Getting WordPress Super Cache to Run on a Windows (IIS or Apache) Server

If you’re a regular reader, you probably know by now that we just love performance and can’t get enough of server performance-improving software/code… Especially when it comes to WordPress.

Donncha has recently released a great plugin for WordPress, called "WordPress Super Cache." It builds on the original WP-Cache plugin by Ricardo Granada – except that it fixes all the bugs in the original implementation and has been written in enough pure PHP that it’ll also run on Windows servers – both IIS and Apache for that matter! <cue applause>

At the moment (as of version 0.3.1) it needs a bit of work to make it run, but not much. So here goes – 10 easy steps to get cached content on your IIS or Apache server under Windows:

  1. Download Donncha’s plugin here.
  2. Extract it so you have a /wp-content/plugins/wp-super-cache/ directory with all the files (like wp-cache.php) in there.
  3. Copy
    /wp-content/plugins/wp-super-cache/wp-cache-phase1.php to
    /wp-content/advanced-cache.php
  4. Open up /wp-content/plugins/wp-super-cache/wp-cache.php and locate this:
    [sourcecode language="php"]function wp_cache_check_link() {
    global $wp_cache_link, $wp_cache_file;[/sourcecode]
  5. Replace that with [sourcecode language="php"]function wp_cache_check_link() {
    global $wp_cache_link, $wp_cache_file;

    if ( file_exists($wp_cache_link) )
    return true;
    else {
    echo “advanced-cache.php does not exist
    “;
    echo “Create it by copying $wp_cache_file to $wp_cache_link on your server
    “;
    return false;
    } [/sourcecode]

  6. Log into your dashboard and enable WP Super Cache in the Plugins page.
  7. Go to the WP Super Cache options page and enable caching.
  8. Open /wp-content/wp-cache-config.php and look for "WPCACHEHOME" and correct
    a) Add an opening quotation mark before "C:\"
    b) Replace all "\" with "\\" or "/"
  9. Create your rewrite rules like it says in readme.txt. If your using Apache on Windows, use mod_rewrite. If you’re using IIS, you’ll need to use the 3rd party (non-free, but quite good) ISAPI_Rewrite 3.0
  10. If you have mod_gzip, mod_deflate, or IIS dynamic content caching enabled, make sure you don’t enable Super Cache gzip because it’s already being done on the server level (which is better, anyway! :))

Don’t forget to install either our XCache or eAccelerator plugins to speed up the stuff that WordPress Super Cache doesn’t cache, such as logged-in users’ visits and comment processing, etc. as well as visits by people who have commented (see below).

Known Issues

  • WordPress Super Cache doesn’t cache the blog homepage. We’ve contacted the author (Donncha) and expect to get this fixed soon – it is not specific to Windows hosts.
  • The non-Super Cache code (basically, caching for users who have commented) does not work for posts. This is a known bug in the WP-Cache code that WordPress Super Cache is using as a second caching layer, and there is no way around it at the moment. Don’t worry, posts are still being cached, just not for people who post a comment. Make sure you’re using the XCache plugin to avoid this being a bottleneck.

Update:

It seems that if you’re on an Apache server, it’s best to add a directive in httpd.conf stopping mod_gzip or mod_deflate from running in your WordPress directory, and instead using WordPress Super Cache’s built-in GZIP support. This is because Apache will not cache GZIP’d output, so you’ll end wasting thousands of precious CPU cycles re-GZIPping the same content over and over again. IIS users do not have to worry, IIS 6 GZIPs and caches all static content by default.

12 thoughts on “Getting WordPress Super Cache to Run on a Windows (IIS or Apache) Server

  1. Thanks, now up and running on my Apache2 WAMP server – much faster now.

    God, PHP (and especially WordPress!) is slow!!!

    I had a hard time getting the rewrite rules working, but now they’re fine :)

  2. Could you please clarify step 3 and 4? I am getting a blank page as soon as I enable caching. It’s different than the other typical blank page problems. It seems to be associated to a syntax error in the code. I appears what you say to replace the code with has syntax errors. Your “{” don’t seem correct but I am not an expert. I also assume you mean to replace the complete function with what you specify above…?

  3. I just thought I would provide an update on my blank page problem in my previous post a couple months ago.

    The syntax I questioned before is fine. After multiple attempts to troubleshoot I had to do 2 things different. Than anything stated so far.

    -1 thing I had to do different was my .htaccess file had one small mod from the readme. I had to use “RewriteRule (.+) index.php/$1 [L,QSA]” rather than the similar line (last line) in the readme’s .htaccess

    -The other thing I had to do different than above is in Step 8, it didn’t work with the absolute path. Instead I just have:
    define( ‘WPCACHEHOME’, ABSPATH . “wp-content/plugins/wp-super-cache/” ); //Added by WP-Cache Manager

  4. Glad to hear you got it to work, Scott.

    Switching from WordPress to PerformancePress broke our code-formatting plugins, makes it look like the syntax is all wrong… we never did get around to fixing that.. (/me makes mental note to do it soon!)

  5. Thanks Scott – that all helped to get it working.

    Also, one other thing I discovered is the the line to enable the cache:

    define(‘WP_CACHE’, true);

    needs to be at the top of the config file (wp-config.php) to get wp-cache to generate cached content. Its some weird bug.

  6. Just thought I would pass along that the latest upgrade to 0.6.5 went without a hitch and more importantly, required no customizations. I backed up my plugin dir and did an automatic upgrade. I expected to have to repeat step 4/5 above as this file would have been overwritten but the code must have been improved as my site is running fine without this step above.

  7. I just upgraded to 0.6.5 and it went without a hitch and more importantly, required no customizations. I backed up my plugin dir and did an automatic upgrade. I expected to have to repeat step 4/5 above as this file would have been overwritten but the code must have been improved as my site is running fine without this step above.

  8. I just upgraded to 0.6.5 and it went without a hitch. More importantly, it required no customizations. I backed up my plugin dir and did an automatic upgrade. I expected to have to repeat step 4/5 above as this file would have been overwritten but the code must have been improved as my site is running fine without this step above.

  9. I’ve installed the wp-super-cache plugin in my windows hosting.
    everthing is fine but , plug-in also caches my wp-admin folder.
    When i delete cache and enter the comments page for example, every page becomes the comments page. But i can enter edit-comments.php?comment_status=moderated or admin.php?page=wp-dbmanager/database-manager.php etc. I can’t access pages like post-new.php , plugins.php etc.

    How can i block of caching the wp-admin folder?

  10. As of the current version (0.8.3), here is my experience so far on IIS.

    1. You still have to copy wp-cache-phase1.php to /wp-content/advanced-cache.php
    2. If you change the wp-cache.php file as instructed in steps 4 and 5, the whole thing breaks and will give you a blank page.
    3. Step 8 you need to delete the entire path up to /plugins, so that WPCACHEHOME is set to WP_CONTENT_DIR . “/plugins/wp-super-cache”
    4. It stll doesn’t actually work on IIS anyway, even if the ISAPI_Rewrite module is installed. It complains about not having mod_rewrite.

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