c# - How do I intercept the output stream of the current actionresult in .NET MVC3?

Question

Hi and thanks for looking!

Background

I am using the Rotativa pdf tool to read a view (html) into a PDF. It works great, but it does not natively offer a way to save the PDF to a file system. Rather, it only returns the file to the user's browser as a result of the action.

Here is what that code looks like:

public ActionResult PrintQuote(FormCollection fc)
        {
            int revisionId = Int32.Parse(Request.QueryString["RevisionId"]);

            var pdf = new ActionAsPdf(
                 "Quote",
                 new { revisionId = revisionId })
                       {
                           FileName = "Quote--" + revisionId.ToString() + ".pdf",
                           PageSize = Rotativa.Options.Size.Letter
                       };

            return pdf;

        } 

This code is calling up another actionresult ("Quote"), converting it's view to a PDF, and then returning the PDF as a file download to the user.

Question

How do I intercept the file stream and save the PDF to my file system. It is perfect that the PDF is sent to the user, but my client also wants the PDF saved to the file system simultaneously.

Any ideas?

Thanks!

Matt

Answer 1

I have the same problem, here's my solution:

You need to basically make an HTTP request to your own URL and save the output as a binary file. Simple, no overload, helper classes, and bloated code.

You'll need this method:

    // Returns the results of fetching the requested HTML page.
    public static void SaveHttpResponseAsFile(string RequestUrl, string FilePath)
    {
        try
        {
            HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(RequestUrl);
            httpRequest.UserAgent = "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)";
            httpRequest.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate");
            HttpWebResponse response = null;
            try
            {
                response = (HttpWebResponse)httpRequest.GetResponse();
            }
            catch (System.Net.WebException ex)
            {
                if (ex.Status == WebExceptionStatus.ProtocolError)
                    response = (HttpWebResponse)ex.Response;
            }

            using (Stream responseStream = response.GetResponseStream())
            {
                Stream FinalStream = responseStream;
                if (response.ContentEncoding.ToLower().Contains("gzip"))
                    FinalStream = new GZipStream(FinalStream, CompressionMode.Decompress);
                else if (response.ContentEncoding.ToLower().Contains("deflate"))
                    FinalStream = new DeflateStream(FinalStream, CompressionMode.Decompress);

                using (var fileStream = System.IO.File.Create(FilePath))
                {
                    FinalStream.CopyTo(fileStream);
                }

                response.Close();
                FinalStream.Close();
            }
        }
        catch
        { }
    }

Then inside your controller, you call it like this:

SaveHttpResponseAsFile("http://localhost:52515/Management/ViewPDFInvoice/" + ID.ToString(), "C:\temp\test.pdf");

And voilà! The file is there on your file system and you can double click and open the PDF, or email it to your users, or whatever you need.