sendou.ink/server/auth.ts

import type { Express } from "express";
import invariant from "tiny-invariant";
import session from "express-session";
import cookieParser from "cookie-parser";
import passport from "passport";
import { Strategy as DiscordStrategy } from "passport-discord";
import { upsertUser } from "../app/services/user";

export function setUpAuth(app: Express): void {
  invariant(
    process.env.DISCORD_CLIENT_ID,
    "env var DISCORD_CLIENT_ID undefined"
  );
  invariant(
    process.env.DISCORD_CLIENT_SECRET,
    "env var DISCORD_CLIENT_SECRET undefined"
  );
  invariant(
    process.env.DISCORD_CALLBACK_URL,
    "env var DISCORD_CALLBACK_URL undefined"
  );
  invariant(process.env.COOKIE_SECRET, "env var COOKIE_SECRET undefined");

  passport.use(
    new DiscordStrategy(
      {
        clientID: process.env.DISCORD_CLIENT_ID,
        clientSecret: process.env.DISCORD_CLIENT_SECRET,
        callbackURL: process.env.DISCORD_CALLBACK_URL,
        scope: ["identify", "connections"],
      },
      function (_accessToken, refreshToken, loggedInUser, cb) {
        upsertUser({ loggedInUser, refreshToken })
          .then((user) => {
            return cb(null, {
              id: user.id,
              discordId: user.discordId,
              discordAvatar: user.discordAvatar,
            });
          })
          .catch((err) => cb(err));
      }
    )
  );

  passport.serializeUser(function (user, done) {
    done(null, user);
  });

  passport.deserializeUser(function (user, done) {
    // @ts-expect-error it is guaranteed it's of a certain shape without an extra check
    done(null, user);
  });

  app.use(cookieParser());
  app.use(
    session({
      secret: process.env.COOKIE_SECRET,
      resave: true,
      saveUninitialized: true,
    })
  );
  app.use(passport.initialize());
  app.use(passport.session());
  app.post("/auth/discord", passport.authenticate("discord"));
  app.get(
    "/auth/discord/callback",
    passport.authenticate("discord", {
      failureRedirect: "/login",
      // TODO: fix for prod + redirect to same page
      successRedirect: "http://localhost:3000",
    })
  );
}