WP Super Cache vs DietPress

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: 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. One cached file can be served thousands of times. Other visitors will be served custom cached files tailored to their visit. If they are logged in, or have left comments those details will be displayed and cached for them. The plugin serves cached files in 3 ways (ranked by speed): Expert. 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 which is risky and may take down your site if modified incorrectly. Simple. Supercached static files can be served by PHP and this is the recommended way of using the plugin. 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. WP-Cache caching. This is mainly used to cache pages for known users, URLs with parameters and feeds. Known users 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 and slightly slower. WP-Cache caching will also cache visits by unknown users if supercaching is disabled. You can have dynamic parts to your page in this mode too. This mode is always enabled but you can disable caching for known users, URLs with parameters, or feeds separately. Set the constant “DISABLE_SUPERCACHE” to 1 in your wp-config.php if you want to only use WP-Cache caching. If you’re not comfortable with editing PHP files then use simple mode. It’s easy to set up and very fast. Recommended Settings Simple 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. Consider deleting the contents of the “Rejected User Agents” text box and allow search engines to cache files for you. Preload as many posts as you can and enable “Preload Mode”. Garbage collection of old cached files will be disabled. 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. Even with preload mode enabled cached files will still be deleted when posts are modified or comments made. Development Active development of this plugin is handled on GitHub. Translation of the plugin into different languages is on the translation page. Documentation If you need more information than the following, you can have a look at the wiki or the Developer documentation. Preloading You can generate cached files for the posts, categories and tags of your site by preloading. Preloading will visit each page of your site generating a cached page as it goes along, just like any other visitor to the site. Due to the sequential nature of this function, it can take some time to preload a complete site if there are many posts. To make preloading more effective it can be useful to disable garbage collection so that older cache files are not deleted. This is done by enabling “Preload Mode” in the settings. Be aware however, that pages will go out of date eventually but that updates by submitting comments or editing posts will clear portions of the cache. Garbage Collection Your cache directory fills up over time, which takes up space on your server. If space is limited or billed by capacity, or if you worry that the cached pages of your site will go stale then garbage collection has to be done. Garbage collection happens on a regular basis and deletes old files in the cache directory. On the advanced settings page you can specify: 1. Cache timeout. How long cache files are considered fresh for. After this time they are stale and can be deleted. 2. Scheduler. Setup how often garbage collection should be done. 3. Notification emails. You can be informed on garbage collection job progress. There’s no right or wrong settings for garbage collection. It depends on your own site. If your site gets regular updates, or comments then set the timeout to 1800 seconds, and set the timer to 600 seconds. If your site is mostly static you can disable garbage collection by entering 0 as the timeout, or use a really large timeout value. The cache directory, usually wp-content/cache/ is only for temporary files. Do not ever put important files or symlinks to important files or directories in that directory. They will be deleted if the plugin has write access to them. CDN A Content Delivery Network (CDN) is usually a network of computers situated around the world that will serve the content of your website faster by using servers close to you. Static files like images, Javascript and CSS files can be served through these networks to speed up how fast your site loads. You can also create a “poor man’s CDN” by using a sub domain of your domain to serve static files too. OSSDL CDN off-linker has been integrated into WP Super Cache to provide basic CDN support. It works by rewriting the URLs of files (excluding .php files) in wp-content and wp-includes on your server so they point at a different hostname. Many CDNs support origin pull. This means the CDN will download the file automatically from your server when it’s first requested, and will continue to serve it for a configurable length of time before downloading it again from your server. Configure this on the “CDN” tab of the plugin settings page. This is an advanced technique and requires a basic understanding of how your webserver or CDNs work. Please be sure to clear the file cache after you configure the CDN. REST API There are now REST API endpoints for accessing the settings of this plugin. You’ll need to be authenticated as an admin user with permission to view the settings page to use it. This has not been documented yet but you can find all the code that deals with this in the “rest” directory. Custom Caching It is now possible to hook into the caching process using the add_cacheaction() function. Three hooks are available: ‘wp_cache_get_cookies_values’ – modify the key used by WP Cache. ‘add_cacheaction’ – runs in phase2. Allows a plugin to add WordPress hooks. ‘cache_admin_page’ – runs in the admin page. Use it to modify that page, perhaps by adding new configuration options. There is one regular WordPress filter too. Use the “do_createsupercache” filter to customize the checks made before caching. The filter accepts one parameter. The output of WP-Cache’s wp_cache_get_cookies_values() function. WP Super Cache has its own plugin system, loaded before most of WordPress. Add your own plugin either by putting it in the wp-content/plugins/wp-super-cache-plugins directory, or by calling wpsc_add_plugin( $name ) with the full path to the plugin. The cookies used to identify “known users” can be modified with wpsc_add_cookie( $name ) and wpsc_delete_cookie( $name ). See plugins/searchengine.php as an example. Troubleshooting If things don’t work when you installed the plugin here are a few things to check: Is wp-content writable by the web server? Is there a wp-content/wp-cache-config.php ? If not, copy the file wp-super-cache/wp-cache-config-sample.php to wp-content/wp-cache-config.php and make sure WPCACHEHOME points at the right place. Is there a wp-content/advanced-cache.php ? If not, then you must copy wp-super-cache/advanced-cache.php into wp-content/. You must edit the file and change the path so it points at the wp-super-cache folder. If pages are not cached at all, remove wp-content/advanced-cache.php and recreate it, following the advice above. Make sure the following line is in wp-config.php and it is ABOVE the “require_once(ABSPATH.’wp-settings.php’);” line: define( 'WP_CACHE', true ); Try the Settings->WP Super Cache page again and enable cache. Look in wp-content/cache/supercache/. Are there directories and files there? Anything in your php error_log? If your browser keeps asking you to save the file after the super cache is installed you must disable Super Cache compression. Go to the Settings->WP Super Cache page and disable it there. File locking errors such as “failed to acquire key 0x152b: Permission denied in…” or “Page not cached by WP Super Cache. Could not get mutex lock.” are a sign that you may have to use file locking. Edit wp-content/wp-cache-config.php and uncomment “$use_flock = true” or set $sem_id to a different value. You can also disable file locking from the Admin screen as a last resort. Make sure cache/wp_cache_mutex.lock is writable by the web server if using coarse file locking. The cache folder cannot be put on an NFS or Samba or NAS share. It has to be on a local disk. File locking and deleting expired files will not work properly unless the cache folder is on the local machine. Garbage collection of old cache files won’t work if WordPress can’t find wp-cron.php. Check your access_logs for wp-cron.php entries and that your hostname resolves to the external IP address other servers on the network/Internet use. If old pages are being served to your visitors via the supercache, you may be missing Apache modules (or their equivalents if you don’t use Apache). 3 modules are required: mod_mime, mod_headers and mod_expires. The last two are especially important for making sure browsers load new versions of existing pages on your site. The error message, “WP Super Cache is installed but broken. The path to wp-cache-phase1.php in wp-content/advanced-cache.php must be fixed!” appears at the end of every page. Open the file wp-content/advanced-cache.php in your favourite editor. Is the path to wp-cache-phase1.php correct? This file will normally be in wp-content/plugins/wp-super-cache/. If it is not correct the caching engine will not load. Caching doesn’t work. The timestamp on my blog keeps changing when I reload. Check that the path in your .htaccess rules matches where the supercache directory is. You may have to hardcode it. Try disabling supercache mode. If supercache cache files are generated but not served, check the permissions on all your wp-content/cache/supercache folders (and each of wp-content cache and supercache folders) and wp-content/cache/.htaccess. If your PHP runs as a different user to Apache and permissions are strict Apache may not be able to read the PHP generated cache files. To fix you must add the following line to your wp-config.php (Add it above the WP_CACHE define.) Then clear your cache. umask( 0022 ); If you see garbage in your browser after enabling compression in the plugin, compression may already be enabled in your web server. In Apache you must disable mod_deflate, or in PHP zlib compression may be enabled. You can disable that in three ways. If you have root access, edit your php.ini and find the zlib.output_compression setting and make sure it’s “Off” or add this line to your .htaccess: php_flag zlib.output_compression off If that doesn’t work, add this line to your wp-config.php: ini_set('zlib.output_compression', 0); After uninstalling, your permalinks may break if you remove the WordPress mod_rewrite rules too. Regenerate those rules by visiting the Settings->Permalink page and saving that form again. If your blog refuses to load make sure your wp-config.php is correct. Are you missing an opening or closing PHP tag? Your front page is ok but posts and pages give a 404? Go to Settings->permalinks and click “Save” once you’ve selected a custom permalink structure. You may need to manually update your .htaccess file. If certain characters do not appear correctly on your website your server may not be configured correctly. You need to tell visitors what character set is used. Go to Settings->Reading and copy the ‘Encoding for pages and feeds’ value. Edit the .htaccess file with all your Supercache and WordPress rewrite rules and add this at the top, replacing CHARSET with the copied value. (for example, ‘UTF-8’) AddDefaultCharset CHARSET The error message, “WP Super Cache is installed but broken. The constant WPCACHEHOME must be set in the file wp-config.php and point at the WP Super Cache plugin directory.” appears at the end of every page. You can delete wp-content/advanced-cache.php and reload the plugin settings page or edit wp-config.php and look for WPCACHEHOME and make sure it points at the wp-super-cache folder. This will normally be wp-content/plugins/wp-super-cache/ but you’ll likely need the full path to that file (so it’s easier to let the settings page fix it). If it is not correct the caching engine will not load. If your server is running into trouble because of the number of semaphores used by the plugin it’s because your users are using file locking which is not recommended (but is needed by a small number of users). You can globally disable file locking by defining the constant WPSC_DISABLE_LOCKING, or defining the constant WPSC_REMOVE_SEMAPHORE so that sem_remove() is called after every page is cached but that seems to cause problems for other processes requesting the same semaphore. Best to disable it. Set the variable $htaccess_path in wp-config.php or wp-cache-config.php to the path of your global .htaccess if the plugin is looking for that file in the wrong directory. This might happen if you have WordPress installed in an unusual way.

DietPress is a free WordPress speed optimization plugin with a built-in page cache. Page caching, browser caching, GZIP and Brotli compression, deferred JavaScript, critical CSS, image loading attributes, preloading, locally hosted Google Fonts and selective asset loading, all in one plugin and all free. And it goes further than a caching plugin: it also puts WordPress itself on a diet, switching off the features your site never uses. It pairs that with a clean, risk-based interface. Everything is configurable, the optimizations are already on by default, and nothing is hidden behind a paid tier. Activate it and your site is faster, or open the settings and tune every detail. By default WordPress loads functions, services and scripts that most sites do not need. They slow down loading times and consume hosting resources. DietPress lets you trim that fat and apply battle-tested performance tweaks, with a clear description of what each option does and what might break, organized by risk level so you always know what is safe. WHY CHOOSE DIETPRESS Page caching, for free. Serve anonymous visitors a copy stored on disk instead of building the page again. The feature people buy WP Rocket or a NitroPack subscription for, with no licence and no monthly fee. No drop-in, no changes to wp-config.php. Unlike WP Super Cache or W3 Total Cache, DietPress installs no advanced-cache.php and never edits wp-config.php. Switching it off leaves your site exactly as it was, with nothing orphaned behind. It tells you why. Most cache plugins leave you guessing when nothing is cached. DietPress reports its own status, tests itself against your home page, and names the exact reason a page was skipped. WooCommerce-safe by design. Carts, checkout, my account and any visitor carrying a cart cookie always get the live site, so nobody ever sees somebody else’s basket. Diet as well as speed. Where Perfmatters focuses on disabling scripts, DietPress covers that ground and adds page caching, critical CSS, local Google Fonts and a dashboard, admin and email cleanup, in one plugin. Light on your server. No account, no external service, no telemetry, no upsell nags. Everything runs on your own hosting. WHAT THE PAGE CACHE DOES TO YOUR RESPONSE TIME Measured on a WordPress 7.0 install with GeneratePress, WooCommerce and a 76 product catalogue, PHP 8.5, taking the median of 15 requests per URL. Your own hosting will give different figures, but the shape of the result will not change. Server response time, the same pages with the page cache off and on: Home page – 52.7 ms without, 15.1 ms with, 71% faster WooCommerce shop – 45.4 ms without, 14.8 ms with, 67% faster A 110 KB article – 43.0 ms without, 15.1 ms with, 65% faster A 98 KB page – 41.0 ms without, 14.9 ms with, 64% faster A product category – 41.3 ms without, 15.1 ms with, 63% faster The interesting part is not the percentage, it is that the cached figure barely moves. Serving a stored file costs the same whether the page was cheap or expensive to build, so the saving grows with the size of your site rather than with the power of your server. The heaviest page in the test is the one that gained most. It also changes how much traffic your hosting can take at once. In the same test the server went from serving about 40 visits a second to more than 210, five times as many, on exactly the same plan. That is what keeps a small site standing up when one of your posts does well. TWO THINGS IN ONE PLUGIN 1. Performance optimizations (on by default) Automatic Critical CSS inlined in the head (optional experimental deferral of non-critical CSS) JavaScript defer parsing with smart dependency handling Image loading attributes safety net: lazy loading, decoding=async and fetchpriority for images that bypass core Automatic image dimensions for better CLS scores (including picture elements) Resource hints: preconnect and DNS prefetch for common third-party origins Theme stylesheet, critical fonts and logo preloading for a faster LCP Google Fonts display=swap Google Fonts local hosting: serve the fonts your theme uses from your own server, GDPR-friendly with a silent fallback to the Google CDN (opt-in) Selective third-party loading: WooCommerce, Contact Form 7, block library, Slider Revolution, TablePress, Smash Balloon, Formidable Forms and Everest Forms assets only load where they are used (opt-in) RSS feed optimization (cache headers and item limit) Server rules in .htaccess: browser caching with a configurable lifetime for media, for styles and scripts and for fonts, GZIP and Brotli compression, immutable cache headers, CORS for fonts and keep-alive (master switch plus per-feature toggles) Database maintenance: daily expired-transient cleanup and safe query optimizations Page cache: store each page on disk and serve it to anonymous visitors without building it again, with automatic purging, gzip precompression and a status panel that says whether it is working (opt-in, in its own tab) 2. Put WordPress on a diet (risk-based, opt-in) Light (safe for any site): emojis, RSD/WLW tags, shortlinks, self-pingbacks, comment pagination, and more Moderate (evaluate first): oEmbed, jQuery Migrate, Dashicons on the frontend, Global Styles and Duotone, remote block patterns, avatars and Gravatar, comment threading, and more Strict (site-specific): granular RSS feed control, Heartbeat API mode, post revisions and autosave, disable comments, XML sitemap, native lazy loading/fetchpriority, content types, selective loading for WooCommerce, Contact Form 7, block assets, Slider Revolution, TablePress, Smash Balloon, Formidable Forms and Everest Forms, and more Widgets: dashboard widgets (including third-party ones from Yoast, WooCommerce, Elementor, Jetpack, Wordfence, Rank Math, Gravity Forms), classic sidebar widgets, block-editor widgets and the Customizer Emails: silence the automatic emails WordPress sends on its own, grouped by area: auto-update results for core, plugins and themes (plus the new-version notice), comment moderation and new-comment notices, and new user, password and email-change notices, plus toggles for the admin email verification prompt and post-by-email. Every option is off by default, and critical notices such as a failed core update are always kept SCALE, PROFILES AND ANALYZER Savings indicator: HTTP requests removed, CSS/JS saved and active optimizations at a glance Quick profiles: Personal Blog, WooCommerce Store, Landing Page and Maximum Cleanup Site analyzer: personalized recommendations based on your active plugins and content, page cache included Import and export your whole configuration as a JSON file COMPATIBILITY AND EXTENSIBILITY The plugin includes filters for developers: dietpress_critical_css – Customize the inline critical CSS dietpress_critical_css_handles – Define which CSS handles are critical dietpress_skip_defer_script_handles – Opt scripts out of the JavaScript defer dietpress_skip_defer_style_handles – Opt stylesheets out of the CSS deferral dietpress_preconnect_hints – Customize preconnect origins dietpress_dns_prefetch_domains – Customize DNS prefetch domains dietpress_critical_fonts – Define critical fonts to preload dietpress_exclude_local_fonts – Exclude Google Fonts stylesheets from local hosting dietpress_selective_{module}_has_content – Mark a page as showing the content of a selective loading module, so its assets are kept. The module is wc, cf7, formidable, everest_forms or revslider dietpress_selective_{module}_styles / dietpress_selective_{module}_scripts – Adjust the handles removed by each module dietpress_selective_page_hides_content – Mark a page as rendering content the content scan cannot reach, so no module removes anything (this is what handles Elementor) dietpress_selective_is_wc_page – Override the WooCommerce page detection of selective loading dietpress_selective_wc_keep_cart_fragments – Keep the cart fragments script when your theme has a hand-coded mini-cart dietpress_selective_cf7_has_form – Mark pages that load a Contact Form 7 form dynamically dietpress_selective_blocks_dequeue – Override the block library dequeue decision dietpress_selective_everest_forms_dequeue_dashicons – Keep Dashicons when another plugin enqueues it directly dietpress_native_sitemap_in_use – Tell DietPress your plugin builds on the native WordPress sitemap, so the option that removes it becomes unavailable dietpress_cache_bypass – Keep the current page out of the page cache dietpress_cache_bypass_cookies – Adjust the cookie name prefixes that make a visitor uncacheable dietpress_cache_ignored_params – Adjust the query parameters that do not change the page dietpress_cache_exclude_urls – Adjust the excluded URL patterns dietpress_cache_post_urls – Adjust the URLs purged along with a post Compatible with: Well-coded themes and page builders (Divi, Elementor, Beaver Builder, Bricks Gutenberg) Cache plugins (WP Rocket, LiteSpeed Cache, W3 Total Cache, WP Super Cache, etc.). The one exception is the optional page cache module, which will not run beside another page cache and says so; everything else in DietPress works alongside them as it always has Security plugins (DietPress focuses on performance and deliberately leaves security to them; we recommend our free Vigilant) CDNs (Cloudflare, StackPath, KeyCDN, etc.) thanks to CORS and Vary headers WordPress Multisite (except the optional page cache module, which does not support it yet) HOW TO VERIFY THE OPTIMIZATIONS Cache rules: check your .htaccess for a block marked # BEGIN DietPress with immutable Cache-Control headers Logo preload: view page source and look for pointing to your logo Critical CSS: view source and look for in the head Compression: test at giftofspeed.com/gzip-test Always measure with tools like Google PageSpeed, GTMetrix or WebPageTest, and run each test at least twice to account for caching. Support Need private support or custom development? Do you need one-on-one help, priority troubleshooting, or a custom feature, integration, or tweak built specifically for your site? I offer private support and custom development. Just contact me and tell me what you need. Need help or have suggestions? Official website WordPress support forum YouTube channel Documentation and tutorials Love the plugin? Please leave us a 5-star review and help spread the word! About AyudaWP We are specialists in WordPress security, SEO, AI and performance optimization plugins. We create tools that solve real problems for WordPress site owners while maintaining the highest coding standards and accessibility requirements.