bug symfony#14497 [HttpFoundation] Allow curly braces in trusted host patterns (sgrodzicki)

This PR was merged into the 2.3 branch.

Discussion
----------

[HttpFoundation] Allow curly braces in trusted host patterns

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

Let's say I want to whilelist Amazon CloudFront hosts:

```php
Request::setTrustedHosts(array('^d[a-z0-9]{13}\.cloudfront\.net$'));
```

See: symfony#14489

Commits
-------

6038b75 [HttpFoundation] Allow curly braces in trusted host patterns

Author: Tobion

src/Symfony/Component/HttpFoundation/Request.php

@@ -553,7 +553,7 @@ public static function getTrustedProxies()
     public static function setTrustedHosts(array $hostPatterns)
     {
         self::$trustedHostPatterns = array_map(function ($hostPattern) {
-            return sprintf('{%s}i', str_replace('}', '\\}', $hostPattern));
+            return sprintf('#%s#i', $hostPattern);
         }, $hostPatterns);
         // we need to reset trusted hosts on trusted host patterns change
         self::$trustedHosts = array();

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

@@ -1601,7 +1601,7 @@ public function testTrustedHosts()
         $this->assertEquals('evil.com', $request->getHost());
 
         // add a trusted domain and all its subdomains
-        Request::setTrustedHosts(array('.*\.?trusted.com$'));
+        Request::setTrustedHosts(array('^([a-z]{9}\.)?trusted\.com$'));
 
         // untrusted host
         $request->headers->set('host', 'evil.com');