Added VoidBackend if PhpFastCache is disabled

Author: Geolim4

phpfastcache.services.yml

@@ -5,4 +5,4 @@ services:
         - {name: event_subscriber}
     cache.backend.phpfastcache:
         class: Drupal\phpfastcache\Cache\PhpFastCacheBackendFactory
-        arguments: ['@settings', '@cache_tags.invalidator.checksum']
+        arguments: ['@database', '@cache_tags.invalidator.checksum']

src/Cache/PhpFastCacheBackend.php

@@ -43,7 +43,6 @@ class PhpFastCacheBackend implements \Drupal\Core\Cache\CacheBackendInterface
 
     public function __construct($bin, $cachePool, CacheTagsChecksumInterface $checksum_provider)
     {
-        //var_dump(func_get_args());exit;
         /**
          * Constructs a new ApcuBackend instance.
          *
@@ -55,6 +54,7 @@ public function __construct($bin, $cachePool, CacheTagsChecksumInterface $checks
          *   The cache tags checksum provider.
          */
         require_once __DIR__ . '/../../phpfastcache-php/src/autoload.php';
+
         $this->cachePool = $cachePool;
         $this->bin = $bin;
         $this->checksumProvider = $checksum_provider;

src/Cache/PhpFastCacheBackendFactory.php

@@ -1,13 +1,10 @@
 <?php
 namespace Drupal\phpfastcache\Cache;
 
-use Drupal\Component\Utility\Crypt;
-use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheTagsChecksumInterface;
 use phpFastCache\Cache\ExtendedCacheItemPoolInterface;
 use phpFastCache\CacheManager;
-use Drupal\Core\Cache\DatabaseBackend;
-
+use Drupal\Core\Database\Connection;
 
 /**
  * Class PhpFastCacheService
@@ -40,9 +37,20 @@ class PhpFastCacheBackendFactory implements \Drupal\Core\Cache\CacheFactoryInter
      */
     protected $settings;
 
-    public function __construct($settings, CacheTagsChecksumInterface $checksum_provider)
+    /**
+     * The database connection.
+     *
+     * @var \Drupal\Core\Database\Connection
+     */
+    protected $connection;
+
+    /**
+     * PhpFastCacheBackendFactory constructor.
+     * @param \Drupal\Core\Database\Connection $connection
+     * @param \Drupal\Core\Cache\CacheTagsChecksumInterface $checksum_provider
+     */
+    public function __construct(Connection $connection, CacheTagsChecksumInterface $checksum_provider)
     {
-        //var_dump(func_get_args());exit;
         /**
          * Due to the low-level execution stack of PhpFastCacheBackend
          * we have to hard-include the PhpFastCache autoload here
@@ -51,6 +59,45 @@ public function __construct($settings, CacheTagsChecksumInterface $checksum_prov
         $this->backendClass = 'Drupal\phpfastcache\Cache\PhpFastCacheBackend';
         $this->checksumProvider = $checksum_provider;
         $this->cachePool = CacheManager::Files(['ignoreSymfonyNotice' => true]);
+        $this->connection = $connection;
+        $this->settings = $this->getSettingsFromDatabase();
+
+        if(!$this->settings['phpfastcache_enabled']){
+            if(strpos($_SERVER['REQUEST_URI'], 'admin/config/development/phpfastcache') === false)
+            {
+                /**
+                 * At this level nothing is efficient
+                 * - drupal_set_message() is not working/displaying anything
+                 * - throwing exception displays a fatal error without backtrace
+                 * - echoing destroys header leading to another fatal error
+                 *
+                 * Let's dying miserably by showing a simple but efficient message
+                 */
+                die('PhpFastCache is not enabled, please go to <strong>admin/config/development/phpfastcache</strong> then configure PhpFastCache.');
+            }
+            else
+            {
+                $this->backendClass = 'Drupal\phpfastcache\Cache\PhpFastCacheVoidBackend';
+            }
+        }
+    }
+
+    /**
+     * Get settings from database.
+     * At this level of runtime execution
+     * settings are not available yet.
+     * @return array
+     */
+    protected function getSettingsFromDatabase()
+    {
+        $query = 'SELECT `data`
+                  FROM {' . $this->connection->escapeTable('config') . '} 
+                  WHERE `name` = :name
+                  LIMIT 1';
+        $params = [':name' => 'phpfastcache.settings'];
+        $result = $this->connection->query($query, $params);
+
+        return unserialize($result->fetchField());
     }
 
     /**

src/Cache/PhpFastCacheVoidBackend.php

@@ -0,0 +1,151 @@
+<?php
+/**
+ * Z
+ */
+namespace Drupal\phpfastcache\Cache;
+
+use Drupal\Core\Cache\Cache;
+use Drupal\Core\Cache\CacheTagsChecksumInterface;
+
+
+/**
+ * Class PhpFastCacheService
+ */
+class PhpFastCacheVoidBackend implements \Drupal\Core\Cache\CacheBackendInterface
+{
+    /**
+     * The name of the cache bin to use.
+     *
+     * @var string
+     */
+    protected $bin;
+
+    /**
+     * Prefix for all keys in this cache bin.
+     *
+     * Includes the site-specific prefix in $sitePrefix.
+     *
+     * @var string
+     */
+    protected $binPrefix;
+
+    /**
+     * The cache tags checksum provider.
+     *
+     * @var \Drupal\Core\Cache\CacheTagsChecksumInterface
+     */
+    protected $checksumProvider;
+
+    public function __construct($bin, $cachePool, CacheTagsChecksumInterface $checksum_provider)
+    {
+        /**
+         * Constructs a new ApcuBackend instance.
+         *
+         * @param string $bin
+         *   The name of the cache bin.
+         * @param string $site_prefix
+         *   The prefix to use for all keys in the storage that belong to this site.
+         * @param \Drupal\Core\Cache\CacheTagsChecksumInterface $checksum_provider
+         *   The cache tags checksum provider.
+         */
+        require_once __DIR__ . '/../../phpfastcache-php/src/autoload.php';
+    }
+
+
+    /**
+     * @inheritDoc
+     */
+    public function get($cid, $allow_invalid = false)
+    {
+        return false;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function getMultiple(&$cids, $allow_invalid = false)
+    {
+        return [];
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = [])
+    {
+
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function setMultiple(array $items)
+    {
+
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function delete($cid)
+    {
+
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function deleteMultiple(array $cids)
+    {
+
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function deleteAll()
+    {
+
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function invalidate($cid)
+    {
+
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function invalidateMultiple(array $cids)
+    {
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function invalidateAll()
+    {
+        throw new UnsupportedMethodException('Method invalidateAll() is currently not supported by PhpFastCache as there no way to list items in cache');
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function garbageCollection()
+    {
+        /**
+         * Does not concerns PhpFastCache
+         */
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function removeBin()
+    {
+        // TODO: Implement removeBin() method.
+    }
+}