Internal usage -- Purge all varnish when WP changes any content

varnish-purge-all.php

<?php
/*
Plugin Name: Purge all varnish
Plugin URI: http://www.beapi.fr
Description: Purge all varnish cache when a post is modified/edited
Version: 1.3
Author: BeAPI
Author URI: http://www.beapi.fr
Network: true
*/

class Varnish_Purge_All {
	
	public function __construct() {
		// Define registered purge events
		$actions = array(
			'save_post',            // Save a post
			'deleted_post',         // Delete a post
			'trashed_post',         // Empty Trashed post
			'edit_post',            // Edit a post - includes leaving comments
			'delete_attachment',    // Delete an attachment - includes re-uploading
			'switch_theme',         // Change theme
		);

		// Add the action for each event
		foreach ( $actions as $event ) {
			add_action( $event, array($this, 'purge_all'), 10 );
		}

		// Add some actions for allow admin bar flush button
		if ( is_admin() ) {
			add_action( 'admin_bar_menu', array($this, 'admin_bar_menu') );
			add_action( 'admin_init', array($this, 'admin_init') );
			add_action( 'admin_head', array($this, 'admin_head') );
		}
	}

	public function purge_all() {
		global $wpdb, $current_blog;
		
		// Flush original WP domain
		$ban = sprintf( 'varnishadm "ban req.http.host == \"%s\" && req.url ~ /"', $current_blog->domain );
		$result = shell_exec( $ban );

		// Debug
		error_log( $ban . ' => ' . $result .  PHP_EOL, 3, WP_CONTENT_DIR . '/debug-varnish.log' );
		
		// Get table name for mapping
		$wpdb->dmtable = ( isset( $wpdb->base_prefix ) ? $wpdb->base_prefix : $wpdb->prefix ) . 'domain_mapping';
		
		// Flush all mapped domains
		$blog_domains = $wpdb->get_col( $wpdb->prepare(
			"
			SELECT dm.domain
			FROM $wpdb->blogs AS b
			INNER JOIN $wpdb->dmtable AS dm ON b.blog_id = dm.blog_id
			WHERE b.blog_id = %d
			",
			$current_blog->blog_id
		) );
		
		if( empty( $blog_domains ) ) {
			return false;
		}
		
		foreach( $blog_domains as $blog_domain ) {
			$ban = sprintf( 'varnishadm "ban req.http.host == \"%s\" && req.url ~ /"', $blog_domain );
			$result = shell_exec( $ban );
			
			// Debug
			error_log( $ban . ' => ' . $result .  PHP_EOL, 3, WP_CONTENT_DIR . '/debug-varnish.log' );
		}

		return true;
	}

	public function admin_bar_menu( $wp_admin_bar ) {
		if ( ! current_user_can( 'manage_options' ) ) {
			return false;
		}

		$url = add_query_arg( array('action' => 'flush_varnish_cache'), admin_url( 'index.php' ) );
		$wp_admin_bar->add_node( array(
			'id'     => 'varnish-cache-flusher-button',
			'title'  => __( 'Flush Cache' ),
			'href'   => wp_nonce_url( $url, 'varnish-cache-flush' ),
			'parent' => 'top-secondary',
		) );

		return true;
	}


	public function admin_init() {
		if ( empty( $_GET['action'] ) ) {
			return false;
		}

		if ( 'flush_varnish_cache' !== $_GET['action'] ) {
			return false;
		}

		if ( ! check_admin_referer( 'varnish-cache-flush' ) ) {
			return false;
		}

		if ( ! current_user_can( 'manage_options' ) ) {
			return false;
		}

		$this->purge_all();
		return true;
	}


	public function admin_head() {
		if ( ! current_user_can( 'manage_options' ) ) {
			return false;
		}

		echo '<style>#wpadminbar #wp-admin-bar-varnish-cache-flusher-button a{background:#a00}</style>';
		return true;
	}
}

new Varnish_Purge_All();