How to send email using Gmail API using Rest Client

Question

We are using VB.NET and developing one Windows Form based application. Where we need to send email using gmail.

Appropriate scope has been approved by Google: scope=https://www.googleapis.com/auth/gmail.send

Using below URL via browser, we are able to retrieve code. https://accounts.google.com/o/oauth2/v2/auth?scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fgmail.send&access_type=offline&include_granted_scopes=true&state=state_parameter_passthrough_value&redirect_uri=**********&response_type=code&client_id=******************

At this point, we have client id, client secret, and code.

But we are unable to send email.

Can someone please share any sample POST request or sample code?

Lanugage used: VB.NET and first URL was called using webbrowser object.

Answer 1

You are using OAuth2 Authorization Code Grant flow. This flows returns you just a code that you need to exchange for an access token and a refresh token using the /token endpoint. The code is just a random identifier and cannot be used for anything else. Without an access token, you cannot access protected resources (GMail). The /token endpoint requires authentication, so you will need your client ID and secret when calling it.

The workflow, request parameters, responses and examples are covered in the OAuth2 RFC.