How-To Tutorials

article-image-windows-phone-8-principles-uiux-and-bindings

28 Oct 2013

12 min read

Windows Phone 8: Principles for UI/UX and Bindings

28 Oct 2013

(For more resources related to this topic, see here.) Principles for UI/UX There are many dos and don'ts in Windows Phone UI development. It is good to remember that we have a screen with a limited size where the elements should be placed comfortably. Fast and fluid This is the main goal of Windows Phone UX. Starting with the phone menu, we can switch between tiles and application lists; if we touch an element action it is performed very fast. We have to remember while creating our own software about providing responsivity to user interaction, even if we need to load some data or connect to a server, the user has to be informed about loading. Going through our application, the user should feel that he or she controls and can touch every element. Many controls provide animation out of the box and we need to use it; we need to impress our users while seeing motion in our application. The application has to be alive! Grid system The following design pattern provides consistency and high UX to Windows Phone users. It helps in organizing the application elements. A grid system will provide unity across applications and will make our application look similar to the Windows Store application. Talking about the grid layout, we mean arranging the content using grid lines. As we can see, the grid is where the application design starts. Each square is located 12 pixels from the other square. Single square has 25 x 25 pixels. In order to provide the best user experience to our application, we need to ensure that the elements are arranged appropriately. Looking at the left-hand side of the image, we find that each big tile contains 6 x 6 squares with 12 pixels margins. Windows is one When using a grid system and other design patterns for Windows Phone, porting to Windows Store will be possible and can be done more easily. Unfortunately at the moment, there are no common markets for Windows Phone application and Windows Store (applications for Windows 8 and Windows RT). The current solution is to create the application in a way that it allows portability to other platforms, such as separating the application's logic from UI. Even then some specific changes have to be done. Controls design best practices Button Use a maximum of two words in the Button content; it can be dynamically set but should never be more than two words To define content use system font Use a minimum height of 40 pixels CheckBox A CheckBox text should present a clear choice to the user If there are many choices, use the ScrollViewer and StackPanel control It is recommended to use single or a maximum of two lines of content text If the meaning of checkbox is not clear, use RadioButton or ListBox HyperlinkButton Don't place two hyperlinks close to each other because it will make it difficult to select either one Hyperlink text should not be longer than two words If some action can be reached by taping in text content, use HyperlinkButton instead of Button Image Size (resolution) of the picture has to be really close or identical to the Image control size Use gestures if it is possible The Image controls displays JPEG or PNG images Provide good quality images-non pixelated ListBox Use ListBox with long list of items; for smaller lists use RadioButton ListBox should be responsive so that it provides an immediate visual reaction for the user action Use at least 12 pixels height with sans-serif font MediaElement Do not show too many controls on one page Do not allow for a situation when more than one media (audio or video) is playing simultaneously Panorama The Panorama control handles only portrait orientation If you are using ApplicationBar with Panorama, make sure that the ApplicationBar control is in minimized mode Do not use too many sections (PanoramaItems); use a maximum of 5 sections to avoid torturing the user with swiping Panorama title can contain image and/or text Use system font; an exception is when your brand uses custom font First PanoramaItem should contain a left-aligned title For section title use plain text Do not use Pivot in PanoramaItem and Panorama in PivotItem Horizontal scrolling can be difficult because of the default behavior of Panorama; use vertical scrolling instead Good quality background photography makes for a very good users' impression, but ensure that all content is readable Background should be low contrast and dark Background image can be maximally 1024 x 800 pixels and minimally 480 x 800 pixels to provide good performance Pivot Do not place Pivot in PanoramaItem Use a maximum of 4 Pivot items Each PivotItem should not contain completely different actions; their functionality should be related Do not use input controls because it disrupts the Pivot flick, if you want to create a form with editing controls, use a separate page that will contain the form Do not use controls that need swipe or scroll inside Panorama like Map, ToggleButton, or Slider because the Pivot default gesture handling it, can make it difficult for the user to use them ProgressBar It is highly recommended to use a label that describes the state of the ProgressBar control-loading, launching, and failed RadioButton Avoid customization Provide 2 short words as content text, with at least 12 pixels height maximally Use ListBox if this control has more than 10 decisions to make Bring user's attention to the selected RadioButton control by making inactive those that are not selected ScrollViewer Avoid creating a situation where a user has too much content to scroll Slider Make sure that the Slider control is the appropriate size for comfortable use Do not use Slider as a progress indicator Do not put Slider too close to the edge of the screen because it can be difficult to select a value It shouldn't be used within Panorama or Pivot because Slider uses dragging gestures, whose usage is difficult in those containers TextBlock Make sure that the text in the TextBlock control looks clear and is readable TextBox To improve the user's experience, update the application content when the user enters text into TextBox; for example while filtering data It is not possible to scroll rich text inputs When it is likely that the user will enter a new value into TextBox, select all content on focus LongListSelector LongListSelector is used for a large number of data items Use at least 12 pixel Sans serif font Fonts From the GUI and UX point of view, it is critical to make text clear and legible. Entire text should be properly contrasted to the background. The font used in Windows Phone, is Sans serif, which is widely used in web and mobile applications. The Sans serif font type has many fonts, which one should we use? There is no simple answer for that, it depends on the control and context in which we use the text. However, it is recommended to use Segoe UI, Calibri, or Cambria font types. Segoe UI: This is best used in UI elements such as buttons, checkboxes, datepickers, and others like these. Calibri: This is best used for input and content text such as e-mail messages. When using this font it is good to set the font size to 13. Cambria: This font type is recommended for articles or any other big pieces of text, depending on content section, we can use 9, 11, 20 pt Cambria font. An example of each of the these fonts is as follows: 11 pt Segoe UI font 13 pt Calibri font 11 pt Cambria font Tiles and notifications My friend who is the owner of a company that creates mobile applications, once said to me that 50% of an application's success depends on how nice and good looking the icon/tile is. After thinking about it, I imagine he was right. The tile is the first thing that a user sees when starting to use our application (remember what I said about first impression?). The Windows Phone tile is not only a static icon that represents our application, but it can be live and show some simplified content as well. A default tile is a static icon and can display some information such as message count after it updates, and it returns to the default tile only after another update. An application tile can be pinned to the Start screen and set in one of 3 sizes: A small tile is built from 3 x 3 grid units. It is half the width and height of medium tile. It was introduced in Windows Phone 8 and 7.8 update of Windows Phone 7. Only a medium-size tile was available in Windows Phone 7. Every application pinned to the Start screen starts with medium tile. Along with the small tile, a large tile was introduced in Windows Phone 8. Why we should use the tile that is updating (live tile)? Because the tile is the front door of our application and if it gives some notification to user it really says, "Hey! Come here and see what I've got for you!". An updated tile assures the users that our application is fresh and active, even if it has not been run for some time. If we want to allow the user to pin our application in large/wide tile, we should provide a wide image, point it in the application manifest, and mark the Supports wide size option. There are some good practices which are worth following. If our application has the content that is refreshed at least once every few days and can be interesting for the user, we should enable our application to use wide tile; if not it is not necessary. Forget about the wide tile if the application doesn't use notifications. There are three available tile templates that will help us to create tiles as follows: Iconic template which is mainly used for e-mails, messaging, RSS, and social networking apps. Flip templates that are used in an application gives the user a lot of information like weather application. Cycle template for galleries and photo applications that cycles 1 to 9 images in a tile—applicable only for medium and wide tile. Bindings Basically, binding is a mechanism that the whole MVVM pattern relays on. It is very powerful and is the "glue" between the view and the exposed fields and commands. The functionality that we want to implement is shown in the following diagram: Model We are going to use the Model class for storing data about users. public class UserModel:INotifyPropertyChanged { private string name {get;set; public string Name { get; set { name = value; RaisePropertyChanged(); } } public string LastName { get; set{(…)} } public string Gender { get; set{(…)} } public DateTime DateOfBirth { get; set{(…)} } public event PropertyChangedEventHandler PropertyChanged; (…) } One thing that we still have to implement is the property changed event subscription for all fields within this UserModel class. ViewModel Now, UserModel will be wrapped into UserViewModel. Our ViewModel will also implement the INotifyPropertyChanged interface for updating View when the VieModels object change. public class UserViewModel:INotifyPropertyChanged { public UserModel CurrentUser { get; set; } public string FullName { get { if (this.CurrentUser != null) { return string.Format("{0} {1}", this.CurrentUser.Name, this.CurrentUser.LastName); } return ""; } } public List<string> ListOfPossibleGenders = new List<string>(){"Male","Female"}; (…) } As we can see, UserModel is wrapped in two ways: the first is wrapping the entire Model and some properties that are transformed into FullName. The FullName property contains Name and LastName that comes from UserModel object. View I'm going to create a view, piece by piece, to show how things should be done. At the beginning, we should create a new UserControl object called UserView in the Views folder. We will do almost everything now in XAML; so, we have to open the UserView.xaml file and add a few things. In the root node, we have to add namespace for our ViewModel folder. Because of this line, our ViewModels will be accessible in the XAML code. <UserControl.DataContext> <models:UserViewModel/> </UserControl.DataContext> It sets DataContext of our view in XAML and has its equivalent in DataContext. If we wish to set DataContext in the code behind, we have to go to the constructor in the .cs file. public UserView() { InitializeComponent(); var viewModel = new SampleViewModel(); this.DataContext = viewModel; } A better approach is to define the ViewModel instance in XAML because we have intellisense support in binding expressions for fields that are public in ViewModel and the exposed model. As we can see, ViewModel contains the CurrentUser property that will store and expose the user data to the view. It has to be public, and thing that is missing here is the change notification in the CurrentUser setter. However, we already know how to do that so it is not described. <StackPanel> <TextBlock Text="Name"></TextBlock> <TextBox Name="txtName" Text="{ Binding CurrentUser.Name, Mode=TwoWay }"> </TextBox> <TextBlock Text="Lastname"></TextBlock> <TextBox Name="txtLastName" Text="{ Binding CurrentUser.LastName , Mode=TwoWay}"> </TextBox> <TextBlock Text="Gender"></TextBlock> <ListBox Name="lstGender" ItemsSource="{ Binding ListOfPossibleGenders}" SelectedItem="{Binding CurrentUser.Gender, Mode=TwoWay}"> </ListBox> </StackPanel> The preceding example shows how to set binding using the exposed model as well as list or property that was implemented directly in ViewModel. We made all these things without any code behind line! This is really good because our sample is testable and is very easy to write unit tests We use the TwoWay binding mode that automatically populates the control value and then the edit control value of the ViewModel property also gets updated. Summary Creating complex applications that will be intuitive and simple to use is really hard without the knowledge of the UI and UX principles that were described in this article. We covered a huge part of XAML— bindings. Resources for Article : Further resources on this subject: Windows 8 with VMware View [Article] How to Build a RSS Reader for Windows Phone 7 [Article] Introducing the Windows Store [Article]

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2626

How-To Tutorials

article-image-getting-started-codeblocks

Packt

28 Oct 2013

7 min read

Getting Started with Code::Blocks

Packt

28 Oct 2013

7 min read

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8147

Packt

28 Oct 2013

29 min read

Availability Management

Packt

28 Oct 2013

29 min read

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2757

Packt

28 Oct 2013

21 min read

Getting into the Store

Packt

28 Oct 2013

21 min read

(For more resources related to this topic, see here.) This all starts by visiting https://appdev.microsoft.com/StorePortals, which will get you to the store dashboard that you use to submit and manage your applications. If you already have an account you'll just log in here and proceed. If not, we'll take a look at ways of getting it set up. There are a couple of ways to get a store account, which you will need before you can submit any game or application to the store. There are also two different types of accounts: Individual accounts Company accounts In most cases you will only need the first option. It's cheaper and easier to get, and you won't require the enterprise features provided by the company account for a game. For this reason we'll focus on the individual account. To register you'll need a credit card for verification, even if you gain a free account another way. Just follow the registration instructions, pay the fee, and complete verification, after which you'll be ready to go. Free accounts Students and developers with MSDN subscriptions can access registration codes that waive the fee for a minimum of one year. If you meet either of these requirements you can gain a code using the respective methods, and use that code during the registration process to set the fee to zero. Students can access their free accounts using the DreamSpark service that Microsoft runs. To access this you need to create an account on www.dreamspark.com and create an account. From there follow the steps to verify your student status and visit https://www.dreamspark.com/Student/Windows-Store-Access.aspx to get your registration code. If you have access to an MSDN subscription you can use this to gain a store account for free. Just log in to your account and in your account benefits overview you should be able to generate your registration code. Submitting your game So your game is polished and ready to go. What do you need to do to get it in the store? First log in to the dashboard and select Submit an App from the menu on the left. Here you can see the steps required to submit the app. This may look like a lot to do, but don't worry. Most of these are very simple to resolve and can be done before you even start working on the game. The first step is to choose a name for your game, and this can be done whenever you want. By reserving a name and creating the application entry you have a year to submit your application, giving you plenty of time to complete it. This is why it's a good idea to jump in and register your application once you have a name for it. If you change your mind later and want a different name you can always change it. The next step is to choose how and where you will sell your game. The other thing you need to choose here are the markets you want to sell your game in. This can be an area you need to be careful of, because the markets you choose here define the localization or content you need to watch for in your game. Certain markets are restrictive and including content that isn't appropriate for a market you say you want to sell in can cause you to fail the certification process. Once that is done you need to choose when you want to release your game—you can choose to release as soon as certification finishes or on a specific date, and then you choose the app category, which in this case will be Games. Don't forget to specify the genre of your game as the sub-category so players can find it. The final option on the Selling Details page which applies to us is the Hardware requirements section. Here we define the DirectX feature-level required for the game, and the minimum RAM required to run it. This is important because the store can help ensure that players don't try to play your game on systems that cannot run it. The next section allows you to define the in-app offers that will be made available to players. The Age rating and rating certificates section allows you to define the minimum age required to play the game, as well as submit official ratings certificates from ratings boards so that they may be displayed in the store to meet legal requirements. The latter part is optional in some cases, and may affect where you can submit your game depending on local laws. Aside from official ratings, all applications and games submitted to the store require a voluntary rating, chosen from one of the following age options: 3+ 7+ 12+ 16+ 18+ While all content is checked, the 7+ and 3+ ratings both have extra checks because of the extra requirements for those age ranges. The 3+ rating is especially restrictive as apps submitted with that age limit may not contain features that could connect to online services, collect personal information, or use the webcam or microphone. To play it safe it's recommended the 12+ rating is chosen, and if you're still uncertain, higher is safer. GDF Certificates The other entry required here if you have official ratings certificates is a GDF file. This is a Game Definition File, which defines the different ratings in a single location and provides the necessary information to display the rating and inform any parental settings. To do this you need to use the GDFMAKER.exe utility that ships with the Windows 8 SDK, and generate a GDF file which you can submit to the store. Alongside that you need to create a DLL containing that file (as a resource) without any entry point to include in the application package. For full details on how to create the GDF as well as the DLL, view the following MSDN article: http://msdn.microsoft.com/en-us/library/windows/apps/hh465153.aspx The final section before you need to submit your compiled application package is the cryptography declaration. For most games you should be able to declare that you aren't using any cryptography within the game and quickly move through this step. If you are using cryptography, including encrypting game saves or data files, you will need to declare that here and follow the instructions to either complete the step or provide an Export Control Classification Number (ECCN). Now you need to upload the compiled app package before you can continue, so we'll take a look at what it takes to do that before you continue. App packages To submit your game to the store, you need to package it up in a format that makes it easy to upload, and easy for the store to distribute. This is done by compiling the application as an .appx file. But before that happens we need to ensure we have defined all of the required metadata, and fulfill the certification requirements, otherwise we'll be uploading a package only to fail soon after. Part of this is done through the application manifest editor, which is accessible in Visual Studio by double-clicking on the Package.appxmanifest file in solution explorer. This editor is where you specify the name that will be seen in the start menu, as well as the icons used by the application. To pass certification all icons have to be provided at 100 percent DPI, which is referred to as Scale 100 in the editor. Icon/Image Base resolution Required Standard 150 x 150 px Yes Wide 310 x 150 px If Wide Tile Enabled Small 30 x 30 px Yes Store 50 x 50 px Yes Badge 24 x 24 px If Toasts Enabled Splash 620 x 300 px Yes If you wish to provide a higher quality images for people running on high DPI setups, you can do so with a simple filename change. If you add scale-XXX to your filename, just before the extension, and replace XXX with one of the following values, Windows will automatically make use of it at the appropriate DPI. scale-100 scale-140 scale-180 In the following image you can see the options available for editing the visual assets in the application. These all apply to the start menu and application start-up experience, including the splash screen and toast notifications. Toast Notifications in Windows 8 are pop-up notifications that slide in from the edge of the screen and show the users some information for a short period of time. They can click on the toast to open the application if they want. Alongside Live Tiles, Toast Notifications allow you to give the user information when the application is not running (although they work when the application is running). The previous table shows the different images you required for a Windows 8 application, and if they are mandatory or just required in certain situations. Note that this does not include the imagery required for the store, which includes some screenshots of the application and optional promotional art in case you want your application to be featured. You must replace all of the required icons with your own. Automated checks during certification will detect the use of the default "box" icon shown in the previous screenshot and automatically fail the submission. Capabilities Once you have the visual aspects in place, you need to declare the capabilities that the application will receive. Your game may not need any, however you should still only specify what you need to run, as some of these capabilities come with extra implications and non-obvious requirements. Adding a privacy policy One of those requirements is the privacy policy. Even if you are creating a game, there may be situations where you are collecting private information, which requires you to have a privacy policy. The biggest issue here is connecting to the internet. If your game marks any of the Internet capabilities in the manifest, you automatically trigger a check for a privacy policy as private information—in this case an IP address—is being shared. To avoid failing certification for this, you need to put together a privacy policy if you collect privacy information, or use any of the capabilities that would indicate you collect information. These include the Internet capabilities as well as location, webcam, and microphone capabilities. This privacy policy just needs to describe what you will do with the information, and directly mention your game and publisher name. Once you have the policy written, it needs to be posted in two locations. The first is a publicly accessible website, which you will provide a link to when filling out the description after uploading your game. The second is within the game itself. It is recommended you place this policy in the Windows 8 provided settings menu, which you can build using XAML or your own code. If you're going with a completely native Windows 8 application you may want to display the policy in your own way and link to it from options within your game. Declarations Once you've indicated the capabilities you want, you need to declare any operating system integration you've done. For most games you won't use this, however if you're taking advantage of Windows 8 features such as share targets (the destination for data shared using the Share Charm), or you have a Game Definition File, you will need to declare it here and provide the required information for the operating system. In the case of the GDF, you need to provide the file so that the parental controls system can make use of the ratings to appropriately control access. Certification kit The next step is to make sure you aren't going to fail the automated tests during certification. Microsoft provides the same automated tests used when you submit your app in the Windows Application Certification Kit (WACK). WACK is installed by default with Visual Studio 2012 or higher version. There are two ways to run the test: after you build your application package, or by running the kit directly against an installed app. We'll look at the latter first, as you might want to run the test on your deployed test game well before you build anything for the store. This is also the only way to run the WACK on a WinRT device, if you want to cover all bases. If you haven't already deployed or tested your app, deploy it using the Build menu in Visual Studio and then search for the Windows App Cert Kit using the start menu (just start typing). When you run this you will be given an option to choose which type of application you want to validate. In this case we want to select the Windows Store App option, which will then give you access to the list of apps installed on your machine. From there it's just a matter of selecting the app you want and starting the test. At this point you will want to leave your machine alone until the automated tests are complete. Any interference could lead to an incorrect failure of the certification tests. The results will indicate ways you can fix any issues; however, you should be fine for most of the tests. The biggest issues will arise from third party libraries that haven't been developed or ported to Windows 8. In this case the only option is to fix them yourself (if they're open source) or find an alternative. Once you have the test passing, or you feel confident that it won't be an issue, you need to create app packages that are compatible with the store. At this point your game will be associated with the submission you have created in the Windows Store dashboard so that it is prepared for upload. Creating your app packages To do this, right click on your game project in Visual Studio and click on Create App Packages inside the Store menu. Once you do that, you'll be asked if you want to create a package for the store. The difference between the two options comes down to how the package is signed. If you choose No here, you can create a package with your test certificate, which can be distributed for testing. These packages must be manually installed and cannot be submitted to the store. You can, however, use this type of package on other machines to install your game for testers to try out. Choosing No will give you a folder with a .ps1 file (Powershell), which you can run to execute the install script. Choosing Yes at this option will take you to a login screen where you can enter your Windows Store developer account details. Once you've logged in you will be presented with a list of applications that you have registered with the store. If you haven't yet reserved the name of your application, you can click on the Reserve Name link, which will take you directly to the appropriate page in the store dashboard. Otherwise select the name of the game you're trying to build and click on Next. The next screen will allow you to specify which architectures to build for, and the version number of the built package. As this is a C++ game, we need to provide separate packages for the ARM, x86, and x64 builds, depending on what you want to support. Simply providing an x86 and ARM build will cover the entire market; 64 bit can be nice to have if you need a lot of memory, but ultimately it is optional, and some users may not even be able to run x64 code. When you're ready click on Create and Visual Studio will proceed to build your game and compile the requested packages, placing them in the directory specified. If you've built for the store, you will need the .appxupload files from this directory when you proceed to upload your game. Once the build has completed you will be asked if you want to launch the Windows Application Certification Kit. As mentioned previously this will test your game for certification failures, and if you're submitting to the store it's strongly recommended you run this. Doing so at this screen will automatically deploy the built package and run the test, so ensure you have a little bit of time to let it run. Uploading and submitting Now that you have a built app package you can return to the store dashboard to submit your game. Just edit the submission you made previously and enter the Packages section, which will take you to the page where you can upload the appxupload file. Once you have successfully uploaded your game you will gain access to the next section, the Description. This is where you define the details that will be displayed in the store. This is also where your marketing skills come into play as you prepare the content that will hopefully get players to buy your game. You start with the description of your game, and any big feature bullet points you want to emphasize. This is the best place to mention any reviews or praise, as well as give a quick description that will help the players decide if they want to try your game. You can have a number of app features listed; however, like any "back of the box" bullet points, keep them short and exciting. Along with the description, the store requires at least one screenshot to display to the potential player. These screenshots need to be of the entire screen, and that means they need to be at least 1366x768, which is the minimum resolution of Windows 8. These are also one of the best ways to promote your game, so ensure you take some great screenshots that show off the fun and appeal of your game. There are a few ways to take a screenshot of your game. If you're testing in the simulator you can use the screenshot icon on the right toolbar of the simulator to take the screenshot. If not, you can use Windows Key + Prt Scr SysRq to take a screenshot of your entire screen, and then use that (or edit it if you have multiple monitors). Screenshots taken with either of these tools can be found in the Screenshots folder within your Pictures library. There are two other small pieces of information that are required during this stage: Copyright Info and Support contact info. For the support info, an e-mail address will usually suffice. At this point you can also include your website and, if applicable to your game, a link to the privacy policy included in your game. Note that if you require a privacy policy, it must be included in two places: your game, and the privacy policy field on this form. The last items you may want to add here are promotional images. These images are intended for use in store promotions and allow Microsoft to easily feature your game with larger promotional imagery in prominent locations within the store. If you are serious about maximizing the reach of your game, you will want to include these images. If you don't, the number of places your game can be featured will be reduced. At a minimum the 414x180 px image should be included if you want some form of promotion. Now you're almost done! The next section allows you to leave notes for the testing team. This is where you would leave test account details for any features in your game that require an account so that they can test those features. This is also the location to leave any notes about testing in case there are situations where you can point out any features that might not be obvious. In certain situations you may have an exemption from Microsoft for a certification requirement; this would be where you include that exemption. When every step has been completed and you have tick marks in all of the stages, the Submit for Certification button will unlock, allowing you to complete your submission and send it off for certification. At this stage a number of automated tests will run before human testers will try your game on a variety of devices to ensure it fits the requirements for the store. If all goes well, you will receive an email notifying you of your successful certification and, depending on if you set the release date as ASAP, you will find your game in the store a few hours later (it may take a few hours to appear in the store once you receive an email informing you that your game or app is in the store). Certification tips Your first stop should be the certification requirements page, which lists all of the current requirements your game will be tested for: http://msdn.microsoft.com/en-us/library/windows/apps/hh694083.aspx. There are some requirements that you should take note of, and in this section we'll take a look at ways to help ensure you pass those requirements. Privacy The first of course is the privacy policy. As mentioned before, if your game collects any sort of personal information, you will need that policy in two places: In full text within the game Accessible through an Internet link The default app template generated by Visual Studio automatically enables the Internet capability, and by simply having that enabled you require a privacy policy. If you aren't connecting to the Internet at all in your game, you should always ensure that none of the Internet options are enabled before you package your game. If you share any personal information, then you need to provide players with a method of opting in to the sharing. This could be done by gating the functionality behind a login screen. Note that this functionality can be locked away, and the requirement doesn't demand that you find a way to remain fully functional even if the user opts out. Features One requirement is that your game support both touch input and keyboard/mouse input. You can easily support this by using an input system like the one described in this article; however, by supporting touch input you get mouse input for free and technically fulfill this requirement. It's all about how much effort you want to put into the experience your player will have, and that's why including gamepad input is recommended as some players may want to use a connected Xbox 360 gamepad for their input device in games. Legacy APIs Although your game might run while using legacy APIs, it won't pass certification. This is checked through an automated test that also occurs during the WACK testing process, so you can easily check if you have used any illegal APIs. This often arises in third party libraries which make use of parts of the standard IO library such as the console, or the insecure versions of functions such as strcpy or fopen. Some of these APIs don't exist in WinRT for good reason; the console, for example, just doesn't exist, so calling APIs that work directly with the console makes no sense, and isn't allowed. Debug Another issue that may arise through the use of third-party libraries is that some of them may be compiled in debug mode. This could present issues at runtime for your app, and the packaging system will happily include these when compiling your game, unless it has to compile them itself. This is detected by the WACK and can be resolved by finding a release mode version, or recompiling the library. WACK The final tip is: run WACK. This kit quickly and easily finds most of the issues you may encounter during certification, and you see the issues immediately rather than waiting for it to fail during the certification process. Your final step before submitting to the store should be to run WACK, and even while developing it's a good idea to compile in release mode and run the tests to just make sure nothing is broken. Summary By now you should know how to submit your game to the store, and get through certification with little to no issues. We've looked at what you require for the store including imagery and metadata, as well as how to make use of the Windows Application Certification Kit to find problems early on and fix them up without waiting hours or days for certification to fail your game. One area unique to games that we have covered in this article is game ratings. If you're developing your game for certain markets where ratings are required, or if you are developing children's games, you may need to get a rating certificate, and hopefully you have an idea of where to look to do this. Resources for Article: Further resources on this subject: Introduction to Game Development Using Unity 3D [Article] HTML5 Games Development: Using Local Storage to Store Game Data [Article] Unity Game Development: Interactions (Part 1) [Article]

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article-image-managing-test-structure-robot-framework

Packt

25 Oct 2013

5 min read

Managing Test Structure with Robot Framework

Packt

25 Oct 2013

5 min read

(For more resources related to this topic, see here.) To manage the increased number of tests and to ensure their execution and quick and effective analysis, robot framework can be used which is a tool written in python which can be used to write different tests that may call other testing tools/software which perform actual tests and report back to the test framework. You should use robot framework because of various advantages that it offers, some of which is detailed in the following section: Uniformity XTest compliant Library support Flexible Distributive Open Uniformity Robot framework tests are uniform and readable from the end user's perspective and even if different technologies are involved in different tests for the same software, the test structure (since it is written in robot framework) for all the tests is consistent across the test project. XTest Compliant Robot framework is also xtest compliant, which means that it follows the same set of testing jargon and process as in other popular testing tools like JUnit, NUnit, and so on; also the developer associated with writing tests in robot framework has the least of surprises. Library Support Robot framework is supported by a vide variety of libraries for third party tools and given its robust community, it is easy to create a custom library as well. Flexible Not only the tests are uniform, but they may also be written according to the needs of the testing project. It is not uncommon to extend robot framework using keywords and associate tests to various keywords. This reduces complexity and brings about changes in writing tests. Test writing strategies like simple, keyword driven or behavior driven tests can be created and the same test can be written in many interesting ways. Distributive Robot framework is network friendly tool, and can also be used remotely to collect and share information. It also works with various network protocols straight out of box and presents advantages of a mature tool that can communicate and control tests present remotely. Open Owing to the open source nature(licensed under Apache version 2.0) of the robot framework, it is possible to see how it has been created and not get limited to its binary. For large scale customization, the source can directly be tweaked to perform work as desired. Environments Being a python based tool, it can work in python and python based environments such as jyton or ironpython which ensures that tests can be executed for newer application platforms like the java and .Net natively. The installations of various environments can be obtained directly or by building the source code . As mentioned by the build script, by using appropriate python instance to call the install.py, robot framework can be installed in different environments where the different executable are generated pertaining to the environment. For python environment, following executable are generated: pybot and rebot. For java environment, following executable are generated: jybot and jyrebot. For .net environment, following executable are generated: ipybot and ipyrebot. Note that in all three environments, the test structure and syntax is the same. What differs is the target applications which could be clr/jvm dependant and running robot framework on the same environment offers it the flexibility to access the software under test (SUT) more clearly. Test Naming Conventions In order to name tests, robot framework is very peculiar; it uses the configuration file and folder names to determine the execution order and test naming. For example, consider the following test hierarchy: application/ tests/ Test1.txt Other tests/ Another test.txt Running the pybot in the application folder will result in the following: The testsuite will be named after the root of test configuration, in this case, tests. Next, the Test1.txt will result in a nested testsuite, Test1 within testsuite tests. Similarly the testsuite another test will be nested under the tests/other tests testsuites. In order to organize the results, it is important to ensure proper naming. So, instead of using spaces, underscore '_' should be used. In order to get proper ordering irrespective of the test names, prefixing the test configuration with numbers can be done. This test hierarchy will therefore result in more understandable tests as well as the execution order of the tests can easily be predetermined. As mentioned, the test hierarchy is similar to any other XUnit based testing solution. Here, note that you can go on inserting test suites with themselves, which is different from other testing tool hierarchies. This approach gives more flexibility over the tests and introduces a new level of nesting. Running tests Running tests in robot framework is also very descriptive and the results of the tests can instantly be seen. In a similar manner, the results of the test can be viewed not only in the form of a detailed report, but also in the form of a log. The test results are also saved in an XML format where the tests can be recreated/merged/compared with other tests at a later date. This is achieved through the rebot command which can recreate the test structure in the generated report and log files through reading the metadata present in the XML file. Summary Through this article, you can clearly see the benefits of grouping and structuring the tests using robot framework and allowing for scalability in the tests by making the tests encapsulated within one another through the use of nested test suites. Robot Framework will not only integrated with your testing tool/solution, but also act as an assistant for your tests and manage, run and report their results back to you in a concise manner. Resources for Article: Further resources on this subject: Cross-browser-distributed testing [Article] Testing Backbone.js Application [Article] Python Testing: Installing the Robot Framework [Article]

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0
8155

How-To Tutorials

article-image-advanced-system-management

Packt

25 Oct 2013

11 min read

Advanced System Management

Packt

25 Oct 2013

11 min read

(For more resources related to this topic, see here.) Beyond backups Of course, backups are not the only issue with managing multiple, remote systems. In particular, managing such multiple configurations using a centralized application is often desirable. Configuration management One of the issues frequently faced by administrators is that of having multiple, remote systems all with similar software for the most part, but with minor differences in what is installed or running. Debian provides several packages that can help manage such an environment in a unified manner. Two of the more popular packages, both available in Debian, are FAI and Puppet. While we don't have the space to go into details, both applications are described briefly here. Fully Automated Installation Fully Automated Installation (FAI) focuses on managing Linux installations, and is developed using Debian, although it works with many different distributions, not just Debian. FAI uses a class concept for categorizing similar systems, and provides a good deal of flexibility and customization via hooks. FAI provides for unattended, automatic installation as well as tools for monitoring and updating groups of systems. FAI is frequently used for creating and maintaining clusters. More information is available at http://fai-project.org/. Puppet Probably the best known application for distributed management is Puppet, developed by Puppet Labs. Unlike FAI, only the Open Source edition is free, the Enterprise edition, which has many additional features, is not. Puppet does include support for environments other than Linux. The desired configuration is described in a custom, high-level definition language, and distributed to systems with installed clients. Unlike FAI, Puppet does not provide its own bare metal remote installation method, but does use existing methods (such as kickstart) to provide this function. A number of companies that make heavy use of distributed and clustered systems use Puppet to manage their environments. More information is available at http://puppetlabs.com/. Other packages There are other packages that can be used to manage a distributed environment, such as Chef and BCFG2. While simpler than Puppet or FAI, they support similar functions and have been used in some distributed and clustered environments. The use of FAI, Puppet, and others in cluster management warrants a brief look at clustering next, and what packages in Debian support clustering. Clusters A cluster is a group of systems that work together in such a way that the whole functions as a single unit. Such clusters can be loosely coupled or tightly coupled. A loosely coupled environment, each system is complete in itself, and can handle all of the tasks any of the other systems can handle. The environment provides mechanisms for redundancy, load sharing, and fail-over between systems, and is often called a High Availability (HA) cluster. In a tightly coupled environment, the systems involved are highly dependent on one another, often sharing memory and disk storage, and all work on the same task together. The environment provides mechanisms for data sharing, avoiding storage conflicts, keeping the systems in synchronization, and splitting up tasks appropriately. This design is often used in super-computing environments. Clustering is an advanced technique that involves more than just installing and configuring software. It also involves hardware integration, and systems and network design, and implementation. Along with the URLs mentioned below, a good text on the subject is Building Clustered Linux Systems, by Robert W. Lucke, Prentice Hall. Here we will only touch the very basics, along with what tools Debian provides. Let's take a brief look at each environment, and some of the tools used to create them. High Availability clusters Two primary functions are required to implement a high availability cluster: A way to handle load balancing and individual host fail-over. A way to synchronize storage so that all servers provide the same view of the data they serve. Debian includes meta packages that bring together software from the Linux High Availability project, including cluster-agents and resource-agents, two of the higher-level meta packages. These packages install various agents that are useful in coordinating and managing load balancing and fail-over. In some cases, a master server is designated to distribute the processing load among other servers. Data synchronization is handled by using shared storage and any of the filesystems that provide for multiple accesses and shared files, such as NFS or AFS. High Availability clusters generally use standard software, along with software that is readily available to manage the dynamics of such environments. Beowulf clusters In addition to the considerations for High Availability clusters, more tightly coupled environments such as Beowulf clusters also require an infrastructure to manage and distribute computing tasks. There are several web pages devoted to creating a Beowulf cluster using Debian as well as packages that aid in creating such a cluster. One such page is https://wiki.debian.org/StartaBeowulf, a Debian Wiki page on Beowulf basics. The manual for FAI also has a section on creating a Beowulf cluster. Books are available as well. Debian provides several packages that are helpful in building such a cluster, such as the OpenMPI libraries for message passing, and various utilities that run commands on multiple systems, such as those in the kadif package. There are even projects that have released scripts and live CDs that allow you to set up a cluster quickly (one such project is the PelicanHPC project, developed for Debian Lenny, hosted at http://www.pelicanhpc.org/. This type of cluster is not something that you can set up and go. Beowulf and other tightly coupled clusters are intended for highly parallel computing, and the programs that do the actual computing must be designed specifically for such an environment. That said, some packages for specific parallel computations do exist in Debian, such as nwchem, which provides several applications for computational chemistry that take advantage of parallelism. Common tools Some common components of clusters have already been mentioned, such as the OpenMPI libraries. Aside from the meta-packages already mentioned, the redhat-cluster suite of tools is available in Debian, as well as many useful libraries, scheduling tools, and failover tools such as booth. All of these can be found using apt-cache or Synaptic by searching for "cluster". Webmin Many administrators will never have to administer a cluster, and many won't be responsible for a large number of systems requiring central backup solutions. However, even administering a single system using command line tools and text editors can be a chore. Even clusters sometimes require administrative tasks on individual systems. Fortunately, there is an application that can ease many administrative tasks, is easy to use, and can handle many aspects of Linux administration. It is called Webmin. Up until Debian Sarge, Webmin was a part of Debian distributions. However, the Debian developer in charge of packaging it had difficulty keeping up with the frequent releases, and it was eventually dropped from Debian. However, the upstream Webmin developers maintain current packages that install cleanly. Some users have reported issues because Webmin does not always handle configuration files exactly as Debian intends, but it most certainly attempts to handle them in a compatible manner, and while some users have experienced problems with upgrades, many administrators are quite happy with Webmin. As long as you are willing to deal with conflicts during upgrades, or restrict use of modules that have major configuration impacts, you will find Webmin quite useful. Installing Webmin Webmin may be installed by adding the following lines to your apt sources file: deb http://download.webmin.com/download/repository sarge contrib deb http://webmin.mirror.somersettechsolutions.co.uk/repository sarge contrib Usually, this is added to a separate webmin.list file in /etc/apt/sources.list.d. The use of 'sarge' for the release name in the configuration is not a mistake. Since Webmin was dropped after the Sarge release (Debian 3.1), the developers update the repository as it is and haven't bothered changing it to keep up with the Debian code names. However, the versions available in the repository are compatible with any Debian release since 3.1. After updating your cache file, Webmin can be installed and maintained using apt-get, aptitude, or Synaptic. Also, if you request a Webmin upgrade from within Webmin itself on a Debian system, it will use the proper Debian package to upgrade. Using Webmin Webmin runs in the background, and provides an HTTP or HTTPS server on localhost port 10,000. You can use any web browser to connect to http://localhost:10000/ to access Webmin. Upon first installation, only the root user or those in a group allowed to use sudo to access the root account, may log in but Webmin users can be managed separately or in conjunction with local users. Webmin provides extensive and easy to understand menus and icons for various configuration tasks. Webmin is also highly modular and extensible, and an extensive list of standard modules is included with the base package. It is not possible to cover Webmin as fully here as it deserves, but a short list of some of its capabilities includes: Configuration of Webmin itself (the server, users, modules, and security) Local system user and password management Filesystem management Bootup and service management CRON job management Software updates Basic filesystem backups Authentication and security configuration APACHE, DNS, SSH, and FTP (if you're using ProFTP) configuration User mail management Qmail or sendmail configuration Network and Firewall configuration and management Bandwidth monitoring Printer management There are even modules that apply to clusters. Also, Webmin can search and allow access to other Webmin servers on the local network or you can define remote servers manually. This allows a central Webmin server, installed on a particular system, to be the gateway to all of the other servers in your environment, essentially providing a single point of access to manage all Webmin enabled servers. Webmin and Debian Webmin understands the configuration file layout of many distributions. The main problem is when a particular module does not handle certain types of configuration in the way the Debian developers prefer, which can make package upgrades somewhat difficult. This can be handled in a couple of ways. Most modules provide a means to edit configuration files directly, so if you have read the Debian documentation you can modify the configuration appropriately to use Debian specific configuration techniques. Or, you may choose to allow Webmin to modify files as it sees fit, and handle any conflicts manually when you upgrade the software involved. Finally, you can avoid those modules involved with specific software that are more likely to cause problems. One such module is Apache, which doesn't use links from sites-enabled to sites-available. Rather, it configures directly in the sites-enabled directory. Some administrators create the configuration in Webmin, and then move and link the files. Others prefer to manually configure Apache outside of Webmin. Webmin modules are constantly changing, and some actually recognize the Debian file layouts well, so it is not possible to give a comprehensive list of modules to avoid at this time. Best practice when using Webmin is to read the documentation and check the configuration files for specific software prior to using Webmin. Then, after configuring with Webmin, check the files again to determine whether changes may be required to work within the particular package's Debian configuration framework. Based upon this, you can decide whether to continue to configure using Webmin or switch back to manual configuration of that particular software. Webmin security Security is always a concern when remote access to a system is involved. Webmin handles this by requiring authentication and providing for detailed access restrictions that provide a layer of control beyond the firewall. Webmin users can be defined separately, or certain local users can be designated. Access to the various modules in Webmin can be restricted to certain users or groups of users, and detailed logs of Webmin actions are kept. Usermin In addition to Webmin, there is a server called Usermin which may be installed from the same repository as Webmin. It allows individual users to perform a number of functions more easily, such as changing their password, accessing their files, read and manage their email, and managing some aspects of their user profile. It is also modular and has the same security features as Webmin. Summary Several powerful and flexible central backup solutions exist that help manage backups for multiple remote servers and sites. Debian provides packages that assist in building High Availability and Beowulf style multiprocessing clusters as well. And, whether you are involved in managing clusters or not, or even a single system, Webmin can ease an administrator's tasks. Resources for Article: Further resources on this subject: Customizing a Linux kernel [Article] Microsoft SharePoint 2010 Administration: Farm Governance [Article] Testing Workflows for Microsoft Dynamics AX 2009 Administration [Article]

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0
5659

article-image-designing-sample-applications-and-creating-reports

Packt

25 Oct 2013

6 min read

Designing Sample Applications and Creating Reports

Packt

25 Oct 2013

6 min read

0
0
1715

Packt

25 Oct 2013

9 min read

General Considerations

Packt

25 Oct 2013

9 min read

0
0
11391

Packt

25 Oct 2013

11 min read

Social-Engineer Toolkit

Packt

25 Oct 2013

11 min read

(For more resources related to this topic, see here.) Social engineering is an act of manipulating people to perform actions that they don't intend to do. A cyber-based, socially engineered scenario is designed to trap a user into performing activities that can lead to the theft of confidential information or some malicious activity. The reason for the rapid growth of social engineering amongst hackers is that it is difficult to break the security of a platform, but it is far easier to trick the user of that platform into performing unintentional malicious activity. For example, it is difficult to break the security of Gmail in order to steal someone's password, but it is easy to create a socially engineered scenario where the victim can be tricked to reveal his/her login information by sending a fake login/phishing page. The Social-Engineer Toolkit is designed to perform such tricking activities. Just like we have exploits and vulnerabilities for existing software and operating systems, SET is a generic exploit of humans in order to break their own conscious security. It is an official toolkit available at https://www.trustedsec.com/, and it comes as a default installation with BackTrack 5. In this article, we will analyze the aspect of this tool and how it adds more power to the Metasploit framework. We will mainly focus on creating attack vectors and managing the configuration file, which is considered the heart of SET. So, let's dive deeper into the world of social engineering. Getting started with the Social-Engineer Toolkit (SET) Let's start our introductory recipe about SET, where we will be discussing SET on different platforms. Getting ready SET can be downloaded for different platforms from its official website: https://www.trustedsec.com/. It has both the GUI version, which runs through the browser, and the command-line version, which can be executed from the terminal. It comes pre-installed in BackTrack, which will be our platform for discussion in this article. How to do it... To launch SET on BackTrack, start the terminal window and pass the following path: root@bt:~# cd /pentest/exploits/set root@bt:/pentest/exploits/set# ./set Copyright 2012, The Social-Engineer Toolkit (SET) All rights reserved. Select from the menu: If you are using SET for the first time, you can update the toolkit to get the latest modules and fix known bugs. To start the updating process, we will pass the svn update command. Once the toolkit is updated, it is ready for use. The GUI version of SET can be accessed by navigating to Applications | BackTrack | Exploitation tools | Social-Engineer Toolkit. How it works... SET is a Python-based automation tool that creates a menu-driven application for us. Faster execution and the versatility of Python make it the preferred language for developing modular tools, such as SET. It also makes it easy to integrate the toolkit with web servers. Any open source HTTP server can be used to access the browser version of SET. Apache is typically considered the preferable server while working with SET. There's more... Sometimes, you may have an issue upgrading to the new release of SET in BackTrack 5 R3. Try out the following steps: You should remove the old SET using the following command: dpkg –r set We can remove SET in two ways. First, we can trace the path to /pentest/exploits/set, making sure we are in the directory and then opt for the 'rm' command for removing all files present there. Or, we can use the method shown previously. Then, for reinstallation, we can download its clone using the following command: Git clone https://github.com/trustedsec/social-engineer-toolkit /set Working with the SET config file In this recipe, we will take a close look at the SET config file, which contains default values for different parameters that are used by the toolkit. The default configuration works fine with most of the attacks, but there can be situations when you have to modify the settings according to the scenario and requirements. So, let's see what configuration settings are available in the config file. Getting ready To launch the config file, move to the config file and open the set_config file: root@bt:/pentest/exploits/set# nano config/set_config The configuration file will be launched with some introductory statements, as shown in the following screenshot: How to do it... Let's go through it step-by-step: First, we will see what configuration settings are available for us: # DEFINE THE PATH TO METASPLOIT HERE, FOR EXAMPLE /pentest/exploits/framework3 METASPLOIT_PATH=/pentest/exploits/framework3 The first configuration setting is related to the Metasploit installation directory. Metasploit is required by SET for proper functioning, as it picks up payloads and exploits from the framework: # SPECIFY WHAT INTERFACE YOU WANT ETTERCAP TO LISTEN ON, IF NOTHING WILL DEFAULT # EXAMPLE: ETTERCAP_INTERFACE=wlan0 ETTERCAP_INTERFACE=eth0 # # ETTERCAP HOME DIRECTORY (NEEDED FOR DNS_SPOOF) ETTERCAP_PATH=/usr/share/ettercap Ettercap is a multipurpose sniffer for switched LAN. Ettercap section can be used to perform LAN attacks like DNS poisoning, spoofing etc. The above SET setting can be used to either set ettercap ON of OFF depending upon the usability. # SENDMAIL ON OR OFF FOR SPOOFING EMAIL ADDRESSES SENDMAIL=OFF The sendmail e-mail server is primarily used for e-mail spoofing. This attack will work only if the target's e-mail server does not implement reverse lookup. By default, its value is set to OFF. The following setting shows one of the most widely used attack vectors of SET. This configuration will allow you to sign a malicious Java applet with your name or with any fake name, and then it can be used to perform a browser-based Java applet infection attack: # CREATE SELF-SIGNED JAVA APPLETS AND SPOOF PUBLISHER NOTE THIS REQUIRES YOU TO # INSTALL ---> JAVA 6 JDK, BT4 OR UBUNTU USERS: apt-get install openjdk-6-jdk # IF THIS IS NOT INSTALLED IT WILL NOT WORK. CAN ALSO DO apt-get install sun-java6-jdk SELF_SIGNED_APPLET=OFF We will discuss this attack vector in detail in a later recipe, that is, the Spear phishing attack vector . This attack vector will also require JDK to be installed on your system. Let's set its value to ON, as we will be discussing this attack in detail: SELF_SIGNED_APPLET=ON # AUTODETECTION OF IP ADDRESS INTERFACE UTILIZING GOOGLE, SET THIS ON IF YOU WANT # SET TO AUTODETECT YOUR INTERFACE AUTO_DETECT=ON The AUTO_DETECT flag is used by SET to auto-discover the network settings. It will enable SET to detect your IP address if you are using NAT/Port forwarding, and it allows you to connect to the external Internet. The following setting is used to set up the Apache web server to perform web-based attack vectors. It is always preferred to set it to ON for better attack performance: # USE APACHE INSTEAD OF STANDARD PYTHON WEB SERVERS, THIS WILL INCREASE SPEED OF # THE ATTACK VECTOR APACHE_SERVER=OFF # # PATH TO THE APACHE WEBROOT APACHE_DIRECTORY=/var/www The following setting is used to set up the SSL certificate while performing web attacks. Several bugs and issues have been reported for the WEBATTACK_SSL setting of SET. So, it is recommended to keep this flag OFF: # TURN ON SSL CERTIFICATES FOR SET SECURE COMMUNICATIONS THROUGH WEB_ATTACK VECTOR WEBATTACK_SSL=OFF The following setting can be used to build a self-signed certificate for web attacks, but there will be a warning message saying Untrusted certificate. Hence, it is recommended to use this option wisely to avoid alerting the target user: # PATH TO THE PEM FILE TO UTILIZE CERTIFICATES WITH THE WEB ATTACK VECTOR (REQUIRED) # YOU CAN CREATE YOUR OWN UTILIZING SET, JUST TURN ON SELF_SIGNED_CERT # IF YOUR USING THIS FLAG, ENSURE OPENSSL IS INSTALLED! # SELF_SIGNED_CERT=OFF The following setting is used to enable or disable the Metasploit listener once the attack is executed: # DISABLES AUTOMATIC LISTENER - TURN THIS OFF IF YOU DON'T WANT A METASPLOIT LISTENER IN THE BACKGROUND. AUTOMATIC_LISTENER=ON The following configuration will allow you to use SET as a standalone toolkit without using Metasploit functionalities, but it is always recommended to use Metasploit along with SET in order to increase the penetration testing performance: # THIS WILL DISABLE THE FUNCTIONALITY IF METASPLOIT IS NOT INSTALLED AND YOU JUST WANT TO USE SETOOLKIT OR RATTE FOR PAYLOADS # OR THE OTHER ATTACK VECTORS. METASPLOIT_MODE=ON These are a few important configuration settings available for SET. Proper knowledge of the config file is essential to gain full control over the SET. How it works... The SET config file is the heart of the toolkit, as it contains the default values that SET will pick while performing various attack vectors. A misconfigured SET file can lead to errors during the operation, so it is essential to understand the details defined in the config file in order to get the best results. The How to do it... section clearly reflects the ease with which we can understand and manage the config file. Working with the spear-phishing attack vector A spear-phishing attack vector is an e-mail attack scenario that is used to send malicious mails to target/specific user(s). In order to spoof your own e-mail address, you will require a sendmail server. Change the config setting to SENDMAIL=ON. If you do not have sendmail installed on your machine, then it can be downloaded by entering the following command: root@bt:~# apt-get install sendmail Reading package lists... Done Getting ready Before we move ahead with a phishing attack, it is imperative for us to know how the e-mail system works. Recipient e-mail servers, in order to mitigate these types of attacks, deploy gray-listing, SPF records validation, RBL verification, and content verification. These verification processes ensure that a particular e-mail arrived from the same e-mail server as its domain. For example, if a spoofed e-mail address, <richyrich@gmail.com>, arrives from the IP 202.145.34.23, it will be marked as malicious, as this IP address does not belong to Gmail. Hence, in order to bypass these security measures, the attacker should ensure that the server IP is not present in the RBL/SURL list. As the spear-phishing attack relies heavily on user perception, the attacker should conduct a recon of the content that is being sent and should ensure that the content looks as legitimate as possible. Spear-phishing attacks are of two types—web-based content and payload-based content. How to do it... The spear-phishing module has three different attack vectors at our disposal: Let's analyze each of them. Passing the first option will start our mass-mailing attack. The attack vector starts with selecting a payload. You can select any vulnerability from the list of available Metasploit exploit modules. Then, we will be prompted to select a handler that can connect back to the attacker. The options will include setting the vnc server or executing the payload and starting the command line, and so on. The next few steps will be starting the sendmail server, setting a template for a malicious file format, and selecting a single or mass-mail attack: Finally, you will be prompted to either choose a known mail service, such as Gmail or Yahoo, or use your own server: 1. Use a gmail Account for your email attack. 2. Use your own server or open relay set:phishing>1 set:phishing> From address (ex: moo@example.com):bigmoney@gmail.com set:phishing> Flag this message/s as high priority? [yes|no]:y Setting up your own server cannot be very reliable, as most of the mail services follow a reverse lookup to make sure that the e-mail has generated from the same domain name as the address name. Let's analyze another attack vector of spear-fishing. Creating a file format payload is another attack vector in which we can generate a file format with a known vulnerability and send it via e-mail to attack our target. It is preferred to use MS Word-based vulnerabilities, as they are difficult to detect whether they are malicious or not, so they can be sent as an attachment via an e-mail: set:phishing> Setup a listener [yes|no]:y [-] *** [-] * WARNING: Database support has been disabled [-] *** At last, we will be prompted on whether we want to set up a listener or not. The Metasploit listener will begin and we will wait for the user to open the malicious file and connect back to the attacking system. The success of e-mail attacks depends on the e-mail client that we are targeting. So, a proper analysis of this attack vector is essential. How it works... As discussed earlier, the spear-phishing attack vector is a social engineering attack vector that targets specific users. An e-mail is sent from the attacking machine to the target user(s). The e-mail will contain a malicious attachment, which will exploit a known vulnerability on the target machine and provide a shell connectivity to the attacker. The SET automates the entire process. The major role that social engineering plays here is setting up a scenario that looks completely legitimate to the target, fooling the target into downloading the malicious file and executing it.

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17989

How-To Tutorials

article-image-image-classification-and-feature-extraction-images

Packt

25 Oct 2013

3 min read

Image classification and feature extraction from images

Packt

25 Oct 2013

3 min read

(For more resources related to this topic, see here.) Classifying images Automated Remote Sensing ( ARS ) is rarely ever done in the visible spectrum. The most commonly available wavelengths outside of the visible spectrum are infrared and near-infrared. The following scene is a thermal image (band 10) from a fairly recent Landsat 8 flyover of the US Gulf Coast from New Orleans, Louisiana to Mobile, Alabama. Major natural features in the image are labeled so you can orient yourself: Because every pixel in that image has a reflectance value, it is information. Python can "see" those values and pick out features the same way we intuitively do by grouping related pixel values. We can colorize pixels based on their relation to each other to simplify the image and view related features. This technique is called classification. Classifying can range from fairly simple groupings based only on some value distribution algorithm derived from the histogram to complex methods involving training data sets and even computer learning and artificial intelligence. The simplest forms are called unsupervised classifications, whereas methods involving some sort of training data to guide the computer are called supervised. It should be noted that classification techniques are used across many fields, from medical doctors trying to spot cancerous cells in a patient's body scan, to casinos using facial-recognition software on security videos to automatically spot known con-artists at blackjack tables. To introduce remote sensing classification we'll just use the histogram to group pixels with similar colors and intensities and see what we get. First you'll need to download the Landsat 8 scene here: http://geospatialpython.googlecode.com/files/thermal.zip Instead of our histogram() function from previous examples, we'll use the version included with NumPy that allows you to easily specify a number of bins and returns two arrays with the frequency as well as the ranges of the bin values. We'll use the second array with the ranges as our class definitions for the image. The lut or look-up table is an arbitrary color palette used to assign colors to classes. You can use any colors you want. import gdalnumeric # Input file name (thermal image) src = "thermal.tif" # Output file name tgt = "classified.jpg" # Load the image into numpy using gdal srcArr = gdalnumeric.LoadFile(src) # Split the histogram into 20 bins as our classes classes = gdalnumeric.numpy.histogram(srcArr, bins=20)[1] # Color look-up table (LUT) - must be len(classes)+1. # Specified as R,G,B tuples lut = [[255,0,0],[191,48,48],[166,0,0],[255,64,64], [255,115,115],[255,116,0],[191,113,48],[255,178,115], [0,153,153],[29,115,115],[0,99,99],[166,75,0], [0,204,0],[51,204,204],[255,150,64],[92,204,204],[38,153,38], [0,133,0],[57,230,57],[103,230,103],[184,138,0]] # Starting value for classification start = 1 # Set up the RGB color JPEG output image rgb = gdalnumeric.numpy.zeros((3, srcArr.shape[0], srcArr.shape[1],), gdalnumeric.numpy.float32) # Process all classes and assign colors for i in range(len(classes)): mask = gdalnumeric.numpy.logical_and(start <= srcArr, srcArr <= classes[i]) for j in range(len(lut[i])): rgb[j] = gdalnumeric.numpy.choose(mask, (rgb[j], lut[i][j])) start = classes[i]+1 # Save the image gdalnumeric.SaveArray(rgb.astype(gdalnumeric.numpy.uint8), tgt, format="JPEG") The following image is our classification output, which we just saved as a JPEG. We didn't specify the prototype argument when saving as an image, so it has no georeferencing information. This result isn't bad for a very simple unsupervised classification. The islands and coastal flats show up as different shades of green. The clouds were isolated as shades of orange and dark blues. We did have some confusion inland where the land features were colored the same as the Gulf of Mexico. We could further refine this process by defining the class ranges manually instead of just using the histogram.

0
0
13101

Packt

25 Oct 2013

5 min read

The solvers – these great unknown

Packt

25 Oct 2013

5 min read

(For more resources related to this topic, see here.) Variable-step versus fixed-step solvers A variable-step solver will choose to use a shorter time step when the signal derivative is changing faster in order to obtain a better approximation, while it will use a longer step when the result changes at a slower pace. The most used variable-step solver is the ode45 solver (this is the default Simulink solver as well). A fixed-step solver will, on the other hand, always use the same step size. The simplest is the ode1 solver (the famous Euler method). We've already run our example with a fixed-step solver. Let's change this to a variable-step solver by opening the Model Configuration Parameters window and setting the ode45 solver. We now have the option to configure more Solver parameters; we'll allow it to use a Max step size of 1 second and a Min step size of 0.2 seconds, setting other parameters to the default value. Running the simulation now will give us the following result: We can see that the step size is indeed variable: the second value has been computed after only 0.2 seconds, and then the step size grew bigger and stayed at 1 second. We got a good approximation in the problematic region while using longer steps in the almost constant region, thus achieving a faster simulation time than a fixed-step solver with a step size of 0.2 seconds. But how does the solver determine when it's necessary to reduce the step size? The answer is by looking at the tolerances defined in the Model Configuration Parameters window. Relative tolerance defines the maximum error as a percentage of the actual value. The default value (1e-3) means that an error of 0.1 percent is accepted. Absolute tolerance defines the maximum error as a scalar value. When it is set to auto, Simulink will assume 1e-6 initially (that is, 0.000001), then change it to the maximum error calculated with the relative tolerance. The Shape preservation option, off ( Disable all ) by default, helps to increase the accuracy when the solution's derivative varies rapidly at the cost of a more computing-intensive simulation (thus increasing the overall time to compute the result). Finally, there's the option Number of consecutive min steps , which defines how many times the solver can use a time step smaller than the minimum step size violations defined before issuing a warning or an error. Let's set the Relative tolerance parameter to 1e-5 and run the simulation. We'll obtain this result: This time, the solver chose to use more shorter steps while the signal was changing to improve the accuracy, thanks to the relative tolerance we've set; then the step size grew gradually back to 1 second. Variable-step solvers give us a good trade-off between result approximation and overall simulation times in models, whereas fixed-step solvers are too computationally intensive to be used efficiently. Fixed-step solvers are required for code generation and real-time control purposes because Simulink can't go back in time to give a more accurate result. Continuous versus discrete A system can be continuous or discrete based on the presence of integrators or derivatives in the model (these are called continuous states). In other words, if the system is represented by the means of one or more differential equations, the system is continuous. Our cruise controller is continuous because it has an integral component. The continuous solver can choose to perform several iteration cycles in a single time step to reach the best possible approximation of the final result. Such solvers fall into the ODE ( Ordinary Differential Equation solvers) category. If a system is discrete, there are no differential equations but only memories and mathematical operands. A discrete solver is unable to perform the numerical integration required by continuous states. The continuous system requires continuous solvers, while Simulink will switch to a discrete solver for discrete systems even if a continuous solver has been specified. Try to set a discrete solver in our example system and run a simulation. An error window will appear, telling us that a discrete solver can't be used because the model contains continuous states. Stiff versus nonstiff In a stiff continuous system, certain solvers are unable to compute the result unless the step size is small enough; thus, a stiff solver is needed. These systems can be identified by an overall slowly changing solution that can vary rapidly in a very small time period. Our example is mildly stiff: the ode45 solver had to use a small step size to compute the result close to t = 0, but it managed to get the job done by changing the time step. A more appropriate choice would have been the ode23t solver (moderately stiff), which would have given the following result: Let's choose another nonstiff solver, the fixed-step ode1 , implementing the Euler method. Set the Fixed step size parameter to 1.5 and run the simulation: That's interesting: Using the Euler method with a long time step shows the result to be oscillating around the mathematical result, but the solution is still convergent. Setting the step size to 2 seconds will show that it can't converge anymore, and any step size higher than 2 seconds will make the simulation diverge from the correct result and go towards infinite oscillation. The following figure shows the result with a step size of 2.1 and a simulation time of 20 seconds: The following article presents stiff solvers in a way that is easy to understand: http://blogs.mathworks.com/seth/2012/07/03/why-do-we-need-stiff-ode-solvers/. The documentation center, accessible by pressing F1 , has detailed information about the solver types and parameters. This information can be found by navigating to Simulink | Simulation | Configure simulation . Summary In this article, we've learned how solvers work and how to choose the right solver to run the simulations Resources for Article: Further resources on this subject: 2-Dimensional Image Filtering [Article] GoboLinux: An Interview with Lucas Villa Real [Article] The NGINX HTTP Server [Article]

0
0
23587

article-image-authenticating-your-application-devise

Packt

25 Oct 2013

11 min read

Authenticating Your Application with Devise

Packt

25 Oct 2013

11 min read

(For more resources related to this topic, see here.) Signing in using authentication other than e-mails By default, Devise only allows e-mails to be used for authentication. For some people, this condition will lead to the question, "What if I want to use some other field besides e-mail? Does Devise allow that?" The answer is yes; Devise allows other attributes to be used to perform the sign-in process. For example, I will use username as a replacement for e-mail, and you can change it later with whatever you like, including userlogin, adminlogin, and so on. We are going to start by modifying our user model. Create a migration file by executing the following command inside your project folder: $ rails generate migration add_username_to_users username:string This command will produce a file, which is depicted by the following screenshot: The generated migration file Execute the migrate (rake db:migrate) command to alter your users table, and it will add a new column named username. You need to open the Devise's main configuration file at config/initializers/devise.rb and modify the code: config.authentication_keys = [:username] config.case_insensitive_keys = [:username] config.strip_whitespace_keys = [:username] You have done enough modification to your Devise configuration, and now you have to modify the Devise views to add a username field to your sign-in and sign-up pages. By default, Devise loads its views from its gemset code. The only way to modify the Devise views is to generate copies of its views. This action will automatically override its default views. To do this, you can execute the following command: $ rails generate devise:views It will generate some files, which are shown in the following screenshot: Devise views files As I have previously mentioned, these files can be used to customize another view. But we are going to talk about it a little later in this article. Now, you have the views and you can modify some files to insert the username field. These files are listed as follows: app/views/devise/sessions/new.html.erb: This is a view file for the sign-up page. Basically, all you need to do is change the email field into the username field. #app/views/devise/sessions/new.html.erb <h2>Sign in</h2> <%= notice %> <%= alert %> <%= form_for(resource, :as => resource_name, :url => session_path (resource_name)) do |f| %> <div><%= f.label :username %><br /> <%= f.text_field :username, :autofocus => true %><div> <div><%= f.label :password %><br /> <%= f.password_field :password %></div> <% if devise_mapping.rememberable? -%> <div><%= f.check_box :remember_me %> <%= f.label :remember_me %></div> <% end -%> <div><%= f.submit "Sign in" %></div> <% end %> %= render "devise/shared/links" %> You are now allowed to sign in with your username. The modification will be shown, as depicted in the following screenshot: The sign-in page with username app/views/devise/registrations/new.html.erb: This file is a view file for the registration page. It is a bit different from the sign-up page; in this file, you need to add the username field, so that the user can fill in their username when they perform the registration. #app/views/devise/registrations/new.html.erb <h2>Sign Up</h2> <%= form_for() do |f| %> <%= devise_error_messages! %> <div><%= f.label :email %><br /> <%= f.email_field :email, :autofocus => true %></div> <div><%= f.label :username %><br /> <%= f.text_field :username %></div> <div><%= f.label :password %><br /> <%= f.password_field :password %></div> <div><%= f.label :password_confirmation %><br /> <%= f.password_field :password_confirmation %></div> <div><%= f.submit "Sign up" %></div> <% end %> <%= render "devise/shared/links" %> Especially for registration, you need to perform extra modifications. Mass assignment rules written in the app/controller/application_controller.rb file, and now, we are going to modify them a little. Add username to the sanitizer for sign-in and sign-up, and you will have something as follows: #these codes are written inside configure_permitted_parameters function devise_parameter_sanitizer.for(:sign_in) {|u| u.permit(:email, :username )} devise_parameter_sanitizer.for(:sign_up) {|u| u.permit(:email, :username, :password, :password_confirmation)} These changes will allow you to perform a sign-up along with the username data. The result of the preceding example is shown in the following screenshot: The sign-up page with username I want to add a new case for your sign-in, which is only one field for username and e-mail. This means that you can sign in either with your e-mail ID or username like in Twitter's sign-in form. Based on what we have done before, you already have username and email columns; now, open /app/models/user.rb and add the following line: attr_accessor :signin Next, you need to change the authentication keys for Devise. Open /config/initializers/devise.rb and change the value for config.authentication_keys, as shown in the following code snippet: config.authentication_keys = [ :signin ] Let's go back to our user model. You have to override the lookup function that Devise uses when performing a sign-in. To do this, add the following method inside your model class: def self.find_first_by_auth_conditions(warden_conditions) conditions = warden_conditions.dup where(conditions).where(["lower(username) = :value OR lower(email) = :value", { :value => signin.downcase }]).first end As an addition, you can add a validation for your username, so it will be case insensitive. Add the following validation code into your user model: validates :username, :uniqueness => {:case_sensitive => false} Please open /app/controller/application_controller.rb and make sure you have this code to perform parameter filtering: before_filter :configure_permitted_parameters, if: :devise_controller? protected def configure_permitted_parameters devise_parameter_sanitizer.for(:sign_in) {|u| u.permit(:signin)} devise_parameter_sanitizer.for(:sign_up) {|u| u.permit(:email, : username, :password, :password_confirmation)} end We're almost there! Currently, I assume that you've already stored an account that contains the e-mail ID and username. So, you just need to make a simple change in your sign-in view file (/app/views/devise/sessions/new.html.erb). Make sure that the file contains this code: <h2>Sign in</h2> <%= notice %> <%= alert %> <%= form_for(resource, :as => resource_name, :url => session_path (resource_name)) do |f| %> <div><%= f.label "Username or Email" %><br /> <%= f.text_field :signin, :autofocus => true %></div> <div><%= f.label :password %><br /> <%= f.password_field :password %></div> <% if devise_mapping.rememberable? -%> <div><%= f.check_box :remember_me %> <%= f.label :remember_me %> </div> <% end -%> <div><%= f.submit "Sign in" %></div> <% end %> <%= render "devise/shared/links" %> You can see that you don't have a username or email field anymore. The field is now replaced by a single field named :signin that will accept either the e-mail ID or the username. It's efficient, isn't it? Updating the user account Basically, you are already allowed to access your user account when you activate the registerable module in the model. To access the page, you need to log in first and then go to /users/edit. The page is as shown in the following screenshot: The edit account page But, what if you want to edit your username or e-mail ID? How will you do that? What if you have extra information in your users table, such as addresses, birth dates, bios, and passwords as well? How will you edit these? Let me show you how to edit your user data including your password, or edit your user data without editing your password. Editing your data, including the password: To perform this action, the first thing that you need to do is modify your view. Your view should contain the following code: <div><%= f.label :username %><br /> <%= f.text_field :username %></div> Now, we are going to overwrite Devise's logic. To do this, you have to create a new controller named registrations_controller. Please use the rails command to generate the controller, as shown: $ rails generate controller registrations update It will produce a file located at app/controllers/. Open the file and make sure you write this code within the controller class: class RegistrationsController < Devise::RegistrationsController def update new_params = params.require(:user).permit(:email,:username, : current_password, :password,:password_confirmation) @user = User.find(current_user.id) if @user.update_with_password(new_params) set_flash_message :notice, :updated sign_in @user, :bypass => true redirect_to after_update_path_for(@user) else render "edit" end end end Let's look at the code. Currently, Rails 4 has a new method in organizing whitelist attributes. Therefore, before performing mass assignment attributes, you have to prepare your data. This is done in the first line of the update method. Now, if you see the code, there's a method defined by Devise named update_with_password. This method will use mass assignment attributes with the provided data. Since we have prepared it before we used it, it will be fine. Next, you have to edit your route file a bit. You should modify the rule defined by Devise, so instead of using the original controller, Devise will use the controller you created before. The modification should look as follows: devise_for :users, :controllers => {:registrations => "registrations"} Now you have modified the original user edit page, and it will be a little different. You can turn on your Rails server and see it in action. The view is as depicted in the following screenshot: The modified account edit page Now, try filling up these fields one by one. If you are filling them with different values, you will be updating all the data (e-mail, username, and password), and this sounds dangerous. You can modify the controller to have better data update security, and it all depends on your application's workflows and rules. Editing your data, excluding the password: Actually, you already have what it takes to update data without changing your password. All you need to do is modify your registrations_controller.rb file. Your update function should be as follows: class RegistrationsController < Devise::RegistrationsController def update new_params = params.require(:user).permit(:email,:username, : current_password, :password,:password_confirmation) change_password = true if params[:user][:password].blank? params[:user].delete("password") params[:user].delete("password_confirmation") new_params = params.require(:user).permit(:email,:username) change_password = false end @user = User.find(current_user.id) is_valid = false if change_password is_valid = @user.update_with_password(new_params) else @user.update_without_password(new_params) end if is_valid set_flash_message :notice, :updated sign_in @user, :bypass => true redirect_to after_update_path_for(@user) else render "edit" end end end The main difference from the previous code is now you have an algorithm that will check whether the user intends to update your data with their password or not. If not, the code will call the update_without_password method. Now, you have codes that allow you to edit with/without a password. Now, refresh your browser and try editing with or without a password. It won't be a problem anymore. Summary Now, I believe that you will be able to make your own Rails application with Devise. You should be able to make your own customizations based on your needs. Resources for Article: Further resources on this subject: Integrating typeahead.js into WordPress and Ruby on Rails [Article] Facebook Application Development with Ruby on Rails [Article] Designing and Creating Database Tables in Ruby on Rails [Article]

0
0
10681

How-To Tutorials

Packt

25 Oct 2013

5 min read

Gesture

Packt

25 Oct 2013

5 min read

(For more resources related to this topic, see here.) Gestures While there are ongoing arguments in the courts of America at the time of writing over who invented the likes of dragging images, it is without a doubt that a key feature of iOS is the ability to use gestures. To put it simply, when you tap the screen to start an app or select a part of an image to enlarge it or anything like that, you are using gestures. A gesture (in terms of iOS) is any touch interaction between the UI and the device. With iOS 6, there are six gestures the user has the ability to use. These gestures, along with brief explanations, have been listed in the following table: Class Name and type Gesture UIPanGesture Recognizer PanGesture; Continuous type Pan images or over-sized views by dragging across the screen UISwipeGesture Recognizer SwipeGesture; Continuous type Similar to panning, except it is a swipe UITapGesture Recognizer TapGesture; Discrete type Tap the screen a number of times (configurable) UILongPressGesture Recognizer LongPressGesture; Discrete type Hold the finger down on the screen UIPinchGesture Recognizer PinchGesture; Continuous type Zoom by pinching an area and moving your fingers in or out UIRotationGesture Recognizer RotationGesture; Continuous type Rotate by moving your fingers in opposite directions Gestures can be added by programming or via Xcode. The available gestures are listed in the following screenshot with the rest of the widgets on the right-hand side of the designer: To add a gesture, drag the gesture you want to use under the view on the View bar (shown in the following screenshot): Design the UI as you want and while pressing the Ctrl key, drag the gesture to what you want to recognize using the gesture. In my example, the object you want to recognize is anywhere on the screen. Once you have connected the gesture to what you want to recognize, you will see the configurable options of the gesture. The Taps field is the number of taps required before the Recognizer is triggered, and the Touches field is the number of points onscreen required to be touched for the Recognizer to be triggered. When you come to connect up the UI, the gesture must also be added. Gesture code When using Xcode, it is simple to code gestures. The class defined in the Xcode design for the tapping gesture is called tapGesture and is used in the following code: private int tapped = 0; public override void ViewDidLoad() { base.ViewDidLoad(); tapGesture.AddTarget(this, new Selector("screenTapped")); View.AddGestureRecognizer(tapGesture); } [Export("screenTapped")]public void SingleTap(UIGestureRecognizer s) { tapped++; lblCounter.Text = tapped.ToString(); } There is nothing really amazing to the code; it just displays how many times the screen has been tapped. The Selector method is called by the code when the tap has been seen. The method name doesn't make any difference as long as the Selector and Export names are the same. Types When the gesture types were originally described, they were given a type. The type reflects the number of messages sent to the Selector method. A discrete one generates a single message. A continuous one generates multiple messages, which requires the Selector method to be more complex. The complexity is added by the Selector method having to check the State of the gesture to decide on what to do with what message and whether it has been completed. Adding a gesture in code It is not a requirement that Xcode be used to add a gesture. To perform the same task in the following code as my preceding code did in Xcode is easy. The code will be as follows: UITapGestureRecognizer t'pGesture = new UITapGestureRecognizer() { NumberOfTapsRequired = 1 }; The rest of the code from AddTarget can then be used. Continuous types The following code, a Pinch Recognizer, shows a simple rescaling. There are a couple of other states that I'll explain after the code. The only difference in the designer code is that I have UIImageView instead of a label and a UIPinchGestureRecognizer class instead of a UITapGestureRecognizer class. public override void ViewDidLoad() { base.ViewDidLoad(); uiImageView.Image =UIImage.FromFile("graphics/image.jpg") Scale(new SizeF(160f, 160f); pinchGesture.AddTarget(this, new Selector("screenTapped")); uiImageView.AddGestureRecognizer(pinchGesture); } [Export("screenTapped")]public void SingleTap(UIGestureRecognizer s) { UIPinchGestureRecognizer pinch = (UIPinchGestureRecognizer)s; float scale = 0f; PointF location; switch(s.State) { case UIGestureRecognizerState.Began: Console.WriteLine("Pinch begun"); location = s.LocationInView(s.View); break; case UIGestureRecognizerState.Changed: Console.WriteLine("Pinch value changed"); scale = pinch.Scale; uiImageView.Image = UIImage FromFile("graphics/image.jpg") Scale(new SizeF(160f, 160f), scale); break; case UIGestureRecognizerState.Cancelled: Console.WriteLine("Pinch cancelled"); uiImageView.Image = UIImage FromFile("graphics/image.jpg") Scale(new SizeF(160f, 160f)); scale = 0f; break; case UIGestureRecognizerState.Recognized: Console.WriteLine("Pinch recognized"); break; } } Other UIGestureRecognizerState values The following table gives a list of other Recognizer states: State Description Notes Possible Default state; gesture hasn't been recognized Used by all gestures Failed Gesture failed No messages sent for this state Translation Direction of pan Used in the pan gesture Velocity Speed of pan Used in the pan gesture In addition to these, it should be noted that discrete types only use Possible and Recognized states. Summary Gestures certainly can add a lot to your apps. They can enable the user to speed around an image, move about a map, enlarge and reduce, as well as select areas of anything on a view. Their flexibility underpins why iOS is recognized as being an extremely versatile device for users to manipulate images, video, and anything else on-screen. Resources for Article: Further resources on this subject: Creating and configuring a basic mobile application [Article] So, what is XenMobile? [Article] Building HTML5 Pages from Scratch [Article]

0
0
7402

Packt

25 Oct 2013

20 min read

Troubleshooting

Packt

25 Oct 2013

20 min read

0
0
9162

article-image-scratching-surface-zend-framework-2

Packt

25 Oct 2013

11 min read

Scratching the Surface of Zend Framework 2

Packt

25 Oct 2013

11 min read

Bootstrap your app There are two ways to bootstrap your ZF2 app. The default is less flexible but handles the entire configuration, and the manual is really flexible but you have to take care of everything. The goal of the bootstrap is to provide to the application, ZendMvcApplication, with all the components and dependencies needed to successfully handle a request. A Zend Framework 2 application relies on the following six components: Configuration array ServiceManager instance EventManager instance ModuleManager instance Request object Response object As these are the pillars of a ZF2 application, we will take a look at how these components are configured to bootstrap the app. To begin with, we will see how the components interact from a high perspective and then we will jump into details of how each one works. When a new request arrives to our application, ZF2 needs to set up the environment to be able to fulfill it. This process implies reading configuration files and creating the required objects and services; attach them to the events that are going to be used and finally create the request object based on the request data. Once we have the request object, ZF2 will tell the router to do his job and will inspect the request object to determine who is responsible for processing the data. Once a controller and action has been identified as the one in charge of the request, ZF2 dispatches it and gives the controller/action the control of the program in order to execute the code that will interpret the request and will do something with it. This can be from accepting an uploaded image to showing a sign-up form and also changing data on an external database. When the controller processes the data, sometimes a view object is generated to encapsulate the data that we should send to the client who made the request, and a response object is created. After we have a response object, ZF2 sends it to the browser and the request ends. Now that we have seen a very simple overview of the lifecycle of a request we will jump into the details of how each object works, the options available and some examples of each one. Configuration array Let's dissect the first component of the list by taking a look at the index.php file: chdir(dirname(__DIR__)); // Setup autoloading require 'init_autoloader.php'; // Run the application! ZendMvcApplication::init(require 'config/application.config.php')->run(); As you can see we only do three things. The first thing is we change the current folder for the convenience of making everything relative to the root folder. Then we require the autoloader file; we will examine this file later. Finally, we initialize a ZendMvcApplication object by passing a configuration file and only then does the run method get called. The configuration file looks like the following code snippet: return array( 'modules' => array( 'Application', ), 'module_listener_options' => array( 'config_glob_paths' => array( 'config/autoload/{,*.}{global,local}.php', ), 'module_paths' => array( './module', './vendor', ), ), ); This file will return an array containing the configuration options for the application. Two options are used: modules and module_listener_options. As ZF2 uses a module organization approach, we should add the modules that we want to use on the application here. The second option we are using is passed as configuration to the ModuleManager object. The config_glob_path array is used when scanning the folders in search of config files and the module_paths array is used to tell ModuleManager a set of paths where the module resides. ZF2 uses a module approach to organize files. A module can contain almost anything, simple PHP files, view scripts, images, CSS, JavaScript, and so on. This approach will allow us to build reusable blocks of functionality and we will adhere to this while developing our project. PSR-0 and autoloaders Before continuing with the key components, let's take a closer look at the init_autoloader.php file used in the index.php file. As is stated on the first block comment, this file is more complicated than it's supposed to be. This is because ZF2 will try to set up different loading mechanisms and configurations. if (file_exists('vendor/autoload.php')) { $loader = include 'vendor/autoload.php'; } The first thing is to check if there is an autoload.php file inside the vendor folder; if it's found, we will load it. This is because the user might be using composer, in which case composer will provide a PSR-0 class loader. Also, this will register the namespaces defined by composer on the loader. PSR-0 is an autoloading standard proposed by the PHP Framework Interop Group (http://www.php-fig.org/) that describes the mandatory requirements for autoloader interoperability between frameworks. Zend Framework 2 is one of the projects that adheres to it. if (getenv('ZF2_PATH')) { $zf2Path = getenv('ZF2_PATH'); } elseif (get_cfg_var('zf2_path')) { $zf2Path = get_cfg_var('zf2_path'); } elseif (is_dir('vendor/ZF2/library')) { $zf2Path = 'vendor/ZF2/library'; } In the next section we will try to get the path of the ZF2 files from different sources. We will first try to get it from the environment, if not, we'll try from a directive value in the php.ini file. Finally, if the previous methods fail the code, we will try to check whether a specific folder exists inside the vendor folder. if ($zf2Path) { if (isset($loader)) { $loader->add('Zend', $zf2Path); } else { include $zf2Path . '/Zend/Loader/AutoloaderFactory.php'; ZendLoaderAutoloaderFactory::factory(array( 'ZendLoaderStandardAutoloader' => array( 'autoregister_zf' => true ) )); } } Finally, if the framework is found by any of these methods, based on the existence of the composer autoloader, the code will just add the Zend namespace or will instantiate an internal autoloader, ZendLoaderAutoloader, and use it as a default. As you can see, there are multiple ways to set up the autoloading mechanism on ZF2 and at the end what matters is which one you prefer, as all of them in essence will behave the same. ServiceManager After all this execution of code, we arrive at the last section of the index.php file where we actually instantiate the ZendMvcApplication object. As we said, there are two methods of creating an instance of ZendMvcApplication. In the default approach, we call the static method init of the class by passing an optional configuration as the first parameter. This method will take care of instantiating a new ServiceManager object, storing the configuration inside, loading the modules specified in the configuration, and getting a configured ZendMvcApplication. ServiceManager is a service/object locator that implements the Service Locator design pattern; its responsibility is to retrieve other objects. $serviceManager = new ServiceManager( new ServiceServiceManagerConfig($smConfig) ); $serviceManager->setService('ApplicationConfig', $configuration); $serviceManager->get('ModuleManager')->loadModules(); return $serviceManager->get('Application')->bootstrap(); As you can see, the init method calls the bootstrap() method of the ZendMvcApplication instance. Service Locator is a design pattern used in software development to encapsulate the process of obtaining other objects. The concept is based on a central repository that stores the objects and also knows how to create them if required. EventManager This component is designed to provide multiple functionalities. It can be used to implement simple observer patterns, and also can be used to do aspect-oriented design or even create event-driven architectures. The basic operations you can do over these components is attaching and detaching listeners to named events, trigger events, and interrupting the execution of listeners when an event is fired. Let's see a couple of examples on how to attach to an event and how to fire them: //Registering an event listener $events = new EventManager(); $events->attach(array('EVENT_NAME'), $callback); //Triggering an event $events->trigger('EVENT_NAME', $this, $params); Inside the bootstrap method of ZendMvcApplication, we are registering the events of RouteListener, DispatchListener, and ViewManager. After that, the code is instantiating a new custom event called MvcEvent that will be used as the target when firing events. Finally, this piece of code will fire the bootstrap event. ModuleManager Zend Framework 2 introduces a completely redesigned ModuleManager. This new module has been built with simplicity, flexibility, and reuse in mind. These modules can hold everything from PHP to images, CSS, library code, views, and so on. The responsibility of this component in the bootstrap process of an app is loading the available modules specified by the config file. This is accomplished by the following code line located in the init method of ZendMvcApplication: $serviceManager->get('ModuleManager')->loadModules(); This line, when executed, will retrieve the list of modules located at the config file and will load each module. Each module has to contain a file called Module.php with the initialization of the components of the module if needed. This will allow the module manager to retrieve the configuration of the module. Let's see the usual content of this file: namespace MyModule; class Module { public function getAutoloaderConfig() { return array( 'ZendLoaderClassMapAutoloader' => array( __DIR__ . '/autoload_classmap.php', ), 'ZendLoaderStandardAutoloader' => array( 'namespaces' => array( __NAMESPACE__ => __DIR__ . '/src/' . __NAMESPACE__, ), ), ); } public function getConfig() { return include __DIR__ . '/config/module.config.php'; } } As you can see we are defining a method called getAutoloaderConfig() that provides the configuration for the autoloader to ModuleManager. The last method getConfig() is used to provide the configuration of the module to ModuleManager; for example, this will contain the routes handled by the module. Request object This object encapsulates all data related to a request and allows the developer to interact with the different parts of a request. This object is used in the constructor of ZendMvcApplication and also is set inside MvcEvent to be able to retrieve when some events are fired. Response object This object encapsulates all the parts of an HTTP response and provides the developer with a fluent interface to set all the response data. This object is used in the same way as the request object. Basically it is instantiated on the constructor and added to MvcEvent to be able to interact with it across all the events and classes. The request object As we said, the request object will encapsulate all the data related to a request and provide the developer with a fluent API to access the data. Let's take a look at the details of the request object in order to understand how to use it and what it can offer to us: use ZendHttpRequest; $string = "GET /foo HTTP/1.1rnrnSome Content"; $request = Request::fromString($string); $request->getMethod(); $request->getUri(); $request->getUriString(); $request->getVersion(); $request->getContent(); This example comes directly from the documentation and shows how a request object can be created from a string, and then access some data related with the request using the methods provided. So, every time we need to know something related to the request, we will access this object to get the data we need. If we check the code on ZendHttpPhpEnvironmentRequest.php, the first thing we can notice is that the data is populated on the constructor using the superglobal arrays. All this data is processed and then populated inside the object to be able to expose it in a standard way using methods. To manipulate the URI of the request you can get/set the data with three methods, two getters and one setter. The only difference with the getters is that one returns a plain string and the other returns an HttpUri object. getUri() and getUriString() setUri() To retrieve the data passed in the request, there are a few specialized methods depending on the data you want to get: getQuery() getPost() getFiles() getHeader() and getHeaders() About the request method, the object has a general way to know the method used, returning a string or nine specialized functions that will test specific methods based on the RFC 2616, which defines the standard methods for an HTTP request. getMethod() isOptions() isGet() isHead() isPost() isPut() isDelete() isTrace() isConnect() isPatch() Finally, two more methods are available in this object that will test special requests such as AJAX and requests made by a flash object. isXmlHttpRequest() isFlashRequest() Notice that the data stored on the superglobal arrays when populated on the object are converted from an Array to a Parameters object. The Parameters object lives in the Stdlib section of ZF2, a folder where common objects can be found and used across the framework. In this case, the Parameters class is an extension of ArrayObject and implements ParametersInterface that will bring ArrayAccess, Countable, Serializable, and Traversable functionality to the parameters stored inside the object. The goal with this object is to provide a common interface to access data stored in the superglobal arrays. This expands the ways you can interact with the data in an object-oriented approach.

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