Setup Hasura JWT Parsing

Usually with Firebase Auth and Hasura we can use the standard JWK url as described here.

However, with Firebase Session cookies they need a different format which we'll have to add manually. Hopefully in the future this can improve.

1. In login.tsx add console.log(cookie) after const cookie = await admin.auth().createSessionCookie(idToken, { expiresIn }); and go through the login process to get the cookie JWT token

2. Open jwt.io and paste your JWT in.

3. In the decoded headers section, note the kid: property. Take the value of that, open https://www.googleapis.com/identitytoolkit/v3/relyingparty/publicKeys, and find the public certificate that matches.

4. We now build our Hasura JWT secret config

{"type":"RS256", "key": "<Firebase public cert from previous step>", "audience": "<firebase project id>", "issuer": "https://session.firebase.google.com/<firebase project id>", "claims_map": {"x-hasura-allowed-roles": ["user"], "x-hasura-default-role": "user", "x-hasura-user-id": {"path":"$.sub"} }}

By default, we assign a logged-in user the role of user using the claims map feature.

Save this config for an upcoming step.