How to incorporate audience in OidcClient?

[FlominatorTM]

I'm using Duende.IdentityModel.OidcClient in a c# application with auth0. Login works well, but now I'm told, that I'm supposed to add an audience parameter to the initial "authorize" request url. Does that make any sense? If yes: how can I do that?

var browser = new WinFormsWebView2.WinFormsWebView(m_strWindowTitle);
var options = new OidcClientOptions
{
	Authority = AUTHORITY,
	ClientId = CLIENT_ID,
	Scope = "openid email api", /* openid email api offline_access */
	RedirectUri = "https://some_site/ok",
	Browser = browser
};
_oidcClient = new OidcClient(options);

Thanks a lot

[wcabus]

If you need to pass additional parameters to the authorize endpoint during a LoginAsync call, you can add a LoginRequest as the first parameter:

var loginResult = _oidcClient.LoginAsync(new LoginRequest
{
    FrontChannelExtraParameters =
    {
        { "audience", "your_audience_value_here" }
    }
});

[FlominatorTM]

Thank you, this did the trick (once somebody fixed the server side ...)

[FlominatorTM]

Does this somehow overwrite the scope, I set at _oidcClient before?

[wcabus]

@FlominatorTM No, it shouldn't. The scope set in OidcClientOptions is passed on to the AuthorizeClient, which is being used when calling LoginAsync.

During the subsequent call to the authorization endpoint, the scope parameter is not being altered by the FrontChannelExtraParameters. The method CreateAuthorizeParameters adds the client_id, scope and redirect_uri parameters from the initially defined options, and the additional front-channel parameters are added last.

You could end up with a duplicate parameter however, if you've added scope to the FrontChannelExtraParameters, and that might cause an issue if that's the case. But if you didn't add scope to FrontChannelExtraParameters, then the scope value from OidcClientOptions will be sent during the call to the authorization endpoint.