Installation

functions.php

@@ -0,0 +1,112 @@
+<?php 
+defined( 'ABSPATH' ) || die( 'Ooops!' );
+
+/**
+ * Instanciate the filesystem class
+ *
+ * @return object WP_Filesystem_Direct instance
+ */
+function redis_direct_filesystem() {
+	require_once ABSPATH . 'wp-admin/includes/class-wp-filesystem-base.php';
+	require_once ABSPATH . 'wp-admin/includes/class-wp-filesystem-direct.php';
+	return new WP_Filesystem_Direct( new StdClass() );
+}
+
+
+/**
+ * Added or set the value of the WP_CACHE constant
+ *
+ * @param bool $turn_on The value of WP_CACHE constant.
+ * @return void
+ */
+function set_redis_wp_cache_define( $turn_on = true ) {
+	// If WP_CACHE is already define, return to get a coffee.
+	if ( $turn_on && defined( 'WP_CACHE' ) && WP_CACHE ) {
+		return;
+	}
+
+	// Get path of the config file OR return if not found or writable
+	$config_file_path = redis_find_wpconfig_path();
+	if ( ! $config_file_path ) {
+		return;
+	}
+
+	// Get content of the config file.
+	$config_file = file( $config_file_path );
+
+	// Get the value of WP_CACHE constant.
+	$turn_on = $turn_on ? 'true' : 'false';
+
+	// Lets find out if the constant WP_CACHE is defined or not.
+	$is_wp_cache_exist = false;
+
+	// Get WP_CACHE constant define.
+	$constant = "define('WP_CACHE', $turn_on); // Added by Redis Page Cache" . "\r\n";
+
+	foreach ( $config_file as &$line ) {
+		if ( ! preg_match( '/^define\(\s*\'([A-Z_]+)\',(.*)\)/', $line, $match ) ) {
+			continue;
+		}
+
+		if ( 'WP_CACHE' === $match[1] ) {
+			$is_wp_cache_exist = true;
+			$line              = $constant;
+		}
+	}
+	unset( $line ); // just clearing
+
+	// If the constant does not exist, create it.
+	if ( ! $is_wp_cache_exist ) {
+		array_shift( $config_file );
+		array_unshift( $config_file, "<?php\r\n", $constant );
+	}
+
+	// Insert the constant in wp-config.php file.
+	$handle = @fopen( $config_file_path, 'w' );
+	foreach ( $config_file as $line ) {
+		@fwrite( $handle, $line );
+	}
+
+	@fclose( $handle );
+
+	// Update the writing permissions of wp-config.php file.
+	$chmod = defined( 'FS_CHMOD_FILE' ) ? FS_CHMOD_FILE : 0644;
+	redis_direct_filesystem()->chmod( $config_file_path, $chmod );
+}
+
+
+/**
+ * Copies the file to destination
+ *
+ * @return bool
+ */
+function redis_copy_advanced_cache_file() {
+	$source = RPC_PLUGIN_PATH . 'advanced-cache.php';
+	$destination = WP_CONTENT_DIR . '/advanced-cache.php';
+	if( ! copy($source, $destination) ) {
+		return false;
+	}
+
+	return true;
+}
+
+
+/**
+ * Searching the correct wp-config.php file, support one level up in file tree
+ *
+ * @return string|bool The path of wp-config.php file or false if not found or permissions not writable
+ */
+function redis_find_wpconfig_path() {
+	$config_file_name = 'wp-config';
+	$config_file      = ABSPATH . $config_file_name . '.php';
+	$config_file_alt  = dirname( ABSPATH ) . '/' . $config_file_name . '.php';
+
+	if ( redis_direct_filesystem()->exists( $config_file ) && redis_direct_filesystem()->is_writable( $config_file ) ) {
+		return $config_file;
+	} elseif ( redis_direct_filesystem()->exists( $config_file_alt ) && redis_direct_filesystem()->is_writable( $config_file_alt ) && ! redis_direct_filesystem()->exists( dirname( ABSPATH ) . '/wp-settings.php' ) ) {
+		return $config_file_alt;
+	}
+
+	// No writable file found.
+	return false;
+}

redis-page-cache.php

@@ -16,3 +16,79 @@
  * Please keep this helper plugin active for update notifications and future
  * helper and CLI functionality.
  */
+
+defined( 'RPC_PLUGIN_PATH' ) ? null : define( 'RPC_PLUGIN_PATH', realpath( plugin_dir_path( __FILE__ ) ) . '/' );
+
+// Adding functions.php file
+require_once( RPC_PLUGIN_PATH . 'functions.php' );
+
+
+/**
+ * Do this while activating the plugin
+ */
+function redis_process_activation() {
+	// Copying the advanced-cache.php file to wp-content
+	if ( function_exists( 'redis_copy_advanced_cache_file' ) ) {
+		redis_copy_advanced_cache_file();
+	}
+
+	// Adding WP_CACHE constant to wp-config.php file
+	if ( function_exists( 'set_redis_wp_cache_define' ) ) {
+		set_redis_wp_cache_define( true );
+	}
+}
+register_activation_hook( __FILE__, 'redis_process_activation' );
+
+
+/**
+ * Do this while deactivating the plugin
+ */
+function redis_process_deactivation() {
+	$errors = array();
+
+	// check if wp-config.php is writable?
+	if ( ! redis_direct_filesystem()->is_writable( redis_find_wpconfig_path() ) ) {
+		$errors[] = 'wpconfig';
+	}
+
+	if ( count( $errors ) ) {
+		// TODO inform user about the error
+		wp_safe_redirect( wp_get_referer() );
+		die();
+	}
+
+	// Setting WP_CACHE constant to false in wp-config.php.
+	set_redis_wp_cache_define( false );
+
+	// Delete advanced-cache.php.
+	wp_delete_file( WP_CONTENT_DIR . '/advanced-cache.php' );
+}
+register_deactivation_hook( __FILE__, 'redis_process_deactivation' );
+
+
+/**
+ * Adding option to the toolbar to clear the cache up
+ */
+function redis_toolbar_option() {
+	global $wp_admin_bar;
+
+	$cache_clear_url = add_query_arg( 'clear_cache', 1 );
+
+	$args = array(
+		'id'    => 'clear_cache',
+		'title' => __( 'Purge Redis Page Cache', 'redis_page_cache' ),
+		'href'  => $cache_clear_url,
+	);
+	$wp_admin_bar->add_menu( $args );
+
+}
+add_action( 'wp_before_admin_bar_render', 'redis_toolbar_option', 999 );
+
+// Clearing up the cache
+if ( isset( $_GET['clear_cache'] ) ) {
+	add_action( 'init', 'mmk_redis_clear_cache' );
+	function mmk_redis_clear_cache() {
+		$_redis = Redis_Page_Cache::get_redis();
+		$_redis->flushDB();
+	}
+}