Escape LIKE metacharacters

lib/Doctrine/DBAL/Platforms/AbstractPlatform.php

@@ -42,6 +42,9 @@ use Doctrine\DBAL\Schema\TableDiff;
 use Doctrine\DBAL\TransactionIsolationLevel;
 use Doctrine\DBAL\Types;
 use Doctrine\DBAL\Types\Type;
+use function sprintf;
+use function strlen;
+use function strtr;
 
 /**
  * Base class for all DatabasePlatforms. The DatabasePlatforms are the central
@@ -3578,4 +3581,27 @@ abstract class AbstractPlatform
     {
         return "'";
     }
+
+    /**
+     * Escapes metacharacters in a string intended to be used with a LIKE
+     * operator.
+     *
+     * @param string $inputString a literal, unquoted string
+     * @param string $escapeChar  should be reused by the caller in the LIKE
+     *                            expression.
+     */
+    final public function escapeStringForLike(string $inputString, string $escapeChar) : string
+    {
+        $replacePairs = [$escapeChar => $escapeChar.$escapeChar];
+        foreach ($this->getLikeWildcardCharacters() as $wildcardChar) {
+            $replacePairs[$wildcardChar] = $escapeChar.$wildcardChar;
+        }
+
+        return strtr($inputString, $replacePairs);
+    }
+
+    protected function getLikeWildcardCharacters() : iterable
+    {
+        return ['%', '_'];
+    }
 }

tests/Doctrine/Tests/DBAL/Functional/LikeWildcardsEscapingTest.php

+<?php
+
+namespace Doctrine\Tests\DBAL\Functional;
+
+use Doctrine\Tests\DbalFunctionalTestCase;
+
+final class LikeWildcardsEscapingTest extends DbalFunctionalTestCase
+{
+    public function testFetchLikeExpressionResult() : void
+    {
+        $string = '_25% off_ your next purchase \o/';
+        $escapeChar = '£';
+        $stmt = $this->_conn->prepare(sprintf(
+            "SELECT '%s' LIKE '%s' ESCAPE '%s' as it_matches",
+            $string,
+            $this->_conn->getDatabasePlatform()->escapeStringForLike($string, $escapeChar),
+            $escapeChar
+        ));
+        $stmt->execute();
+        $this->assertTrue((bool) $stmt->fetch()['it_matches']);
+    }
+}

tests/Doctrine/Tests/DBAL/Platforms/AbstractPlatformTestCase.php

@@ -1468,4 +1468,12 @@ abstract class AbstractPlatformTestCase extends \Doctrine\Tests\DbalTestCase
             array(array('precision' => 8, 'scale' => 2), 'DOUBLE PRECISION'),
         );
     }
+
+    public function testItEscapesStringsForLike() : void
+    {
+        self::assertSame(
+            '\_25\% off\_ your next purchase \\\\o/',
+            $this->_platform->escapeStringForLike('_25% off_ your next purchase \o/', '\\')
+        );
+    }
 }