Including a MVC View or string in a javascript bundle using Bundling framework - asp.net-mvc

Question

I'm trying to bundle several javascript files together, but I also need to include a variable from app.config in the js.
My thought was to use a Controller to return a string to set the variable, so going to
~/Javascript/Index would return var foo = "bar"; This works fine.
But when I try to build a bundle, the static files are being included, but the string (or view) isn't showing up. In looking around I found that the Optimizing framework was limited to static files up until 1.1 when support for VirtualPathProviders was implemented.
I upgraded to the latest package, but I can't find any information on how to get a mix of static files and ones generated by a Controller/View to bundle. I guess I just want to use the MVC path provider?
My other thought was to try to use the bundling engine to build a string of the bundled static files and then just append my string and return it all to the browser. But, I can't find a method that allows me to use the bundling engine to return a result of the bundling process.

Answer 1

Integration of dynamic content into the bundling process requires the following steps:
Writing the logic that requests / builds the required content. Generating content from Controller directly requires a bit of work:
public static class ControllerActionHelper
{
public static string RenderControllerActionToString(string virtualPath)
{
HttpContext httpContext = CreateHttpContext(virtualPath);
HttpContextWrapper httpContextWrapper = new HttpContextWrapper(httpContext);
RequestContext httpResponse = new RequestContext()
{
HttpContext = httpContextWrapper,
RouteData = RouteTable.Routes.GetRouteData(httpContextWrapper)
};
// Set HttpContext.Current if RenderActionToString is called outside of a request
if (HttpContext.Current == null)
{
HttpContext.Current = httpContext;
}
IControllerFactory controllerFactory = ControllerBuilder.Current.GetControllerFactory();
IController controller = controllerFactory.CreateController(httpResponse,
httpResponse.RouteData.GetRequiredString("controller"));
controller.Execute(httpResponse);
return httpResponse.HttpContext.Response.Output.ToString();
}
private static HttpContext CreateHttpContext(string virtualPath)
{
HttpRequest httpRequest = new HttpRequest(string.Empty, ToDummyAbsoluteUrl(virtualPath), string.Empty);
HttpResponse httpResponse = new HttpResponse(new StringWriter());
return new HttpContext(httpRequest, httpResponse);
}
private static string ToDummyAbsoluteUrl(string virtualPath)
{
return string.Format("http://dummy.net{0}", VirtualPathUtility.ToAbsolute(virtualPath));
}
}
Implement a virtual path provider that wraps the existing one and intercept all virtual paths that should deliver the dynamic content.
public class ControllerActionVirtualPathProvider : VirtualPathProvider
{
public ControllerActionVirtualPathProvider(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 (ControllerActionHelper.IsControllerActionRoute(virtualPath))
{
return true;
}
return VirtualPathProvider.FileExists(virtualPath);
}
public override CacheDependency GetCacheDependency(string virtualPath, IEnumerable virtualPathDependencies,
DateTime utcStart)
{
AggregateCacheDependency aggregateCacheDependency = new AggregateCacheDependency();
List<string> virtualPathDependenciesCopy = virtualPathDependencies.Cast<string>().ToList();
// Create CacheDependencies for our virtual Controller Action paths
foreach (string virtualPathDependency in virtualPathDependenciesCopy.ToList())
{
if (ControllerActionHelper.IsControllerActionRoute(virtualPathDependency))
{
aggregateCacheDependency.Add(new ControllerActionCacheDependency(virtualPathDependency));
virtualPathDependenciesCopy.Remove(virtualPathDependency);
}
}
// Aggregate them with the base cache dependency for virtual file paths
aggregateCacheDependency.Add(VirtualPathProvider.GetCacheDependency(virtualPath, virtualPathDependenciesCopy,
utcStart));
return aggregateCacheDependency;
}
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 (ControllerActionHelper.IsControllerActionRoute(virtualPath))
{
return new ControllerActionVirtualFile(virtualPath,
new MemoryStream(Encoding.Default.GetBytes(ControllerActionHelper.RenderControllerActionToString(virtualPath))));
}
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 ControllerActionVirtualFile : VirtualFile
{
public CustomVirtualFile (string virtualPath, Stream stream)
: base(virtualPath)
{
Stream = stream;
}
public Stream Stream { get; private set; }
public override Stream Open()
{
return Stream;
}
}
You also have to implement CacheDependency if you need it:
public class ControllerActionCacheDependency : CacheDependency
{
public ControllerActionCacheDependency(string virtualPath, int actualizationTime = 10000)
{
VirtualPath = virtualPath;
LastContent = GetContentFromControllerAction();
Timer = new Timer(CheckDependencyCallback, this, actualizationTime, actualizationTime);
}
private string LastContent { get; set; }
private Timer Timer { get; set; }
private string VirtualPath { get; set; }
protected override void DependencyDispose()
{
if (Timer != null)
{
Timer.Dispose();
}
base.DependencyDispose();
}
private void CheckDependencyCallback(object sender)
{
if (Monitor.TryEnter(Timer))
{
try
{
string contentFromAction = GetContentFromControllerAction();
if (contentFromAction != LastContent)
{
LastContent = contentFromAction;
NotifyDependencyChanged(sender, EventArgs.Empty);
}
}
finally
{
Monitor.Exit(Timer);
}
}
}
private string GetContentFromControllerAction()
{
return ControllerActionHelper.RenderControllerActionToString(VirtualPath);
}
}
Register your virtual path provider:
public static void RegisterBundles(BundleCollection bundles)
{
// Set the virtual path provider
BundleTable.VirtualPathProvider = new ControllerActionVirtualPathProvider(BundleTable.VirtualPathProvider);
bundles.Add(new Bundle("~/bundle")
.Include("~/Content/static.js")
.Include("~/JavaScript/Route1")
.Include("~/JavaScript/Route2"));
}
Optional: Add Intellisense support to your views. Use <script> tags within your View and let them be removed by a custom ViewResult:
public class DynamicContentViewResult : ViewResult
{
public DynamicContentViewResult()
{
StripTags = false;
}
public string ContentType { get; set; }
public bool StripTags { get; set; }
public string TagName { get; set; }
public override void ExecuteResult(ControllerContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
if (string.IsNullOrEmpty(ViewName))
{
ViewName = context.RouteData.GetRequiredString("action");
}
ViewEngineResult result = null;
if (View == null)
{
result = FindView(context);
View = result.View;
}
string viewResult;
using (StringWriter viewContentWriter = new StringWriter())
{
ViewContext viewContext = new ViewContext(context, View, ViewData, TempData, viewContentWriter);
View.Render(viewContext, viewContentWriter);
if (result != null)
{
result.ViewEngine.ReleaseView(context, View);
}
viewResult = viewContentWriter.ToString();
// Strip Tags
if (StripTags)
{
string regex = string.Format("<{0}[^>]*>(.*?)</{0}>", TagName);
Match res = Regex.Match(viewResult, regex,
RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace | RegexOptions.Multiline | RegexOptions.Singleline);
if (res.Success && res.Groups.Count > 1)
{
viewResult = res.Groups[1].Value;
}
else
{
throw new InvalidProgramException(
string.Format("Dynamic content produced by View '{0}' expected to be wrapped in '{1}' tag.", ViewName, TagName));
}
}
}
context.HttpContext.Response.ContentType = ContentType;
context.HttpContext.Response.Output.Write(viewResult);
}
}
Use an extension method or add an helper function to your controller:
public static DynamicContentViewResult JavaScriptView(this Controller controller, string viewName, string masterName, object model)
{
if (model != null)
{
controller.ViewData.Model = model;
}
return new DynamicContentViewResult
{
ViewName = viewName,
MasterName = masterName,
ViewData = controller.ViewData,
TempData = controller.TempData,
ViewEngineCollection = controller.ViewEngineCollection,
ContentType = "text/javascript",
TagName = "script",
StripTags = true
};
}
The steps are similiar for other type of dynamic contents. See Bundling and Minification and Embedded Resources for example.
I added a proof of concept repository to GitHub if you want to try it out.