What's behind the special .XAP.PNG archives on RRS feed

  • Question

  • On the HTML source file I came across some links (streetsidePrefetchFileUrls) to strange looking .xap.png archives like the following one:


    I found out that this file is in fact a PNG with no pixel data inside but a (corrupt) PKZIP archive which contains Microsoft DLLs (Microsoft.Maps.Network.dll, Microsoft.Maps.PluginContainer.dll, Microsoft.Maps.Plugins.dll and Microsoft.Maps.Plugins.Internal.dll).

    Does anybody know why the PNG image file format is used as a container for Zip-Archives here? I've tried to unpack the refered file with unzip and 7z. They all detect the ZIP-Archive inside the PNG but abort unpacking with an error.

    • Moved by Ricky_Brundritt Saturday, March 10, 2012 1:38 PM (From:Bing Maps: Map Control and Web services Development)
    Wednesday, February 22, 2012 8:39 AM


  • Even if it's not allowed to decompile or reverse engineer a part of a component of the platform (see ToU), from my point I think it's the way that you wan load modules inside you silverlight application like you're using MEF and other dynamic loading framework (plugin-like framework). Those modules are transmitted in PNG as their compressed, obfuscated and sent in binary and you can't easily take a look inside the Bing Maps App and module.

    But that's only my point.

    MVP - Bing Maps - My blog (FR): Twitter:

    Wednesday, February 22, 2012 8:50 AM