google-strategy.ts

/**
 * This file defines the "google strategy" for passport.
 * Passport requires three main things for a strategy to work:
 * - A deserialize method to turn an ID into a database object (a User)
 * - A serialize method to turn a database object (a User) into an ID
 * - The actual Strategy used to perform authentication
 */

import passport from 'passport';
import { OAuth2Strategy as GoogleStrategy } from 'passport-google-oauth';
import config from '../../config';
import * as callbackify from '../../util/callbackify';
import UserRepository, { User } from '../storage/user';

/**
 * Deserialize a given user by their google ID (this is the defined method of serde as contractually defined
 * in serializeUser, which requires us to accept ids)
 * @param googleId - The google ID of the database user
 */
export async function deserializeUser(googleId: string): Promise<User> {
    return await UserRepository.findByGoogleId(googleId);
}

/**
 * Serialize a given user from a database object to their google ID.
 * @param user - The database User object
 */
export async function serializeUser(user: User): Promise<string> {
    return user.googleId;
}

/**
 * Create a Google strategy suitable for passport.use
 */
export function createGoogleStrategy(): GoogleStrategy {
    return new GoogleStrategy({
        clientID:     process.env.GOOGLE_CLIENT_ID,
        clientSecret: process.env.GOOGLE_CLIENT_SECRET,
        // todo: replace with a better callback URL once this is running somewhere else
        callbackURL:  `http://localhost:${config.port}/auth/google/callback`,
        // only allow accounts from msu.edu for now
        hostedDomain: config.google.permittedEmailDomains.join(',')
    },(accessToken, refreshToken, profile, done) => {
        callbackify.attachResultToCallback(UserRepository.findOrCreateFromProfile(profile), done);
    });
}

export const strategyName = 'google';