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Easy Background Processing with WebAPI and Windows Azure

The Problem

Assume, for example, that you are developing your own mobile app (or apps, in my case) and want to be able to send push notifications to these apps every once in a while.

You would require a server that will run somewhere in the background, collect new information every given interval and send relevant notifications to the client apps. You would also need to allow the mobile apps to register and unregister from that server, and supply a simple management console user interface for operations such as browsing though your logs, changing intervals and behaviors and so on.

Thinking it through you realize that you also require a SQL database, that the server has to be fully secured (you would not like anyone hacking in and pushing messages in your behalf into your mobile app, used by unknown users..), and that it has to be reliable and always ready.

Now, you could start by trying to locate a suitable and available server(s) and get it allocated for your purposes, or go out and purchase one. You would also have to make sure that the server (or servers) is licensed and installed with all that is required, from operating system through database engines, all the way to the web-server and other packages with the latest version. Your server should also be exposed to the internet but yet secured.

But even when you finally have that server running, who is going to make sure that the server is always up, operational and taken care of? What about variable bandwidth and storage capacities?

A simple and great solution for your background processing – Windows Azure.

The Solution

For my server, I start off by creating a Windows Azure SQL Database (No need to put up a fully secured, reliable, always ready SQL Server – CHECK!).

Back in my Visual Studio 2012, I use the “Server Explorer” tab to further create the tables, relations, keys etc., as Windows Azure SQL Databases act as any standard remote SQL server databases, just in the cloud. (No special tools – CHECK!)

Two pieces were still missing from the puzzle: the background service and a management console. Simple solution there – I create a Windows Azure Cloud Service composed of a Worker role and Web role. The Worker role would be used for background processing and the Web role would serve as the management console and Web-API host.

NOTE     A Windows Azure Web Site would not be a good enough solution for these purposes as it becomes dormant after a short timeout of not receiving new calls, thus any background service will stop working.

You have two options: create both elements through the Windows Azure console and download a ready-made Visual Studio project, or create what you need in Visual Studio using wizards and have Visual Studio take care of creating whatever is required on Azure for you.

I usually choose the latter as it is easier for me to do it all from the Visual Studio environment, where I have everything I need. You would need to install the Windows Azure SDK in order to have the cloud options in your Visual Studio.

Creating a cloud service is as simple as “File/New/Cloud/Windows Azure Cloud Service” (assuming you already have the required live account):

Adding a Windows Azure Cloud Service project

and selecting the desired roles:

image

The wizard creates ready-made solution and projects for the selected roles, already set to work with Entity Framework 5. The Worker role project already contains stubs for the “Run” and “OnStart” method overrides, allowing you to inject your business logic into the background service, while the Web role (if the preferred MVC 4 pattern selected) is already a full-blown website, with REST support, controllers, models, and everything that you need to form a secured websites, including pre-defined ASP.NET membership.

At this stage, both projects can already be published to Windows Azure.  You only have to worry about your specific code. You can also debug both projects using the Visual Studio and the “Windows Azure Compute Emulator” and “IIS Express”, that are installed as part of the Windows Azure SDK install.

So, what do we have here?

We just setup a WebAPI server, a website and a background service running against a SQL server in record time and with minimal effort. Having all of them running on Windows Azure, we also ensured reliability, manageability and consistency for our services.

Using the above steps, it took me less than a day to complete the rest of the code logic and get a push notifications server up and running. Want to see it in action? Check out the Toronto Events and Festivals Windows 8 and Windows Phone 8 apps as well as the Trashswag Windows 8 and Windows Phone 8 apps. Both use this background processing cloud service architecture to collect new information and send notifications to the apps.

If you’d like to go deeper into this concept, I’ve put some demo code on my SkyDrive. Going through the examples, you’ll see that there was very little code required in order to get Windows 8/Windows Phone 8 apps connected to the WebAPI based Windows Azure app. Please note that the WebAPI MVC 4 project uses a bunch of NuGet packages, automatically installed by the wizard within my project. Write me or comment below if you have any questions or need some help.

Featured on MSDN Canada’s Canadian Developer Connection

Developers, There Are UI Updates for You in Windows 8.1

Windows 8.1

With the RTM bits now available for MSDN subscribers, as you would have read in Jonathan Rozenblit’s editorial in the latest MSDN eNews newsletter, Windows 8.1 is here and should not be ignored.

For those of you who already have some experience developing Windows 8 apps, I compiled a (partial) list of changes that I find notable on the UI side. For those that haven’t, the below are things that you should absolutely not think twice about implementing in your apps.

The best part about these changes – Visual Studio 2013 now includes new and updated controls for XAML/C# and HTML/JavaScript to make these UI updates simple to implement. So let’s to through them:

Tiles
  • Tiles now have two new sizes, while older ones has been renamed. The new sizes : “Small” and “Large”, while “Normal” was renamed to “Medium”.
  • This does not mean that your old code would stop working, as the older names are still mapped to new ones in the enums for backward compatibility, but if you want to support the newer tile types, you would have to update your code.
  • The only restriction is that in order to support the Large tiles, you will also have to support Wide tiles in you app.

Multiple windows/No more snap-view

  • Snap view was replaced by a variable size window mechanism allowing the user to have multiple apps and windows running on the screen at the same time, with different widths, while an app may also spawn other apps and share the available space with it.
  • On the code side, this means that the older code dealing with snap-view will now render obsolete, such as: snap-view visual elements in XAML which are not required anymore, and ApplicationView.Value property, ApplicationView.TryUnsnap method and ApplicationViewState enum references becoming obsolete in your C#/JavaScript.
  • You now have to the following new properties in the ApplicationView class: AdjacentToLeftDisplayEdge and AdjacentToRightDisplayEdge used to determine if your app window is adjacent to one of the edges, IsFullscreen and Orientation.

Search

  • The Search charm, while still there, will now act more of a global (computer-wide and/or web) search, and less of an in-app search. Visual Studio 2013 now offers new SearchBox control to be included in the apps themselves and used for in-app searches. Older, search-ready Windows 8 apps will still work with the search charm as they did before, but in order to search within the app the user would have to run it first and select it as target on the search target combobox. Not as intuitive as it used to be, or as using the in-app SearchBox control.

New/Improved Controls

  • Flyout: No need to use third party vendors’ flyout controls anymore. The Flyout control allows you to display a floating window which is not a dialog (unlike MessageDialog). Deriving from the Flyout control, you now also have the MenuFlyout and the SettingsFlyout controls.
  • Hub: New navigation control allowing you to to aggregate different types of information controls within one content control, therefore controlling the width of your app’s main screen. For example: Displaying a GridView of images in one hub section, a ListView of detailed information in another, and a form on a third section.
  • AppBar: Windows 8 already allowed you to include various controls in the app-bar, but Windows 8.1 offers the AppBarButton, AppBarToggleButton, and AppBarSeperator controls right out of the box to be used as part of the new CommandBar control within your app-bars. So, what is the difference? It’s all about styles and conventions. Using the new controls allows you to have your app-bars look and behave in a more conventional way while the CommandBar control automatically lays out the commands on the bar,
  • NavBar (HTML5/JavaScript only): A navigation list, similar to the AppBar, displaying hierarchical links at the top of each page.
  • BackButton (HTML5/JavaScript only): Similar to the back button that was already available in Windows 8 XAML code as part of the LayoutAware pages created by the wizard, this control allows the user to browse back through the page history up to the first page.
  • WebView: (HTML5/JavaScript only): Similar to the WebView control that was available in Windows 8 XAML, this control can be used to replace the use of iFrames to display external pages. The main advantage is in the content and browse history isolation.

As you can see, developing for Windows 8.1 is definitely not different than developing for Windows 8. It is actually easier. Migrating your apps to Windows 8.1 is mostly performed automatically, and you can make the required changes to support the new features in a fraction of the time it took you to develop your app originally. I would definitely suggest migrating your apps to allow your users to benefit from these improved UI capabilities.

While I did not cover all of the changes in Windows 8.1, and not even all of the changes to the UI, what you do have here are the ones that will make your development easier, while, and most importantly, enhancing the experience of your app for your users.

Featured on MSDN Canada’s Canadian Developer Connection