If refresh token is invalid, rather than returning invalid_grant, just remove token and retry

[jonespm]

I believe that when calling this get_oauth_token code if the access token is invalid it ends up printing Error: refresh_token request failed to get a token: Error: invalid_grant

We'd ideally want it to try to remove this users token and try the process again. It's possible that something changed that caused the token to become invalid and clearing it automatically would fix it.

I'm not 100% sure where the error is pushed up from but we'd have to investigate a little and hopefully can take care if it in our code rather than the library.

To reproduce

• Launch the app and get a token.
• Go into the Admin interface and click on Canvas Oauth2 Tokens
• Click on the token for your user id
• Change the refresh token and update the date to be "now" so it invalidates it
• Try to launch again. You should get this error.

Expectation is that it does one refresh to try to clear out and retry rather than just fail.

We may also want to test the case if the user removes their token from Canvas, it should be able to handle this.

This workaround is currently referenced at the bottom of the wiki with a manual workaround.

TEST PLAN:

• Launch the app and get a token.
• Go into the Admin interface and click on "Canvas Oauth2 Tokens"
• Click on the token for your user id
• Change the refresh token and clicks the Now link in the "Expires" Time field, so it invalidates it
• Save the update
• Refresh the browser. You should the OAuth screen. Click on the Authorize button
• You can now in the CAE tool home page again.

[zqian]

I think this error occurs after the Canvas test instance reset, which invalidates the old Canvas OAuth2 token?

[jonespm]

Yes, this will also happen after every Canvas test refresh. I'm not sure if there's other cases it could happen. We haven't tested many exception cases for OAuth.

[roujiawang]

Performed tests according to the TEST PLAN No unexpected behavior found.