Merge pull request #1 from dennisinteractive/27724_lock_sanitisation

Case 27724; Updated MemcacheBacked lock sanitisation.

src/DrupalMemcacheBase.php

@@ -14,6 +14,8 @@
  */
 abstract class DrupalMemcacheBase implements DrupalMemcacheInterface {
 
+  use MemcacheCacheNormalizerTrait;
+
   /**
    * The memcache config object.
    *
@@ -29,13 +31,6 @@ abstract class DrupalMemcacheBase implements DrupalMemcacheInterface {
    */
   protected $memcache;
 
-  /**
-   * The hash algorithm to pass to hash(). Defaults to 'sha1'
-   *
-   * @var string
-   */
-  protected $hashAlgorithm;
-
   /**
    * The prefix memcache key for all keys.
    *
@@ -52,7 +47,6 @@ abstract class DrupalMemcacheBase implements DrupalMemcacheInterface {
   public function __construct(DrupalMemcacheConfig $settings) {
     $this->settings = $settings;
 
-    $this->hashAlgorithm = $this->settings->get('key_hash_algorithm', 'sha1');
     $this->prefix = $this->settings->get('key_prefix', '');
   }
 
@@ -79,17 +73,7 @@ public function get($key) {
    * {@inheritdoc}
    */
   public function key($key) {
-    $full_key = urlencode($this->prefix . '-' . $key);
-
-    // Memcache only supports key lengths up to 250 bytes.  If we have generated
-    // a longer key, we shrink it to an acceptable length with a configurable
-    // hashing algorithm. Sha1 was selected as the default as it performs
-    // quickly with minimal collisions.
-    if (strlen($full_key) > 250) {
-      $full_key = urlencode(hash($this->hashAlgorithm, $this->prefix . '-' . $key));
-    }
-
-    return $full_key;
+    return $this->normalizeKey($this->prefix . '-' . $key);
   }
 
   /**

src/MemcacheBackend.php

@@ -17,6 +17,8 @@
  */
 class MemcacheBackend implements CacheBackendInterface {
 
+  use MemcacheCacheNormalizerTrait;
+
   /**
    * The cache bin to use.
    *
@@ -128,7 +130,7 @@ public function getMultiple(&$cids, $allow_invalid = FALSE) {
    * @return bool
    */
   protected function valid($cid, \stdClass $cache) {
-    $lock_key = "memcache_$cid:$this->bin";
+    $lock_key = $this->normalizeKey("memcache_$cid:$this->bin");
     $cache->valid = FALSE;
 
     if ($cache) {
@@ -316,7 +318,7 @@ public function isEmpty() {
    * @return string
    */
   protected function key($cid) {
-    return $this->bin . '-' . $cid;
+    return $this->normalizeKey($this->bin . '-' . $cid);
   }
 
 }

src/MemcacheCacheNormalizerTrait.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Drupal\memcache;
+
+/**
+ * Class MemcacheCacheNormalizer.
+ */
+trait MemcacheCacheNormalizerTrait {
+
+  /**
+   * Normalizes a cache ID in order to comply with key length limitations.
+   *
+   * @param string $key
+   *   The passed in cache ID.
+   *
+   * @return string
+   *   An ASCII-encoded cache ID that is at most 250 characters long.
+   */
+  protected function normalizeKey($key) {
+    $key = urlencode($key);
+    // Nothing to do if the ID is a US ASCII string of 250 characters or less.
+    $key_is_ascii = mb_check_encoding($key, 'ASCII');
+    if (strlen($key) <= 250 && $key_is_ascii) {
+      return $key;
+    }
+    // Memcache only supports key lengths up to 250 bytes.  If we have generated
+    // a longer key, we shrink it to an acceptable length with a configurable
+    // hashing algorithm. Sha1 was selected as the default as it performs
+    // quickly with minimal collisions.
+    // Return a string that uses as much as possible of the original cache ID
+    // with the hash appended.
+    /** @var DrupalMemcacheConfig $this->settings */
+    $hash_algorithm = $this->settings->get('key_hash_algorithm', 'sha1');
+    $hash = hash($hash_algorithm, $key);
+    if (!$key_is_ascii) {
+      return $hash;
+    }
+    return substr($key, 0, 250 - strlen($hash)) . $hash;
+  }
+
+}