WP Super Cache
This plugin generates static html files from your dynamic WordPress blog. After a html file is generated your webserver will serve that file instead of processing the comparatively heavier and more expensive WordPress PHP scripts.
The static html files will be served to the vast majority of your users, but because a user's details are displayed in the comment form after they leave a comment those requests are handled by the legacy caching engine. Static files are served to:
- Users who are not logged in.
- Users who have not left a comment on your blog.
- Or users who have not viewed a password protected post.
99% of your visitors will be served static html files. Those users who don't see the static files will still benefit because they will see different cached files that aren't quite as efficient but still better than uncached. This plugin will help your server cope with a front page appearance on digg.com or other social networking site.
If for some reason "supercaching" doesn't work on your server then don't worry. Caching will still be performed, but every request will require loading the PHP engine. In normal circumstances this isn't bad at all. Visitors to your site will notice no slowdown or difference. Supercache really comes into it's own if your server is underpowered, or you're experiencing heavy traffic. Super Cached html files will be served more quickly than PHP generated cached files but in every day use, the difference isn't noticeable.
The plugin serves cached files in 3 ways (ranked by speed):
- Mod_Rewrite. The fastest method is by using Apache mod_rewrite (or whatever similar module your web server supports) to serve "supercached" static html files. This completely bypasses PHP and is extremely quick. If your server is hit by a deluge of traffic it is more likely to cope as the requests are "lighter". This does require the Apache mod_rewrite module (which is probably installed if you have custom permalinks) and a modification of your .htaccess file. Visits by anonymous or unknown users will be served this way.
- PHP. Supercached static files can now be served by PHP. The plugin will serve a "supercached" file if it exists and it's almost as fast as the mod_rewrite method. It's easier to configure as the .htaccess file doesn't need to be changed. You still need a custom permalink. You can keep portions of your page dynamic in this caching mode. Your server may not cope as well with a really large amount of traffic. (You're gaming Digg aren't you? You'll need mod_rewrite, the rest of us are ok with PHP!)
- Legacy caching. This is mainly used to cache pages for known users. These are logged in users, visitors who leave comments or those who should be shown custom per-user data. It's the most flexible caching method but also the slowest. As each page is different it's often better not to cache pages for these users at all and avoid legacy caching. Legacy caching will also cache visits by unknown users if this caching mode is selected. You can have dynamic parts to your page in this mode too.
If you're new to caching use PHP caching. It's easy to set up and very fast. Avoid legacy caching if you can.
Recommended Settings
Advanced users will probably want to use mod_rewrite caching, but PHP caching is almost as good and recommended for everyone else. Enable the following:
- PHP caching.
- Compress pages.
- Don't cache pages for known users.
- Cache rebuild.
- CDN support.
- Extra homepage checks.
Garbage collection is the act of cleaning up cache files that are out of date and stale. There's no correct value for the expiry time but a good starting point is 1800 seconds if you're not using legacy mode. If you are using that mode start with an expiry time of 600 seconds.
If you are not using legacy mode caching consider deleting the contents of the "Rejected User Agents" text box and allow search engines to create supercache static files.
Likewise, preload as many posts as you can and enable "Preload Mode". Garbage collection will still occur but it won't affect the preloaded files. If you don't care about sidebar widgets updating often set the preload interval to 2880 minutes (2 days) so all your posts aren't recached very often. When the preload occurs the cache files for the post being refreshed is deleted and then regenerated. Afterwards a garbage collection of all old files is performed to clean out stale cache files. With preloading on cached files will still be deleted when posts are made or edited or comments made.
See the WP Super Cache homepage for further information. Developer documentation is also available for those who need to interact with the cache or write plugins.
The changelog is a good place to start if you want to know what has changed since you last downloaded the plugin.
Interested in translating WP Super Cache to your language? Grab the development version where you will find an up to date wp-super-cache.pot. Send any translation files to donncha @ ocaoimh.ie and thank you!
0.9.9.9
- Fixed typo, is_front_page.
- Serve repeated static files from the same CDN hostname.
- Updated translations.
- Make supercache dir lowercase to avoid problems with unicode URLs.
- Add option to skip https loaded static content.
- Remove 5 second check on age of existing cache files. Should help with posts that get lots of comments and traffic.
- Lots of bugs fixed.
0.9.9.8
- CDN updates: can be switched off, multiple CNAMEs.
- Uninstall process improved. It removes generated files and fixes edited files.
- Cached dynamic pages can now be stored in Supercache files and compressed.
- 1and1 Webhosting fix (/kunden/)
- Remove log by email functionality as it caused problems for users who were inundated by email
- Many more minor fixes and changes.
0.9.9.6
- Fixed problem serving cached files with PHP
- Added support for 304 "file not modified" header to help browser caching. (PHP caching only)
- Added French & German translations, updated Italian translation and fixed translation strings.
- Sleep 4 seconds between preload urls to reduce load on the server
- Updated docs and FAQs.
0.9.9.5
- Disable compression on on easy setup page. Still causes problems on some hosts.
- Remove footerlink on easy setup page.
- Don't delete mod_rewrite rules when caching is disabled.
- Don't stop users using settings page when in safe mode.
0.9.9.4
- Settings page split into tabbed pages.
- Added new "Easy" settings page for new users.
- New PHP caching mode to serve supercached files.
- Mobile support fixes.
- Added Domain mapping support plugin.
- Added "awaiting moderation" plugin that removes that text from posts.
- Terminology change. Changed "half on" to "legacy caching".
- Fixed cache tester on some installs of WordPress.
- Updated documentation
- Added $wp_super_cache_lock_down config variable to hide lockdown and directly cached pages admin items.
- Preloaded checks if it has stalled and reschedules the job to continue.
- Serve the gzipped page when first cached if the client supports compression.
- Lots more bug fixes..
0.9.9.3
- Fixed division by zero error in half on mode.
- Always show "delete cache" button.
- Fixed "Update mod_rewrite rules" button.
- Minor text changes to admin page.
0.9.9.2
- Forgot to change version number in wp-cache.php
0.9.9.1
- Added preloading of static cache.
- Better mobile plugin support
- .htaccess rules can be updated now. Added wpsc_update_htaccess().
- Fixed "page on front" cache clearing bug.
- Check for wordpress_logged_in cookie so test cookie isn't detected.
- Added clear_post_supercache() to clear supercache for a single post.
- Put quotes around rewrite rules in case paths have spaces.
0.9.9
- Added experimental object cache support.
- Added Chinese(Traditional) translation by Pseric.
- Added FAQ on WP-Cache vs Supercache files.
- Use Supercache file if WP-Cache file not found. Useful if mod_rewrite rules are broken or not working.
- Get mobile browser list from WP Mobile Edition if found. Warn user if .htaccess out of date.
- Make sure writer lock is unlocked after writing cache files.
- Added link to developer docs in readme.
- Added Ukranian translation by Vitaly Mylo.
- Added Upgrade Notice section to readme.
- Warn if zlib compression in PHP is enabled.
- Added compression troubleshooting answer. Props Vladimir (http://blog.sjinks.pro/)
- Added Japanese translation by Tai (http://tekapo.com/)
- Updated Italian translation.
- Link to WP Mobile Edition from admin page for mobile support.
0.9.8
- Added Spanish translation by Omi.
- Added Italian translation by Gianni Diurno.
- Addded advanced debug code to check front page for category problem. Enable by setting $wp_super_cache_advanced_debug to 1 in the config file.
- Fixed wordpress vs wordpress_logged_in cookie mismatch in cookie checking function.
- Correctly check if WP_CACHE is set or not. PHP is weird.
- Added wp_cache_clear_cache() to clear out cache directory.
- Only show logged in message when debugging enabled.
- Added troubleshooting point 20. PHP vs Apache user.
- Fixed problem deleting cache file.
- Don't delete cache files when moderated comments are deleted.
0.9.7
- Fixed problem with blogs in folders.
- Added cache file listing and delete links to admin page.
- Added "Newest Cached Pages" listing in sidebox.
- Made admin page translatable.
- Added "How do I make certain parts of the page stay dynamic?" to FAQ.
- Advanced: added "late init" feature so that plugin activates on "init". Set $wp_super_cache_late_init to true in config file to use.
- Disable supercaching when GET parameters present instead of disabling all caching. Disable on POST (as normal) and preview.
- Fixed problem with cron job and mutex filename.
- Warn users they must enable mobile device support if rewrite rules detected. Better detection of when to warn that .htaccess rules must be updated (no need when rewrite rules not present)
- Advanced: Added "wpsupercache_404" filter. Return true to cache 404 error pages.
- Use the wordpress_test_cookie in the cache key.
- Show correct number of cache files when compression off.
- Fixed problem with PHP safe_mode detection.
- Various bugfixes and documentation updates. See Changelog.txt
0.9.6.1
- Move "not logged in" message init below check for POST.
- Add is_admin() check so plugin definitely can't cache the backend.
- Add "do not cache" page type to admin page.
0.9.6
- Add uninstall.php uninstall script.
- Updated cache/.htaccess rules (option to upgrade that)
- Added FAQ about category and static homepage problem.
- Add wp_cache_user_agent_is_rejected() back to wp-cache-phase2.php
- Show message for logged in users when caching disable for them.
- Check filemtime on correct supercache file
0.9.5
- Show next and last GC times in minutes, not local time.
- Don't serve wp_cache cache files to rejected user agents. Supercache files are still served to them.
- If enabled, mobile support now serves php cached files to mobile clients and static cached files to everyone else.
- Added checks for "WPSC_DISABLE_COMPRESSION" and "WPSC_DISABLE_LOCKING" constants to disable compression and file locking. For hosting companies primarily.
- Added check for DONOTCACHEPAGE constant to avoid caching a page.
- Use PHP_DOCUMENT_ROOT when creating .htaccess if necessary.
0.9.4.3
- Added "Don't cache for logged in users" option.
- Display file size stats on admin page.
- Clear the cache when profile page is updated.
- Don't cache post previews.
- Added backslashes to rejected URI regex list.
- Fixed problems with posts and comments not refreshing.
2 comments
Recommend this plugin?
This is the best caching plugin for me. I love the clear and easy settings and admin pages.
works for me much better than the W3 plugin