feature #21469 [HttpFoundation] Find the original request protocol ve…

…rsion (thewilkybarkid)

This PR was submitted for the master branch but it was merged into the 3.4 branch instead (closes #21469).

Discussion
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[HttpFoundation] Find the original request protocol version

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #21415
| License       | MIT
| Doc PR        |

Adds a new method to `Request` to find the original protocol version from the `Via` header, if the request is from a trusted proxy.

Commits
-------

5a37f84 [HttpFoundation] Find the original request protocol version

src/Symfony/Component/HttpFoundation/Request.php

@@ -1581,6 +1581,30 @@ public function isMethodCacheable()
         return in_array($this->getMethod(), array('GET', 'HEAD'));
     }
 
+    /**
+     * Returns the protocol version.
+     *
+     * If the application is behind a proxy, the protocol version used in the
+     * requests between the client and the proxy and between the proxy and the
+     * server might be different. This returns the former (from the "Via" header)
+     * if the proxy is trusted (see "setTrustedProxies()"), otherwise it returns
+     * the latter (from the "SERVER_PROTOCOL" server parameter).
+     *
+     * @return string
+     */
+    public function getProtocolVersion()
+    {
+        if ($this->isFromTrustedProxy()) {
+            preg_match('~^(HTTP/)?([1-9]\.[0-9]) ~', $this->headers->get('Via'), $matches);
+
+            if ($matches) {
+                return 'HTTP/'.$matches[2];
+            }
+        }
+
+        return $this->server->get('SERVER_PROTOCOL');
+    }
+
     /**
      * Returns the request body content.
      *

src/Symfony/Component/HttpFoundation/Tests/RequestTest.php

@@ -2188,6 +2188,36 @@ public function testGetTrustedHeaderName()
         Request::setTrustedHeaderName(Request::HEADER_CLIENT_PORT, 'X_FORWARDED_PORT');
         Request::setTrustedHeaderName(Request::HEADER_CLIENT_PROTO, 'X_FORWARDED_PROTO');
     }
+
+    /**
+     * @dataProvider protocolVersionProvider
+     */
+    public function testProtocolVersion($serverProtocol, $trustedProxy, $via, $expected)
+    {
+        if ($trustedProxy) {
+            Request::setTrustedProxies(array('1.1.1.1'));
+        }
+
+        $request = new Request();
+        $request->server->set('SERVER_PROTOCOL', $serverProtocol);
+        $request->server->set('REMOTE_ADDR', '1.1.1.1');
+        $request->headers->set('Via', $via);
+
+        $this->assertSame($expected, $request->getProtocolVersion());
+    }
+
+    public function protocolVersionProvider()
+    {
+        return array(
+            'untrusted without via' => array('HTTP/2.0', false, '', 'HTTP/2.0'),
+            'untrusted with via' => array('HTTP/2.0', false, '1.0 fred, 1.1 nowhere.com (Apache/1.1)', 'HTTP/2.0'),
+            'trusted without via' => array('HTTP/2.0', true, '', 'HTTP/2.0'),
+            'trusted with via' => array('HTTP/2.0', true, '1.0 fred, 1.1 nowhere.com (Apache/1.1)', 'HTTP/1.0'),
+            'trusted with via and protocol name' => array('HTTP/2.0', true, 'HTTP/1.0 fred, HTTP/1.1 nowhere.com (Apache/1.1)', 'HTTP/1.0'),
+            'trusted with broken via' => array('HTTP/2.0', true, 'HTTP/1^0 foo', 'HTTP/2.0'),
+            'trusted with partially-broken via' => array('HTTP/2.0', true, '1.0 fred, foo', 'HTTP/1.0'),
+        );
+    }
 }
 
 class RequestContentProxy extends Request