Re: GZipStream - incorrect Content-Length

I changed the output type of my methods: they all return a Stream now.

So at the end of each method, instead of doing:

return myObject;

I now do :

return GetStream(myObject);

        private Stream GetStream(object o)
        {
            MemoryStream ms1 = new MemoryStream();
            MemoryStream ms2;
            DataContractJsonSerializer dcjs = new DataContractJsonSerializer(o.GetType());
            dcjs.WriteObject(ms1, o);
            string AcceptEncoding = WebOperationContext.Current.IncomingRequest.Headers["Accept-Encoding"];

            if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate")))
            {
                byte[] raw = ms1.ToArray();
                ms1.Close();

                ms2 = new MemoryStream();
                if (AcceptEncoding.Contains("gzip"))
                {
                    Logger.MainLogger.Info("gzip actif", AcceptEncoding, "GZipEncodePage");
                    HttpContext.Current.Response.AppendHeader("Content-Encoding", "gzip");

                    GZipStream compress = new GZipStream(ms2, CompressionMode.Compress);
                    compress.Write(raw, 0, raw.Length);
                    compress.Close();
                }
                else
                {
                    Logger.MainLogger.Info("deflate actif", AcceptEncoding, "GZipEncodePage");
                    HttpContext.Current.Response.AppendHeader("Content-Encoding", "deflate");

                    DeflateStream compress = new DeflateStream(ms2, CompressionMode.Compress);
                    compress.Write(raw, 0, raw.Length);
                    compress.Close();
                }
            }
            else
            {
                ms2 = ms1;
            }

            return new MemoryStream(ms2.ToArray());
        }

and all works well... :)

The only side effect so far is that my http response now has Content-Type = "application/octet-stream" (instead of "application/json")

Hello

I'm trying to compress the output of a WCF restful service, using GZipStream:

I put this in my global.asax:

protected void Application_BeginRequest(object sender, EventArgs e)
        {
            HttpResponse response = HttpContext.Current.Response;

            string AcceptEncoding = Request.Headers["Accept-Encoding"];
            if (AcceptEncoding == null)
                return;

            if (AcceptEncoding.Contains("gzip"))
            {
                Logger.MainLogger.Info("gzip actif", AcceptEncoding, "GZipEncodePage");
                response.Filter = new GZipStream(response.Filter, CompressionMode.Compress);
                response.AppendHeader("Content-Encoding", "gzip");
                
            }
            else if (AcceptEncoding.Contains("deflate"))
            {
                Logger.MainLogger.Info("deflate actif", AcceptEncoding, "GZipEncodePage");
                response.Filter = new DeflateStream(response.Filter, CompressionMode.Compress);
                response.AppendHeader("Content-Encoding", "deflate");
                response.AppendHeader("Vary", "Content-Encoding");
            }
        }

The problem is that the field "Content-Length" of the response header still gets the value of the uncompressed stream.

For example, when I use fiddler to see what happens:
response header:
HTTP/1.1 200 OK
Date: Thu, 16 Feb 2012 14:25:32 GMT
Cache-Control: private
Content-Length: 472810
Content-Type: application/json
Content-Encoding: gzip
Vary: Content-Encoding

But I also get a fiddler pop up with the error:
Fiddler has detected a protocol violation in session #569.
Content-Length mismatch: Response Header indicated 472 810 bytes, but server sent 152 488 bytes.

Do you know what I've done wrong ?
Thanks