WordPress MU

just for those who were not aware:

it seems there is a modified version of wp-cache2 available, which aims to improve it and is wpmu compatible.

http://wordpress.org/extend/plugins/wp-super-cache/ and
http://ocaoimh.ie/wp-super-cache/

Looks good

Which one do we have to choose ?
Is it different from the built-in cache system ? Is it better ?

They are both the same. One linsk to the other, there's just two places to read about it. (Donncha's blog has way more info.) Did you read either link?

Is it different? YES. It is explained in the links above. Is it better? For sites that can expect huge jumps in traffic, oh you betcha.

Just installed,

seems to work fine.

erm.... As i understand it, wp-super-chache dir should go into mu-plugins? I 've done that but nothing happens. No options page called WP Super Cache or anything :(

I've tested the plugin on a regular WP install (2.1) and there it works fine after a bit of work. But on MU version 1.3 (on the same server) it does not work. I do not even get any errors...

Follow instructions in readme file. I did it and it works.

thanks ironcube, but i did that. and like i said, it works on a regular wp 2.1 install on the same server...

now on the MU 1.3 install: if i move the wp-super-cache folder to the plugins folder (from mu-plugins), it shows in the plugins list. after activation, there is the same issue. nothing there! no Options > WP Super Cache page to activate caching on :(

anybody running this plugin on MU 1.3? any ideas what is happening here?

I run it on MU 1.3
It adds a submenu under "Site Admin". Not under options like on regular wp.

RavanH: Read the readme :)

4. If you are using WordPress MU you will need to install this in 'wp-content/mu-plugins/wp-super-cache/' and the file wp-cache.php must be copied into the mu-plugins directory.

so from the plugin description I guess you can't use this in conjunction with SK2, or any sort of statistics plugin / "who's online" plugin ?

donncha, thanks but i cannot seem to stress this enough, i DID follow the instructions *sighs*

luckily, ironcube, you are of clear mind :) -- you are right: i was looking in the wrong place! *sighs again, this time of relief*

finally i get at least an error message :) "Error: Your WP-Cache config file (/var/www/vhosts/free-jazz.net/httpdocs/wp-content/wp-cache-config.php) is not writable by the Web server." which was easily fixed by removing the file (i had manually uploaded it) and refreshing the options page. now the whole thing works!

thanks guys :)

btw, i suppose i have to disable normal caching -- ie either remove
define( 'ENABLE_CACHE', true );
or set it to false in wp-config.php?

ENABLE_CACHE = internal object caching. Leave it be.

Happily using Super Cache on MU 1.3.3 for a while now but wondering one thing:

Is there a way to disable caching for certain blogs while leaving it running for others? I find the option to disable caching for certain pages / URL's quite useful but not for complete subdomains (I have tried things like http://certainblog.mu-site.tld/ in that field) it does not seem to work...

Donncha ?

Make an array of blogs you want to cache, then do an if check in your config file of that array against the http_host. Inside that if check is where you would make your call to define the check as true for wp cache.

Thank you lunabyte, interesting approach... I'll give it a try :)

I've been testing this plugin but have heard reports of people seeing previous commenter's email addresses that have been saved in the comment form. This isn't good as when you leave your email address in the comment form, it's under the assumption that it's not displayed publicly. Has anyone worked out a way around this issue?

I haven't noticed that but my users get annoyed not being able to see their bloh changes right away. We need a hack/plugin that will allow each user to clear the cache for their blog only.

I was recently dealing with the problem that changes to widgets and sidebars do not invalidate the cache. I did some web searching and came up with the following:
http://www.ringofblogs.com/2008/01/17/using-wp-super-cache-plugin-with-wordpress-mu

However, the example given was out of date since new versions have been released since it was written. I researched widgets.php to find out more. I believe the correct approach to detecting changes would be to hook wp_set_sidebars_widgets. Unfortunately this is not a pluggable function, nor is it set up as a hook. (Note that wp_set_sidebars_widgets is called from a few places within wp-admin/widgets.php but is defined in wp-includes/widgets.php.)

My temporary solution was to add this code (suggested by the above-linked blog author) after line 367 in wp-includes/widgets.php:


if(function_exists('wp_cache_no_postid')) {
wp_cache_no_postid(0);
}


So does that work? Is that code likely to be added to WordPressMU Core, or in an update to WP Super Cache?