option to configure image cache clearing #1481

CHANGELOG.md

@@ -2,7 +2,8 @@
 ## 07/xx/2017
 
 1. [](#new)
-    * Added a new `cache-control` system and page level property [#1591](https://github.com/getgrav/grav/issues/1591)
+    * Added a new `cache_control` system and page level property [#1591](https://github.com/getgrav/grav/issues/1591)
+    * Added a new `clear_images_by_default` system property to stop cache clear events from removing processed images [#1481](https://github.com/getgrav/grav/pull/1481)
 
 # v1.3.1
 ## 07/19/2017

system/blueprints/config/system.yaml

@@ -514,6 +514,17 @@ form:
                     help: PLUGIN_ADMIN.CACHE_PREFIX_HELP
                     placeholder: PLUGIN_ADMIN.CACHE_PREFIX_PLACEHOLDER
 
+                cache.clear_images_by_default:
+                    type: toggle
+                    label: PLUGIN_ADMIN.CLEAR_IMAGES_BY_DEFAULT
+                    help: PLUGIN_ADMIN.CLEAR_IMAGES_BY_DEFAULT_HELP
+                    highlight: 1
+                    options:
+                        1: PLUGIN_ADMIN.YES
+                        0: PLUGIN_ADMIN.NO
+                    validate:
+                        type: bool
+
                 cache.cli_compatibility:
                     type: toggle
                     label: PLUGIN_ADMIN.CLI_COMPATIBILITY

system/config/system.yaml

@@ -74,6 +74,7 @@ cache:
     method: file                                 # Method to check for updates in pages: file|folder|hash|none
   driver: auto                                   # One of: auto|file|apc|xcache|memcache|wincache
   prefix: 'g'                                    # Cache prefix string (prevents cache conflicts)
+  clear_images_by_default: true                  # By default grav will include processed images in cache clear, this can be disabled
   cli_compatibility: false                       # Ensures only non-volatile drivers are used (file, redis, memcache, etc.)
   lifetime: 604800                               # Lifetime of cached data in seconds (0 = infinite)
   gzip: false                                    # GZip compress the page output

system/src/Grav/Common/Cache.php

@@ -63,6 +63,14 @@ class Cache extends Getters
         'asset://',
     ];
 
+    protected static $standard_remove_no_images = [
+        'cache://twig/',
+        'cache://doctrine/',
+        'cache://compiled/',
+        'cache://validated-',
+        'asset://',
+    ];
+
     protected static $all_remove = [
         'cache://',
         'cache://images',
@@ -360,7 +368,12 @@ class Cache extends Getters
                 $remove_paths = self::$tmp_remove;
                 break;
             default:
-                $remove_paths = self::$standard_remove;
+                if (Grav::instance()['config']->get('system.cache.clear_images_by_default')) {
+                    $remove_paths = self::$standard_remove;
+                } else {
+                    $remove_paths = self::$standard_remove_no_images;
+                }
+
         }
 
         // Clearing cache event to add paths to clear