Add ability to upgrade to a revocable session (#368)

* Adds ParseSession::upgradeToRevocableSession

* added exception & exception test

Author: montymxb

src/Parse/ParseSession.php

@@ -86,6 +86,32 @@ public static function _isRevocable($token)
         return strpos($token, 'r:') === 0;
     }
 
+    /**
+     * Upgrades the current session to a revocable one
+     *
+     * @throws ParseException
+     */
+    public static function upgradeToRevocableSession()
+    {
+        $user = ParseUser::getCurrentUser();
+        if ($user) {
+            $token = $user->getSessionToken();
+            $response = ParseClient::_request(
+                'POST',
+                'upgradeToRevocableSession',
+                $token,
+                null,
+                false
+            );
+            $session = new self();
+            $session->_mergeAfterFetch($response);
+            $session->handleSaveResult();
+            ParseUser::become($session->getSessionToken());
+        } else {
+            throw new ParseException('No session to upgrade.');
+        }
+    }
+
     /**
      * After a save, perform Session object specific logic.
      */

tests/Parse/ParseSessionTest.php

@@ -56,4 +56,37 @@ public function testRevocableSession()
         $this->setExpectedException('Parse\ParseException', 'invalid session token');
         ParseUser::become($sessionToken);
     }
+
+    /**
+     * @group upgrade-to-revocable-session
+     */
+    public function testUpgradeToRevocableSession()
+    {
+        $user = new ParseUser();
+        $user->setUsername('revocable_username');
+        $user->setPassword('revocable_password');
+        $user->signUp();
+
+        $session = ParseSession::getCurrentSession();
+        $this->assertEquals($user->getSessionToken(), $session->getSessionToken());
+
+        // upgrade the current session (changes our session as well)
+        ParseSession::upgradeToRevocableSession();
+
+        // verify that our session has changed, and our updated current user matches it
+        $session = ParseSession::getCurrentSession();
+        $user = ParseUser::getCurrentUser();
+        $this->assertEquals($user->getSessionToken(), $session->getSessionToken());
+        $this->assertTrue($session->isCurrentSessionRevocable());
+    }
+
+    /**
+     * @group upgrade-to-revocable-session
+     */
+    public function testBadUpgradeToRevocableSession()
+    {
+        // upgrade the current session (changes our session as well)
+        $this->setExpectedException('Parse\ParseException', 'No session to upgrade.');
+        ParseSession::upgradeToRevocableSession();
+    }
 }