Scalr_Account_User::getPermissions PHP Method

    public function getPermissions()
    {
        if (!$this->permissions) {
            $this->permissions = new Scalr_Permissions($this);
        }
        return $this->permissions;
    }

 private function AuthenticateREST($request)
 {
     if (!$request['Signature']) {
         throw new Exception("Signature is missing");
     }
     if (!$request['KeyID']) {
         throw new Exception("KeyID is missing");
     }
     if (!$request['Timestamp'] && !$request['TimeStamp']) {
         throw new Exception("Timestamp is missing");
     }
     ksort($request);
     $string_to_sign = "";
     foreach ($request as $k => $v) {
         if (!in_array($k, array("Signature"))) {
             if (is_array($v)) {
                 foreach ($v as $kk => $vv) {
                     $string_to_sign .= "{$k}[{$kk}]{$vv}";
                 }
             } else {
                 $string_to_sign .= "{$k}{$v}";
             }
         }
     }
     $this->debug['stringToSign'] = $string_to_sign;
     $this->user = Scalr_Account_User::init()->loadByApiAccessKey($request['KeyID']);
     if (!$this->user) {
         throw new Exception("API Key #{$request['KeyID']} not found in database");
     }
     $auth_key = $this->user->getSetting(Scalr_Account_User::SETTING_API_SECRET_KEY);
     if ($this->user->getAccountId()) {
         if (!$request['EnvID']) {
             $envs = $this->user->getEnvironments();
             if (!$envs[0]['id']) {
                 throw new Exception("User has no access to any environemnts");
             }
             $this->Environment = Scalr_Environment::init()->loadById($envs[0]['id']);
         } else {
             $this->Environment = Scalr_Environment::init()->loadById($request['EnvID']);
         }
         $this->user->getPermissions()->setEnvironmentId($this->Environment->id)->validate($this->Environment);
         //We must set environment to DI Container.
         $this->getContainer()->environment = $this->Environment;
     }
     $valid_sign = base64_encode(hash_hmac(self::HASH_ALGO, trim($string_to_sign), $auth_key, 1));
     if ($valid_sign != $request['Signature']) {
         throw new Exception("Signature doesn't match");
     }
 }