avoid duplicate requests to the cache proxy.

composer.json

@@ -42,7 +42,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "1.0.x-dev"
+            "dev-master": "1.1.x-dev"
         }
     }
 }

src/ProxyClient/AbstractProxyClient.php

@@ -130,7 +130,26 @@ public function flush()
      */
     protected function queueRequest($method, $url, array $headers = array())
     {
-        $this->queue[] = $this->createRequest($method, $url, $headers);
+        $signature = $this->getSignature($method, $url, $headers);
+        if (!isset($this->queue[$signature])) {
+            $this->queue[$signature] = $this->createRequest($method, $url, $headers);
+        }
+    }
+
+    /**
+     * Calculate a unique hash for the request, based on all significant information.
+     *
+     * @param string $method  HTTP method
+     * @param string $url     URL
+     * @param array  $headers HTTP headers
+     *
+     * @return string A hash value for this request.
+     */
+    private function getSignature($method, $url, array $headers)
+    {
+        ksort($headers);
+
+        return md5($method . "\n" . $url . "\n" . var_export($headers, true));
     }
 
     /**

tests/Unit/ProxyClient/VarnishTest.php

@@ -351,6 +351,41 @@ function ($requests) use ($self) {
         );
     }
 
+    public function testEliminateDuplicates()
+    {
+        $self = $this;
+        $client = \Mockery::mock('\Guzzle\Http\Client[send]', array('', null))
+            ->shouldReceive('send')
+            ->once()
+            ->with(
+                \Mockery::on(
+                    function ($requests) use ($self) {
+                        /** @type Request[] $requests */
+                        $self->assertCount(4, $requests);
+                        foreach ($requests as $request) {
+                            $self->assertEquals('PURGE', $request->getMethod());
+                        }
+
+                        return true;
+                    }
+                )
+            )
+            ->getMock();
+
+        $varnish = new Varnish(array('127.0.0.1', '127.0.0.2'), 'fos.lo', $client);
+
+        $this->assertEquals(
+            2,
+            $varnish
+                ->purge('/c', array('a' => 'b', 'c' => 'd'))
+                ->purge('/c', array('c' => 'd', 'a' => 'b')) // same request (header order is not significant)
+                ->purge('/c') // different request as headers different
+                ->purge('/c')
+                ->flush()
+        );
+    }
+
+
     protected function setUp()
     {
         $this->mock = new MockPlugin();