README.md

passport-firebase-jwt

Based on passport-jwt

A Passport strategy to authenticate with Firebase Auth.

This module lets you authenticate endpoints when using Firebase Auth in a Node.js application.

Install

npm install passport-firebase-jwt

Usage

NestJS TypeScript usage example:

Strategy name is: firebase-jwt.

index.ts

Make sure firebase is initialized before starting NestJs

import { credential, initializeApp } from 'firebase-admin';
import * as express from 'express';
import * as serviceAccount from './serviceAccountKey.json';

const config = {
    apiKey: '***',
    authDomain: '***.firebaseapp.com',
    databaseURL: 'https://***.firebaseio.com',
    projectId: '***',
    storageBucket: '***.appspot.com',
    messagingSenderId: '***',
    credential: credential.cert(***)
};
initializeApp(config);

firebase-auth.strategy.ts

import { PassportStrategy } from '@nestjs/passport';
import { Injectable, UnauthorizedException } from '@nestjs/common';
import { Strategy, ExtractJwt } from 'passport-firebase-jwt';
import { auth } from 'firebase-admin';

@Injectable()
export class FirebaseAuthStrategy extends PassportStrategy(Strategy) {

    constructor() {
        super({
            jwtFromRequest: ExtractJwt.fromAuthHeaderAsBearerToken()
        });
    }

    validate(token) {
        return auth()
            .verifyIdToken(token, true)
            .catch((err) => {
                console.log(err);
                throw new UnauthorizedException();
            });
    }
}

auth.module.ts

import { Module } from '@nestjs/common';
import { PassportModule } from '@nestjs/passport';
import { FirebaseAuthStrategy } from './firebase-auth.strategy';

@Module({
    imports: [
        PassportModule.register({ defaultStrategy: 'firebase-jwt' })
    ],
    providers: [
        FirebaseAuthStrategy
    ],
    exports: [
        PassportModule
    ]
})
export class AuthModule {}

Extracting the JWT from the request

There are a number of ways the JWT may be included in a request. In order to remain as flexible as possible the JWT is parsed from the request by a user-supplied callback passed in as the jwtFromRequest parameter. This callback, from now on referred to as an extractor, accepts a request object as an argument and returns the encoded JWT string or null.

Included extractors

A number of extractor factory functions are provided in passport-jwt.ExtractJwt. These factory functions return a new extractor configured with the given parameters.

• fromHeader(header_name) creates a new extractor that looks for the JWT in the given http header
• fromBodyField(field_name) creates a new extractor that looks for the JWT in the given body field. You must have a body parser configured in order to use this method.
• fromUrlQueryParameter(param_name) creates a new extractor that looks for the JWT in the given URL query parameter.
• fromAuthHeaderWithScheme(auth_scheme) creates a new extractor that looks for the JWT in the authorization header, expecting the scheme to match auth_scheme.
• fromAuthHeaderAsBearerToken() creates a new extractor that looks for the JWT in the authorization header with the scheme 'bearer'
• fromExtractors([array of extractor functions]) creates a new extractor using an array of extractors provided. Each extractor is attempted in order until one returns a token.