added: setting prepare callback before validation (#19363)

2 files changed, 18 insertions, 0 deletions

diff --git a/core/Settings/FieldConfig.php b/core/Settings/FieldConfig.php
index a6480216b6..a74878757c 100644
--- a/core/Settings/FieldConfig.php
+++ b/core/Settings/FieldConfig.php
@@ -191,6 +191,20 @@ class FieldConfig
     public $inlineHelp = null;
 
     /**
+     * A closure that prepares the setting value. If supplied, this closure will be executed before
+     * the setting has been validated.
+     *
+     * **Example**
+     *
+     *     $setting->prepare = function ($value, Setting $setting) {
+     *         return mb_strtolower($value);
+     *     }
+     *
+     * @var null|\Closure
+     */
+    public $prepare = null;
+
+    /**
      * A closure that does some custom validation on the setting before the setting is persisted.
      *
      * The closure should take two arguments: the setting value and the {@link Setting} instance being
diff --git a/core/Settings/Setting.php b/core/Settings/Setting.php
index d7b791fb2c..67ed0833e1 100644
--- a/core/Settings/Setting.php
+++ b/core/Settings/Setting.php
@@ -221,6 +221,10 @@ class Setting
 
         $config = $this->configureField();
 
+        if ($config->prepare && $config->prepare instanceof \Closure) {
+            $value = call_user_func($config->prepare, $value, $this);
+        }
+
         $this->validateValue($value);
 
         if ($config->transform && $config->transform instanceof \Closure) {