From cdee59f7a2282ae2eb07ebb9c03ab895813f283f Mon Sep 17 00:00:00 2001
From: Tim Otten <totten@civicrm.org>
Date: Wed, 20 Jun 2018 17:51:55 -0700
Subject: [PATCH] (dev/core#174) Implement CRM_Utils_Cache::assertValidKey

---
 CRM/Utils/Cache.php                           | 26 +++++++++++++++++++
 .../CRM/common/civicrm.settings.php.template  |  8 ++++++
 2 files changed, 34 insertions(+)

diff --git a/CRM/Utils/Cache.php b/CRM/Utils/Cache.php
index 13aeec68ee..171e4d5437 100644
--- a/CRM/Utils/Cache.php
+++ b/CRM/Utils/Cache.php
@@ -214,4 +214,30 @@ class CRM_Utils_Cache {
     throw new CRM_Core_Exception("Failed to instantiate cache. No supported cache type found. " . print_r($params, 1));
   }
 
+  /**
+   * Assert that a key is well-formed.
+   *
+   * @param string $key
+   * @return string
+   *   Same $key, if it's valid.
+   * @throws \CRM_Utils_Cache_InvalidArgumentException
+   */
+  public static function assertValidKey($key) {
+    $strict = CRM_Utils_Constant::value('CIVICRM_PSR16_STRICT', FALSE) || defined('CIVICRM_TEST');
+
+    if (!is_string($key)) {
+      throw new CRM_Utils_Cache_InvalidArgumentException("Invalid cache key: Not a string");
+    }
+
+    if ($strict && !preg_match(';^[A-Za-z0-9_\-\. ]+$;', $key)) {
+      throw new CRM_Utils_Cache_InvalidArgumentException("Invalid cache key: Illegal characters");
+    }
+
+    if ($strict && strlen($key) > 255) {
+      throw new CRM_Utils_Cache_InvalidArgumentException("Invalid cache key: Too long");
+    }
+
+    return $key;
+  }
+
 }
diff --git a/templates/CRM/common/civicrm.settings.php.template b/templates/CRM/common/civicrm.settings.php.template
index ae4d6e269f..2895fed38c 100644
--- a/templates/CRM/common/civicrm.settings.php.template
+++ b/templates/CRM/common/civicrm.settings.php.template
@@ -399,6 +399,14 @@ if (!defined('CIVICRM_DB_CACHE_PREFIX')) {
   define('CIVICRM_DB_CACHE_PREFIX', '');
 }
 
+/**
+ * The cache system traditionally allowed a wide range of cache-keys, but some
+ * cache-keys are prohibited by PSR-16.
+ */
+if (!defined('CIVICRM_PSR16_STRICT')) {
+  define('CIVICRM_PSR16_STRICT', FALSE);
+}
+
 /**
  * If you have multilingual site and you are using the "inherit CMS language"
  * configuration option, but wish to, for example, use fr_CA instead of the
-- 
2.25.1