In IWP61: Building for Windows Phone and Windows 8 - The Basics, Matthias Shapiro and Matt Hidinger talked about how to build apps for both Windows Phone and for Windows 8, how to use an architecture that allows the developer to share as much code as possible between them.
In this edition, Andy Wigley and Mike Taulty from Microsoft UK dig deeper into one particular area: writing shareable HTTP networking code using the HttpClient API. HttpClient is a new API originally released for Windows 8 Store apps and .NET Framework 4.5, but is not included in the Windows Phone 8 SDK. This and other differences in the networking APIs for Windows Phone SDK and the Windows 8 (Windows Store Apps) SDK makes writing shareable code for HTTP networking challenging. However, the .NET Framework Base Class Libraries team recently released a portable implementation of HttpClient that works on Windows Phone 7.1 and above, .NET Framework 4.0 and higher, Silverlight and Windows 8 Store Apps.
Andy walks through the basics of programming with HttpClient including how to take advantage of the automatic decompression support, and then Mike shows an example of a Windows Phone and a Windows 8 version of an app that use the same portable class library containing HttpClient code for fetching images from Flickr.
If you want to take a deeper look at this demo and how it was built, take a look at this post on Mike Taulty's blog: Windows 8, Windows Phone 8: Building for Both.