public static function getUserEnvironmentVariable($var_name) {
    $result = getenv($var_name);
    if ($result === false) {
      $result = getenv(self::HTTP_X_APPENGINE . $var_name);
    }
    return $result;
  }
public static function getUserEnvironmentVariable($var_name) {
    $result = getenv($var_name);
    if ($result === false) {
      $result = getenv(self::HTTP_X_APPENGINE . $var_name);
    }
    return $result;
  }
public static function getUserEnvironmentVariable ( $ var_name ) { $ result = getenv ( $ var_name ) ; if ( $ result === false ) { $ result = getenv ( self :: HTTP_X_APPENGINE . $ var_name ) ; } return $ result ; }
Retrieve an environment variable specifically for the UserService.

Under managed VMs, the UserService environment variables are sent as
HTTP headers with the prefix 'HTTP_X_APPENGINE_'. This function first
checks if the environment variable is set, and if not checks if it is
set with the prefix string.

@param string $var_name The variable name to check.

@return The environment value, or false if not found.
Retrieve an environment variable specifically for the UserService .