is known as half-open. Since the server has created a buffer for that connection, certain amounts of memory or server resources are consumed. If thousands of such half-open connections are created maliciously, the server resources may be completely consumed resulting in a denial-of-service to legitimate requests. TCP SYN attacks are technically establishing thousands of half-open connections to consume the server resources. Two actions can be taken by an attacker. The attacker, or malicious software, will send thousands of SYN to the server and withhold the ACK. This is known as SYN flooding. Depending on the capacity of the network bandwidth and the server resources, in a span of time the entire resources will be consumed. This will result in a denial-of-service. If the source IP were blocked by some means, then the attacker, or the malicious software, would try to spoof the source IP addresses to continue the attack. This is known as SYN spoofing. SYN attacks, such as SYN flooding and SYN spoofing, can be controlled using SYN cookies with cryptographic hash functions. In this method, the server does not create the connection at the SYN-ACK stage. The server creates a cookie with the computed hash of the source IP address, source port, destination IP, destination port, and some random values based on an algorithm, which it sends as SYN-ACK. When the server receives an ACK, it checks the details and creates the connection. A cookie is a piece of information, usually in a form of text file, sent by the server to client. Cookies are generally stored on a client's computer and are used for purposes such as authentication, session tracking, and management. User Datagram Protocol (UDP) UDP is a connectionless protocol similar to TCP. However, UDP does not provide delivery guarantee of data packets.