Minify Action Filter Attribute in ASP.NET MVC

I have a controller action that returns a large amount of dynamic JavaScript (gets served once to the client) and I already have GZip compression enabled. One开发者_开发百科 thing I'd like to do is read the executed result stream and apply JS minification on it.

Is it possible to do this using an Action Filter Attribute. I think my question boils down to - Assuming my minifier takes a string of JavaScript is there a way to pull the executed result as a string out of View(view).ExecuteResult(ControllerContext) ?

I think the YUI Compressor for .NET will do exactly what you need.

http://yuicompressor.codeplex.com/

EDIT: Above is wrong as I misread the question. The code below will install a response filter allowing you to manipulate the output, in this case it just removes newline characters.

Hope this helps.

[HandleError]
public class HomeController : Controller
{
    [Minify]
    public ActionResult Index()
    {
        ViewData["Message"] = "Welcome to ASP.NET MVC!";

        return View();
    }
}

public class Minify : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        //You can check if the content type is CSS/JS here and prevent the filter running on HTML pages 

        filterContext.HttpContext.Response.Filter = new MinifyFilter(filterContext.HttpContext.Response.Filter);

        base.OnActionExecuting(filterContext);
    }
}

public class MinifyFilter : MemoryStream
{
    private StringBuilder outputString = new StringBuilder();
    private Stream outputStream = null;

    public MinifyFilter(Stream outputStream)
    {
        this.outputStream = outputStream;
    }

    public override void Write(byte[] buffer, int offset, int count)
    {
        outputString.Append(Encoding.UTF8.GetString(buffer));
    }

    public override void Close()
    {
        //Call the minifier here, your data is in outputString
        string result = outputString.ToString().Replace(Environment.NewLine, string.Empty);

        byte[] rawResult = Encoding.UTF8.GetBytes(result);
        outputStream.Write(rawResult, 0, rawResult.Length);

        base.Close();
        outputStream.Close();
    }
}