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by 11 comments

A WordPress index page shouldn't be cached by wp-cache the same as posts or other pages not as frequently updated. This 30 second fix gives you control to not cache / or /index.php on your blog. You can use this hack to disable caching anything you want.

Disable caching specific URI's

First clear the cache from the WP-Cache Options Page. Then modify the wp_cache_is_rejected function.

  1. [ PRESS ]Delete cache on the WP-Cache Options Page
  2. [ OPEN ]wp-content/plugins/wp-cache/wp-cache-phase2.php
  3. [ FIND ]if (strstr($uri, '/wp-admin/'))
  4. [ REPLACE WITH ]if(strstr($uri,'/wp-admin/') || $uri==='/' || strstr($uri,'/index.php'))

NOTE: If anyone comes up with an improvement to this technique or a different/better implementation, please let me know so we can help with the development of an updated WP-Cache plugin!

WP-Cache Links

A WordPress index page shouldn't be cached by wp-cache the same as
posts or other pages not as frequently updated. This 30 second fix gives you control to not cache / or /index.php on your blog. You can use this hack to disable caching
anything you want.

Attached Files

  1. WP-Cache Version 2.1.1

Modified wp_cache_is_rejected function

function wp_cache_is_rejected($uri) {
	global $cache_rejected_uri;

	if(strstr($uri,'/wp-admin/') || $uri==='/' || strstr($uri,'/index.php'))
		return true; //we don't allow cacheing wp-admin for security
	foreach ($cache_rejected_uri as $expr) {
		if (strlen($expr) > 0 && strstr($uri, $expr))
			return true;
	return false;

About WP-Cache Caching Plugin

WP-Cache works by caching WordPress pages and storing them in a static file for serving future requests directly from the file rather than loading and compiling the whole PHP code and the building the page from the database...

Wp-Cache uses 2 phases

The first is called at the very begining wp-cache-phase1.php when just few code has been compiled. The second wp-cache-phase2.php after all plugins have been executed. The first phase checks if the requested URL is already cached, if so it serves from the static file and finishes. The second phase stores the generated page in a static file for further request.


December 7th, 2007

Comments Welcome

  • Richard H

    Hey AA... I've been reading your material for several months --you've helped a lot with my various projects along the way. Thank you!

    I haven't tested this plugin yet, but I presume Wp-Cache would also affect the post comments?

    For example, 5 people have commented on post #39, but they're seeing a cached page, so the latest comments would not be shown.

    Is this correct?

  • AskApache

    @ Richard

    Yes this plugin takes care of it by refreshing the cache when a comment/edit/etc. happens to the post.

    If I was only allowed to have one plugin, this would be it.

  • Richard H

    Thanks. Looking forward to the updated WP-Cache plugin.

  • ivanhoe

    is this mod-rewrite safe? Since if using pretty urls are being used everything goes to index.php, will it really disable just a home page?

  • AskApache

    @ ivanhoe

    Yes, at least when using pretty-urls with mod_rewrite. mod_rewrite takes care of the redirection/rewriting of * to /index.php transparently, so the $uri seen by wp-cache is the same $uri seen in the browser.

  • Alex Kessaris

    Thank you! It's really funny because WP Super Cache (based on WP Cache) has an input field to accept rejected paths, but it's impossible to input / or index.php into it!

  • Itai

    Nice. i looking for this solution.

  • Nico

    i've done this i hope it works

  • Norman Hoffmann

    I found the following code below in "wp-content/plugins/wp-super-cache/wp-cache-phase2.php".

    I changed;

    $auto_rejected = array( '/wp-admin/', 'xmlrpc.php', 'wp-app.php' );
    $auto_rejected = array( '/wp-admin/', 'xmlrpc.php', 'wp-app.php', 'index.php' );

    by adding 'index.php' to the line. I hope this works. It's not quite the same as above but I am using Wordpress Version 3.9.1 and WP Super Cache 1.4. So, maybe things have changed a bit.

    Here is the chunk of code below:

    function wp_cache_is_rejected($uri) {
    global $cache_rejected_uri;

    $auto_rejected = array( '/wp-admin/', 'xmlrpc.php', 'wp-app.php', 'index.php' );
    foreach( $auto_rejected as $u ) {
    if( strstr( $uri, $u ) )
    return true; // we don't allow caching of wp-admin for security reasons
    if ( false == is_array( $cache_rejected_uri ) )
    return false;
    foreach ( $cache_rejected_uri as $expr ) {
    if( $expr != '' && @preg_match( "~$expr~", $uri ) )
    return true;
    return false;

    • Norman Hoffmann

      This did not work. I don't know why.

    • Norman Hoffmann

      In the end I followed this advice and added define( "DONOTCACHEPAGE", true ); to my home.php which is my version of index.php with the theme I am using. It seems to have worked.

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