MVC last chance to change the response before it is passed to the user

Question

I need to modify the full html response stream (using html parsing) before it is displayed to the user. Where / when is the last chance to do this?

Answer 1

IMHO, the best way to modify the HTML response in ASP.NET MVC is to use action filters. This is an example of an action filter for compressing output:

public class CompressFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        HttpRequestBase request = filterContext.HttpContext.Request;

        string acceptEncoding = request.Headers["Accept-Encoding"];

        if (string.IsNullOrEmpty(acceptEncoding)) return;

        acceptEncoding = acceptEncoding.ToUpperInvariant();

        HttpResponseBase response = filterContext.HttpContext.Response;

        if (acceptEncoding.Contains("GZIP"))
        {
            response.AppendHeader("Content-encoding", "gzip");
            response.Filter = new GZipStream(response.Filter, CompressionMode.Compress);
        }
        else if (acceptEncoding.Contains("DEFLATE"))
        {
            response.AppendHeader("Content-encoding", "deflate");
            response.Filter = new DeflateStream(response.Filter, CompressionMode.Compress);
        }
    }
}

You can use it as described in your action methods:

    [CompressFilter]
    // Minifies, compresses JavaScript files and stores the response in client (browser) cache for a day
    public JavaScriptResult GetJavaScript(string jsPath)

NTN

Answer 2

I believe you can do this with the HttpModule.

http://msdn.microsoft.com/en-us/library/aa719858%28VS.71%29.aspx

http://www.netfxharmonics.com/2007/08/Real-World-HttpModule-Examples.aspx
: http://www.netfxharmonics.com/n/2007/08/real-world-httpmodule-examples

http://www.15seconds.com/Issue/020417.htm