From 51a7b688036d72d1d19512371798663a95ec2893 Mon Sep 17 00:00:00 2001
From: Thomas Gelf <thomas@gelf.net>
Date: Thu, 23 Feb 2023 11:44:13 +0100
Subject: [PATCH] PropertyModifierRegexReplace: w/o match allow null

fixes #2705
---
 doc/82-Changelog.md                           |  3 ++
 .../PropertyModifierRegexReplace.php          | 40 +++++++++++++------
 2 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/doc/82-Changelog.md b/doc/82-Changelog.md
index c67055e4..74d878e2 100644
--- a/doc/82-Changelog.md
+++ b/doc/82-Changelog.md
@@ -19,6 +19,9 @@ This version hasn't been released yet
 ### Icinga Configuration
 * FIX: render Set Services to individual zones where required (#1589, #2356)
 
+### Import and Sync
+* FEATURE: regular expression based modifier allows explicit NULL on no match (#2705)
+
 ### Configuration Branches
 * FEATURE: with this release, directorbranches v1.3 supports a "default branch" (#2688)
 * FEATURE: users with default branches get warnings in the main branch (#2689)
diff --git a/library/Director/PropertyModifier/PropertyModifierRegexReplace.php b/library/Director/PropertyModifier/PropertyModifierRegexReplace.php
index 59cb245e..eeae69e8 100644
--- a/library/Director/PropertyModifier/PropertyModifierRegexReplace.php
+++ b/library/Director/PropertyModifier/PropertyModifierRegexReplace.php
@@ -9,25 +9,36 @@ class PropertyModifierRegexReplace extends PropertyModifierHook
 {
     public static function addSettingsFormFields(QuickForm $form)
     {
-        $form->addElement('text', 'pattern', array(
-            'label'       => 'Regex pattern',
+        $form->addElement('text', 'pattern', [
+            'label'       => $form->translate('Regex pattern'),
             'description' => $form->translate(
                 'The pattern you want to search for. This can be a regular expression like /^www\d+\./'
             ),
             'required'    => true,
-        ));
+        ]);
 
-        $form->addElement('text', 'replacement', array(
-            'label'       => 'Replacement',
+        $form->addElement('text', 'replacement', [
+            'label'       => $form->translate('Replacement'),
             'description' => $form->translate(
-                'The string that should be used as a preplacement'
+                'The string that should be used as a replacement'
             ),
-        ));
+        ]);
+        $form->addElement('select', 'when_not_matched', [
+            'label'       => $form->translate('When not matched'),
+            'description' => $form->translate(
+                "What should happen, if the given pattern doesn't match"
+            ),
+            'value' => 'keep',
+            'multiOptions' => [
+                'keep'     => $form->translate('Keep the given string'),
+                'set_null' => $form->translate('Set the value to NULL')
+            ]
+        ]);
     }
 
     public function getName()
     {
-        return 'Regular expression based replacement';
+        return mt('director', 'Regular expression based replacement');
     }
 
     public function transform($value)
@@ -36,10 +47,13 @@ class PropertyModifierRegexReplace extends PropertyModifierHook
             return null;
         }
 
-        return preg_replace(
-            $this->getSetting('pattern'),
-            $this->getSetting('replacement'),
-            $value
-        );
+        $result = preg_replace($this->getSetting('pattern'), $this->getSetting('replacement'), $value);
+        if ($result === $value && $this->getSetting('when_not_matched', 'keep') === 'set_null') {
+            if (!preg_match($this->getSetting('pattern'), $value)) {
+                return null;
+            }
+        }
+
+        return $result;
     }
 }