refactor findBetween method and add other tests

Author: salehhashemi1992

framework/CHANGELOG.md

@@ -14,6 +14,7 @@ Yii Framework 2 Change Log
 - Enh #20030: Improve performance of handling `ErrorHandler::$memoryReserveSize` (antonshevelev, rob006)
 - Enh #20042: Add empty array check to `ActiveQueryTrait::findWith()` (renkas)
 - Enh #20032: Added `mask` method for string masking with multibyte support (salehhashemi1992)
+- Enh #20034: Added `findBetween` to retrieve a substring that lies between two strings (salehhashemi1992)
 
 
 2.0.49.2 October 12, 2023

framework/helpers/BaseStringHelper.php

@@ -535,22 +535,23 @@ public static function mask($string, $start, $length, $mask = '*') {
      * @param string $string The input string.
      * @param string $start The string marking the start of the portion to extract.
      * @param string $end The string marking the end of the portion to extract.
-     * @return string The portion of the string between the first occurrence of start and the last occurrence of end.
+     * @return string|null The portion of the string between the first occurrence of
+     * start and the last occurrence of end, or null if either start or end cannot be found.
      */
     public static function findBetween($string, $start, $end)
     {
         $startPos = mb_strpos($string, $start);
 
         if ($startPos === false) {
-            return '';
+            return null;
         }
 
         // Cut the string from the start position
         $subString = mb_substr($string, $startPos + mb_strlen($start));
         $endPos = mb_strrpos($subString, $end);
 
         if ($endPos === false) {
-            return '';
+            return null;
         }
 
         return mb_substr($subString, 0, $endPos);

tests/framework/helpers/StringHelperTest.php

@@ -522,14 +522,18 @@ public function testFindBetween($string, $start, $end, $expectedResult)
     public function dataProviderFindBetween()
     {
         return [
-            ['hello world hello', 'hello ', ' world', ''],  // end before start
-            ['This is a sample string', 'is ', ' string', 'is a sample'],  // normal case
+            ['hello world hello', ' hello', ' world', null],  // end before start
+            ['This is a sample string', ' is ', ' string', 'a sample'],  // normal case
             ['startendstart', 'start', 'end', ''],  // end before start
             ['startmiddleend', 'start', 'end', 'middle'],  // normal case
             ['startend', 'start', 'end', ''],  // end immediately follows start
             ['multiple start start end end', 'start ', ' end', 'start end'],  // multiple starts and ends
-            ['', 'start', 'end', ''],  // empty string
-            ['no delimiters here', 'start', 'end', ''],  // no start and end
+            ['', 'start', 'end', null],  // empty string
+            ['no delimiters here', 'start', 'end', null],  // no start and end
+            ['start only', 'start', 'end', null], // start found but no end
+            ['end only', 'start', 'end', null], // end found but no start
+            ['spécial !@#$%^&*()', 'spé', '&*()', 'cial !@#$%^'],  // Special characters
+            ['من صالح هاشمی هستم', 'من ', ' هستم', 'صالح هاشمی'], // other languages
         ];
     }
 }