How to generate access token using refresh token through google drive API?

Question

I have completed steps of authorization and obtained access token and refresh token.

What should I do next to generate access token using refresh token that I have stored through google drive API?

I won't be able to use any sdk since I am working on Force.com so please suggest the way to implement it directly through the API.

Answer 1

If you are using web api then you should make a http POST call to URL : https://www.googleapis.com/oauth2/v4/token with following request body

client_id: <YOUR_CLIENT_ID> client_secret: <YOUR_CLIENT_SECRET> refresh_token: <REFRESH_TOKEN_FOR_THE_USER> grant_type: refresh_token 

refresh token never expires so you can use it any number of times. The response will be a JSON like this:

{   "access_token": "your refreshed access token",   "expires_in": 3599,   "scope": "Set of scope which you have given",   "token_type": "Bearer" }