How to add bundles with dynamic content to asp.net web optimization - asp.net-mvc

Question

I'm using SignalR, which maps to asp.net application on virtual path "~/signalr".
SignalR dynamically creates javascript proxy hubs on app start with virtual path "~/signalr/hubs".
So the url "[http://myapp]/signalr/hubs" is where dynamic javascript content is.
How can I add this virtual path to Asp.Net Web Optimization Bundling?
Asp.Net Web Optimization Framework starting from 1.1 supports VirtuPathProvider's:
ASP.NET bundling/minification: including dynamically generated Javascript
Actually I don't understand how to use these VPP's. Could somebody explain in details or better give an example?

Answer 1

Integration of dynamic content into the bundling process requires the following steps:
Writing the logic that requests / builds the required content. For SignalR you could use this code snippet:
public static string GetSignalRContent()
{
var resolver = new DefaultHubManager(new DefaultDependencyResolver());
var proxy = new DefaultJavaScriptProxyGenerator(resolver, new NullJavaScriptMinifier());
return proxy.GenerateProxy("/signalr");
}
Implement a virtual path provider that wraps the existing one and intercept all virtual paths that should deliver the dynamic content (just "~/signalr/hubs" in your case).
public class CustomVirtualPathProvider : VirtualPathProvider
{
public CustomActionVirtualPathProvider(VirtualPathProvider virtualPathProvider)
{
// Wrap an existing virtual path provider
VirtualPathProvider = virtualPathProvider;
}
protected VirtualPathProvider VirtualPathProvider { get; set; }
public override string CombineVirtualPaths(string basePath, string relativePath)
{
return VirtualPathProvider.CombineVirtualPaths(basePath, relativePath);
}
public override bool DirectoryExists(string virtualDir)
{
return VirtualPathProvider.DirectoryExists(virtualDir);
}
public override bool FileExists(string virtualPath)
{
if (virtualPath == "~/signalr/hubs")
{
return true;
}
return VirtualPathProvider.FileExists(virtualPath);
}
public override CacheDependency GetCacheDependency(string virtualPath, IEnumerable virtualPathDependencies, DateTime utcStart)
{
// BaseClass can't create a CacheDependency for your content, remove it
// You could also add your own CacheDependency and aggregate it with the base dependency
List<string> virtualPathDependenciesCopy = virtualPathDependencies.Cast<string>().ToList();
virtualPathDependenciesCopy.Remove("~/signalr/hubs");
return VirtualPathProvider.GetCacheDependency(virtualPath, virtualPathDependenciesCopy, utcStart);
}
public override string GetCacheKey(string virtualPath)
{
return VirtualPathProvider.GetCacheKey(virtualPath);
}
public override VirtualDirectory GetDirectory(string virtualDir)
{
return VirtualPathProvider.GetDirectory(virtualDir);
}
public override VirtualFile GetFile(string virtualPath)
{
if (virtualPath == "~/signalr/hubs")
{
return new CustomVirtualFile(virtualPath,
new MemoryStream(Encoding.Default.GetBytes(GetSignalRContent())));
}
return VirtualPathProvider.GetFile(virtualPath);
}
public override string GetFileHash(string virtualPath, IEnumerable virtualPathDependencies)
{
return VirtualPathProvider.GetFileHash(virtualPath, virtualPathDependencies);
}
public override object InitializeLifetimeService()
{
return VirtualPathProvider.InitializeLifetimeService();
}
}
public class CustomVirtualFile : VirtualFile
{
public CustomVirtualFile (string virtualPath, Stream stream)
: base(virtualPath)
{
Stream = stream;
}
public Stream Stream { get; private set; }
public override Stream Open()
{
return Stream;
}
}
Register your virtual path provider:
public static void RegisterBundles(BundleCollection bundles)
{
// Set the virtual path provider
BundleTable.VirtualPathProvider =
new CustomVirtualPathProvider(BundleTable.VirtualPathProvider);
Bundle include = new Bundle("~/bundle")
.Include("~/Content/static.js")
.Include("~/signalr/hubs");
bundles.Add(include);
}
For some samples of virtual path providers + bundling, see Bundling and Minification and Embedded Resources or Bundling Dynamic Generated Controller / Action Content for example.

Answer 2

I'm not sure whether there is a way to do that, but another alternative is to generate the /signalr/hubs javascript at build time. That way you can just bundle the generated js file.
See the "How to create a physical file for the SignalR generated proxy" section in http://www.asp.net/signalr/overview/signalr-20/hubs-api/hubs-api-guide-javascript-client.