merged branch tiraeth/host (PR #648)

This PR was squashed before being merged into the master branch (closes #648).

Discussion
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Added support for URL host from Routing Component

Hi everyone,

Firstly, I wanted to thank you all for Silex. It's fabulous.

I needed URL host support in Silex to manage different subdomains of my small application and came up with an idea of introducing `->host($host)` chained method to `Silex\Route` class. This way users can apply host resolution to controllers in Silex.

This PR includes above functionality + one unit test to check if everything works as expected.

URL host support is of course available in Routing Component from version `>=2.2`, but Silex relies on 2.2 anyway.

Example:
```php
<?php

// ...

$app->match('/', function() {
    // app-specific action
})->host('example.com');

$app->match('/', function ($user) {
    // user-specific action
})->host('{user}.example.com');

// ...
```

I am open for comments.

Commits
-------

f0124c7f Added support for URL host from Routing Component

src/Silex/Route.php

@@ -86,6 +86,20 @@ class Route extends BaseRoute
         return $this;
     }
 
+    /**
+     * Sets the requirement of host on this Route
+     *
+     * @param string $host The host for which this route should be enabled
+     *
+     * @return Route $this The current Route instance
+     */
+    public function host($host)
+    {
+        $this->setHost($host);
+
+        return $this;
+    }
+
     /**
      * Sets the requirement of HTTP (no HTTPS) on this Route.
      *

tests/Silex/Tests/RouterTest.php

@@ -179,6 +179,14 @@ class RouterTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals('/foo/', $response->getTargetUrl());
     }
 
+    public function testHostSpecification()
+    {
+        $route = new \Silex\Route();
+
+        $this->assertSame($route, $route->host('{locale}.example.com'));
+        $this->assertEquals('{locale}.example.com', $route->getHost());
+    }
+
     public function testRequireHttpRedirect()
     {
         $app = new Application();