Changed configuration cacheKeyFn to work via call_user_func

Added tests

src/Cache/Cache.php

@@ -4,6 +4,9 @@
 
 use Psr\SimpleCache\CacheInterface;
 
+/**
+ * Generic implementation of a cache system using an associative array.
+ */
 class Cache implements CacheInterface
 {
     /**

src/MobileDetect.php

@@ -251,6 +251,8 @@ class MobileDetect
         // Maximum HTTP User-Agent value allowed.
         // @var int
         'maximumUserAgentLength' => 500,
+        // Function that creates the cache key. e.g. (base64, sha1, custom fn).
+        'cacheKeyFn' => 'base64_encode',
         // Cache TTL
         // @var null|int|\DateInterval
         'cacheTtl' => 86400,
@@ -1700,18 +1702,23 @@ public function getCache(): Cache
         return $this->cache;
     }
 
+    /**
+     * @throws CacheException
+     */
     protected function createCacheKey(string $key): string
     {
         $userAgentKey = $this->hasUserAgent() ? $this->userAgent : '';
         $httpHeadersKey = $this->hasHttpHeaders() ? static::flattenHeaders($this->httpHeaders) : '';
 
         $cacheKey = "$key:$userAgentKey:$httpHeadersKey";
 
-        $cacheKeyUsing = $this->config['cacheKeyUsing'] ?? function (string $cacheKey) {
-            return base64_encode($cacheKey);
-        };
+        $cacheKeyFn = $this->config['cacheKeyFn'];
+
+        if (!is_callable($cacheKeyFn)) {
+            throw new CacheException('cacheKeyFn is not a function.');
+        }
 
-        return call_user_func($cacheKeyUsing, $cacheKey);
+        return call_user_func($cacheKeyFn, $cacheKey);
     }
 
     public static function flattenHeaders(array $httpHeaders): string

tests/MobileDetectWithCacheTest.php

@@ -2,6 +2,8 @@
 
 namespace DetectionTests;
 
+use Detection\Cache\Cache;
+use Detection\Cache\CacheItem;
 use Detection\Exception\MobileDetectException;
 use Detection\MobileDetect;
 use PHPUnit\Framework\TestCase;
@@ -112,4 +114,54 @@ public function testDefaultCacheClassCreatesMultipleCacheRecordsForAllCalls()
             base64_decode($detect->getCache()->getKeys()[3])
         );
     }
+
+    /**
+     * @throws MobileDetectException
+     */
+    public function testCustomCacheWithInvalidFnThrowsException()
+    {
+        $this->expectException(MobileDetectException::class);
+        $this->expectExceptionMessage('Cache problem in isMobile(): cacheKeyFn is not a function.');
+        $cache = new Cache();
+
+        $detect = new MobileDetect($cache, ['cacheKeyFn' => 'not a function']);
+        $detect->setUserAgent('iPad; AppleWebKit/533.17.9 Version/5.0.2 Mobile/8C148 Safari/6533.18.5');
+        $detect->isMobile();
+    }
+
+    public function testCustomCacheForConsecutiveCalls()
+    {
+        $cache = new Cache();
+
+        $detect = new MobileDetect($cache, ['cacheKeyFn' => fn ($key) => base64_encode($key)]);
+        $detect->setUserAgent('iPad; AppleWebKit/533.17.9 Version/5.0.2 Mobile/8C148 Safari/6533.18.5');
+
+        $detect->isMobile();
+        $this->assertCount(1, $cache->getKeys());
+
+        $detect->isMobile();
+        $this->assertCount(1, $cache->getKeys());
+    }
+
+    public function testGetCacheKeyIsUsedInConsecutiveCallsIfFoundIn()
+    {
+        $cache = $this->getMockBuilder(Cache::class)
+            ->onlyMethods(["get", "set"])
+            ->getMock();
+        $cache->method('get')->withAnyParameters()->willReturn(new CacheItem('name', 'value'));
+        $cache->method('set')->withAnyParameters()->willReturn(true);
+
+
+        $cache->expects($spy = $this->exactly(2))->method('get');
+        $cache->expects($spy = $this->never())->method('set');
+
+
+
+        $detect = new MobileDetect($cache);
+        $detect->setUserAgent('iPad; AppleWebKit/533.17.9 Version/5.0.2 Mobile/8C148 Safari/6533.18.5');
+
+        $detect->isMobile();
+        $detect->isMobile();
+
+    }
 }

tests/benchmark/MobileDetectBench.php

@@ -124,4 +124,25 @@ public function benchIsSamsungTablet(): void
         $detect->setUserAgent('Mozilla/5.0 (Linux; Android 12; SM-X906C Build/QP1A.190711.020; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/80.0.3987.119 Mobile Safari/537.36');
         $detect->isSamsungTablet();
     }
+
+    public function benchIsMobileCacheKeyFnBase64AgainstBestMatch(): void
+    {
+        $detect = new MobileDetect(null, ['cacheKeyFn' => 'base64_encode']);
+        $detect->setUserAgent('iPhone');
+        $detect->isMobile();
+    }
+
+    public function benchIsMobileCacheKeyFnSha1AgainstBestMatch(): void
+    {
+        $detect = new MobileDetect(null, ['cacheKeyFn' => 'sha1']);
+        $detect->setUserAgent('iPhone');
+        $detect->isMobile();
+    }
+
+    public function benchIsMobileCacheKeyFnCustomCryptFnAgainstBestMatch(): void
+    {
+        $detect = new MobileDetect(null, ['cacheKeyFn' => fn ($key) => crypt($key, 'bla')]);
+        $detect->setUserAgent('iPhone');
+        $detect->isMobile();
+    }
 }