Conteg v0.13 - Content Negotiation + Cache-Control for PHP-originated Web Output.
Conteg with Static HTML Pages + Apache Compression Stats
----------------------------- ------------------------
Overview
--------
There are situations where you wish to use PHP to both parse and deliver html disk files. PHP is
designed to do that very easily, but has one major downside: all the Content Negotiation (provided
by default by web-servers for static files) is lost.
This little help file is designed to indicate how to get those lost facilities back, using the Conteg
Class. The web-server setup for PHP (below) will use the Apache httpd.conf file. Apart from that, the
examples given will work with any setup.
This help-file will NOT explain any details of Conteg setup (other than Apache Notes) - please refer
to the other help-files for that info - but instead will restrict itself to:
* Apache setup re: auto-appended & -prepended files (Apache + PHP)
* Apache setup re: Apache Notes (Apache + Conteg)
* Example PHP coding for append/prepend files (Conteg)
Introduction
------------
Conteg utilises the content-negotiation features of the HTTP protocol to:
* Reduce bandwidth
* Increase perceived (and actual) server responsiveness
The requirements are:
* PHP 4.1.0+
* zlib (for compression - odds are you have it)
* `ExtendedStatus On' in httpd.conf (Apache) (re: $_SERVER-type variables)
By default, with static disk-bound files, most web-servers will auto-send the correct:
* 304 Not Modified
* 406 Not Acceptable
* 412 Precondition Failed
* 416 Requested Range Not Satisfiable
* 206 Partial content, or
* 200 OK page
+ full headers
With the appropriate switches, Conteg will restore those identical features.
By default, Conteg auto-negotiates `Accept-Encoding' (load-balanced compression). By default, Apache
does NOT store compression stats within the log-file. Conteg contains switches which make it very
simple to instruct Apache to store this info (via the `Apache Notes' mechanism). This help-file will
also set out how to achieve that
Implementation - Overview
-------------------------
1 Setup the web-server for auto-appended & -prepended files (+ compression stats for Apache)
2 Use the auto-prepend PHP file to include Conteg
3 Use the auto-append PHP file to setup Conteg
1 Setup the web-server
----------------------
# httpd.conf
# foll required to provide full `$_SERVER' variables
ExtendedStatus On
# foll required by some Apache2 users to obtain `PATH_INFO'
AcceptPathInfo = On
# setup auto-appended + -prepended files
# Check! - IfModule value may vary on your server
<IfModule mod_php4.c>
AddType application/x-httpd-php .html
php_value auto_append_file "/server/path/to/auto_append.php"
php_value auto_prepend_file "/server/path/to/auto_prepend.php"
</IfModule>
# Info to put deflate stats into logs
# Note: (LogFormat) last 2 lines are best as one single line
DeflateFilterNote Input instream
DeflateFilterNote Output outstream
DeflateFilterNote Ratio ratio
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" In:%{instream}n \
Out:%{outstream}n:%{ratio}npct." deflate
# declare for logs
CustomLog logs/access_log deflate
# Use `apachectl graceful' (Command line) after these changes.
2 The auto-prepend file
-----------------------
<?php
// -------------- auto-prepend file : top code --------
ob_start(); // Conteg requirement
require_once( 'Conteg.include' );
?>
3 The auto-append file
-----------------------
<?php
// -------------- auto-append file : bottom code --------
if( !empty( $GLOBALS[ '_SERVER' ])) {
$_SERVER_ARRAY = '_SERVER';
} elseif( !empty( $GLOBALS[ 'HTTP_SERVER_VARS' ])) {
$_SERVER_ARRAY = 'HTTP_SERVER_VARS';
} else {
$_SERVER_ARRAY = 'GLOBALS';
}
// this declaration causes auto-despatch of the file
new Conteg( array(
'modified' => filemtime( ${$_SERVER_ARRAY}[ 'PATH_TRANSLATED' ]),
'use_etag' => TRUE,
'use_apache_notes' => TRUE
));
// any prog cleanup or end-processing goes here
// careful not to cause any more output
?>
Notes: 1 There are other Conteg defaults which may need varying; see basic-howto.0.13.txt.
2 The `DeflateFilterNote' values above are Conteg defaults, and may be varied by
+means of the setup parameter (any, all or none); these are the defaults:
- 'input' => 'instream'
- 'output' => 'outstream'
- 'ratio' => 'ratio'
(Obviously, non of the above contains the coding )
(which will cause you to use PHP in the first place.)
Some references
---------------
* HTTP/1.1: : http://www.w3.org/Protocols/rfc2616/rfc2616.html
* HTTP/1.0: : http://www.w3.org/Protocols/rfc1945/rfc1945.txt
* v0.13 release announcement : http://forums.modem-help.com/viewtopic.php?t=670
* v0.12.3 : http://forums.modem-help.com/viewtopic.php?t=603
* v0.12.2 : http://forums.modem-help.com/viewtopic.php?t=581
* v0.12.1 : http://forums.modem-help.com/viewtopic.php?t=568
* v0.10 : http://forums.modem-help.com/viewtopic.php?t=128
(c) Alex Kemp 02 March, 2007
website: http://www.modem-help.com/
(email address with-held due to historical/hysterical problems)
(contact instead via PM at http://forums.modem-help.com/)
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