Questions[deflate](server)

"GET /Symfony/web/app.php/app/dashboard HTTP/1.1" 4513/37979 (11%)
"GET /Symfony/web/css/application.css HTTP/1.1" -/- (-%)
"GET /Symfony/web/js/application.js HTTP/1.1" -/- (-%)
"GET /Symfony/web/js/highcharts.js HTTP/1.1" -/- (-%)
"GET /Symfony/app/Resources/public/img/logo.png HTTP/1.1" -/- (-%)

Don't know if there is something wrong with my configuration, but the no compression for css and js seems strange to me.

However both css and js are already minified. Here is Apache relevant section in cong/httpd.conf:

# Deflate
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript

DeflateCompressionLevel 9

BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4\.0[678] no-gzip
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
# IE5.x and IE6 get no gzip, but allow 7+
BrowserMatch \bMSIE\s7 !no-gzip

Header append Vary User-Agent env=!dont-vary

DeflateFilterNote Input instream
DeflateFilterNote Output outstream
DeflateFilterNote Ratio ratio
LogFormat '"%r" %{outstream}n/%{instream}n (%{ratio}n%%)' deflate
CustomLog logs/deflate.log deflate

I'm running into a problem with a new production server whereto I'm transferring projects. The HTML output of the PHP applications isn't compressed by the Apache mod_deflate module. Other resources, as stylesheet and javascript files, even html pages, which are served with the same Content-type (text/html) as the PHP output, are compressed!

The projects use the following rules (from HTML5 boilerplate) in the .htaccess:

<IfModule mod_deflate.c>
  # Force deflate for mangled headers developer.yahoo.com/blogs/ydn/posts/2010/12/pushing-beyond-gzipping/
  <IfModule mod_setenvif.c>
    <IfModule mod_headers.c>
      SetEnvIfNoCase ^(Accept-EncodXng|X-cept-Encoding|X{15}|~{15}|-{15})$ ^((gzip|deflate)\s*,?\s*)+|[X~-]{4,13}$ HAVE_Accept-Encoding
      RequestHeader append Accept-Encoding "gzip,deflate" env=HAVE_Accept-Encoding
    </IfModule>
  </IfModule>

  # HTML, TXT, CSS, JavaScript, JSON, XML, HTC:
  <IfModule filter_module>
    FilterDeclare   COMPRESS
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/html
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/css
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/plain
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/xml
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/x-component
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/javascript
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/json
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/xml
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/xhtml+xml
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/rss+xml
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/atom+xml
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/vnd.ms-fontobject
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $image/svg+xml
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $image/x-icon
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/x-font-ttf
    FilterProvider  COMPRESS  DEFLATE resp=Content-Type $font/opentype
    FilterChain     COMPRESS
    FilterProtocol  COMPRESS  DEFLATE change=yes;byteranges=no
  </IfModule>
 </IfModule>                                                                                                                                                                 

We have a testing machine that runs the same Apache, OS and PHP version. On that machine the compression works just fine on the PHP output. I've checked and compared Apache and PHP config files, all the same as far as I can tell.

I've tried several manners of outputting the content of the PHP, using output buffering or just plain echoing the content. Same thing, no compression.

Example response headers of a PHP output:

HTTP/1.1 200 OK
Date: Wed, 25 Apr 2012 23:30:59 GMT
Server: Apache
Accept-Ranges: bytes
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: public
Pragma: no-cache
Vary: User-Agent
Keep-Alive: timeout=5, max=98
Connection: Keep-Alive
Transfer-Encoding: chunked
Content-Type: text/html; charset=utf-8

Example of response headers on a css file:

HTTP/1.1 200 OK
Date: Wed, 25 Apr 2012 23:30:59 GMT
Server: Apache
Last-Modified: Mon, 04 Jul 2011 19:12:36 GMT
Vary: Accept-Encoding,User-Agent
Content-Encoding: gzip
Cache-Control: public
Expires: Fri, 25 May 2012 23:30:59 GMT
Content-Length: 714
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/css; charset=utf-8

Does anyone has a clue or experienced the same "problem"?

thanks!

I posted this on stack overflow but it was suggested I may have more luck here:

I have not used deflate before to encode web pages so this is new ground for me but when I look at nework traffic in ff my all.js file is now 117kb from 427kb so I seem to have it working here. But there is no change in IE9. My response header says Content-Encoding: gzip in FF but not IE9

here is my .htaccess:

<ifModule mod_deflate.c>
  AddOutputFilterByType DEFLATE text/html text/plain text/xml application/xml application/xhtml+xml text/css text/javascript application/javascript application/x-javascript
</ifModule>

Request Header for all.js in IE9:

   Key  Value
Request GET /all.js HTTP/1.1
Accept  application/javascript, */*;q=0.8
Referer http://www.alexchapman.co.uk/
Accept-Language en-GB
User-Agent  Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)
Accept-Encoding gzip, deflate
Host    static.alexchapman.co.uk
Connection  Keep-Alive
Cache-Control   no-cache

Response Header for all.js in IE9:

Key Value
Response    HTTP/1.1 200 OK
Date    Tue, 28 Feb 2012 15:53:41 GMT
Server  Apache/2
Last-Modified   Tue, 28 Feb 2012 15:53:40 GMT
Accept-Ranges   bytes
Cache-Control   private
Expires Fri, 02 Mar 2012 03:53:41 GMT
Keep-Alive  timeout=15, max=100
Connection  Keep-Alive
Transfer-Encoding   chunked
Content-Type    text/javascript

Request Header for all.js in Firefox:

Accept: */*
Accept-Encoding: gzip, deflate
Accept-Language: en-gb,en;q=0.5
Cache-Control: no-cache
Connection: keep-alive
Cookie: DELETED - this should not be sent and isnt sent with IE
Host: static.alexchapman.co.uk
Pragma: no-cache
Referer: http://www.alexchapman.co.uk/
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:10.0.2) Gecko/20100101 Firefox/10.0.2

Response header for all.js in Firefox:

Accept-Ranges: bytes
Cache-Control: private
Connection: Keep-Alive
Content-Encoding: gzip
Content-Type: text/javascript
Date: Tue, 28 Feb 2012 15:55:26 GMT
Expires: Fri, 02 Mar 2012 03:55:26 GMT
Keep-Alive: timeout=15, max=100
Last-Modified: Tue, 28 Feb 2012 15:55:26 GMT
Server: Apache/2
Transfer-Encoding: chunked
Vary: Accept-Encoding

To be clear this is not just happening with all.js - I have used this as an example since it is the biggest file that will benefit from compression. Any suggestions as to what I am doing wrong would be much appreciated.

**********UPDATE************

My hosting provider has got back to me and said that they can confirm that gzip and deflate are both enabled and working on my site, they have said that The issue with Internet Explorer is specific to that browser so I recommend trying compatibility mode as this is not caused by our servers.

I know of a compatability view in IE and this is supposed to help render old sites properly so I dont know what they are on about here and I can confirm this makes no difference to the file compression.

I have a CentOS box running Apache 2.2.3 and compression is working fine on HTTP connections, with the relevant information being logged to a separate deflate log. However, no information is being logged for HTTPS connections. I believe this is because the compression is being negotiated at the SSL layer but I'm not completely certain.

Compression over HTTPS has been tested and verified using information from this site, so I know it's working. Of course that test doesn't really tell me anything useful about how well compression is working or for which browsers. As the site in question has no static content it's not easily tested without using a browser, so just faking user agent strings won't help much.

Is there a way I can get information about compression logged for HTTPS connections?

It seems to me, that mod_deflate in Apache 2.2 will always return:

Content-Encoding: gzip

and never:

Content-Encoding: deflate

It was explained to me, that although there may be a deflate algorithm, mod_deflate is named after a file-format, in which the algorithm could be any of:

gzip, bzip. pkzip

Of those three, mod_deflate provides gzip.

It seems as though gzip is the most popular and widely-supported algorithm in web browsers, but I know some web servers and proxies do return Content-Encoding: deflate.

Aside from the confusion of the module's name, it true that mod_deflate will only return Content-Encoding: gzip?

Thank you.