I was looking to try and add a Protobuf ValueProviderFactory to MVC3 so that I could pick out the MIME type and deserialize the raw data into objects for action parameters. I could also use this to change the default Json serializer.
Looking at JsonValueProviderFactory.cs this shouldn't be too difficult, but the factories all appear to be hard-coded.
For Protobuf I may be able to do something with an IValueProvider but I haven't even checked yet what MVC3 does when it recieves an MIME type of application/x-protobuf.
Am I going about this the right way?
UPDATE
I found this blog post that talks about creating an IValueProvider. It then mentions at the bottom that this changed around MCV2. He changed it to a ValueProviderFactory and calls :
ValueProviderFactories.Factories.Add(new HttpCookieValueProviderFactory());
But in MVC3 this property is read only.