feature #20644 [HttpFoundation] Compute cookie max-age attribute (ro0NL)

This PR was merged into the 3.3-dev branch.

Discussion
----------

[HttpFoundation] Compute cookie max-age attribute

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | comma-separated list of tickets fixed by the PR, if any
| License       | MIT
| Doc PR        | reference to the documentation PR, if any

See https://wiki.php.net/rfc/cookie_max-age, PHP sends it since 5.5.

~~The date format actually differs now from PHP (`Saturday` instead of `Sat`). But it really doesnt matter much imo, using the constant seems more reliable to me and max-age overrules anyway ;)~~

Relates to #20569

Commits
-------

8c28317 [HttpFoundation] Compute cookie max-age attribute

src/Symfony/Component/HttpFoundation/Cookie.php

@@ -94,12 +94,12 @@ public function __toString()
         $str = urlencode($this->getName()).'=';
 
         if ('' === (string) $this->getValue()) {
-            $str .= 'deleted; expires='.gmdate('D, d-M-Y H:i:s T', time() - 31536001);
+            $str .= 'deleted; expires='.gmdate('D, d-M-Y H:i:s T', time() - 31536001).'; max-age=-31536001';
         } else {
             $str .= urlencode($this->getValue());
 
             if ($this->getExpiresTime() !== 0) {
-                $str .= '; expires='.gmdate('D, d-M-Y H:i:s T', $this->getExpiresTime());
+                $str .= '; expires='.gmdate('D, d-M-Y H:i:s T', $this->getExpiresTime()).'; max-age='.$this->getMaxAge();
             }
         }
 
@@ -166,6 +166,16 @@ public function getExpiresTime()
         return $this->expire;
     }
 
+    /**
+     * Gets the max-age attribute.
+     *
+     * @return int
+     */
+    public function getMaxAge()
+    {
+        return 0 !== $this->expire ? $this->expire - time() : 0;
+    }
+
     /**
      * Gets the path on the server in which the cookie will be available on.
      *

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

@@ -72,9 +72,13 @@ public function testGetPath()
 
     public function testGetExpiresTime()
     {
-        $cookie = new Cookie('foo', 'bar', 3600);
+        $cookie = new Cookie('foo', 'bar');
+
+        $this->assertEquals(0, $cookie->getExpiresTime(), '->getExpiresTime() returns the default expire date');
+
+        $cookie = new Cookie('foo', 'bar', $expire = time() + 3600);
 
-        $this->assertEquals(3600, $cookie->getExpiresTime(), '->getExpiresTime() returns the expire date');
+        $this->assertEquals($expire, $cookie->getExpiresTime(), '->getExpiresTime() returns the expire date');
     }
 
     public function testConstructorWithDateTime()
@@ -107,21 +111,21 @@ public function testGetExpiresTimeWithStringValue()
 
     public function testGetDomain()
     {
-        $cookie = new Cookie('foo', 'bar', 3600, '/', '.myfoodomain.com');
+        $cookie = new Cookie('foo', 'bar', 0, '/', '.myfoodomain.com');
 
         $this->assertEquals('.myfoodomain.com', $cookie->getDomain(), '->getDomain() returns the domain name on which the cookie is valid');
     }
 
     public function testIsSecure()
     {
-        $cookie = new Cookie('foo', 'bar', 3600, '/', '.myfoodomain.com', true);
+        $cookie = new Cookie('foo', 'bar', 0, '/', '.myfoodomain.com', true);
 
         $this->assertTrue($cookie->isSecure(), '->isSecure() returns whether the cookie is transmitted over HTTPS');
     }
 
     public function testIsHttpOnly()
     {
-        $cookie = new Cookie('foo', 'bar', 3600, '/', '.myfoodomain.com', false, true);
+        $cookie = new Cookie('foo', 'bar', 0, '/', '.myfoodomain.com', false, true);
 
         $this->assertTrue($cookie->isHttpOnly(), '->isHttpOnly() returns whether the cookie is only transmitted over HTTP');
     }
@@ -142,14 +146,14 @@ public function testCookieIsCleared()
 
     public function testToString()
     {
-        $cookie = new Cookie('foo', 'bar', strtotime('Fri, 20-May-2011 15:25:52 GMT'), '/', '.myfoodomain.com', true);
-        $this->assertEquals('foo=bar; expires=Fri, 20-May-2011 15:25:52 GMT; path=/; domain=.myfoodomain.com; secure; httponly', $cookie->__toString(), '->__toString() returns string representation of the cookie');
+        $cookie = new Cookie('foo', 'bar', $expire = strtotime('Fri, 20-May-2011 15:25:52 GMT'), '/', '.myfoodomain.com', true);
+        $this->assertEquals('foo=bar; expires=Fri, 20-May-2011 15:25:52 GMT; max-age='.($expire - time()).'; path=/; domain=.myfoodomain.com; secure; httponly', (string) $cookie, '->__toString() returns string representation of the cookie');
 
         $cookie = new Cookie('foo', null, 1, '/admin/', '.myfoodomain.com');
-        $this->assertEquals('foo=deleted; expires='.gmdate('D, d-M-Y H:i:s T', time() - 31536001).'; path=/admin/; domain=.myfoodomain.com; httponly', $cookie->__toString(), '->__toString() returns string representation of a cleared cookie if value is NULL');
+        $this->assertEquals('foo=deleted; expires='.gmdate('D, d-M-Y H:i:s T', $expire = time() - 31536001).'; max-age='.($expire - time()).'; path=/admin/; domain=.myfoodomain.com; httponly', (string) $cookie, '->__toString() returns string representation of a cleared cookie if value is NULL');
 
         $cookie = new Cookie('foo', 'bar', 0, '/', '');
-        $this->assertEquals('foo=bar; path=/; httponly', $cookie->__toString());
+        $this->assertEquals('foo=bar; path=/; httponly', (string) $cookie);
     }
 
     public function testRawCookie()
@@ -160,4 +164,16 @@ public function testRawCookie()
         $cookie = new Cookie('foo', 'bar', 3600, '/', '.myfoodomain.com', false, true, true);
         $this->assertTrue($cookie->isRaw());
     }
+
+    public function testGetMaxAge()
+    {
+        $cookie = new Cookie('foo', 'bar');
+        $this->assertEquals(0, $cookie->getMaxAge());
+
+        $cookie = new Cookie('foo', 'bar', $expire = time() + 100);
+        $this->assertEquals($expire - time(), $cookie->getMaxAge());
+
+        $cookie = new Cookie('foo', 'bar', $expire = time() - 100);
+        $this->assertEquals($expire - time(), $cookie->getMaxAge());
+    }
 }

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

@@ -128,7 +128,7 @@ public function testToStringIncludesCookieHeaders()
 
         $bag->clearCookie('foo');
 
-        $this->assertRegExp('#^Set-Cookie: foo=deleted; expires='.gmdate('D, d-M-Y H:i:s T', time() - 31536001).'; path=/; httponly#m', $bag->__toString());
+        $this->assertRegExp('#^Set-Cookie: foo=deleted; expires='.gmdate('D, d-M-Y H:i:s T', time() - 31536001).'; max-age=-31536001; path=/; httponly#m', $bag->__toString());
     }
 
     public function testClearCookieSecureNotHttpOnly()
@@ -137,7 +137,7 @@ public function testClearCookieSecureNotHttpOnly()
 
         $bag->clearCookie('foo', '/', null, true, false);
 
-        $this->assertRegExp('#^Set-Cookie: foo=deleted; expires='.gmdate('D, d-M-Y H:i:s T', time() - 31536001).'; path=/; secure#m', $bag->__toString());
+        $this->assertRegExp('#^Set-Cookie: foo=deleted; expires='.gmdate('D, d-M-Y H:i:s T', time() - 31536001).'; max-age=-31536001; path=/; secure#m', $bag->__toString());
     }
 
     public function testReplace()