I am trying to get new access token from my refresh token for google drive api. In my google playground it works but when I want to create the same request in postman or my code it doesn't work and I always get error "Invalid grand type". I don't know to find what is problem.
google developers playground
postman headers and body
You need to understand that there is three steps to the Oauth2 dance.
step one is requesting access of the user and getting the authorization code.
Note &response_type=code tells the server you want an authorization code returned.
POST https://accounts.google.com/o/oauth2/token code=4/X9lG6uWd8-MMJPElWggHZRzyFKtp.QubAT_P-GEwePvB8fYmgkJzntDnaiAI&client_id={ClientId}.apps.googleusercontent.com&client_secret={ClientSecret}&redirect_uri=urn:ietf:wg:oauth:2.0:oob&grant_type=authorization_code
Note the part where it says &grant_type=authorization_code. this tells the server you are giving them an authorization code.
3 the final step is refreshing your access token.
POST https://accounts.google.com/o/oauth2/token client_id={ClientId}.apps.googleusercontent.com&client_secret={ClientSecret}&refresh_token=1/ffYmfI0sjR54Ft9oupubLzrJhD1hZS5tWQcyAvNECCA&grant_type=refresh_token
Note &grant_type=refresh_token you are telling the server you are sending them a refresh token.
You appear to be sending a refresh token with the wrong grant type.
I have a video on how to set up postman to use google oauth2
Note: Due to a recent change with Making Google OAuth interactions safer by using more secure OAuth flows redirect uri of urn:ietf:wg:oauth:2.0:oob is going to stop working soon.
