How-To Tutorials

Several methods were introduced to reduce the usage of IP addresses in the internet including: Classless Interdomain Routing (CIDR): This introduced the death of classful addressing (for example Class A, B, C) by a new subnetting method which is not limited, unlike the classful method. Network Address Translation (NAT): Using NAT you do not need to use public IP addresses on your internal hosts. Using CIDR subnets and NAT only helped IPv4 to live a few years longer, but was not the ultimate cure to the problem. Besides the addressing issues, there were other problems with IPv4 which could not be easily solved. These issues include the following: The size of internet routing tables was growing rapidly and this forced backbone providers to upgrade their networking gears. The IPv4 was very inefficient for high throughput links and did not support QoS by nature. Back in the early 90s, IETF had started a workgroup to solve the deficiencies of the IP protocol. In 1995, the IETF published the initial drafts of IPv6 as the next generation IP. Since then, the protocol has matured enormously and been implemented in many operating systems. IPv6 Facts If you are not familiar with IPv6, here is a very quick look at the difference between IPv4 and IPv6. (For a more detailed insight into IPv6 and its configuration in various operating systems, it is recommended that you read Running IPv6 book by Iljitsch van Beijnum). Fact One—Addressing Addressing in IPv6 is quite different from legacy IPv4 addresses. IPv6 uses 128-bit address space unlike the 32-bit addressing system in IPv4. A typical IPv6 address would look like—2002:a00:1:5353:20a:95ff:fef5:246e Fact Two—Address Types There are 4 types of addresses in IPv6: Unicast: A typical IPv6 address you use on a host. Multicast: Addresses that start with ff:: are equivalent to IPv4 multicast. Anycast: A typical IPv6 address that is used on a router. Reserved: Includes loopback, link-local, site-local, and so on. Fact Three—ARP There is no ARP! MAC to IP mapping is no longer needed as MAC addresses are embedded into IPv6 addresses. Instead, ND is born. ND is used to auto-configure addresses on hosts, duplicated detection, and so on. Fact Four—Interface Configuration If you are new to IPv6, you will be shocked to see an IPv6 address, telling yourself that you are in trouble assigning addresses to interfaces or remembering the addresses. However, it is not all that hard. In most cases, you can have your host autoconfigure IPv6 address on its interfaces. Typically, you should set this up only on your network gateway (router) manually. Using IPv6 Running FreeBSD 7, the kernel is already IPv6 enabled. However, you should manually enable IPv6 in the UserLand, by adding the following line to the /etc/rc.conf configuration file: ipv6_enable="YES" And manually start the appropriate rc script (or reboot the system) for the changes to take effect: # /etc/rc.d/network_ipv6 start This will enable IPv6 on all interfaces that are IPv6 capable. This behavior is changed by modifying the following variable in the /etc/rc.conf file: ipv6_network_interfaces="fxp0 bge0" This will enable IPv6 support on specified interfaces. The default value for this variable is auto. Once you enable IPv6, interfaces will discover the IPv6 enabled routers on the network and build their own IPv6 addresses based on the network prefix they receive from the router. Configuring Interfaces In a typical scenario, IPv6 network stack will automatically look for an IPv6 enabled router on the same network for each interface and try to automatically configure the IPv6 address on the interface. The following is an example of an automatically configured interface(replace the $ with %): # ifconfig ed0 ed0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 ether 00:1c:42:8d:5d:bf inet6 fe80::21c:42ff:fe8d:5dbf$ed0 prefixlen 64 scopeid 0x1 inet 192.168.0.225 netmask 0xffffff00 broadcast 192.168.0.255 inet6 2a01:3c8::21c:42ff:fe8d:5dbf prefixlen 64 autoconf media: Ethernet autoselect (10baseT/UTP) Beside the IPv4 address, there are two IPv6 addresses on the interface. One address begins with fe80:: and identified with the scopeid 0x1 tag, which is called a link-local address. Another address begins with 2a01:3c8::, which is the unicast address of this interface. The unicast address prefix is obtained from the IPv6 router on the network. The whole address is created using the 64 bits Extended Unique Identifier (EUI-64) algorithm, which consists of the hosts MAC address with some minor modifications. The link-local address (that is from the reserved address pool) always starts with fe80:: and is used for local network usage. This can be compared with RFC1819 private addresses that are suitable for local use. The network stack will automatically assign a link-local address to each IPv6 enabled interface, regardless whether an IPv6 router is discovered on the network. This means that in a scenario of a home network or a lab network, you do not need to run an IPv6 router or have a valid IPv6 prefix in order to establish an IPv6 network. All the hosts will be automatically provisioned with a link-local address, so they can exchange IPv6 traffic. The network discovery protocol (NDP) helps the host find the router on the network and then create a unicast address for the interface. NDP is known as the equivalent to ARP protocol in IPv6. The ndp(8) utility is used to control the behavior of this protocol: # ndp -a Neighbor Linklayer Address Netif Expire S Flags 2a01:3c8:: 0:16:cb:98:d4:bf ed0 20s R R 2a01:3c8::21c:42ff:fe8d:5dbf 0:1c:42:8d:5d:bf ed0 permanent R fe80::216:cbff:fe98:d4bf$ed0 0:16:cb:98:d4:bf ed0 23h58m48s S R fe80::21c:42ff:fe8d:5dbf$ed0 0:1c:42:8d:5d:bf ed0 permanent R fe80::1%lo0 (incomplete) lo0 permanent R The above example shows the discovered IPv6 hosts(replace the $ with %). The ed0 interface is connected to an IPv6 enabled network and receives a valid prefix via a router (the first entry of the list). The second entry is the unicast address of the ed0. The third and the fourth entries are link-local address for the router and our host. And the last entry belongs to the local host. As you have seen so far, there are some special (reserved) IPv6 addresses. The following table shows a list of reserved addresses:   Address Name Description :: Unspecified Equivalent to 0.0.0.0 in Pv4 ::1 Loopback address Equivalent to 127.0.0.1 in IPv4 fe80:: Link-local fec0:: Site-local ff00:: Multicast   In case you want to configure the static IPv6 address on an interface, it can be done as in a typical IPv4 scenario: # ifconfig vr0 inet6 2a01:3c8::21c:42ff:dead:beef prefixlen 64 This will manually configure an IP address on the specified interface. Note the prefixlen keyword that is equivalent to subnet mask in IPv4.

Before we get to manage the VMs in the Oracle VM Manager, let's take a quick look at the Oracle VM Manager by logging into it. Getting started with Oracle VM Manager In this article, we will perform the following actions while exploring the Oracle VM Manager: Registering an account Logging in to Oracle VM Manager Create a Server Pool After we are done with the Oracle VM Manager installation, we will use one of the following links to log on to the Oracle VM Manager: Within the local machine: http://127.0.0.1:8888/OVS Logging in remotely: http://vmmgr:8888/OVS Here, vmmgr refers to the host name or IP address of your Oracle VM Manager host. How to register an account Registering of an account can be done in several ways. If, during the installation of Oracle VM Manager, we have chosen to configure the default admin account "admin", then we can use this account directly to log on to Oracle's IntraCloud portal we call Oracle VM Manager. We will explain later in detail about the user accounts and why we would need separate accounts for separate roles for fine-grained access control; something that is crucial for security purposes. So let's have a quick look at the three available options: Default installation: This option applies if we have performed the default installation ourselves and have gone ahead to create the account ourselves. Here we have the default administrator role. Request for account creation: Contacting the administrator of Oracle VM Manager is another way to attain an account with the privileges, such as administrator, manager, and user. Create yourself: If we need to conduct basic functions of a common user with operator's role such as creating and using virtual machines, or importing resources, we can create a new account ourselves. However, we will need the administrator to assign us the server pools and groups to our account before we can get started. Here by default we are granted a user role. We will talk more about roles later in this article. Now let's go about registering a new account with Oracle VM Manager. Once on the Oracle VM Manager Login page click on the Register link. We are presented with the following screen. We must enter a Username of our choice and a hard-to-crack password twice. Also, we have to fill in our First Name and Last Name and complete the registration with a valid email address. Click Next: Next, we need to confirm our account details by clicking on the Confirm button. Now our account will be created and a confirmation message is displayed on the Oracle VM Manager Login screen. It should be noted that we will need some Server Pools and groups before we can get started. We will have to ask the administrator to assign us access to those pools and groups. It's time now to login to our newly created account. Logging in to Oracle VM Manager Again we will need to either access the URL locally by typing http://127.0.0.1:8888/OVS or by typing the following: http://hostname:8888/ OVS. If we are accessing the Oracle VM Manager Portal remotely, replace the "hostname" with either the FQDN (Fully Qualified Distinguished Name) if the machine is registered in our DNS or just the hostname of the VM Manager machine. We can login to the portal by simply typing in our Username and Password that we just created. Depending on the role and the server pools that we have been assigned, we will be displayed with the tabs upon the screen as shown in the following table. To change the role, we will need to contact our enterprise domain administrator. Only administrators are allowed to change the roles of accounts. If we forget our password, we can click on Forgot Password and on submitting our account name, the password will be sent to the registered email address that we had provided when we registered the account. The following table discusses the assigned tabs that are displayed for each Oracle VM Manager roles:   Role Grants User Virtual Machines, Resources Administrator Virtual Machines, Resources, Servers, Server Pools, Administration Manager Virtual Machines, Resources, Servers, Server Pools   We can obviously change the roles by editing the Profile (on the upper-right section of the portal). As it can be seen in the following screenshot, we have access to the Virtual Machines pane and the Resources pane. We will continue to add Servers to the pool when logged in as admin. Oracle VM management: Managing Server Pool A Server Pool is logically an autonomous region that contains one or more physical servers and the dynamic nature of such pool and pools of pools makes what we call  an infinite Cloud infrastructure. Currently Oracle has its Cloud portal with Amazon but it is very much viable to have an IntraCloud portal or private Cloud where we can run all sorts of Linux and Windows flavors on our Cloud backbone. It eventually rests on the array of SAN, NAS, or other next generation storage substrate on which the VMs reside. We must ensure that we have the following prerequisites properly checked before creating the Virtual Machines on our IntraCloud Oracle VM. Oracle VM Servers: These are available to deploy as Utility Master, Server Master pool, and Virtual Machine Servers. Repositories: Used for Live Migration or Hot Migration of the VMs and for local storage on the Oracle VM Servers. FQDN/IP address of Oracle VM Servers: It is better to have the Oracle VM Servers known as OracleVM01.AVASTU.COM and OracleVM02.AVASTU. COM. This way you don't have to bother about the IP changes or infrastructural relocation of the IntraCloud to another location. Oracle VM Agent passwords: Needed to access the Oracle VM Servers. Let's now go about exploring the designing process of the Oracle VM. Then we will do the following systematically: Creating the Server Pool Editing Server Pool information Search and retrieval within Server Pool Restoring Server Pool Enabling HA Deleting a Server Pool However, we can carry out these actions only as a Manager or an Administrator. But first let's take a look at the decisions on what type of Server Pools will suit us the best and what the architectural considerations could be around building your Oracle VM farm.

The following table gives you a brief description of each kind of activity. The sections that follow the table describe how and when to use these activities. Activity Description Assignment   An assignment is an activity completed offline, outside of Moodle. When the student completes the assignment, he or she either uploads a file for the instructor's review, or reports to the instructor in some other way. Regardless of whether the assignment requires uploading a file, the student receives a grade for the assignment. Choice   A choice is essentially a single, multiple-choice question that the instructor asks the class. The result can either be displayed to the class, or kept between the individual student and the instructor. Choices are a good way to get feedback from the students about the class. You can plant these choices in your course ahead of time, and keep them hidden until you need the students' feedback. You can also add them as needed. Journal   You can create an online journal, which will be unique for each student. A journal can be seen only by the student who writes it, and the instructor. Remember that a journal is attached to the course in which it appears. If you want to move a student's journal to another course, you'll need to make creative usage of the backup and restore functions.

Accordion's structure Let's take a moment to familiarize ourselves with what an accordion is made of. Within the outer container is a series of links. These links are the headings within the accordion and each heading will have a corresponding content panel, or drawer as they are sometimes referred to, which opens when the heading is clicked. The following screenshot shows these elements as they may appear in an accordion: It's worth remembering that when using the accordion widget, only one content panel can be open at any one time. Let's implement a basic accordion now. In a blank page in your text editor, create the following page: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>jQuery UI Accordion Widget Example 1</title> </head> <body> <ul id="myAccordion"> <li> <a href="#">Header 1</a> <div>Wow, look at all this content that can be shown or hidden with a simple click!</div> </li> <li> <a href="#">Header 2</a> <div>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean sollicitudin. Sed interdum pulvinar justo. Nam iaculis volutpatligula. Integer vitae felis quis diam laoreet ullamcorper. Etiam tincidunt est vitae est. Ut posuere, mauris at sodales rutrum, turpis tellus fermentum metus, ut bibendum velit enim eu lectus. Suspendisse potenti. </div> </li> <li> <a href="#">Header 3</a> <div>Donec at dolor ac metus pharetra aliquam. Suspendisse purus. Fusce tempor ultrices libero. Sed quis nunc. Pellentesque tincidunt viverra felis. Integer elit mauris, egestas ultricies, gravida vitae, feugiat a, tellus.</div> </li> </ul> <script type="text/javascript" src="jqueryui1.6rc2/jquery-1.2.6.js"></script> <script type="text/javascript" src="jqueryui1.6rc2/ui/ui.core.js"></script> <script type="text/javascript" src="jqueryui1.6rc2/ui/ui.accordion.js"></script> <script type="text/javascript"> //function to execute when doc ready $(function() { //turn specified element into an accordion $("#myAccordion").accordion(); }); </script> </body></html> Save the file as accordion1.html in your jqueryui folder and try it out in a browser. We haven't specified any styling at all at this stage, but as you can see from the following screenshot, it still functions exactly as intended: Little code is required for a basic working version of the accordion widget. A simple unordered list element is the mark-up foundation which is transformed by the library into the accordion object. The following three separate external script files are required for an accordion: The jQuery library itself (jquery-1.2.6.js) The UI base file (ui.core.js) The accordion source file (ui.accordion.js) The first two files are mandatory requirements of all components of the UI library. They should be linked to in the order shown here. Each widget also has its own source file, and may depend on other components as well. The order in which these files appear is important. The jQuery library must always appear first, followed by the UI base file. After these files, any other files that the widget depends upon should appear before the widget's own script file. The library components will not function as expected if files are not loaded in the correct order. Finally, we use a custom <script> block to turn our <ul> element into the accordion. We can use the jQuery object shortcut $ to specify an anonymous function which will be executed as soon as the document is ready. This is analogous to using $(document).ready(function(){}) and helps to cut down on the amount of code we have to type. Following this, we use the simple ID selector $("#myAccordion") to specify the element on the page we want to transform. We then use the accordion() constructor method to create the accordion Other elements can be turned into accordions as well. All list element variants are supported including ordered lists and definition lists. You don't even need to base the accordion on a list element at all. You can build a perfectly functional accordion using just nested <div> and <a> elements, although additional configuration will be required In the above example, we used an empty fragment (#) as the value of the href attribute. You should note that any URLs supplied for accordion headers will not be followed when the header is clicked within the accordion when using the default implementation. Styling the accordion With no styling, the accordion will take up 100% of the width of its container. Like with other widgets, we have several options for styling the accordion. We can create our own custom stylesheet to control the appearance of the accordion and its content, we can use the default or flora themes that come with the library, or we can use Theme Roller to create an extensive skin for the whole library. Let's see how using the flora theme for the accordion will cause it to render. In accordion1.html, add the following <link> tag to the <head> of the page: <link rel="stylesheet" type="text/css" href="jqueryui1.6rc2/themes/flora/flora.accordion.css"> Save the new file as accordion2.html, also in the jqueryui folder, and view it again in a browser. It should appear something like this: The accordion theme file assumes that an unordered list is being used as the basis of the widget and specifically targets <li> elements with certain style rules. We can easily create our own custom theme to style the accordion for situations where we want to use a non-list-based accordion widget, or if we simply want different colors or font styles. You can use the excellent Firebug plugin for Firefox, or another DOM viewer, to see the class names that are automatically added to certain elements when the accordion is generated. You can also read through an un-minified version of the source file if you really feel like it. These will be the class names that we'll be targeting with our custom CSS. The following screenshot shows Firebug in action: Change accordion2.html so that it appears as follows (new code is shown in bold): <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html lang="en"> <head> <link rel="stylesheet" type="text/css" href="styles/accordionTheme.css"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>jQuery UI Accordion Widget Example 3</title> </head> <body> <div id="myAccordion"> <span class="corner topLeft"></span><span class="corner topRight"></span><span class="corner bottomLeft"></span><span class="corner bottomRight"></span> <div><a href="#">Header 1</a><div>Wow, look at all this content that can be shown or hidden with a simple click!</div></div> <div><a href="#">Header 2</a><div>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean sollicitudin. Sed interdum pulvinar justo. Nam iaculis volutpatligula. Integer vitae felis quis diam laoreet ullamcorper. Etiam tincidunt est vitae est. Ut posuere, mauris at sodales rutrum, turpis tellus fermentum metus, ut bibendum velit enim eu lectus. Suspendisse potenti.</div></div> <div><a href="#">Header 3</a><div>Donec at dolor ac metus pharetra aliquam. Suspendisse purus. Fusce tempor ultrices libero. Sed quis nunc. Pellentesque tincidunt viverra felis. Integer elit mauris, egestas ultricies, gravida vitae, feugiat a, tellus.</div></div> </div> <script type="text/javascript" src="jqueryui1.6rc2/jquery-1.2.6.js"></script> <script type="text/javascript" src="jqueryui1.6rc2/ui/ui.core.js"></script> <script type="text/javascript" src="jqueryui1.6rc2/ui/ui.accordion.js"></script> <script type="text/javascript"> //function to execute when doc ready $(function() { //turn specified element into an accordion $("#myAccordion").accordion(); }); </script> </body></html> Save this version as accordion3.html in the jqueryui folder. The class name ui-accordion is automatically added to the accordion's container element. Therefore, we can use this as a starting point for most of our CSS selectors. The links that form our drawer headers are given the class ui-accordion-header so we can also target this class name. In a new file, create the following stylesheet: #myAccordion { width:200px; border:2px solid #000000; position:relative; list-style-type:none; padding-left:0;}.ui-accordion-header { text-decoration:none; font-weight:bold; color:#000000; display:block; width:100%; text-align:center;}.ui-accordion div div { font-size:90%;}.ui-accordion a { color:#ffffff; background:url(../img/accordion/header-sprite.gif) repeat-x 0px 0px;}.ui-accordion a.selected { background:url(../img/accordion/header-sprite.gif) repeat-x 0px -22px;}.ui-accordion a:hover { background:url(../img/accordion/header-sprite.gif) repeat-x 0px -44px;}/* container rounded corners */.corner { position:absolute; width:12px; height:13px; background:url(../img/accordion/corner-sprite.gif) no-repeat;}.topLeft { top:-2px; left:-2px; background-position:0px 0px;}.topRight { top:-2px; right:-2px; background-position:0px -13px;}.bottomRight { bottom:-2px; right:-2px; background-position:0px -26px;}.bottomLeft { bottom:-2px; left:-2px; background-position:0px -39px;} Save this file as accordionTheme.css in your styles folder and preview accordion3.html in a browser. We will need a new folder for the images we use in this and subsequent examples. Create a new folder inside the img folder and name it accordion. With just two images, and a few simple style rules, we can drastically change the default appearance of the accordion with our own custom skin as shown in the following screenshot: Configuring accordion The accordion has a range of configurable properties which allow us to easily change the default behaviour of the widget. The following table lists the available properties, their default value, and gives a brief description of their usage:

(For more resources on Plone, see here.) Graphic design tools Any serious skinner needs a graphic design tool with certain capabilities in order to take the design files and assemble them into a finished web site. In particular, layers and the ability to slice pieces of a design and export those pieces are essential. Layers allow a themer to hide pieces not needed in a finished CSS theme, such as text that will eventually become real HTML on a page. Slices, meanwhile, are the pieces of an overall design that are exported during the layer manipulation process. They are the images the end user eventually sees on the rendered page. This is different from cropping, which actually alters the size of the canvas; slices are just pieces of the overall design, cut with precision, exported, and then manipulated with CSS. The most commonly used graphic design tools used for web design are Adobe® Photoshop®, Adobe® Fireworks® (formerly Macromedia) tool, and open source tools such as GIMP. It is not generally recommended to use tools such as Adobe® Illustrator®, Corel Draw and other vector-based packages. Web designs primarily use raster-based media, meaning that raster images are based on pixels and thus scale with loss of clarity. Conversely, vector-based images can be scaled infinitely without degrading, but are typically not appropriate for web design. Adobe Photoshop The most popular tool for processing image files is Adobe Photoshop. The files generated for designs are PSD, or Photoshop Document files. Adobe Photoshop meets the basic requirements of being able to manipulate the vector and raster images, layers, and slices, and offers a lot of additional functionality. The ability to control anti-aliasing and the quality and size of an exported image is essential in web design, and Adobe Photoshop (also, Adobe Fireworks) is quite powerful in this respect. A quick look at the Layers panel illustrates how sections can be grouped together, moved, or be shown or hidden via the "eyeball" icon. This show/hide functionality is very important. One situation where this becomes valuable is when you have a PSD file that indicates graphical buttons with text over them. For accessibility reasons, you may want to render the text as real HTML-rendered text, and not as an image. You need to be able to export the buttons in both their on and off states in order to get a proper rollover effect, and you need to hide the graphical text in order to do this. One site that illustrates this concept is http://greenforall.org. Using Adobe Photoshop, the layers where the text appears on the top navigation were hidden, and just the background on/off images were imported. On the finished web site, the top menu used the background images and real rendered text. The other core functionality that Adobe Photoshop offers is the ability to slice images and export them. The Copper River Watershed Project web site (http://www.copperriver.org) illustrates how slices might be used. The original Adobe Photoshop document is here: If you look closely, you can see a few key slices: the "Go" button next to the search field has been sliced, as has the Tour Our Watershed map and the gradation on the top navigation, which will be tiled horizontally. Below the orange navigation is a long slice that spans from the left-hand shadow over to the right-hand shadow. This image can be used to tile the length of the page. Additionally, the entire Information For... box has been sliced; in this case, for the final implementation, the text overlaying this slice was hidden and replaced with rendered text. If you look at the finished web site, you can see how these slices were applied. Photoshop provides a great deal of power, but in general, you may only use about 20% of the power it offers. You can visit http://adobe.com to see the tutorials on how to use the Adobe Photoshop effectively. Additionally, you may want to investigate Photoshop Elements; it doesn't allow you to slice images for the Web, but for the current price of $139.99, it's still a great tool for many web design activities: http://www.adobe.com/products/photoshopelwin. Adobe Fireworks At the time Macromedia was purchased by Adobe in 2005, the interface was a little clumsy at times, but it did have a basic implementation of layers and slices. Over the past few years, based on the demos available, it appears that the interface has seen some great improvements, though it does not have the same power or market share as Adobe Photoshop has. However, at nearly $400 less than Adobe Photoshop, it's a great option. According to the Adobe web site, "Adobe Fireworks CS4 software is used to rapidly prototype web sites and application interfaces and to create and optimize images for the Web more quickly and accurately. It is ideal for web designers, web developers, and visual designers." It differs from Photoshop in that "Adobe Photoshop software is the industry standard for digital imaging, with a broad array of features and functionality used by photographers, graphic designers, web designers, and many other creative professionals. Fireworks is a much more focused tool, with the features for prototyping vectors and bitmaps for the web and application interfaces." The real selling point here, though, is integration with Adobe Photoshop, as a design may be shared between multiple people, each using different graphical programs. The ability to manipulate the vector and raster images is also important. Additionally, like Adobe Photoshop, Adobe Fireworks provides the ability to work with layers and slices, and preserves many of the settings in an Adobe Photoshop PSD file. It's not as good at compositing and photo manipulation as Photoshop, but is a lot stronger with text, shapes, and final optimization. Selective JPEG optimization is also very handy, and allows you to heavily compress the portions of a JPEG while keeping text legible. Additionally, it's great for generating image maps (not often used in Plone), rollovers, and other common tricks. Finally, it allows you to view your work with either Windows or Mac gamma. Gamma correction basically refers to the ability to correct for differences in how computers (and especially computer monitors) interpret color values. There are two factors here: the ability to predict what an image, say a photograph, will look like on another monitor and the ability to match the colors from different sources on a single page—Adobe Fireworks excels at both. While Adobe Fireworks is not as feature-rich as Adobe Photoshop, it is still an extremely competent tool for slicing and exporting design elements at implementation time, not to mention more affordable. GIMP GIMP, also known as the GNU Image Manipulation Program, can be downloaded for free from http://www.gimp.org. It is a freely distributed program for such tasks as photo retouching, image composition and image authoring, and is covered by the GNU GPL license. According to the GIMP's web site, it can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, an image format converter, and more. From the perspective of how it compares to the key aspects of Adobe Photoshop® and Adobe Fireworks®, it has full support of layers and channels, plug-ins that allow for the easy addition of new file formats (that is, it can read Adobe Photoshop or Adobe Fireworks files), and best of all, it is open source. You can visit http://www.gimp.org/docs to download the user manual for the current release. GIMP also lists several user groups and resources at http://www.gimp.org/links that may be helpful. Even so, the latest releases are still quite recent, so development is still happening For a free solution to the image processing needs, GIMP is an excellent choice, but weak in terms of the user interface and layer compatibility with Adobe Photoshop. Browser add-ons and important notes Now that you have sense of the tools that are available for manipulating design files and exporting the necessary images for building your web site, let's look at how browsers affect the web site building process, either through add-on tools or through sheer bugginess. It's also worth mentioning that users should reference the A-List of popular browsers to see which browsers are still considered to be supported by web developers: http://developer.yahoo.com/yui/articles/gbs/index.html. This can help to ease the quality assurance load during web site testing. Many of these A-List browsers come with browser-specific tools that allow you to inspect your web site to descry the CSS (Cascading Style Sheets) ID and class selectors, manipulate your CSS on-the-fly, optimize your site, explore color options, and more. We'll look at the available options for three major browsers: Internet Explorer, Firefox, and Safari, but you should always be conscious of general browser penetration statistics so that you know which browsers are still in popular use: http://en.wikipedia.org/wiki/Usage_share_of_web_browsers. Now, let's get back to our key browsers. Internet Explorer From a themer's perspective, Internet Explorer is the most finicky browser against which to implement, as older versions of Internet Explorer followed the W3C's (World Wide Web Consortium's) standards differently than many other popular browsers. According to http://positioniseverything.net, a leading collector of browser fixes, "All browsers have CSS bugs, and IE leads the pack in this area, but that is not the end of the story. Microsoft has seen fit to engineer their browser to deliberately violate the standards in several critical ways. It might just be a misguided attempt to 'make it simple' for newbie coders, or it might be a cynical ploy to crush the competition, but in any case it creates huge headaches for those of us who desire to employ CSS positioning on our pages." While this may be true, many fixes for Internet Explorer have been identified, and thankfully, IE6, one of the more problematic browsers in recent years, is finally becoming obsolete. It was replaced by IE7, which was a vast improvement, but still did not implement the W3C conventions for CSS faithfully. As of this writing, Internet Explorer 8 was released and showing signs of having finally made strides toward real compliance to W3C standards. What this equates to is that web developers tend do their initial browser testing in browsers that are more compliant; that means doing most upfront testing in Firebug and Safari, and then rounding out the testing at the end against IE6, IE7, and IE8. Where possible, it's also important to test against other major browsers and handheld media. For testing against Internet Explorer, IE provides a tool called the Web Developer Toolbar for debugging. It is available for both IE6 and IE7 as an add-on and can be downloaded here: http://www.microsoft.com/downloads/details.aspx?FamilyId=E59C3964-672D-4511-BB3E-2D5E1DB91038&displaylang=en. Web Developer Toolbar will no longer be the tool of choice for IE8, however, instead use the developer tools included with IE8. To use the developer tools in IE8, press Shift+F12 or click the "Developer Tools" icon in the command bar to begin using the tool. For IE6 and IE7, Web Developer Toolbar provides several features for exploring and understanding web pages. These features enable you to: Explore and modify the document object model (DOM) of a web page. Locate and select the specific elements on a web page. Selectively disable the Internet Explorer settings. View HTML object class names, IDs, and details such as link paths, tab index values, and access keys. Outline tables, table cells, images, or selected tags. Validate HTML, CSS, WAI, and RSS web feed links. Display image dimensions, file sizes, path information, and alternate (ALT) text. Immediately resize the browser window to a new resolution. Selectively clear the browser cache and saved cookies. Choose from all objects or those associated with a given domain. Display a fully-featured design ruler to help accurately align and measure objects on your pages. Find the style rules used to set specific style values on an element. Right clicking on a style rule will allow you to trace the rules to a specific CSS file, if one is found. View the formatted and syntax colored source of HTML and CSS. The Developer Toolbar can be popped up within the Internet Explorer browser window or opened as a separate window. If you are using a PC to test your sites, VMware, parallels, or a Windows emulator, you should download the Toolbar from http://go.microsoft.com/fwlink/?LinkId=125120, install it, and restart IE. You can then click the Developer Toolbar icon in the command bar to display or hide the Developer Toolbar. Alternately, you can open the View menu and then use the Explorer Bar menu. In Internet Explorer 7, open the Tools menu and then use Toolbars/Explorer Bars to display or hide the Developer Toolbar. There are a few caveats here: The Developer Toolbar icon may not be visible by default. If you do not see it after restarting Internet Explorer, click the right-facing arrows at the end of the IE7 command bar to view all the available Toolbar buttons. Some menu items are unavailable (grayed out) when running Internet Explorer in Protected Mode on Windows Vista. To use those options, temporarily turn off Protected Mode or right-click the Internet Explorer icon in the Programs menu and choose Run as administrator. In IE6 or in IE7 with tabbed browsing off, using the validation links will navigate the current window to the validation page. To launch the validation links in a new window, open the Tools menu, click Internet Options, and uncheck Reuse windows for launching shortcuts in the Advanced tab, or use IE7 with tabbed browsing enabled. Generally, you can use this tool by expanding the left side of the panel displayed to navigate through your site's structure. It displays CSS IDs and classes in a hierarchical fashion. On the right-hand side, it displays the properties assigned to each of those IDs or classes. You can modify those by using the + icon in the center Attributes section to add a new property and using that to add to or alter the existing CSS. As stated before, the left-hand pane allows you to expand and walk through the structure of your web site. When you refresh, unfortunately, the entire tree closes. To continue troubleshooting a specific element on the page, you must drill down to it again or use the "selector" tool. It's somewhat clumsy, but it works and is invaluable when debugging web pages in Internet Explorer.  

The central activity you'll be doing with your blog is adding posts. A post is like an article in a magazine; it's got a title, content, and an author (you). If a blog is like an online diary, then every post is an entry in that diary. A blog post also has a lot of other information attached to it, such as a date and categories. In this article, you will learn how to create a new post and what kind of information you can attach to it. Adding a simple post Let's review the process of adding a simple post to your blog. Whenever you want to do maintenance on your WordPress website, you have to start by logging in to the WP Admin (WordPress Administration panel) for your site. To get to the admin panel, just point your web browser to http://yoursite.com/wp-admin. Remember that if you have installed WordPress in a subfolder (for example, blog), then your URL has to include the subfolder (that is, http://yoursite.com/blog/wp-admin). When you first log into the WP Admin, you'll be at the Dashboard. The Dashboard has a lot of information on it. The very top bar, which I'll refer to as the top menu, is mostly dark grey and on the left, of course, is the main menu. The top menu and the main menu exist on every page within the WP Admin. The main section on the right contains information for the current page you're on. In this case, we're on the Dashboard. It contains boxes that have a variety of information about your blog, and about WordPress in general. The quickest way to get to the Add New Post page at any time is to click on the New Post link at the top of the page in the top bar (top menu). This is the Add New Post page: To quickly add a new post to your site, all you have to do is: Type in a title into the text field under Add New Post (for example, Making Lasagne). Type the text of your post in the content box. Note that the default view is Visual, but you actually have a choice of the HTML view as well. Click on the Publish button, which is at the far right. Note that you can choose to save a draft or view a preview of your post. In the following image, the title field, the content box, and the Publish button of the Add New Post page are highlighted: Once you click on the Publish button, you have to wait while WordPress performs its magic. You'll see yourself still on the Edit Post page, but now the following message has appeared telling you that your post was published and giving you a link to View post: If you go to the front page of your site, you'll see that your new post has been added at the top (newest posts are always at the top): Common post options Now that we've reviewed the basics of adding a post, let's investigate some of the other options on the Add New Post page. In this section we'll look at the most commonly used options, and in the next section we'll look at the more advanced options. Categories and tags Categories and tags are two similar types of information that you can add to a blog post. We use them to organize the information in your blog by topic and content (rather than just by, say, date), and to help visitors find what they are looking for on your blog. Categories are primarily used for structural organizing. They can be hierarchical. A relatively busy blog will probably have at least 10 categories, but probably not more than 15 or 20. Each post in this blog will likely have one to four categories assigned to it. For example, a blog about food might have these categories: Cooking Adventures, In The Media, Ingredients, Opinion, Recipes Found, Recipes Invented, and Restaurants. Tags are primarily used as shorthand for describing the topics covered in a particular blog post. A relatively busy blog will have anywhere from 15 to 30 tags in use. Each post in this blog will likely have three to ten tags assigned to it. For example, a post on the food blog about a recipe for butternut squash soup may have these tags: soup, vegetarian, autumn, hot, easy. Let's add a new post to the blog. This time, we'll give it not only a title and content, but also tags and categories. When adding tags, just type your list of tags into the Tags box on the right, separated by commas: Then click on the Add button. The tags you just typed in will appear below the text field with little xs next to them. You can click on an x to delete a tag. Once you've used some tags in your blog, you'll be able to click on the Choose from the most popular tags link in this box so that you can easily re-use tags. Categories work a bit differently than tags. Once you get your blog going, you'll usually just check the boxes next to existing categories in the Categories box. In this case, as we don't have any existing categories, we'll have to add one or two. In the Categories box on the right, click on the + Add New Category link. Type your category into the text field and click on the Add button. Your new category will show up in the list, already checked. Look at the following screenshot: If in the future you want to add a category that needs a parent category, select Parent category from the pull-down menu before clicking on the Add button. If you want to manage more details about your categories, move them around, rename them, assign parent categories, and assign descriptive text. You can do this on the Categories page, which we'll see in detail later in this article. Now fill in your title and content here: Click on the Publish button and you're done. When you look at the front page of your site, you'll see your new post on the top, your new category in the sidebar, and the tags and category (that you chose for your post) listed under the post itself: Adding an image to a post You may often want to have an image show up in your post. WordPress makes this very easy. Let's add an image to the post we just created. You can click on Edit underneath your post on the front page of your site to get there quickly. Alternatively, go back to the WP Admin, open Posts in the main menu, and then click on Edit underneath your new post. To add an image to a post, first you'll need to have that image on your computer. Before you get ready to upload an image, make sure that your image is optimized for the Web. Huge files will be uploaded slowly and slow down the process of viewing your site. You can re-size and optimize images using software such as GIMP or Photoshop. For the example in this article, I have used a photo of butternut squash soup that I have taken from the website where I got the recipe, and I know it's on the desktop of my computer. Once you have a picture on your computer and know where it is, follow these steps to add the photo to your blog post: Click on the little photo icon, which is next to the word Upload/Insert and below the box for the title: In the box that appears, click on the Select Files button and browse to your image. Then click on Open and watch the uploader bar. When it's done, you'll have a number of fields you can fill in: The only fields that are important right now are Title, Alignment, and Size. Title is a description for the image, Alignment will tell the image whether to have text wrap around it, and Size is the size of the image. As you can see, I've chosen the Right alignment and the Thumbnail size. Now click on Insert into Post. This box will disappear, and your image will show up in the post on the edit page itself: Now click on the Update Post button and go look at the front page of your site again. There's your image! You may be wondering about those image sizes. What if you want bigger or smaller thumbnails? You can set the pixel dimensions of your uploaded images and other preferences by opening Settings in the main menu and then clicking on Media. This takes you to the Media Settings page: Here you can specify the size of the uploaded images for: Thumbnail Medium Large If you change the dimensions on this page and click on the Save Changes button, only images you upload in the future will be affected. Images you've already uploaded to the site will have had their thumbnail, medium, and large versions created already using the old dimensions. Using the Visual editor versus the HTML editor WordPress comes with a Visual editor, otherwise known as a WYSIWYG editor (pronounced wissy-wig, which stands for What You See Is What You Get). This is the default editor for typing and editing your posts. If you're comfortable with HTML, you may prefer to write and edit your posts using the HTML editor—particularly useful if you want to add special content or styling. To switch from the rich text editor to the HTML editor, click on the HTML tab next to the Visual tab at the top of the content box: You'll see your post in all its raw HTML glory and you'll get a new set of buttons that lets you quickly bold and italicize text as well as add link code, image code, and so on. You can make changes and swap back and forth between the tabs to see the result. If you want the HTML tab to be your default editor, you can change this on your Profile page. Navigate to Users | Your Profile, and select the Disable the visual editor when writing checkbox. Drafts, timestamps, and managing posts There are three additional, simple but common, items I'd like to cover in this section: drafts, timestamps, and managing posts. Drafts WordPress gives you the option to save a draft of your post so that you don't have to publish it right away but can still save your work. If you've started writing a post and want to save a draft, just click on the Save Draft button at the right (in the Publish box), instead of the Publish button. Even if you don't click on the Save Draft button, WordPress will attempt to save a draft of your post for you about once a minute. You'll see this in the area just below the content box. The text will say Saving Draft... and then the time of the last draft saved: At this point, after a manual save or an auto-save, you can leave the Edit Post page and do other things. You'll be able to access all of your draft posts from the Dashboard or from the Edit Posts page. Timestamps WordPress will also let you alter the timestamp of your post. This is useful if you are writing a post today that you wish you'd published yesterday, or if you're writing a post in advance and don't want it to show up until the right day. The default timestamp will always be set to the moment you publish your post. To change it, just find the Publish box and click on the Edit link (next to the calendar icon and Publish immediately), and fields will show up with the current date and time for you to change: Change the details, click on the OK button, and then Publish your post (or save a draft). Managing posts If you want to see a list of your posts so that you can easily skim and manage them, you just need to go to the Edit Posts page in the WP Admin by navigating to Posts in the main menu. You'll see a detailed list of your posts, as seen in the next screenshot: There are so many things you can do on this page! You can: Choose a post to edit—click on a post title and you'll go back to the main Edit Post page Quick-edit a post—click on the Quick Edit link for any post and new options will appear right in the list, which will let you edit the title, timestamp, categories, tags, and more Delete one or more posts—click on the checkboxes next to the posts you want to delete, choose Delete from the Bulk Actions drop-down menu at the bottom, and click on the Apply button Bulk edit posts—choose Edit from the Bulk Actions menu at the bottom, click on the Apply button, and you'll be able to assign categories and tags to multiple posts, as well as edit other information about them You can experiment with the other links and options on this page. Just click on the pull-down menus and links, and see what happens.

Reviewing Jayaram's other OLAP related articles may greatly help in understanding this article. Creating the CUBE will be essential to work with this hands-on. If you are already experienced and have an appropriate CUBE to work with you may directly go to the section on deriving a dataset. The CUBE used in this hands-on is a simple one. It does not even have a "Time" dimension although Microsoft in Visual Studio gives a warning that you should have one. However for the purposes of demonstration and doing the hands-on a CUBE without the "Time" dimension should be adequate. The two previous articles on creating a CUBE provide the necessary background for this article. Create a data source with a CUBE Create an Analysis Services Cube (herein called MyNwind.cube) using the TestNorthwind as the database. The Measures and Dimensions for this cube are as shown in the next figure. Start your Report Builder 2.0. Make sure you have started the reporting services using the Reporting Services Configuration Manager. In Report Builder 2.0 click on New | Data source... under Report Data. Provide the following information: Name: SrcCubeSelect connection type: Microsoft SQL Server Analysis ServicesConnection String: Data Source=Hodentek2SANGAM; Initial Catalog=NwindRTM Herein NwindRTM is the name of the Datasource in the Analysis Server. (Alternately you may build this source as shown). Click OK on the Data Source Properties window. Add a dataset to the report Right click on SrcCube and choose Add DataSet... In the Dataset Properties window make the following changes: Name: QryCubeData source: SrcCubeQuery Type: text Click on Query Designer... button. At first you will see only the Metadata of the cube displayed as in the left side of the next figure. Expand Customers, Orders, and Products in the dimensions and drop them on the list header in the bottom pane on the right hand side of the next figure. Drag and drop Freight from Orders under Measures as shown. For each of the dimensions using an operator create a filter expression as shown. For example, the Products included in the query range from Product IDs 3 to 9; the Customer ID (some specific ones are chosen), similarly theCategory ID (only those with ID's 2, 3, 4, and 5 are included in the query). The design of the query with these filtering choices is as shown in the previous figure. The filtering tool is very flexible and all the items namely Dimension, Hierarchy, Operator and Filter Expression can be designed in this interface using either drop-down pick lists choices or drop-downs with checkboxes as shown here. Run the query by clicking on the toolbar item (!) and review the results. Click OK on the Query Designer. The Dataset Properties window shows up with this query designed according to your choices in the query item window as shown. Close the Dataset Properties window. Report Design In Report Builder 2.0 click on New Table or Matrix wizard. In the Choose a dataset window accept the default and click Next. Drag and drop Customer_ID in the Row Groups drop area. Drag and drop Order_ID below Customer_ID in the Row Groups drop area. Drag and drop Product_ID in the Column Groups drop area. Drag and drop Freight into the Values drop area and click on Next. In the Choose the layout window accept Expand/collapse groups and choose the option Stepped, subtotal above. Click Next and choose some style (herein Ocean) and click Finish. The final report design is as shown here. Click Home | Run. The report gets displayed after processing as shown here. The orders from a particular customer have been expended in this view. Summary Report Builder 2.0 can used to author reports based on Analysis Services Cubes. The interface is very flexible and the Query Designer is very easy to use as shown in this article. If you have read this article you may be interested to view : Creating an Analysis Services Cube with Visual Studio 2008 - Part 1 Creating an Analysis Services Cube with Visual Studio 2008 - Part 2

Arrays Now that you know the basic primitive data types in JavaScript, it's time to move to a more interesting data structure—the array. To declare a variable that contains an empty array, you use square brackets with nothing between them: >>> var a = [];>>> typeof a;"object" typeof returns "object", but don't worry about this for the time being, we'll get to that when we take a closer look at objects. To define an array that has three elements, you do this: >>> var a = [1,2,3]; When you simply type the name of the array in the Firebug console, it prints the contents of the array: >>> a[1, 2, 3] So what is an array exactly? It's simply a list of values. Instead of using one variable to store one value, you can use one array variable to store any number of values as elements of the array. Now the question is how to access each of these stored values? The elements contained in an array are indexed with consecutive numbers starting from zero. The first element has index (or position) 0, the second has index 1 and so on. Here's the three-element array from the previous example: Index Value 0 1 1 2 2 3 In order to access an array element, you specify the index of that element inside square brackets. So a[0] gives you the first element of the array a, a[1] gives you the second, and so on. >>> a[0]1>>> a[1]2 Adding/Updating Array Elements Using the index, you can also update elements of the array. The next example updates the third element (index 2) and prints the contents of the new array. >>> a[2] = 'three';"three">>> a[1, 2, "three"] You can add more elements, by addressing an index that didn't exist before. >>> a[3] = 'four';"four">>> a[1, 2, "three", "four"] If you add a new element, but leave a gap in the array, those elements in between are all assigned the undefined value. Check out this example: >>> var a = [1,2,3];>>> a[6] = 'new';"new">>> a[1, 2, 3, undefined, undefined, undefined, "new"] Deleting Elements In order to delete an element, you can use the delete operator. It doesn't actually remove the element, but sets its value to undefined. After the deletion, the length of the array does not change. >>> var a = [1, 2, 3];>>> delete a[1];true>>> a[1, undefined, 3] Arrays of arrays An array can contain any type of values, including other arrays. >>> var a = [1, "two", false, null, undefined];>>> a[1, "two", false, null, undefined]>>> a[5] = [1,2,3][1, 2, 3]>>> a[1, "two", false, null, undefined, [1, 2, 3]] Let's see an example where you have an array of two elements, each of them being an array. >>> var a = [[1,2,3],[4,5,6]];>>> a[[1, 2, 3], [4, 5, 6]] The first element of the array is a[0] and it is an array itself. >>> a[0][1, 2, 3] To access an element in the nested array, you refer to the element index in another set of square brackets. >>> a[0][0]1>>> a[1][2]6 Note also that you can use the array notation to access individual characters inside a string. >>> var s = 'one';>>> s[0]"o">>> s[1]"n">>> s[2]"e" There are more ways to have fun with arrays, but let's stop here for now, remembering that: An array is a data store An array contains indexed elements Indexes start from zero and increment by one for each element in the array To access array elements we use the index in square brackets An array can contain any type of data, including other arrays

PHP-CLI vs PHP-CGI Most Linux distributions include both versions of PHP when installed, especially if you are using a modern distribution such as CentOS or Mandriva. When writing AGI scripts with PHP, it is imperative that you use PHP-CLI, and not PHP-CGI. Why is this so important? The main issue is that PHP-CLI and PHP-CGI handle their STDIN (standard input) slightly differently, which makes the reading of channel variables via PHP-CGI slightly more problematic. The php.ini configuration file The PHP interpreter includes a configuration file that defines a set of defaults for the interpreter. For your scripts to work in an efficient manner, the following must be set—either via the php.ini file, or by your PHP script: ob_implicit_flush(false); set_time_limit(5); error_log = filename;error_reporting(0); The above code snippet performs the following: Directive Description ob_implicit_flush(false); Sets your PHP output buffering to false, in order to make sure that output from your AGI script to Asterisk is not buffered, and takes longer to execute set_time_limit(5); Sets a time limit on your AGI scripts to verify that they don't extend beyond a reasonable time of execution; there is no rule of thumb relating to the actual value; it is highly dependant on your implementation Depending on your system and applications, your maximum time limit may be set to any value; however, we suggest that you verify your scripts, and are able to work with a maximum limit of 30 seconds. error_log=filename; Excellent for debugging purposes; always creates a log file error_reporting(E_NONE); Does not report errors to the error_log; changes the value to enable different logging parameters; check the PHP website for additional information about this AGI script permissions All AGI scripts must be located in the directory /var/lib/asterisk/agi-bin, which is Asterisk's default directory for AGI scripts. All AGI scripts should have the execute permission, and should be owned by the user running Asterisk. If you are unfamiliar with these, consult with your system administrator for additional information. The structure of a PHP based AGI script Every PHP based AGI script takes the following form: #!/usr/bin/php -q <? $stdin = fopen(‘php://stdin’, ‘r’); $stdout = fopen(‘php://stdout’, ‘w’); $stdlog = fopen(‘my_agi.log’, ‘w’); /* Operational Code starts here */ .. .. ..?> Upon execution, Asterisk transmits a set of information to our AGI script via STDIN. Handling of that input is best performed in the following manner: #!/usr/bin/php -q <? $stdin = fopen(‘php://stdin’, ‘r’); $stdout = fopen(‘php://stdout’, ‘w’); $stdlog = fopen(‘my_agi.log’, ‘w’); /* Handling execution input from Asterisk */ while (!feof($stdin)) { $temp = fgets($stdin); $temp = str_replace("n","",$temp); $s = explode(":",$temp); $agivar[$s[0]] = trim($s[1]); if $temp == "") { break; } } /* Operational Code starts here */ .. .. ..?> Once we have handled our inbound information from the Asterisk server, we can start our actual operational flow. Communication between Asterisk and AGI The communication between Asterisk and an AGI script is performed via STDIN and STDOUT (standard output). Let's examine the following diagram: In the above diagram, ASC refers to our AGI script, while AST refers to Asterisk itself. As you can see from the diagram above, the entire flow is fairly simple. It is just a set of simple I/O queries and responses that are carried through the STDIN/STDOUT data streams. Let's now examine a slightly more complicated example: The above figure shows an example that includes two new elements in our AGI logic—access to a database, and to information provided via a web service. For example, the above image illustrates something that may be used as a connection between the telephony world and a dating service. This leads to an immediate conclusion that just as AGI is capable of connecting to almost any type of information source, depending solely on the implementation of the AGI script and not on Asterisk, Asterisk is capable of interfacing with almost any type of information source via out-of-band facilities. Enough of talking! Let's write our first AGI script.

  The article is intended towards developers who have never used Flex before and would like to exercise a “Hello World” kind of tutorial. The article does not aim to cover Flex and FB4 in detail but rather focuses on the mechanics of FB4 and getting an application running with minimal effort. For developers familiar with Flex and the predecessor to Flash Builder 4 (Flex Builder 2 or 3), it contains an introduction to FB4 and some differences in the way you go about building Flex Applications using FB4. Even if you have not programmed before and are looking at understanding how to make a start in developing applications, this would serve as a good start. The Flex Ecosystem The Flex ecosystem is a set of libraries, tools, languages and a deployment runtime that provides an end-to-end framework for designing, developing and deploying RIAs. All these together are being branded as a part of the Flash platform. In its latest release, Flex 4, special efforts have been put in to address the designer to developer workflow by letting graphic designers address layout, skinning, effects and general look and feel of your application and then the developers taking over to address the application logic, events, etc. To understand this at a high level, take a look at the diagram shown below. This is a very simplified diagram and the intention is to project a 10,000 ft view of the development, compilation and execution process. Let us understand the diagram now: The developer will typically work in the Flash Builder Application. Flash Builder is the Integrated Development Environment (IDE) that provides an environment for coding, compiling, running / debugging your Flex based applications. Your Flex Application will typically consist of MXML and ActionScript code. ActionScript is an ECMAScript compatible Object Oriented language, whereas MXML is an XML-based markup language. Using MXML you can define/layout your visual components like buttons, combobox, data grids, and others. Your application logic will be typically coded inside ActionScript classes/methods. While coding your Flex Application, you will make use of the Flex framework classes that provide most of the core functionality. Additional libraries like Flex Charting libraries and 3rd party components can be used in your application too. Flash Builder compiles all of this into object byte code that can be executed inside the Flash Player. Flash Player is the runtime host that executes your application. This is high level introduction to the ecosystem and as we work through the samples later on in the article, things will start falling into place. Flash Builder 4 Flash Builder is the new name for the development IDE previously known as Flex Builder. The latest release is 4 and it is currently in public beta. Flash Builder 4 is based on the Eclipse IDE, so if you are familiar with Eclipse based tools, you will be able to navigate your way quite easily. Flash Builder 4 like Flex Builder 3 previously is a commercial product and you need to purchase a development license. FB4 currently is in public beta and is available as a 30-day evaluation. Through the rest of the article, we will make use of FB4 and will be focused completely on that to build and run the sample applications. Let us now take a look at setting up FB4. Setting up your Development Environment To setup Flash Builder 4, follows these steps: The first step should be installing Flash Player 10 on your system. We will be developing with the Flex 4 SDK that comes along with Flash Builder 4 and it requires Flash Player 10. You can download the latest version of Flash Player from here: http://www.adobe.com/products/flashplayer/ Download Flash Builder 4 Public Beta from http://labs.adobe.com/technologies/flashbuilder4/. The page is shown below: After you download, run the installer program and proceed with the rest of the installation. Launch the Adobe Flash Builder Beta. It will prompt first with a message that it is a Trial version as shown below: To continue in evaluation mode, select the option highlighted above and click Next. This will launch the Flash Builder IDE. Let us start coding with Flash Builder 4 IDE. We will stick to tradition and write the “Hello World” application. Hello World using Flash Builder 4 In this section, we will be developing a basic Hello World application. While the application does not do much, it will help you get comfortable with the Flash Builder IDE. Launch the Flash Builder IDE. We will be creating a Flex Project. Flash Builder will help us create the Project that will contain all our files. To create a new Flex Project, click on the File → New → Flex Project as shown below: This will bring up a dialog in which you will need to specify more details about the Flex Project that you plan to develop. The dialog is shown below: You will need to provide at least the following information: Project Name: This is the name of your project. Enter a name that you want over here. In our case, we have named our project MyFirstFB4App. Application Type: We can develop both a Web version and a desktop version of our application using Flash Builder. The web application will then run inside of a web browser and execute within the Flash Player plug-in. We will go with the Web option over here. The Desktop application runs inside the Adobe Integrated Runtime environment and can have more desktop like features. We will skip that option for now. We will let the other options remain as is. We will use the Flex 4.0 SDK and currently we are not integrating with any Server side layer so we will leave that option as None/Other. Click on Finish at this point to create your Flex Project. This will create a main application file called MyFirstFB4App.mxml as shown below. We will come back to our coding a little later but first we must familiarize ourselves with the Flash Builder IDE. Let us first look at the Package Explorer to understand the files that have been created for the Flex Project. The screenshot is shown below: It consists of the main source file MyFirstFB4App.mxml. This is the main application file or in other words the bootstrap. All your source files (MXML and ActionScript code along with assets like images, and others should go under the src folder. They can optionally be placed in packages too. The Flex 4.0 framework consists of several libraries that you compile your code against. You would end up using its framework code, components (visual and non-visual) and other classes. These classes are packaged in a library file with an extension .swc. A list of library files is shown above. You do not need to typically do anything with it. Optionally, you can also use 3rd party components written by other companies and developers that are not part of the Flex framework. These libraries are packages as .SWC files too and they can be placed in the libs folder as shown in the previous screenshot. The typical step is to write and compile your code—build your project. If your build is successful, the object code is generated in the bin-debug folder. When you deploy your application to a Web Server, you will need to pickup the contents from this folder. We will come to that a little later. The html-template folder contains some boiler-plate code that contains the container HTML into which your object code will be referenced. It is possible to customize this but for now, we will not discuss that. Double-click MyFirstFB4App.mxml file. This is our main application file. The code listing is given below: <?xml version="1.0" encoding="utf-8"?> <s:Application minWidth="1024" minHeight="768"> </s:Application> As discussed before, you will typically write one or more MXML files that will contain typically your visual components (although there can be non-visual components also). By visual components, we mean controls like button, combobox, list, tree, and others. It could also contain layout components and containers that help you layout your design as per the application screen design. To view what components, you can place on the main application canvas, select the Design View as shown below: Have a look at the lower half of the left pane. You will see the Components tab as shown below, which would address most needs of your Application Visual design. Click on the Controls tree node as shown below. You will see several controls that you can use and from which, we will use the Button control for this application. Simply select the Button control and drag it to the Design View Canvas as shown below: This will drop an instance of the Button control on the Design View as shown below: Select the Button to see its properties panel as shown below. Properties Panel is where you can set several attributes at design time for the control. In case the Properties panel is not visible, you can get to that by selecting Window → Properties from the main menu. In the Properties panel, we can change several key attributes. All controls can be uniquely identified and addressed in your code via the ID attribute. This is a unique name that you need to provide. Go ahead and give it some meaningful name. In our case, we name it btnSayHello. Next we can change the label so that instead of Button, it can display a message for example, Say Hello. Finally we want to wire some code such that if the button is clicked, we can do some action like display a Message Box saying Hello World. To do that, click the icon next to the On click edit field as shown below. It will provide you two options. Select the option for Generate Event Handler. This will generate the code and switch to the Source view. The code is listed below for your reference. <?xml version="1.0" encoding="utf-8"?> <s:Application minWidth="1024" minHeight="768"> <fx:Script> <![CDATA[ protected function btnSayHello_clickHandler(event:MouseEvent):void { // TODO Auto-generated method stub } ]]> </fx:Script> <s:Button x="17" y="14" label="Button" id="btnSayHello" click="btnSayHello_clickHandler(event)"/> </s:Application> There are few things to note here. As mentioned most of your application logic will be written in ActionScript and that is exactly what Flash Builder has generated for you. All such code is typically added inside a scripting block marked with the <fx:Script> tag. You can place your ActionScript methods over here that can be used by the rest of the application. When we clicked on Generate Event Handler, Flash Builder generated the Event Handler code. This code is in ActionScript and was appropriately placed inside the <fx:Script> block for us. If you look at the code, you can see that it has added a function that is invoked when the click event is fired on the button. The method is btnSayHello_clickHandler and if you notice it has an empty method that is, no implementation. Let us run the application now to see what it looks like. To run the application, click on the   Run icon in the main toolbar of Flash Builder. This will launch the web application as shown below. Clicking the Say Hello button will not do anything at this point since there is no code written inside the handler as we saw above. To display the MessageBox, we add the code shown below (Only the Script section is shown below): <fx:Script> <![CDATA[ import mx.controls.Alert; protected function btnSayHello_clickHandler(event:MouseEvent):void { Alert.show("Hello World"); } ]]> </fx:Script> We use one of the classes (called Alert) from the Flex framework. Like any other language, we need to specify which package we are using the class from so that the compiler can understand it. The Alert class belongs to the mx.controls package and it has a static method called show() which takes a single parameter of type String. This String parameter is the message to be displayed and in our case it is "Hello World". To run this, click Ctrl-S to save your file or File →  Save from the main menu. And click on Run icon in the main toolbar. This will launch the application and on clicking the SayHello button, you will see the Hello World Alert window as shown below.

(For more resources on this subject, see here.) Provider—Consumer Contract In the JBI environment, the provider and consumer always interact based on a services model. A service interface is the common aspect between them. WSDL 1.1 and 2.0 are used to define the contract through the services interface. The following figure represents the two parts of the WSDL representation of a service: In the Abstract Model, WSDL describes the propagation of a message through a type system. A message has sequence and cardinality specified by its Message Exchange Pattern (MEP). A Message can be a Fault Message also. An MEP is associated with one or more messages using an Operation. An Interface can contain a single Operation or a group of Operations represented in an abstract fashion—independent of wire formats and transport protocols. An Interface in the Abstract Model is bound to a specific wire format and transport protocol via Binding. A Binding is associated with a network address in an Endpoint and a single Service in the concrete model aggregates multiple Endpoints implementing common interfaces. Detached Message Exchange JBI-based message exchange occurs between a Provider and Consumer in a detached fashion. This means, the Provider and Consumer never interact directly. In technical terms, they never share the same thread context of execution. Instead, the Provider and Consumer use JBI NMR as an intermediary. Thus, the Consumer sends a request message to the NMR. The NMR, using intelligent routers decides the best matched service provider and dispatches the message on behalf of the Consumer. The Provider component can be a different component or the same component as the Consumer itself. The Provider can be an SE or a BC and based on the type it will execute the business process by itself or delegate the actual processing to the remotely bound component. The response message is sent back to the NMR by the Provider, and the NMR in turn passes it back to the Consumer. This completes the message exchange. The following figure represents the JBI-based message exchange: There are multiple patterns by which messages are exchanged, which we will review shortly. Provider—Consumer Role Though a JBI component can function as a Consumer, a Provider, or as both a Consumer and Provider, there is clear cut distinction between the Provider and Consumer roles. These roles may be performed by bindings or engines, in any combination of the two. When a binding acts as a service Provider, an external service is implied. Similarly, when the binding acts as a service Consumer, an external Consumer is implied. In the same way, the use of a Service Engines in either role implies a local actor for that role. This is shown in the following figure: The Provider and Consumer interact with each other through the NMR. When they interact, they perform the distinct responsibilities (not necessarily in the same order). The following is the list of responsibilities, performed by the Provider and Consumer while interacting with NMR: Provider: Once deployed, the JBI activates the service provider endpoint. Provider: Provider then publishes the service description in WSDL format. Consumer: Consumer then discovers the required service. This can happen at design time (static binding) or run time (dynamic binding). Consumer: Invokes the queried service. Provider and Consumer: Send and respond to message exchanges according to the MEP, and state of the message exchange instance. Provider: Provides the service by responding to the function invocations. Provider and Consumer: Responds with status (fault or done) to complete the message exchange. During run-time activation, a service provider activates the actual services it provides, making them known to the NMR. It can now route service invocations to that service. javax.jbi.component.ComponentContext context ;// Initialized via. AOPjavax.jbi.messaging.DeliveryChannel channel = context. getDeliveryChannel();javax.jbi.servicedesc.ServiceEndpoint serviceEndpoint = null; if (service != null && endpoint != null) { serviceEndpoint = context.activateEndpoint (service, endpoint); } The Provider creates a WSDL described service available through an endpoint. As described in the Provider-Consumer contract, the service implements a WSDL-based interface, which is a collection of operations. The consumer creates a message exchange to send a message to invoke a particular service. Since consumers and providers only share the abstract service definition, they are decoupled from each other. Moreover, several services can implement the same WSDL interface. Hence, if a consumer sends a message for a particular interface, the JBI might find more than one endpoint conforming to the interface and can thus route to the best-fit endpoint. Message Exchange A message exchange is the "Message Packet" transferred between a consumer and a provider in a service invocation. It represents a container for normalized messages which are described by an exchange pattern. Thus message exchange encapsulates the following: Normalized message Message exchange metadata Message exchange state Thus, message exchange is the JBI local portion of a service invocation. Service Invocation An end-to-end interaction between a service consumer and a service provider is a service invocation. Service consumers employ one or more service invocation patterns. Service invocation through a JBI infrastructure is based on a 'pull' model, where a component accepts message exchange instances when it is ready. Thus, once a message exchange instance is created, it is sent back and forth between the two participating components, and this continues till the status of the message exchange instance is either set to 'done' or 'error', and sent one last time between the two components. Message Exchange Patterns (MEP) Service consumers interact with service providers for message exchange employing one or more service invocation patterns. The MEP defines the names, sequence, and cardinality of messages in an exchange. There are many service invocation patterns, and, from a JBI perspective, any JBI-compliant ESB implementation must support the following four service invocations: One-Way: Service consumer issues a request to the service provider. No error (fault) path is provided. Reliable One-Way: Service consumer issues a request to the service provider. Provider may respond with a fault if it fails to process the request. Request-Response: Service Consumer issues a request to the service provider, with expectation of response. Provider may respond with a fault if it fails to process request. Request Optional-Response: Service consumer issues a request to the service provider, which may result in a response. Both consumer and provider have the option of generating a fault in response to a message received during the interaction. The above service invocations can be mapped to four different MEPs that are listed as follows. In-Only MEP In-Only MEP is used for one-way exchanges. The following figure diagrammatically explains the In-Only MEP: In the In-Only MEP normal scenario, the sequence of operations is as follows: Service Consumer initiates with a message. Service Provider responds with the status to complete the message exchange. In the In-Only MEP normal scenario, since the Consumer issues a request to the Provider with no error (fault) path, any errors at the Provider-level will not be propagated to the Consumer.    

Adding Validation to Components The Start page of the web application Celebrity Collector has a login form that expects the user to enter some values into its two fields. But, what if the user didn't enter anything and still clicked on the Log In button? Currently, the application will decide that the credentials are wrong and the user will be redirected to the Registration page, and receive an invitation to register. This logic does make some sense; but, it isn't the best line of action, as the button might have been pressed by mistake. These two fields, User Name and Password, are actually mandatory, and if no value was entered into them, then it should be considered an error. All we need to do for this is to add a required validator to every field, as seen in the following code: <tr> <td> <t:label t_for="userName"> Label for the first text box</t:label>: </td> <td> <input type="text" t_id="userName" t_type="TextField" t:label="User Name" t_validate="required"/> </td></tr><tr> <td> <t:label t_for="password"> The second label</t:label>: </td><td> <input type="text" t_id="password" t_label="Password" t:type="PasswordField" t_validate="required"/></td></tr> Just one additional attribute for each component, and let's see how this works now. Run the application, leave both fields empty and click on the Log In button. Here is what you should see: Both fields, including their labels, are clearly marked now as an error. We even have some kind of graphical marker for the problematic fields. However, one thing is missing—a clear explanation of what exactly went wrong. To display such a message, one more component needs to be added to the page. Modify the page template, as done here: <t:form t_id="loginForm"> <t:errors/> <table> The Errors component is very simple, but one important thing to remember is that it should be placed inside of the Form component, which in turn, surrounds the validated components. Let's run the application again and try to submit an empty form. Now the result should look like this: This kind of feedback doesn't leave any space for doubt, does it? If you see that the error messages are strongly misplaced to the left, it means that an error in the default.css file that comes with Tapestry distribution still hasn't been fixed. To override the faulty style, define it in our application's styles.css file like this: DIV.t-error LI{ margin-left: 20px;} Do not forget to make the stylesheet available to the page. I hope you will agree that the efforts we had to make to get user input validated are close to zero. But let's see what Tapestry has done in response to them: Every form component has a ValidationTracker object associated with it. It is provided automatically, we do not need to care about it. Basically, ValidationTracker is the place where any validation problems, if they happen, are recorded. As soon as we use the t:validate attribute for a component in the form, Tapestry will assign to that component one or more validators, the number and type of them will depend on the value of the t:validate attribute (more about this later). As soon as a validator decides that the value entered associated with the component is not valid, it records an error in the ValidationTracker. Again, this happens automatically. If there are any errors recorded in ValidationTracker, Tapestry will redisplay the form, decorating the fields with erroneous input and their labels appropriately. If there is an Errors component in the form, it will automatically display error messages for all the errors in ValidationTracker. The error messages for standard validators are provided by Tapestry while the name of the component to be mentioned in the message is taken from its label. A lot of very useful functionality comes with the framework and works for us "out of the box", without any configuration or set-up! Tapestry comes with a set of validators that should be sufficient for most needs. Let's have a more detailed look at how to use them. Validators The following validators come with the current distribution of Tapestry 5: Required—checks if the value of the validated component is not null or an empty string. MinLength—checks if the string (the value of the validated component) is not shorter than the specified length. You will see how to pass the length parameter to this validator shortly. MaxLength—same as above, but checks if the string is not too long. Min—ensures that the numeric value of the validated component is not less than the specified value, passed to the validator as a parameter. Max—as above, but ensures that the value does not exceed the specified limit. Regexp—checks if the string value fits the specified pattern. We can use several validators for one component. Let's see how all this works together. First of all, let's add another component to the Registration page template: <tr> <td><t:label t_for="age"/>:</td> <td><input type="text" t_type="textfield" t_id="age"/></td></tr> Also, add the corresponding property to the Registration page class, age, of type double. It could be an int indeed, but I want to show that the Min and Max validators can work with fractional numbers too. Besides, someone might decide to enter their age as 23.4567. This will be weird, but not against the laws. Finally, add an Errors component to the form at the Registration page, so that we can see error messages: <t:form t_id="registrationForm"> <t:errors/> <table> Now we can test all the available validators on one page. Let's specify the validation rules first: Both User Name and Password are required. Also, they should not be shorter than three characters and not longer than eight characters. Age is required, and it should not be less than five (change this number if you've got a prodigy in your family) and not more than 120 (as that would probably be a mistake). Email address is not required, but if entered, should match a common pattern. Here are the changes to the Registration page template that will implement the specified validation rules: <td> <input type="text" t_type="textfield" t_id="userName" t:validate="required,minlength=3,maxlength=8"/></td>...<td> <input type="text" t_type="passwordfield" t_id="password" t:validate="required,minlength=3,maxlength=8"/></td>...<td> <input type="text" t_type="textfield" t_id="age" t:validate="required,min=5,max=120"/></td>...<input type="text" t_type="textfield" t_id="email" t:validate="regexp"/> As you see, it is very easy to pass a parameter to a validator, like min=5 or maxlength=8. But, where do we specify a pattern for the Regexp validator? The answer is, in the message catalog. Let's add the following line to the app.properties file: email-regexp=^([a-zA-Z0-9_.-])+@(([a-zA-Z0-9-])+.)+([a-zA-Z0-9]{2,4})+$ This will serve as a regular expression for all Regexp validators applied to components with ID email throughout the application. Run the application, go to the Registration page and, try to submit the empty form. Here is what you should see: Looks all right, but the message for the age could be more sensible, something like You are too young! You should be at least 5 years old. We'll deal with this later. However for now, enter a very long username, only two characters for password and an age that is more than the upper limit, and see how the messages will change: Again, looks good, except for the message about age. Next, enter some valid values for User Name, Password and Age. Then click on the check box to subscribe to the newsletter. In the text box for email, enter some invalid value and click on Submit. Here is the result: Yes! The validation worked properly, but the error message is absolutely unacceptable. Let's deal with this, but first make sure that any valid email address will pass the validation.   Providing Custom Error Messages We can provide custom messages for validators in the application's (or page's) message catalog. For such messages we use keys that are made of the validated component's ID, the name of validator and the "message" postfix. Here is an example of what we could add to the app.properties file to change error messages for the Min and Max validators of the Age component as well as the message used for the email validation: email-regexp-message=Email address is not valid.age-min-message=You are too young! You should be at least 5 years old.age-max-message=People do not live that long! Still better, instead of hard-coding the required minimal age into the message, we could insert into the message the parameter that was passed to the Min validator (following the rules for java.text.Format), like this: age-min-message=You are too young! You should be at least %s years old. If you run the application now and submit an invalid value for age, the error message will be much better: You might want to make sure that the other error messages have changed too. We can now successfully validate values entered into separate fields, but what if the validity of the input depends on how two or more different values relate to each other? For example, at the Registration page we want two versions of password to be the same, and if they are not, this should be considered as an invalid input and reported appropriately. Before dealing with this problem however, we need to look more thoroughly at different events generated by the Form component.  

Building a kiosk locator feature for your site Your company has just deployed 500 multi-purpose payment kiosks around the country, cash cows for the milking. Another 500 more are on the way, promising to bring in the big bucks for all the hardworking employees in the company. Naturally your boss wants as many people as possible to know about them and use them. The problem is that while the marketing machine churns away on the marvels and benefits of the kiosks, the customers need to know where they are located to use them. He commands you: "Find a way to show our users where the nearest kiosks to him are, and directions to reach them!" What you have is a database of all the 500 locations where the kiosks are located, by their full address. What can you do? Requirements overview Quickly gathering your wits, you penned down the following quick requirements: Each customer who comes to your site needs to be able to find the closest kiosk to his or her current location. He or she might also want to know the closest kiosk to any location. You want to let the users determine the radius of the search. Finding the locations of the closest kiosks, you need to show him how to reach them. You have 500 kiosks now, (and you need to show where they are) but another 500 will be coming, in 10s and 20s, so the location of the kiosks need to be specified during the entry of the kiosks. You want to put all of these on some kind of map. Sounds difficult? Only if you didn't know about web mashups! Design The design for this first project is rather simple. We will build a simple database application using Rails and create a main Kiosk class in which to store the kiosk information including its address, longitude, and latitude information. After populating the database with the kiosk information and address, we will use a geolocation service to discover its longitude and latitude. We store the information in the same table. Next, we will take the kiosk information and mash it up with Google Maps and display the kiosks as pushpins on the online map and place its information inside an info box attached to each pushpin. Mashup APIs on the menu In this article we will be using the following services to create a 'find closest' mashup plugin: Google Maps APIs including geocoding services Yahoo geocoding services (part of Yahoo Maps APIs) Geocoder.us geocoding services Geocoder.ca geocoding services Hostip.info Google Maps Google Maps is a free web-based mapping service provided by Google. It provides a map that can be navigated by dragging the mouse across it and zoomed in and out using the mouse wheel or a zoom bar. It has three forms of views—map, satellite and a hybrid of map and satellite. Google Maps is coded almost entirely in JavaScript and XML and Google provides a free JavaScript API library that allows developers to integrate Google Maps into their own applications. Google Maps APIs also provide geocoding capabilities, that is, they able to convert addresses to longitude and latitude coordinates. We will be using two parts of Google Maps: Firstly to geocode addresses as part of GeoKit's APIs Secondly to display the found kiosk on a customized Google Maps map Yahoo Maps Yahoo Maps is a free mapping service provided by Yahoo. Much like Google Maps it also provides a map that is navigable in a similar way and also provides an extensive set of APIs. Yahoo's mapping APIs range from simply including the map directly from the Yahoo Maps website, to Flash APIs and JavaScript APIs. Yahoo Maps also provides geocoding services. We will be using Yahoo Maps geocoding services as part of GeoKit's API to geocode addresses. Geocoder.us Geocoder.us is a website that provides free geocoding of addresses and intersections in the United States. It relies on Geo::Coder::US, a Perl module available for download from the CPAN and derives its data from the TIGER/Line data set, public-domain data from the US Census Bureau. Its reliability is higher in urban areas but lower in the other parts of the country. We will be using Geocoder.us as part of GeoKit's API to geocode addresses. Geocoder.ca Geocoder.ca is a website that provides free geocoding of addresses in the United States and Canada. Like Geocoder.us. it uses data from TIGER/Line but in addition, draws data from GeoBase, the Canadian government-related initiative that provides geospatial information on Canadian territories. We will be using Geocoder.ca as part of GeoKit's API to geocode addresses. Hostip.info Hostip.info is a website that provides free geocoding of IP addresses. Hostip.info offers an HTTP-based API as well as its entire database for integration at no cost. We will be using Hostip.info as part of GeoKit's API to geocode IP addresses. GeoKit GeoKit is a Rails plugin that enables you to build location-based applications. For this article we will be using GeoKit for its geocoding capabilities in two ways: To determine the longitude and latitude coordinates of the kiosk from its given address To determine the longitude and latitude coordinates of the user from his or her IP address GeoKit is a plugin to your Rails application so installing it means more or less copying the source files from the GeoKit Subversion repository and running through an installation script that adds certain default parameters in your environment.rb file. To install the GeoKit, go to your Rails application folder and execute this at the command line: $./script/plugin install svn://rubyforge.org/var/svn/geokit/trunk This will copy the necessary files to your RAILS_ROOT/vendor/plugins folder and run the install.rb script. Configuring GeoKit After installing GeoKit you will need to configure it properly to allow it to work. GeoKit allows you to use a few sets of geocoding APIs, including Yahoo, Google, Geocoder.us, and Geocoder.ca. These geocoding providers can be used directly or through a cascading failover sequence. Using Yahoo or Google requires you to register for an API key but they are free. Geocoder.us is also free under certain terms and conditions but both Geocoder.us and Geocoder.ca have commercial accounts. In this article I will briefly go through how to get an application ID from Yahoo and a Google Maps API key from Google. Getting an application ID from Yahoo Yahoo's application ID is needed for any Yahoo web service API calls. You can use the same application ID for all services in the same application or multiple applications or one application ID per service. To get the Yahoo application ID, go to https://developer.yahoo.com/wsregapp/index.php and provide the necessary information. Note that for this application you don't need user authentication. Once you click on submit, you will be provided an application ID. Getting a Google Maps API key from Google To use Google Maps you will need to have a Google Maps API key. Go to http://www.google.com/apis/maps/signup.html. After reading the terms and conditions you will be asked to give a website URL that will use the Google Maps API. For geocoding purposes, this is not important (anything will do) but to display Google Maps on a website, this is important because Google Maps will not display if the URL doesn't match. However all is not lost if you have provided the wrong URL at first; you can create any number of API keys from Google. Configuring evironment.rb Now that you have a Yahoo application ID and a Google Maps API key, go to environment.rb under the RAILS_ROOT/config folder. Installing GeoKit should have added the following to your environment.rb file: # Include your application configuration below # These defaults are used in GeoKit::Mappable.distance_to and in acts_as_mappable GeoKit::default_units = :miles GeoKit::default_formula = :sphere # This is the timeout value in seconds to be used for calls to the geocoder web # services. For no timeout at all, comment out the setting. The timeout unit is in seconds. # GeoKit::Geocoders::timeout = 3 # These settings are used if web service calls must be routed through a proxy. # These setting can be nil if not needed, otherwise, addr and port must be filled in at a minimum. If the proxy requires authentication, the username and password can be provided as well. GeoKit::Geocoders::proxy_addr = nil GeoKit::Geocoders::proxy_port = nil GeoKit::Geocoders::proxy_user = nil GeoKit::Geocoders::proxy_pass = nil # This is your yahoo application key for the Yahoo Geocoder # See http://developer.yahoo.com/faq/index.html#appid and http://developer.yahoo.com/maps/rest/V1/geocode.html GeoKit::Geocoders::yahoo = <YOUR YAHOO APP ID> # This is your Google Maps geocoder key. # See http://www.google.com/apis/maps/signup.html and http://www.google.com/apis/maps/documentation/#Geocoding_Examples GeoKit::Geocoders::google = <YOUR GOOGLE MAPS KEY> # This is your username and password for geocoder.us # To use the free service, the value can be set to nil or false. For usage tied to an account, the value should be set to username:password. # See http://geocoder.us and http://geocoder.us/user/signup GeoKit::Geocoders::geocoder_us = false # This is your authorization key for geocoder.ca. # To use the free service, the value can be set to nil or false. For usage tied to an account, set the value to the key obtained from Geocoder.ca # See http://geocoder.ca and http://geocoder.ca/?register=1 GeoKit::Geocoders::geocoder_ca = false # This is the order in which the geocoders are called in a failover scenario # If you only want to use a single geocoder, put a single symbol in the array. # Valid symbols are :google, :yahoo, :us, and :ca # Be aware that there are Terms of Use restrictions on how you can use the various geocoders. Make sure you read up on relevant Terms of Use for each geocoder you are going to use. GeoKit::Geocoders::provider_order = [:google,:yahoo] Go to the lines where you are asked to put in the Yahoo and Google keys and change the values accordingly. Make sure the keys are within apostrophes. Then go to the provider order and put in the order you want (the first will be tried; if that fails it will go to the next until all are exhausted): GeoKit::Geocoders::provider_order = [:google,:yahoo] This completes the configuration of GeoKit. YM4R/GM YM4R/GM is another Rails plugin, one that facilitates the use of Google Maps APIs. We will be using YM4R/GM to display the kiosk locations on a customized Google Map. This API essentially wraps around the Google Maps APIs but also provides additional features to make it easier to use from Ruby. To install it, go to your Rails application folder and execute this at the command line: $./script/plugin install svn://rubyforge.org/var/svn/ym4r/Plugins/GM/trunk/ym4r_gm During the installation, the JavaScript files found in the RAILS_ROOT/vendors/plugin/javascript folder will be copied to the RAILS_ROOT/public/javascripts folder. A gmaps_api_key.yml file is also created in the RAILS_ROOT/config folder. This file is a YAML representation of a hash, like the database.yml file in which you can set up a test, development, and production environment. This is where you will put in your Google Maps API key (in addition to the environment.rb you have changed earlier). For your local testing you will not need to change the values but once you deploy this in production on an Internet site you will need to put in a real value according to your domain.

{literal} What Are Feeds? Feeds are the way to publish news in Facebook. As we have already mentioned before, there are two types of feeds in Facebook, News feed and Mini feed. News feed instantly tracks activities of a user's online friends, ranging from changes in relationship status to added photos to wall comments. Mini feed appears on individuals' profiles and highlights recent social activity. You can see your news feed right after you log in, and point your browser to http://www.facebook.com/home.php. It looks like the following, which is, in fact, my news feed. Mini feeds are seen in your profile page, displaying your recent activities and look like the following one: Only the last 10 entries are being displayed in the mini feed section of the profile page. But you can always see the complete list of mini feeds by going to http://www.facebook.com/minifeed.php. Also the mini feed of any user can be accessed from http://www.facebook.com/minifeed.php?id=userid. There is another close relation between news feed and mini feed. When applications publish a mini feed in your profile, it will also appear in your friend's news feed page. How to publish Feeds Facebook provides three APIs to publish mini feeds and news feeds. But these are restricted to call not more than 10 times for a particular user in a 48 hour cycle. This means you can publish a maximum of 10 feeds in a specific user's profile within 48 hours. The following three APIs help to publish feeds: feed_publishStoryToUser—this function publishes the story to the news feed of any user (limited to call once every 12 hours). feed_publishActionOfUser—this one publishes the story to a user's mini feed, and to his or her friend's news feed (limited to call 10 times in a rolling 48 hour slot). feed_publishTemplatizedAction—this one also publishes mini feeds and news feeds, but in an easier way (limited to call 10 times in a rolling 48 hour slot). You can test this API also from http://developers.facebook.com/tools.php?api, and by choosing Feed Preview Console, which will give you the following interface: And once you execute the sample, like the previous one, it will preview the sample of your feed. Sample application to play with Feeds Let's publish some news to our profile, and test how the functions actually work. In this section, we will develop a small application (RateBuddies) by which we will be able to send messages to our friends, and then publish our activities as a mini feed. The purpose of this application is to display friends list and rate them in different categories (Awesome, All Square, Loser, etc.). Here is the code of our application: index.php<?include_once("prepend.php"); //the Lib and key container?><div style="padding:20px;"><?if (!empty($_POST['friend_sel'])){ $friend = $_POST['friend_sel']; $rating = $_POST['rate']; $title = "<fb:name uid='{$fbuser}' useyou='false' /> just <a href='http://apps.facebook.com/ratebuddies/'>Rated</a> <fb:name uid='{$friend}' useyou='false' /> as a '{$rating}' "; $body = "Why not you also <a href='http://apps.facebook.com/ratebuddies/'>rate your friends</a>?";try{//now publish the story to user's mini feed and on his friend's news feed $facebook->api_client->feed_publishActionOfUser($title, $body, null, $null,null, null, null, null, null, null, 1); } catch(Exception $e) { //echo "Error when publishing feeds: "; echo $e->getMessage(); }}?> <h1>Welcome to RateBuddies, your gateway to rate your friends</h1> <div style="padding-top:10px;"> <form method="POST"> Seect a friend: <br/><br/> <fb:friend-selector uid="<?=$fbuser;?>" name="friendid" idname="friend_sel" /> <br/><br/><br/> And your friend is: <br/> <table> <tr> <td valign="middle"><input name="rate" type="radio" value="funny" /></td> <td valign="middle">Funny</td> </tr> <tr> <td valign="middle"><input name="rate" type="radio" value="hot tempered" /></td> <td valign="middle">Hot Tempered</td> </tr> <tr> <td valign="middle"><input name="rate" type="radio" value="awesome" /></td> <td valign="middle">Awesome</td> </tr> <tr> <td valign="middle"><input name="rate" type="radio" value="naughty professor" /></td> <td valign="middle">Naughty Professor</td> </tr> <tr> <td valign="middle"><input name="rate" type="radio" value="looser" /></td> <td valign="middle">Looser</td> </tr> <tr> <td valign="middle"><input name="rate" type="radio" value="empty veseel" /></td> <td valign="middle">Empty Vessel</td> </tr> <tr> <td valign="middle"><input name="rate" type="radio" value="foxy" /></td> <td valign="middle">Foxy</td> </tr> <tr> <td valign="middle"><input name="rate" type="radio" value="childish" /></td> <td valign="middle">Childish</td> </tr> </table> &nbsp; <input type="submit" value="Rate Buddy"/> </form> </div></div> index.php includes another file called prepend.php. In that file, we initialized the facebook api client using the API key and Secret key of the current application. It is a good practice to keep them in separate file because we need to use them throughout our application, in as many pages as we have. Here is the code of that file: prepend.php<?php// this defines some of your basic setupinclude 'client/facebook.php'; // the facebook API library// Get these from ?http://www.facebook.com/developers/apps.phphttp://www.facebook.com/developers/apps.php$api_key = 'your api key';//the api ket of this application$secret = 'your secret key'; //the secret key$facebook = new Facebook($api_key, $secret); //catch the exception that gets thrown if the cookie has an invalid session_key in it try { if (!$facebook->api_client->users_isAppAdded()) { $facebook->redirect($facebook->get_add_url()); } } catch (Exception $ex) { //this will clear cookies for your application and redirect them to a login prompt $facebook->set_user(null, null); $facebook->redirect($appcallbackurl); }?> The client is a standard Facebook REST API client, which is available directly from Facebook. If you are not sure about these API keys, then point your browser to http://www.facebook.com/developers/apps.php and collect the API key and secret key from there. Here is a screenshot of that page: Just collect your API key and Secret Key from this page, when you develop your own application. Now, when you point your browser to http://apps.facebooks.com/ratebuddies and successfully add that application, it will look like this: To see how this app works, type a friend in the box, Select a friend, and click on any rating such as Funny or Foxy. Then click on the Rate Buddy button. As soon as the page submits, open your profile page and you will see that it has published a mini feed in your profile.

Tracking user activity The name of this module is slightly misleading. It allows you to view the recent contributions of a user to the site. One particular use for it, is that if one user found a particular user's posts interesting (perhaps, they both owned troublesome T-Rexes!), they could view the user's track page, and look for other contributions from that user which they might be interested in. This is only one way of interaction though, as opposed to two users interacting with each other. Settings and rules Within User management, we have three areas that we are yet to cover. They are: Access rules Gravatar User settings Let's look at these now. Access rules With the access rules, we can explicitly permit or prohibit certain usernames, email addresses, or hosts (computers) from accessing or joining our social networking site. There are quite a few different reasons why we may wish to do this. Let's take a look at a few specific examples: Disposable email addresses Perhaps all accounts originating from a free email provider should be blocked, except for one or two individual exceptions We may wish to prohibit swear words from our users' usernames Blocking email domains To block an entire email domain such as pookmail.com or hotmail.com, we would create two rules, both with Deny as the access type and E-Mail as the Rule type, and then %@ followed by their respective domain names. The % character tells the rule to match anything that comes before the @ symbol With an exception If we want to block all hotmail.com e-mail addresses except our friend's, our.friend@hotmail.com, then we would create an allow rule for this account. Preventing swear words in our user's usernames Creating rules with Username as the Rule type and the swear word (with a % on either side) will prevent such usernames from being registered. Checking rules The Check rules link at the top of the access rules page, allows us to check these rules by entering a username, email address, or hostname to see if that would be permitted or prohibited on our site. Be careful! If you add certain "bad words" with the wildcard (%) character on both sides, you can prevent some genuine signups; so this should be used only for extreme words. User settings From here, we can configure the registration requirements of our users, email templates used for new accounts and so on, and users' picture settings. User registration settings We can determine what security precautions should be taken when a new account is registered. New accounts: Can only be created by an administrator Can be created by a visitor, but require administrator approval Can be created by a visitor without administrator approval and in addition to the previous two, require user email verification Requiring email verification is a good idea. It is the very first and most basic method to help prevent spam and abusive user accounts. The User registration guidelines box can be used to provide some help for our users, and perhaps a link to some legal terms and conditions to help protect ourselves from liability. User email settings Users will often receive an email from our site automatically when: We create a new account for them They create an account They create an account which is pending our approval They request a new password They need to verify their email addresses Their accounts have been blocked Their accounts have been deleted The User e-mail settings area allows us to change the contents of these emails. Click on Administer | User management | User settings | User e-mail settings further down the page. Selecting an email allows us to change the template. Within these templates, there are tokens that are replaced with specific information when they are sent, for example, the user's username or a specific link. So it is important to ensure that these are still in the template. These variables are clearly defined when editing the template. They are all listed under the template name, each of them starting with an explanation mark, for example. !username for the username, !login_uri for the link to the log in page.