# Method Web.Auth.OAuth2.Client()->refresh_access_token()

Method refresh_access_token

  `string refresh_access_token(void|function(bool, string:void) async_cb)`

Description

  Refreshes the access token, if a refresh token exists in the object.

Parameter `async_cb`

  If given an async request will be made and this function will be called when the request is finished. The first argument passed to the callback will be `true` or `false` depending on if the request was successfull or not. The second argument will be a string. If the request failed it will be an error message. If it succeeded it will be the result as a string encoded with encode_value().