Apache/Dynagzip version 0.16
============================

mod_perl extension for Apache-1.3.X to compress the response with gzip format.


ABSTRACT

This Apache handler provides dynamic content compression of the response data stream
for HTTP/1.0 and HTTP/1.1 requests.

Standard gzip compression is optionally combined with an extra light compression
that eliminates leading blank spaces and/or blank lines within the source document.
This C<extra light> compression could be applied even when the client (browser)
is not capable to decompress gzip format.

This handler helps to compress the outbound HTML content usually by 3 to 20 times,
and provides a list of useful features.

This handler is particularly useful for compressing outgoing web content
that is dynamically generated on the fly (using templates, DB data, XML,
etc.), when at the time of the request it is impossible to determine the
length of the document to be transmitted. Support for Perl, Java, and C
source generators is provided.

Besides the benefits of reduced document size, this approach gains efficiency
from being able to overlap the various phases of data generation, compression,
transmission, and decompression. In fact, the browser can start to
decompress a document, which has not yet been completely generated.


INSTALLATION

The installation consists of the two steps:

 - Installation to your Perl Library
 - Configuration of your Apache Server

Installation to your Perl Library
---------------------------------

Use the regular procedure to install this module to your Perl Library.

When you have your local copy of the package type the following:

   perl Makefile.PL
   make; make test
   make install

Note: You should be a root to succeed with the last step...

To install the package from the CPAN try to run

   perl -MCPAN -e "install Apache::Dynagzip"

on your UNIX machine.

Configuration of your Apache Server
-----------------------------------

Read "Web Content Compression FAQ" at
http://perl.apache.org/docs/tutorials/client/compression/compression.html

Use the following examples in order to create your own configuration:

 ======================================================
 Static html file (size=149208) no light compression:
 ======================================================
 httpd.conf:

  PerlModule Apache::Dynagzip
  <Files ~ "*\.html">
      SetHandler perl-script
      PerlHandler Apache::Dynagzip
  </Files>

 client-side log:

  C05 --> S06 GET /html/wowtmovie.html HTTP/1.1
  C05 --> S06 Accept: */*
  C05 --> S06 Referer: http://devl4.outlook.net/html/
  C05 --> S06 Accept-Language: en-us
  C05 --> S06 Accept-Encoding: gzip, deflate
  C05 --> S06 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)
  C05 --> S06 Host: devl4.outlook.net
  C05 --> S06 Pragma: no-cache
  C05 --> S06 Accept-Charset: ISO-8859-1
  == Body was 0 bytes ==

  C05 <-- S06 HTTP/1.1 200 OK
  C05 <-- S06 Date: Fri, 31 May 2002 17:36:57 GMT
  C05 <-- S06 Server: Apache/1.3.22 (Unix) Debian GNU/Linux mod_perl/1.26
  C05 <-- S06 X-Module-Sender: Apache::Dynagzip
  C05 <-- S06 Transfer-Encoding: chunked
  C05 <-- S06 Expires: Friday, 31-May-2002 17:41:57 GMT
  C05 <-- S06 Vary: Accept-Encoding
  C05 <-- S06 Content-Type: text/html; charset=iso-8859-1
  C05 <-- S06 Content-Encoding: gzip
  C05 <-- S06 == Incoming Body was 9411 bytes ==
  == Transmission: text gzip chunked ==
  == Chunk Log ==
  a (hex) = 10 (dec)
  1314 (hex) = 4884 (dec)
  3ed (hex) = 1005 (dec)
  354 (hex) = 852 (dec)
  450 (hex) = 1104 (dec)
  5e6 (hex) = 1510 (dec)
  0 (hex) = 0 (dec)
  == Latency = 0.170 seconds, Extra Delay = 0.440 seconds
  == Restored Body was 149208 bytes ==

 ======================================================
 Static html file (size=149208) with light compression:
 ======================================================
 httpd.conf:

  PerlModule Apache::Dynagzip
  <Files ~ "*\.html">
        SetHandler perl-script
        PerlHandler Apache::Dynagzip
        PerlSetVar LightCompression On
  </Files>

 client-side log:

  C05 --> S06 GET /html/wowtmovie.html HTTP/1.1
  C05 --> S06 Accept: */*
  C05 --> S06 Referer: http://devl4.outlook.net/html/
  C05 --> S06 Accept-Language: en-us
  C05 --> S06 Accept-Encoding: gzip, deflate
  C05 --> S06 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)
  C05 --> S06 Host: devl4.outlook.net
  C05 --> S06 Pragma: no-cache
  C05 --> S06 Accept-Charset: ISO-8859-1
  == Body was 0 bytes ==

  C05 <-- S06 HTTP/1.1 200 OK
  C05 <-- S06 Date: Fri, 31 May 2002 17:49:06 GMT
  C05 <-- S06 Server: Apache/1.3.22 (Unix) Debian GNU/Linux mod_perl/1.26
  C05 <-- S06 X-Module-Sender: Apache::Dynagzip
  C05 <-- S06 Transfer-Encoding: chunked
  C05 <-- S06 Expires: Friday, 31-May-2002 17:54:06 GMT
  C05 <-- S06 Vary: Accept-Encoding
  C05 <-- S06 Content-Type: text/html; charset=iso-8859-1
  C05 <-- S06 Content-Encoding: gzip
  C05 <-- S06 == Incoming Body was 8515 bytes ==
  == Transmission: text gzip chunked ==
  == Chunk Log ==
  a (hex) = 10 (dec)
  119f (hex) = 4511 (dec)
  3cb (hex) = 971 (dec)
  472 (hex) = 1138 (dec)
  736 (hex) = 1846 (dec)
  0 (hex) = 0 (dec)
  == Latency = 0.280 seconds, Extra Delay = 0.820 seconds
  == Restored Body was 128192 bytes ==

Default values for the minChunkSizeSource and minChunkSize will be in effect
in this case. To overwrite them try for example

        <IfModule mod_perl.c>
                PerlModule Apache::Dynagzip
		<Files ~ "*\.html">
                        SetHandler perl-script
                        PerlHandler Apache::Dynagzip
			PerlSetVar minChunkSizeSource 36000
			PerlSetVar minChunkSize 9
		</Files>
	</IfModule>

 ===============================================================================
 GET dynamically generated (by perl script) html file with no light compression:
 ===============================================================================
 httpd.conf:

 PerlModule Apache::Filter
 PerlModule Apache::Dynagzip
 <Directory /var/www/perl/>
      SetHandler perl-script
      PerlHandler Apache::RegistryFilter Apache::Dynagzip
      PerlSetVar Filter On
      PerlSendHeader Off
      PerlSetupEnv On
      AllowOverride None
      Options ExecCGI FollowSymLinks
      Order allow,deny
      Allow from all
 </Directory>

 client-side log:

  C05 --> S06 GET /perl/start_example.cgi HTTP/1.1
  C05 --> S06 Accept: image/gif, image/jpeg, image/pjpeg, */*
  C05 --> S06 Accept-Language: en-us
  C05 --> S06 Accept-Encoding: gzip, deflate
  C05 --> S06 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)
  C05 --> S06 Host: devl4.outlook.net
  C05 --> S06 Accept-Charset: ISO-8859-1
  == Body was 0 bytes ==

  C05 <-- S06 HTTP/1.1 200 OK
  C05 <-- S06 Date: Sat, 01 Jun 2002 16:59:47 GMT
  C05 <-- S06 Server: Apache/1.3.22 (Unix) Debian GNU/Linux mod_perl/1.26
  C05 <-- S06 X-Module-Sender: Apache::Dynagzip
  C05 <-- S06 Transfer-Encoding: chunked
  C05 <-- S06 Expires: Saturday, 01-June-2002 17:04:47 GMT
  C05 <-- S06 Vary: Accept-Encoding
  C05 <-- S06 Content-Type: text/html; charset=iso-8859-1
  C05 <-- S06 Content-Encoding: gzip
  C05 <-- S06 == Incoming Body was 758 bytes ==
  == Transmission: text gzip chunked ==
  == Chunk Log ==
  a (hex) = 10 (dec)
  2db (hex) = 731 (dec)
  0 (hex) = 0 (dec)
  == Latency = 0.220 seconds, Extra Delay = 0.050 seconds
  == Restored Body was 1434 bytes ==

 ============================================================================
 GET dynamically generated (by perl script) html file with light compression:
 ============================================================================
 httpd.conf:

  PerlModule Apache::Filter
  PerlModule Apache::Dynagzip
 <Directory /var/www/perl/>
        SetHandler perl-script
	PerlHandler Apache::RegistryFilter Apache::Dynagzip
	PerlSetVar Filter On
	PerlSetVar LightCompression On
	PerlSendHeader Off
	PerlSetupEnv On
	AllowOverride None
	Options ExecCGI FollowSymLinks
	Order allow,deny
        Allow from all
 </Directory>

 client-side log:

  C05 --> S06 GET /perl/start_example.cgi HTTP/1.1
  C05 --> S06 Accept: */*
  C05 --> S06 Accept-Language: en-us
  C05 --> S06 Accept-Encoding: gzip, deflate
  C05 --> S06 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)
  C05 --> S06 Host: devl4.outlook.net
  C05 --> S06 Pragma: no-cache
  C05 --> S06 Accept-Charset: ISO-8859-1
  == Body was 0 bytes ==

  C05 <-- S06 HTTP/1.1 200 OK
  C05 <-- S06 Date: Sat, 01 Jun 2002 17:09:13 GMT
  C05 <-- S06 Server: Apache/1.3.22 (Unix) Debian GNU/Linux mod_perl/1.26
  C05 <-- S06 X-Module-Sender: Apache::Dynagzip
  C05 <-- S06 Transfer-Encoding: chunked
  C05 <-- S06 Expires: Saturday, 01-June-2002 17:14:14 GMT
  C05 <-- S06 Vary: Accept-Encoding
  C05 <-- S06 Content-Type: text/html; charset=iso-8859-1
  C05 <-- S06 Content-Encoding: gzip
  C05 <-- S06 == Incoming Body was 750 bytes ==
  == Transmission: text gzip chunked ==
  == Chunk Log ==
  a (hex) = 10 (dec)
  2d3 (hex) = 723 (dec)
  0 (hex) = 0 (dec)
  == Latency = 0.280 seconds, Extra Delay = 0.000 seconds
  == Restored Body was 1416 bytes ==

In order to use your own handler (that might be generating its own HTTP headers)
inside the Apache::Filter chain, make sure to register your handler with the
Apache::Filter chain like

  $r->filter_register();

when necessary. See Apache::Filter documentation for details.

 ====================================================================================
 GET dynamically generated (by C-written binary) html file with no light compression:
 ====================================================================================
 httpd.conf:

 PerlModule Apache::Dynagzip
 <Directory /var/www/cgi-bin/>
     SetHandler perl-script
     PerlHandler Apache::Dynagzip
     AllowOverride None
     Options +ExecCGI
     PerlSetupEnv On
     PerlSetVar BinaryCGI On
     Order allow,deny
     Allow from all
 </Directory>

 client-side log:

  C05 --> S06 GET /cgi-bin/mylook.cgi HTTP/1.1
  C05 --> S06 Accept: */*
  C05 --> S06 Accept-Language: en-us
  C05 --> S06 Accept-Encoding: gzip, deflate
  C05 --> S06 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)
  C05 --> S06 Host: devl4.outlook.net
  C05 --> S06 Pragma: no-cache
  C05 --> S06 Accept-Charset: ISO-8859-1
  == Body was 0 bytes ==

  C05 <-- S06 HTTP/1.1 200 OK
  C05 <-- S06 Date: Fri, 31 May 2002 23:18:17 GMT
  C05 <-- S06 Server: Apache/1.3.22 (Unix) Debian GNU/Linux mod_perl/1.26
  C05 <-- S06 X-Module-Sender: Apache::Dynagzip
  C05 <-- S06 Transfer-Encoding: chunked
  C05 <-- S06 Expires: Friday, 31-May-2002 23:23:17 GMT
  C05 <-- S06 Vary: Accept-Encoding
  C05 <-- S06 Content-Type: text/html; charset=iso-8859-1
  C05 <-- S06 Content-Encoding: gzip
  C05 <-- S06 == Incoming Body was 1002 bytes ==
  == Transmission: text gzip chunked ==
  == Chunk Log ==
  a (hex) = 10 (dec)
  3cf (hex) = 975 (dec)
  0 (hex) = 0 (dec)
  == Latency = 0.110 seconds, Extra Delay = 0.110 seconds
  == Restored Body was 1954 bytes ==

 =================================================================================
 GET dynamically generated (by C-written binary) html file with light compression:
 =================================================================================
  httpd.conf:

   PerlModule Apache::Dynagzip
   <Directory /var/www/cgi-bin/>
       SetHandler perl-script
       PerlHandler Apache::Dynagzip
       AllowOverride None
       Options +ExecCGI
       PerlSetupEnv On
       PerlSetVar BinaryCGI On
       PerlSetVar LightCompression On
       Order allow,deny
       Allow from all
   </Directory>

 client-side log:

  C05 --> S06 GET /cgi-bin/mylook.cgi HTTP/1.1
  C05 --> S06 Accept: */*
  C05 --> S06 Accept-Language: en-us
  C05 --> S06 Accept-Encoding: gzip, deflate
  C05 --> S06 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)
  C05 --> S06 Host: devl4.outlook.net
  C05 --> S06 Pragma: no-cache
  C05 --> S06 Accept-Charset: ISO-8859-1
  == Body was 0 bytes ==

  C05 <-- S06 HTTP/1.1 200 OK
  C05 <-- S06 Date: Fri, 31 May 2002 23:37:45 GMT
  C05 <-- S06 Server: Apache/1.3.22 (Unix) Debian GNU/Linux mod_perl/1.26
  C05 <-- S06 X-Module-Sender: Apache::Dynagzip
  C05 <-- S06 Transfer-Encoding: chunked
  C05 <-- S06 Expires: Friday, 31-May-2002 23:42:45 GMT
  C05 <-- S06 Vary: Accept-Encoding
  C05 <-- S06 Content-Type: text/html; charset=iso-8859-1
  C05 <-- S06 Content-Encoding: gzip
  C05 <-- S06 == Incoming Body was 994 bytes ==
  == Transmission: text gzip chunked ==
  == Chunk Log ==
  a (hex) = 10 (dec)
  3c7 (hex) = 967 (dec)
  0 (hex) = 0 (dec)
  == Latency = 0.170 seconds, Extra Delay = 0.110 seconds
  == Restored Body was 1862 bytes ==


DEPENDENCIES

This module requires these other modules and libraries:

   Apache::Constants;
   Apache::File;
   Apache::Filter 1.019;
   Apache::Log;
   Apache::URI;
   Apache::Util;
   Fcntl;
   FileHandle;

   Compress::LeadingBlankSpaces;
   Compress::Zlib 1.16;
       
  Note 1: the Compress::Zlib 1.16 requires the Info-zip zlib 1.0.2 or better
        (it is NOT compatible with versions of zlib <= 1.0.1).
        The zlib compression library is available at http://www.gzip.org/zlib/
  
  Note 2: it is recommended to have a mod_perl compiled with the EVERYTHING=1
        switch. However, Apache::Dynagzip uses just fiew phases of the request
        processing flow:
              Content generation phase
              Logging phase


AUTHOR

Slava Bizyayev <slava@cpan.org> - Freelance Software Developer & Consultant.


COPYRIGHT AND LICENSE

Copyright (C) 2002 - 2004 Slava Bizyayev. All rights reserved.

This package is free software. You can use it, redistribute it, and/or modify it
under the same terms as Perl itself.

The latest version of this module can be found on CPAN.

