You use the refresh token grant when the current access token is expired or when a new access token is needed. With this grant type, the refresh token acts as credentials that are issued to the client by the authorization server. Issuing a refresh token is optional. If the authorization server issues a refresh token, it is included when issuing an access token. Refresh tokens are issued for all other grant types other than the implicit grant as recommended by the OAuth 2.0 specification.
Tip: Be sure to keep the refresh token private, similar to the access token as this token issues access tokens without user interactions.
To use this grant type, you need a refresh token, using which you can get a new access token along with a new refresh token. Given below is how to get a token:
- The
<RefreshTokenValidityPeriod>element is in seconds. By default, it is valid for one day. You can configure this accordingly. The
<RenewRefreshTokenForRefreshGrant>element is by default set to true.The refresh token is renewed when the refresh grant is used to get an access token. A new refresh token is issued with a new expiry time and the previous refresh token is then inactive and can no longer be used.
If this element is set to false, unless the refresh token has expired, the same refresh token is returned.
<!-- Validity period for refresh token -->
<RefreshTokenValidityPeriod>84600</RefreshTokenValidityPeriod>
...
<!-- Enable renewal of refresh token for refresh_token grant -->
<RenewRefreshTokenForRefreshGrant>true</RenewRefreshTokenForRefreshGrant>
Try out scenario
Run the following cURL command to try out the refresh token grant.
curl -k -d "grant_type=refresh_token&refresh_token=<refresh_token>" -H "Authorization: Basic <Base64Encoded(Client_Id:Client_Secret)>" -H "Content-Type: application/x-www-form-urlencoded" https://localhost:9443/oauth2/token