Resolve ASP.NET environments without HTTP contexts

[coka]

Sometimes, a user might wish to render HTML in an ASP.NET MVC web application outside of the context of a web request. An example would be email rendering in a separate thread. With the current implementations of AspNetCache and AspNetFileSystem, TinyIoC fails to inject the necessary objects because, internally, an httpContext is null.

For AspNetCache, we can obtain the cache from HttpRuntime, which HttpContextBase calls under the hood (as pointed out in the comments here).

For AspNetFileSystem, HttpServerUtilityBase is used only for .MapPath(), which HostingEnvironment provides as a static method. This method is slightly different, but that should be a non-issue. For example, if the provided relative path is null, React.Core will throw sooner anyway.

[Daniel15]

I'd prefer if this was injected via the dependency injection container, to more easily facilitate unit testing and decouple the components. Could you register this AssemblyRegistration.cs? Something like:

container.Register<Cache>((c, o) => HttpRuntime.Cache);

Then inject it into the constructor:

public AspNetCache(Cache cache)

[coka]

@Daniel15 I have amended the commit to use dependency injection. The build seems flaky, because it passed on the first amend, and failed on the second one, which contained only comment / whitespace changes.

[Daniel15]

Yeah, one of the tests seems flaky :/ This looks good to me!