From ab46cf185997025fa2363405ec7e347dbe51fff1 Mon Sep 17 00:00:00 2001
From: eileen <emcnaughton@wikimedia.org>
Date: Tue, 10 Mar 2020 16:39:35 +1300
Subject: [PATCH] Do not create smarty cached templates for processed greetings

Currrently whenever a greeting is parsed through smarty a smarty template file is stored to disk. This has
impacts on disk use, cache clearing time and performance. Where we know that the template will be of low value
we are better not to cache it. Smarty provides eval (not that eval) for this

The technical details are in the code comment block
---
 CRM/Contact/BAO/Contact/Utils.php |  7 +----
 CRM/Utils/String.php              | 45 +++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/CRM/Contact/BAO/Contact/Utils.php b/CRM/Contact/BAO/Contact/Utils.php
index b32745f670..032895063a 100644
--- a/CRM/Contact/BAO/Contact/Utils.php
+++ b/CRM/Contact/BAO/Contact/Utils.php
@@ -1117,12 +1117,7 @@ WHERE id IN (" . implode(',', $contactIds) . ")";
    */
   public static function processGreetingTemplate(&$templateString, $contactDetails, $contactID, $className) {
     CRM_Utils_Token::replaceGreetingTokens($templateString, $contactDetails, $contactID, $className, TRUE);
-    if (!CRM_Utils_String::stringContainsTokens($templateString)) {
-      // Skip expensive smarty processing.
-      return;
-    }
-    $smarty = CRM_Core_Smarty::singleton();
-    $templateString = $smarty->fetch("string:$templateString");
+    $templateString = CRM_Utils_String::parseOneOffStringThroughSmarty($templateString);
   }
 
   /**
diff --git a/CRM/Utils/String.php b/CRM/Utils/String.php
index 9b2652a28a..6ff0308591 100644
--- a/CRM/Utils/String.php
+++ b/CRM/Utils/String.php
@@ -985,4 +985,49 @@ class CRM_Utils_String {
     return strpos($string, '{') !== FALSE;
   }
 
+  /**
+   * Parse a string through smarty without creating a smarty template file per string.
+   *
+   * This function is for swapping out any smarty tokens that appear in a string
+   * and are not re-used much if at all. For example parsing a contact's greeting
+   * does not need to be cached are there are some minor security / data privacy benefits
+   * to not caching them per file. We also save disk space, reduce I/O and disk clearing time.
+   *
+   * Doing this is cleaning in Smarty3 which we are alas not using
+   * https://www.smarty.net/docs/en/resources.string.tpl
+   *
+   * However, it highlights that smarty-eval is not evil-eval and still have the security applied.
+   *
+   * In order to replicate that in Smarty2 I'm using {eval} per
+   * https://www.smarty.net/docsv2/en/language.function.eval.tpl#id2820446
+   * From the above:
+   * - Evaluated variables are treated the same as templates. They follow the same escapement and security features just as if they were templates.
+   * - Evaluated variables are compiled on every invocation, the compiled versions are not saved! However if you have caching enabled, the output
+   *   will be cached with the rest of the template.
+   *
+   * Our set up does not have caching enabled and my testing suggests this still works fine with it
+   * enabled so turning it off before running this is out of caution based on the above.
+   *
+   * When this function is run only one template file is created (for the eval) tag no matter how
+   * many times it is run. This compares to it otherwise creating one file for every parsed string.
+   *
+   * @param string $templateString
+   *
+   * @return string
+   */
+  public static function parseOneOffStringThroughSmarty($templateString) {
+    if (!CRM_Utils_String::stringContainsTokens($templateString)) {
+      // Skip expensive smarty processing.
+      return $templateString;
+    }
+    $smarty = CRM_Core_Smarty::singleton();
+    $cachingValue = $smarty->caching;
+    $smarty->caching = 0;
+    $smarty->assign('smartySingleUseString', $templateString);
+    $templateString = $smarty->fetch('string:{eval var=$smartySingleUseString}');
+    $smarty->caching = $cachingValue;
+    $smarty->assign('smartySingleUseString', NULL);
+    return $templateString;
+  }
+
 }
-- 
2.25.1