Exchange google idToken for local openId token C #

Question

I am using this github project https://github.com/openiddict/openiddict-core which is great. But I stick to what procedures should be or how to implement them when the user uses an external identity provider. In this example, I will use Google.

I have an angular2 application working with the basic aspnet webAPI. All my local logins work fine, I call connect/tokenwith username and password, and accessToken is returned.

Now I need to implement google as an external identity provider. I followed all the steps here to implement the Google login button. This will open a popup when the user logs in. This is the code I created for my google button.

// Angular hook that allows for interaction with elements inserted by the
// rendering of a view.
ngAfterViewInit() {
    // check if the google client id is in the pages meta tags
    if (document.querySelector("meta[name='google-signin-client_id']")) {
        // Converts the Google login button stub to an actual button.
        gapi.signin2.render(
            'google-login-button',
            {
                "onSuccess": this.onGoogleLoginSuccess,
                "scope": "profile",
                "theme": "dark"
            });
    }
}

onGoogleLoginSuccess(loggedInUser) {
    let idToken = loggedInUser.getAuthResponse().id_token;

    // here i can pass the idToken up to my server and validate it
}

Now I have idToken from google. The next step on the google pages found here says that I need to check the google accessToken, what can I do, but how can I exchange the accessToken that I have from google and create local access for access that can be used in my application?

Answer 1

google, , , google accessToken, , accessToken, google, Token, ?

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OpenIddict , :

[HttpPost("~/connect/token")]
[Produces("application/json")]
public IActionResult Exchange(OpenIdConnectRequest request)
{
    if (request.IsPasswordGrantType())
    {
        // ...
    }

    else if (request.GrantType == "urn:ietf:params:oauth:grant-type:google_identity_token")
    {
        // Reject the request if the "assertion" parameter is missing.
        if (string.IsNullOrEmpty(request.Assertion))
        {
            return BadRequest(new OpenIdConnectResponse
            {
                Error = OpenIdConnectConstants.Errors.InvalidRequest,
                ErrorDescription = "The mandatory 'assertion' parameter was missing."
            });
        }

        // Create a new ClaimsIdentity containing the claims that
        // will be used to create an id_token and/or an access token.
        var identity = new ClaimsIdentity(OpenIdConnectServerDefaults.AuthenticationScheme);

        // Manually validate the identity token issued by Google,
        // including the issuer, the signature and the audience.
        // Then, copy the claims you need to the "identity" instance.

        // Create a new authentication ticket holding the user identity.
        var ticket = new AuthenticationTicket(
            new ClaimsPrincipal(identity),
            new AuthenticationProperties(),
            OpenIdConnectServerDefaults.AuthenticationScheme);

        ticket.SetScopes(
            OpenIdConnectConstants.Scopes.OpenId,
            OpenIdConnectConstants.Scopes.OfflineAccess);

        return SignIn(ticket.Principal, ticket.Properties, ticket.AuthenticationScheme);
    }

    return BadRequest(new OpenIdConnectResponse
    {
        Error = OpenIdConnectConstants.Errors.UnsupportedGrantType,
        ErrorDescription = "The specified grant type is not supported."
    });
}

, OpenIddict:

// Register the OpenIddict services, including the default Entity Framework stores.
services.AddOpenIddict()
    // Register the Entity Framework stores.
    .AddEntityFrameworkCoreStores<ApplicationDbContext>()

    // Register the ASP.NET Core MVC binder used by OpenIddict.
    // Note: if you don't call this method, you won't be able to
    // bind OpenIdConnectRequest or OpenIdConnectResponse parameters.
    .AddMvcBinders()

    // Enable the token endpoint.
    .EnableTokenEndpoint("/connect/token")

    // Enable the password flow, the refresh
    // token flow and a custom grant type.
    .AllowPasswordFlow()
    .AllowRefreshTokenFlow()
    .AllowCustomFlow("urn:ietf:params:oauth:grant-type:google_identity_token")

    // During development, you can disable the HTTPS requirement.
    .DisableHttpsRequirement();

grant_type id_token assertion, . Postman ( Facebook, ):

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