Howto: WP-Cache and protected posts

If you use protected posts on your WordPress blog you may have noticed that WP-Cache doesn’t cache those password protected posts properly. I didn’t know this, but James Farmer did so I went looking and found a fix.

In the plugins/wp-cache/ directory, open wp-cache-phase1.php in your favourite text editor and look for the following line:

if (preg_match(“/^wordpress|^comment_author_email_/”, $key)) {

Replace that line with this one:

if (preg_match(“/^wp-postpass|^wordpress|^comment_author_email_/”, $key)) {

Save and upload the file if necessary and clear your cache. Password protect posts should be cached properly now!

Ironically, this post wasn’t being cached by WP-Cache because the url contains the string “wp-“. Here’s how to fix that bug. Open wp-cache-phase2.php and look for the following line:

if (strlen($expr) > 0 && strstr($uri, $expr))

Change it to read:

if (strlen($expr) > 0 && substr( $uri, 1, strlen($expr) ) == $expr )

Phew. This post is now cached.

By Donncha

Donncha Ó Caoimh is a software developer at Automattic and WordPress plugin developer. He posts photos at In Photos and can also be found on Twitter.

16 replies on “Howto: WP-Cache and protected posts”

Hi! I use Wp-Cache and some posts are password protected and this fixed really worked! I applied both of them, to phrase 1 and 2.


What version of WP-Cache are you running? There was a 2.1.2 release a couple weeks ago, so just wondering if that was the version you did this fix too.

If so, it might also be good measure to let the plugin author know about your wonderful fix.

Thanks for the information… I’m now off to fix mine 🙂

Sean – it’s for version 2.1.2, I will be contacting Ricardo, although he says he wants to pass the baton on because he doesn’t have much time to maintain wp-cache any more unfortunately.

Adam – did you check your error log? Anything obvious there? The small changes above shouldn’t cause your site to die. Sounds like a syntax error!

I don’t know what you’ve got happening on your blog here but your single page posts are missing the background making them impossible to read.

@Adam and Donncha:

Donnacha: Thanks for your nice modification, some of my friends have said they can now visit the pages with WP-Cache on (2.1.2 version).

Adam: Have you’ve cleared the cached pages and expired pages?

[…] Howto: WP-Cache and protected posts at Holy Shmoly! 让wp-cache支持密码保护。不过这个插件我现在很少用了,貌似不时有点问题。 (tags: wordpress) […]

Just found a bug with the second modification – if your blog isn’t installed in the root of your server then it’ll never return true. The solution probably is to add all the wp-* files that in the index directory of your install. That’ll be files like wp-cron.php, wp-login.php, etc. Or don’t use “wp-” in your posts 🙂

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