Sending gzipped data in WebRequest?

Question

I have a large amount of data (~100k) that my C# app is sending to my Apache server with mod_gzip installed. I\'m attempting to gzip the data first using System.IO.Compressi

Answer 1

According to http://www.dominoexperts.com/articles/GZip-servlet-to-gzip-your-pages

You should setContentType() to the original format, as you are doing with the application/x-www-form-urlencoded I assume. Then...

 // See if browser can handle gzip
 String encoding=req.getHeader("Accept-Encoding");
 if (encoding != null && encoding.indexOf("gzip") >=0 ) {  // gzip browser 
      res.setHeader("Content-Encoding","gzip");
      OutputStream o=res.getOutputStream();
      GZIPOutputStream gz=new GZIPOutputStream(o);
      gz.write(content.getBytes());
      gz.close();
      o.close();
            } else {  // Some old browser -> give them plain text.                        PrintWriter o = res.getWriter();
                    o.println(content);
                    o.flush();
                    o.close();
            }

Answer 2

Regarding your question whether Content-Encoding is applicable to client-supplied headers - according to HTTP/1.1 standard, it is:

(from section 7)

Request and Response messages MAY transfer an entity if not otherwise restricted by the request method or response status code.

(from section 7.1)

   entity-header  = Allow                    ; Section 14.7
                  | Content-Encoding         ; Section 14.11
                  | Content-Language         ; Section 14.12
                  | Content-Length           ; Section 14.13
                  | Content-Location         ; Section 14.14
                  | Content-MD5              ; Section 14.15
                  | Content-Range            ; Section 14.16
                  | Content-Type             ; Section 14.17
                  | Expires                  ; Section 14.21
                  | Last-Modified            ; Section 14.29
                  | extension-header

Answer 3

On the PHP side this will strip out header and footer from file

function gzip_stream_uncompress($data) { return gzinflate(substr($data, 10, -8)); }

Answer 4

I looked at the source code for mod_gzip and I could not find any code that decompresses data. Apparently mod_gzip only compresses outgoing data which isn't too surprising after all. The functionality you are looking for is probably rarely used, and I'm afraid you have to do your own decompression on the server.

Answer 5

You need to change

req.Headers.Add("Content-Encoding: gzip");

to

req.Headers.Add("Content-Encoding","gzip");