Fix merging default headers if overwritten with custom case headers

Author: clue

src/RequestData.php

@@ -23,15 +23,24 @@ private function mergeDefaultheaders(array $headers)
         $connectionHeaders = ('1.1' === $this->protocolVersion) ? array('Connection' => 'close') : array();
         $authHeaders = $this->getAuthHeaders();
 
-        return array_merge(
+        $defaults = array_merge(
             array(
                 'Host'          => $this->getHost().$port,
                 'User-Agent'    => 'React/alpha',
             ),
             $connectionHeaders,
-            $authHeaders,
-            $headers
+            $authHeaders
         );
+
+        // remove all defaults that already exist in $headers
+        $lower = array_change_key_case($headers, CASE_LOWER);
+        foreach ($defaults as $key => $_) {
+            if (isset($lower[strtolower($key)])) {
+                unset($defaults[$key]);
+            }
+        }
+
+        return array_merge($defaults, $headers);
     }
 
     public function getScheme()

tests/RequestDataTest.php

@@ -34,6 +34,23 @@ public function toStringReturnsHTTPRequestMessageWithProtocolVersion()
         $this->assertSame($expected, $requestData->__toString());
     }
 
+    /** @test */
+    public function toStringReturnsHTTPRequestMessageWithHeadersInCustomCase()
+    {
+        $requestData = new RequestData('GET', 'http://www.example.com', array(
+            'user-agent' => 'Hello',
+            'LAST' => 'World'
+        ));
+
+        $expected = "GET / HTTP/1.0\r\n" .
+            "Host: www.example.com\r\n" .
+            "user-agent: Hello\r\n" .
+            "LAST: World\r\n" .
+            "\r\n";
+
+        $this->assertSame($expected, $requestData->__toString());
+    }
+
     /** @test */
     public function toStringReturnsHTTPRequestMessageWithProtocolVersionThroughConstructor()
     {