Pantheon Advanced Page Cache vs SpinupWP

For sites wanting fine-grained control over how their responses are represented in their edge cache, Pantheon Advanced Page Cache is the golden ticket. Here’s a high-level overview of how the plugin works: When a response is generated, the plugin uses surrogate keys based on WordPress’ main WP_Query object to “tag” the response with identifers for the data used in the response. See the “Adding Custom Keys” section for including your own surrogate keys. When WordPress data is modified, the plugin triggers a purge request for the data’s corresponding surrogate keys. Because of its surrogate key technology, Pantheon Advanced Page Cache empowers WordPress sites with a significantly more accurate cache purge mechanism, and generally higher cache hit rate. It even works with the WordPress REST API. Go forth and make awesome! And, once you’ve built something great, send us feature requests (or bug reports). How It Works Pantheon Advanced Page Cache makes heavy use of surrogate keys, which enable responses to be “tagged” with identifiers that can then later be used in purge requests. For instance, a home page response might include the Surrogate-Key header with these keys: Surrogate-Key: front home post-43 user-4 post-41 post-9 post-7 post-1 user-1 Similarly, a GET requests to /wp-json/wp/v2/posts might include the Surrogate-Key header with these keys: Surrogate-Key: rest-post-collection rest-post-43 rest-post-43 rest-post-9 rest-post-7 rest-post-1 Because cached responses include metadata describing the data therein, surrogate keys enable more flexible purging behavior like: When a post is updated, clear the cache for the post’s URL, the homepage, any index view the post appears on, and any REST API endpoints the post is present in. When an author changes their name, clear the cache for the author’s archive and any post they’ve authored. There is a limit to the number of surrogate keys in a response, so we’ve optimized them based on a user’s expectation of a normal WordPress site. See the “Emitted Keys” section for full details on which keys are included, and the “Adding Custom Keys” section following for information on how to add your own. Adding Custom Keys By default, Pantheon Advanced Page Cache generates surrogate keys based on an interpretation of the main WP_Query query object. Because WordPress sends headers before the page is rendered, you need to use the pantheon_wp_main_query_surrogate_keys filter to include additional surrogate keys for any data present on the page. For example, to include surrogate keys for a sidebar rendered on the homepage, you can filter the keys using the is_home() template tag: /** * Add surrogate key for the featured content sidebar rendered on the homepage. */ add_filter( 'pantheon_wp_main_query_surrogate_keys', function( $keys ){ if ( is_home() ) { $keys[] = 'sidebar-home-featured'; } return $keys; }); Then, when sidebars are updated, you can use the pantheon_wp_clear_edge_keys() helper function to emit a purge event specific to the surrogate key: /** * Trigger a purge event for the featured content sidebar when widgets are updated. */ add_action( 'update_option_sidebars_widgets', function() { pantheon_wp_clear_edge_keys( array( 'sidebar-home-featured' ) ); }); Similarly, to include surrogate keys for posts queried on the homepage, you can pre-fetch the posts before the page is rendered: /** * An example of pre-fetching a WP_Query to tag the * response with queried data. You'd use `papcx_wp_query()` * a second time within your template to use the data. */ add_filter( 'pantheon_wp_main_query_surrogate_keys', function( $keys ) { if ( is_home() ) { $query = papcx_wp_query( array( 'post_type' => 'page', ) ); foreach( $query->posts as $post ) { $keys[] = 'post-' . $post->ID; } } return $keys; }); /** * Register a 'papc-non-persistent' cache group to cache data * in a non-persistent manner. We only want data in this group * to be cached within the page request. */ add_action( 'init', function(){ wp_cache_add_non_persistent_groups( array( 'papc-non-persistent' ) ); }); /** * Helper function to instantiate a WP_Query object only * once per page request. * * @param array $args Arguments to pass to WP_Query. * @return WP_Query */ function papcx_wp_query( $args = array() ) { $cache_key = md5( serialize( $args ) ); // WP_Query object will be in cache the second time we use the function. $cache_value = wp_cache_get( $cache_key, 'papc-non-persistent' ); if ( false !== $cache_value ) { return $cache_value; } $query = new WP_Query( $args ); wp_cache_set( $cache_key, $query, 'papc-non-persistent' ); return $query; } Because Pantheon Advanced Page Cache already handles WordPress post purge events, there’s no additional call to pantheon_wp_clear_edge_keys(). Lastly, the pantheon_wp_rest_api_surrogate_keys filter lets you filter surrogate keys present in a REST API response. Additional purging by path When a post is published for the first time, the permalink’s path is also purged even if it has no matching keys. This can be further filtered with the pantheon_clear_post_path filter. add_action('pantheon_clear_post_path', function($paths) { // Add or remove paths from $paths return $paths }, 10, 3); Need a bit more power? In addition to pantheon_wp_clear_edge_keys(), there are two additional helper functions you can use: pantheon_wp_clear_edge_paths( $paths = array() ) – Purge cache for one or more paths. pantheon_wp_clear_edge_all() – Warning! With great power comes great responsibility. Purge the entire cache, but do so wisely. Ignoring Specific Post Types By default, Pantheon Advanced Page Cache is pretty aggressive in how it clears its surrogate keys. Specifically, any time wp_insert_post is called (which can include any time a post of any type is added or updated, even private post types), it will purge a variety of keys including home, front, 404 and feed. To bypass or override this behavior, since 1.5.0 we have a filter allowing an array of post types to ignore to be passed before those caches are purged. By default, the revision post type is ignored, but others can be added: /** * Add a custom post type to the ignored post types. * * @param array $ignored_post_types The array of ignored post types. * @return array */ function filter_ignored_posts( $ignored_post_types ) { $ignored_post_types[] = 'my-post-type'; // Ignore my-post-type from cache purges. return $ignored_post_types; } add_filter( 'pantheon_purge_post_type_ignored', 'filter_ignored_posts' ); This will prevent the cache from being purged if the given post type is updated. Setting the Cache Max Age with a filter The cache max age setting is controlled by the Pantheon Page Cache admin page. As of 2.0.0, there are three cache age options by default — 1 week, 1 month, 1 year. Pantheon Advanced Page Cache automatically purges the cache of updated and related posts and pages, but you might want to override the cache max age value and set it programmatically. In this case, you can use the pantheon_cache_default_max_age filter added in Pantheon MU plugin 1.4.0+. For example: add_filter( 'pantheon_cache_default_max_age', function() { return 10 * DAY_IN_SECONDS; } ); When the cache max age is filtered in this way, the admin option is disabled and a notice is displayed. Updating the cache max age based on nonces Nonces created on the front-end, often used to secure forms and other data, have a lifetime, and if the cache max age is longer than the nonce lifetime, the nonce may expire before the cache does. To avoid this, you can use the pantheon_cache_nonce_lifetime action to set the pantheon_cache_default_max_age to less than the nonce lifetime. For example: do_action( 'pantheon_cache_nonce_lifetime' ); It’s important to wrap your do_action in the appropriate conditionals to ensure that the action is only called when necessary and not filtering the cache max age in cases when it’s not necessary. This might mean only running on certain pages or in certain contexts in your code. WP-CLI Commands This plugin implements a variety of WP-CLI commands. All commands are grouped into the wp pantheon cache namespace. $ wp help pantheon cache NAME wp pantheon cache DESCRIPTION Manage the Pantheon Advanced Page Cache. SYNOPSIS wp pantheon cache SUBCOMMANDS purge-all Purge the entire page cache. purge-key Purge one or more surrogate keys from cache. purge-path Purge one or more paths from cache. Use wp help pantheon cache to learn more about each command. Debugging By default, Pantheon’s infrastructure strips out the Surrogate-Key response header before responses are served to clients. The contents of this header can be viewed as Surrogate-Key-Raw by adding on a debugging header to the request. A direct way of inspecting headers is with curl -I. This command will make a request and show just the response headers. Adding -H "Pantheon-Debug:1" will result in Surrogate-Key-Raw being included in the response headers. The complete command looks like this: curl -IH "Pantheon-Debug:1" https://scalewp.io/ Piping to grep will filter the output down to just the Surrogate-Key-Raw header: curl -IH "Pantheon-Debug:1" https://scalewp.io/ | grep -i Surrogate-Key-Raw Tada! Emitted Keys and Purge Events Emitted Keys on Traditional Views Home / Emits surrogate keys: home, front, post- (all posts in main query) Single post /2016/10/14/surrogate-keys/ Emits surrogate keys: single, post- , post-user- , post-term- (all terms assigned to post) Author archive /author/pantheon/ Emits surrogate keys: archive, user- , post- (all posts in main query) Term archive /tag/cdn/ Emits surrogate keys: archive, term- , post- (all posts in main query) Day archive /2016/10/14/ Emits surrogate keys: archive, date, post- (all posts in main query) Month archive /2016/10/ Emits surrogate keys: archive, date, post- (all posts in main query) Year archive /2016/ Emits surrogate keys: archive, date, post- (all posts in main query) Search /?s= Emits surrogate keys: search, either search-results or search-no-results, post- (all posts in main query) Not found (404) Emits surrogate keys: 404 Emitted Keys on REST API Endpoints Posts /wp-json/wp/v2/posts emits surrogate keys: rest-post-collection, rest-post- /wp-json/wp/v2/posts/ emits surrogate keys: rest-post- Pages /wp-json/wp/v2/pages emits surrogate keys: rest-page-collection, rest-post- /wp-json/wp/v2/pages/ emits surrogate keys: rest-post- Categories /wp-json/wp/v2/categories emits surrogate keys: rest-category-collection, rest-term- /wp-json/wp/v2/categories/ emits surrogate keys: rest-term- Tags /wp-json/wp/v2/tags emits surrogate keys: rest-post_tag-collection, rest-term- /wp-json/wp/v2/tags/ emits surrogate keys: rest-term- Comments /wp-json/wp/v2/comments emits surrogate keys: rest-comment-collection, rest-comment-post- , rest-comment- /wp-json/wp/v2/comments/ emits surrogate keys: rest-comment-post- , rest-comment- Users /wp-json/wp/v2/users emits surrogate keys: rest-user-collection, rest-user- /wp-json/wp/v2/users/ emits surrogate keys: rest-user- Settings /wp-json/wp/v2/settings emits surrogate keys: rest-setting- Purge Events Different WordPress actions cause different surrogate keys to be purged, documented here. wp_insert_post / transition_post_status / before_delete_post / delete_attachment Purges surrogate keys: home, front, 404, post- , user- , term- , rest- -collection, rest-comment-post- Affected views: homepage, single post, any page with 404 header, any archive where post displays, author archive, term archive, REST API collection and resource endpoints clean_post_cache Purges surrogate keys: post- , rest-post- Affected views: single post, REST API resource endpoint created_term / edited_term / delete_term Purges surrogate keys: term- , post-term- , rest- -collection Affected views: term archive, any post where the term is assigned, REST API collection and resource endpoints clean_term_cache Purges surrogate keys: term- , rest-term- Affected views: term archive, REST API resource endpoint wp_insert_comment / transition_comment_status Purges surrogate keys: rest-comment-collection, rest-comment- Affected views: REST API collection and resource endpoints clean_comment_cache Purges surrogate keys: rest-comment- Affected views: REST API resource endpoint clean_user_cache Purges surrogate keys: user- , rest-user- Affected views: author archive, any post where the user is the author updated_option Purges surrogate keys: rest-setting- Affected views: REST API resource endpoint Surrogate Keys for taxonomy terms Setting surrogate keys for posts with large numbers of taxonomies (such as WooCommerce products with a large number of global attributes) can suffer from slower queries. Surrogate keys can be skipped for ‘product’ post types’ taxonomy terms (or any other criteria you see fit) with the following filter: function custom_should_add_terms($should_add_terms, $wp_query) { if ( $wp_query->is_singular( 'product' ) ) { return false; } return $should_add_terms; } add_filter('pantheon_should_add_terms', 'custom_should_add_terms', 10, 2); Other Filters pantheon_apc_disable_admin_notices Since 2.0.0, Pantheon Advanced Page Cache displays a number of admin notices about your current cache max age value. You can disable these notices with the pantheon_apc_disable_admin_notices filter. add_filter( 'pantheon_apc_disable_admin_notices', '__return_true' ); Alternately, the function callback is passed into the pantheon_apc_disable_admin_notices filter, allowing you to specify precisely which notice to disable, for example: add_filter( 'pantheon_apc_disable_admin_notices', function( $disable_notices, $callback ) { if ( $callback === '\\Pantheon_Advanced_Page_Cache\\Admin_Interface\\admin_notice_maybe_recommend_higher_max_age' ) { return true; } return $disable_notices; }, 10, 2 ); The above example would disable only the admin notice recommending a higher cache max age. Plugin Integrations Pantheon Advanced Page Cache integrates with WordPress plugins, including: WPGraphQL Contributing See CONTRIBUTING.md for information on contributing.

This plugin ensures that the SpinupWP page cache is cleared when your site’s content changes. Not using SpinupWP yet? Sign up here. SpinupWP is a modern server control panel that’s here to help you implement best practices for every server you spin up. Designed for WordPress. This companion plugin should be installed on sites created using SpinupWP to allow the page cache to be cleared when your site’s content changes. Not using SpinupWP yet? Sign up here. Any Provider We support DigitalOcean, Linode, AWS, and any other provider. If your server has an IP address, you can connect SpinupWP. It does need to be a fresh install of Ubuntu though. Latest & Greatest Software SpinupWP will install the latest stable versions of Nginx, PHP, MySQL/MariaDB, and Redis from the standard apt-get repos. No who-knows-what-they-did custom builds of packages. Disconnect from SpinupWP in the future and you can still keep your packages up-to-date with apt-get upgrade. Automatic Security Updates SpinupWP will configure your server to install security updates as soon as they are available to reduce the likelihood of a software vulnerability putting your server at risk. Free SSL/TLS Certificates Serving your site over HTTPS is essential these days, not only for security, but to take advantage of the performance improvements of HTTP/2 as well. When you add a site to SpinupWP, a free Let’s Encrypt SSL/TLS certificate will be acquired, installed, and configured for your site. And SpinupWP will handle certificate renewals as well, so you hardly need to think about certificates. Cache All the Things One of the keys to a great performing WordPress site is caching. All sites are set up with Redis object caching to greatly reduce database requests. And with the check of a box you can enable full-page caching to serve pages lightning fast without even hitting PHP. Git Push-to-Deploy Developers! Developers! Developers! Add a git repository to your SpinupWP site and simply push to master to deploy your code. GitHub, Bitbucket, or a custom git repo will work. You can also configure a build script to run some tasks on the server after deployment is complete. Error Logs WordPress doesn’t enable error logging by default. Probably because the log is saved to a publicly accessible directory and can quickly balloon to take up a lot of hard drive space. SpinupWP enables error logs by default but stores them in a safe place and makes sure they’re rotated regularly like other server logs. Security Security Security Each server provisioned by SpinupWP is security-hardened from the word go. SSH login is disabled for the root user (you login with your user and use sudo instead). The firewall only allows connections to Nginx and SSH and failed attempts are monitored and blocked when the reach a threshold. Nginx is configured to defend against XSS, clickjacking, MIME sniffing, and other attacks. Software security updates are installed automatically. Scheduled Posts Published on Schedule For every site you add via SpinupWP, a server-side cron job will be configured to make sure that your WordPress site’s cron is executed every minute, as it should be. WP-CLI Preloaded If you love WP-CLI (we do! ❤) you’ll be very pleased to find it available on the command line the first time you login to your server. Security Isolation for Sites For each site that you add to your server via SpinupWP, a new system user is created for that site. All site files are owned by the site user and a PHP-FPM pool is configured to run as that user as well. Each site only has access to its files and so if only one site has a security vulnerability and gets infected with malware for example, only the files for that one site can be infected. SFTP Access for Your Clients If you’re hosting a site for someone else, you can easily give them SFTP/SSH access to just that site. And because of the security isolation between sites, they will only have access to files for that site. Professional Guidance & Best Practices SpinupWP will actively point you in the right direction and offer suggestions for maintaining your server. And because it provides detailed feedback about the operations it runs on your server, you can learn what is happening with your server. New release of Ubuntu just came out, should I upgrade? We’ll add a notice to the app about that, why we don’t recommend upgrading your existing servers, and how you can spin up a new server with the new release of Ubuntu and migrate your sites to that server instead. Should I install Varnish to improve page caching performance? We’ve benchmarked Varnish and Nginx FastCGI Cache performed better. Varnish would add complexity too, so one less moving part is another reason. Much of the time SpinupWP will suggest things that you may not have even thought of. Email deliverability for example. SpinupWP will strongly encourage you to configure an email sending plugin for the best email deliverability. SpinupWP’s guidance is especially helpful for those new to managing a server, but can also help those who’ve been at it a while, providing transparency to our decisions. Scheduled Backups of Site Files & Database All server providers (DigitalOcean, Linode, etc) offer automated backups of your entire server for a fee. These services are great and we highly recommend having backups of your whole server. But what happens if some media or data was deleted by accident from your WordPress site? You’re not going to restore your entire server just to get that data back. That’s where site backups come in. Site backups are full backups of your site files (media, themes, and plugins) and database. They allow you to easily restore a single site or just some files or data from a single site. With SpinupWP’s site backups, you choose your preferred provider to stash your backups whether that’s Amazon S3, DigitalOcean Spaces, or Google Cloud Storage. You plug in your account details and SpinupWP will send your site backups there in an easy-to-see format. Teamwork Makes the Dream Work Create a new team account, invite a member of your team, and allow them to spin up their own servers. Or just only allow them to add sites, the permissions you give them is up to you. Features Page cache purging Persistent object caching Ensures debug.log files aren’t saved in a publicly-accessible location