Adding tie-breaker functionality

This allows you to specify a preferred mime-type in the event a tie
occurs in the best fit and best fit quality values.

Author: Ben Ramsey

src/Bitworking/Mimeparse.php

@@ -201,9 +201,10 @@ public static function quality($mimeType, $ranges)
      *
      * @param  array  $supported
      * @param  string $header
+     * @param  string $tieBreaker In case of a tie, this mime-type is preferred
      * @return mixed  $mimeType or NULL
      */
-    public static function bestMatch($supported, $header)
+    public static function bestMatch($supported, $header, $tieBreaker = null)
     {
         $parsedHeader = explode(',', $header);
 
@@ -235,6 +236,18 @@ public static function bestMatch($supported, $header)
         array_multisort($weightedMatches);
         $a = array_pop($weightedMatches);
 
+        // If there's a tie breaker specified, see if we have any ties
+        // and then break them with the $tieBreaker
+        if ($tieBreaker) {
+            array_push($weightedMatches, $a);
+            $ties = array_filter($weightedMatches, function ($val) use ($a) {
+                return ($val[0] == $a[0]);
+            });
+            if (count($ties) > 1) {
+                return $tieBreaker;
+            }
+        }
+
         return (empty($a[0][0]) ? null : $a[1]);
     }
 

tests/Bitworking/MimeparseTest.php

@@ -191,4 +191,27 @@ public function testStarSlashStarWithHigherQualityThanMoreSpecificType()
 
         $this->assertEquals('image/jpeg', Mimeparse::bestMatch($supportedMimeTypes, $httpAcceptHeader));
     }
+
+    /**
+     * @covers Bitworking\Mimeparse::bestMatch
+     */
+    public function testBestMatchWithTieBreaker()
+    {
+        $supportedMimeTypes = array('text/html', 'application/json', 'application/hal+xml', 'application/hal+json');
+        $httpAcceptHeader = 'application/*, text/*;q=0.8';
+
+        $this->assertEquals('application/json', Mimeparse::bestMatch($supportedMimeTypes, $httpAcceptHeader));
+        $this->assertEquals('application/hal+json', Mimeparse::bestMatch($supportedMimeTypes, $httpAcceptHeader, 'application/hal+json'));
+    }
+
+    /**
+     * @covers Bitworking\Mimeparse::bestMatch
+     */
+    public function testBestMatchWithTieBreakerAndNoTies()
+    {
+        $supportedMimeTypes = array('text/html', 'application/hal+json');
+        $httpAcceptHeader = 'application/*, text/*;q=0.8';
+
+        $this->assertEquals('application/hal+json', Mimeparse::bestMatch($supportedMimeTypes, $httpAcceptHeader, 'application/hal+json'));
+    }
 }