Custom provider: Reading token_endpoint from .well-known configuration inside token request handler

[bardsol]

Hi!

I'm using a custom provider that bridges two different providers. First I request a token from the first provider, and then use the id_token from that provider to get a new access_token from the second provider. This second provider is the token I need to store in the JWT cookie.

const TSDProvider = ({
  id = 'tsd',
  name = id,
  accountType,
  OIDCProvider,
}: {
  id?: string;
  name?: string;
  accountType: Role;
  OIDCProvider: (config: Omit<OAuthUserConfig<Profile>, 'clientId' | 'clientSecret'>) => OAuthConfig<Profile>;
}) => {

  return OIDCProvider({
    id,
    name,
    token: {
      async request(request) {
        const {
          client: { redirect_uris },
          checks: { code_verifier },
          params: { code, iss },
          provider: { clientId, clientSecret },
        } = request;

        if (!clientId || !clientSecret || !code || !redirect_uris || !code_verifier) throw new Error('Auth error');

        const providerToken = await getProviderToken(`TOKEN_ENDPOINT_SHOULD_GO_HERE`, {
          clientId,
          clientSecret,
          code,
          redirect_uri: redirect_uris[0],
          code_verifier,
        });

        if (!providerToken || !providerToken.id_token) throw new Error('Missing provider token');
        if (!process.env.TSD_CLIENT_SECRET) throw new Error('Missing TSD Client Secret');

        const token = await getTSDToken(process.env.TSD_CLIENT_SECRET, providerToken.id_token, accountType);

        return { tokens: { id_token: providerToken.id_token, access_token: token.token } };
      },
    },
  });
};

Inside the request where I use the "getProviderToken" method, I need to read the original providers token_endpoint, but this endpoint is not present on the request object in the request handler. Is there a way to read this or do I need to hard code it for each provider?