Could not obtain Google oAuth 2 token on POSTMan

Question

Well, since the Other problem(solved) remain unsolved, I was thinking to use POSTMan to do Trial and Error on each steps that the Client library will do.

So I read the Basic steps of Google OAuth2 again, created another OAuth 2 ID at Api Manager > Credentials in Dev Console and ID type is Web Application, and filled them into the POSTMan:

1. New tab in POSTMan, then click the Authorization label.
2. Choose type as OAuth 2.0 and select "Add token to the url"
3. Auth URL: https://accounts.google.com/o/oauth2/v2/auth
4. Access Token URL: https://www.googleapis.com/oauth2/v4/token
5. Client ID: [the Client ID that I just received]
6. Client Secret: [the Client secret that I just received]
7. Scope: [empty]
8. Grant Type: Authorization Code
9. Request access token locally: Selected
10. Click "Request Token"
11. POSTMan replied me: "Could not complete OAuth2.0 login"

Do I missed something?

(Google redirect URI could be found here)

(API scope could be found here)

Answer 1

You get access Token only when a Google User Logs in through the google signin page.

Step 1: Redirect https://accounts.google.com/o/oauth2/auth?client_id=" + GoogleClientID + "&redirect_uri=" + Url.Encode(GoogleRedirectURL) + "&response_type=code&scope=email"

Step 2: Now you are on google signin page and you would enter your google credentials.

Step 3 : Google will redirect you back to the redirect_uri that you have configured in the Google Developer Console and you can get the "code" from the QueryString

Step 4: Now you post a form to https://www.googleapis.com/oauth2/v4/token with client_id, client_secret, redirect_uri, code(you obtained in Step 3), and the grant_type=authorization_code

Result: You should now receive the access_token from Google

Answer 2

I followed Rajat's instructions, and they worked but afterward I tried what the OP did again but this time setting the scope to 'email' instead of leaving it blank, I got a prompt to enter my gmail creds, and was able to get access token.

Answer 3

BigHomie's suggestion of scope to 'email' worked for me as well. But I used a different Auth URL and Access Token URL than BigHomie, because I think it's been updated.

Auth URL: https://accounts.google.com/o/oauth2/auth

Access Token URL: https://accounts.google.com/o/oauth2/token