Proxy Cache Purge的作者是Mika Epstein，目前有60,000+个有效安装。已经Tested with 5.4.1版本的wordpress。
This plugin does not install nor configure a cache proxy. It acts as an interface with such services.
One common method of caching content for websites is via the use of reverse proxy caching. Common examples of this are Varnish and Nginx. These systems allow a website to update content and have the visitor’s experience cached without the need for complex plugins storing the files locally and using up a user’s disk space.
A reverse proxy cache is installed in front of a server and reviews requests. If the page being requested is already cached, it delivers the cached content. Otherwise it generates the page and the cache on demand.
The Proxy Cache Purge plugin sends a request to delete (aka flush) the cached data of a page or post every time it’s modified.
HOW IT WORKS
When content on a site is updated by WordPress, the plugin reaches out to the proxy cache service with the URL of the page, requesting the cache be deleted.
Not all page are deleted from the cache on every change. For example, when a post, page, or custom post type is edited, or a new comment is added, only the following pages will purge:
The front page
The post/page edited
Any categories, tags, and/or custom taxonomies associated with the page
Associated JSON API pages
In addition, your entire cache will be deleted on the following actions:
Pressing the Empty Cache button on the toolbar
Plugins can hook into the purge actions as well, to filter their own events to trigger a purge.
On a multisite network using subfolders, only network admins can purge the main site.
If you’re working on a site and need to turn off caching in one of two ways:
Add define( 'VHP_DEVMODE', true ); to your wp-config.php file
Go to Proxy Cache -> Settings and enable debug mode for 24 hours at a time
That will break cache on page loads. It is not recommended for production!
wp varnish purge – Flush the entire cache
wp varnish debug  – Help for debugging how well your cache is (or isn’t) working
wp varnish devmode  – Change development mode state
By default, no data is tracked. If you use the site scanner/debugging tool, your domain and IP address will access a remote service hosted on DreamObjects. No personally identifying transaction data is recorded or stored, only overall usage. IP addresses of the website making the request may be recorded by the service, but there is no way to access them and use it to correspond with individuals or processes.
Use of this service is required for the cache checking in order to provide up to date compatibility checks on plugins and themes that may conflict with running a server based cache without needing to update the plugin every day.
No visitor information from your site is tracked.