CODEWITHSUNDEEP
node.jsreactjsfirebaseexpressfirebase-authentication
Gustavo Sales
Gustavo Sales

Reputation: 169

Express backend with Firebase auth and my own database to persist users

I'm creating a system where the client in React will implement Firebase authentication, so Firebase will signIn users, but I have a backend server with Express and I need those users in my own DB (postgresql). I can use firebase-admin in the backend to verify the token sent from the client on each request, and from this token, extract user data, as well as its uid. So I could create a user in my own database with these information.

The problem is that since I'm not handling user signup in my own server, I would have to add a verification in the authentication middleware. Each time the user makes a request to the server, the backend verifies the token (with firebase-admin) and checks if the user already exists in my own database, because if it doensn't, then create this user.

I wanted to see if there is another way to handle this, since every request is not only going to verify a token but also query the database looking for the user.

Upvotes: 1

Views: 647

Answers (1)

Frank van Puffelen
Frank van Puffelen

Reputation: 598603

Verifying the ID token in the backend code is pretty much how all Firebase backend services handle it too. They receive the ID token, request the public key from the project, decode the token, and then validate that the user is authorized for the action they're performing.

You seem to want to create a record for the user in some shared database however, which I'd typically recommend against as it affects scalability. The only thing most Firebase backend services cache is the project keys (as those require an expensive HTTP lookup) and recent encoded/decoded token pairs. But there are caches on each server separately, so it's quite different from having shared state in a database as you seem to want.

Upvotes: 1

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