From 21d40964c87507703faa23c3e74fb46d6c0277d2 Mon Sep 17 00:00:00 2001
From: Pradeep Nayak <pradpnayak@gmail.com>
Date: Thu, 11 Jul 2019 21:11:38 +0100
Subject: [PATCH 1/2] Add hook to alter display value or Custom field value

---
 CRM/Core/BAO/CustomField.php |  7 ++++++-
 CRM/Utils/Hook.php           | 18 ++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/CRM/Core/BAO/CustomField.php b/CRM/Core/BAO/CustomField.php
index bd50263945e3..05298e5e79c7 100644
--- a/CRM/Core/BAO/CustomField.php
+++ b/CRM/Core/BAO/CustomField.php
@@ -1067,7 +1067,12 @@ public static function displayValue($value, $field, $entityId = NULL) {
 
     $fieldInfo = ['options' => $field->getOptions()] + (array) $field;
 
-    return self::formatDisplayValue($value, $fieldInfo, $entityId);
+    $displayValue = self::formatDisplayValue($value, $fieldInfo, $entityId);
+
+    // Call hook to alter display value.
+    CRM_Utils_Hook::alterCustomFieldDisplayValue($displayValue, $value, $entityId, $fieldInfo);
+
+    return $displayValue;
   }
 
   /**
diff --git a/CRM/Utils/Hook.php b/CRM/Utils/Hook.php
index 00e217789c80..0d09ab914bfc 100644
--- a/CRM/Utils/Hook.php
+++ b/CRM/Utils/Hook.php
@@ -2649,4 +2649,22 @@ public static function alterUFFields(&$fields) {
     );
   }
 
+  /**
+   * This hook is called to alter Custom field value before its displayed.
+   *
+   * @param string $displayValue
+   * @param mixed $value
+   * @param int $entityId
+   * @param array $fieldInfo
+   *
+   * @return mixed
+   */
+  public static function alterCustomFieldDisplayValue(&$displayValue, $value, $entityId, $fieldInfo) {
+    return self::singleton()->invoke(
+      ['displayValue', 'value', 'entityId', 'fieldInfo'],
+      $displayValue, $value, $entityId, $fieldInfo, self::$_nullObject,
+      self::$_nullObject, 'civicrm_alterCustomFieldDisplayValue'
+    );
+  }
+
 }

From 3566563f588476fb31794a93745fc24030f399fe Mon Sep 17 00:00:00 2001
From: Pradeep Nayak <pradpnayak@gmail.com>
Date: Sun, 29 Mar 2020 20:57:39 +0100
Subject: [PATCH 2/2] Added unit test

---
 .../phpunit/CRM/Core/BAO/CustomFieldTest.php  | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/tests/phpunit/CRM/Core/BAO/CustomFieldTest.php b/tests/phpunit/CRM/Core/BAO/CustomFieldTest.php
index 0b97de581618..e0a1cf9b62cc 100644
--- a/tests/phpunit/CRM/Core/BAO/CustomFieldTest.php
+++ b/tests/phpunit/CRM/Core/BAO/CustomFieldTest.php
@@ -731,4 +731,50 @@ public function testFileDisplayValueNoDescription() {
     $this->assertEquals($expectedDisplayValue, CRM_Core_BAO_CustomField::displayValue($file['id'], $fileField['id']));
   }
 
+  /**
+   * Test for hook_civicrm_alterCustomFieldDisplayValue().
+   */
+  public function testAlterCustomFieldDisplayValueHook() {
+    CRM_Utils_Hook_UnitTests::singleton()->setHook('civicrm_alterCustomFieldDisplayValue', [$this, 'alterCustomFieldDisplayValue']);
+    $customGroupId = $this->customGroupCreate([
+      'extends' => 'Individual',
+      'title' => 'Test Contactcustom Group',
+    ])['id'];
+    $fieldId = $this->customFieldCreate([
+      'custom_group_id' => $customGroupId,
+      'name' => 'alter_cf_field',
+      'label' => 'Alter CF Field',
+    ])['id'];
+    $contactId = $this->individualCreate(['custom_' . $fieldId => 'Test']);
+
+    $this->assertEquals('Test', $this->callAPISuccessGetValue('Contact',
+      ['id' => $contactId, 'return' => "custom_{$fieldId}"]
+    ));
+
+    $values = [];
+    $fields = [
+      'custom_' . $fieldId => $this->callAPISuccess('Contact', 'getfield', [
+        'name' => 'custom_' . $fieldId,
+        'action' => 'get',
+      ])['values'],
+    ];
+
+    // CRM_Core_BAO_UFGroup::getValues() invokes CRM_Core_BAO_CustomField::displayValue() function.
+    CRM_Core_BAO_UFGroup::getValues($contactId, $fields, $values);
+    $this->assertEquals('New value', $values['Alter CF Field']);
+  }
+
+  /**
+   * @param string $displayValue
+   * @param mixed $value
+   * @param int $entityId
+   * @param array $fieldInfo
+   *
+   */
+  public function alterCustomFieldDisplayValue(&$displayValue, $value, $entityId, $fieldInfo) {
+    if ($fieldInfo['name'] == 'alter_cf_field') {
+      $displayValue = 'New value';
+    }
+  }
+
 }