Implemented a simple authentication scheme with Firebase and Iron Session

src/pages/api/login.ts

@@ -0,0 +1,38 @@
+import {NextApiRequest, NextApiResponse} from "next";
+import {getAuth, signInWithEmailAndPassword} from "firebase/auth";
+import {app} from "@/firebase";
+import {sessionOptions} from "@/lib/session";
+import {withIronSessionApiRoute} from "iron-session/next";
+import {User} from "@/interfaces/user";
+import {getFirestore, getDoc, doc} from "firebase/firestore";
+
+const auth = getAuth(app);
+const db = getFirestore(app);
+
+export default withIronSessionApiRoute(login, sessionOptions);
+
+async function login(req: NextApiRequest, res: NextApiResponse) {
+	const {email, password} = req.body as {email: string; password: string};
+
+	signInWithEmailAndPassword(auth, email, password)
+		.then(async (userCredentials) => {
+			const userId = userCredentials.user.uid;
+
+			const docUser = await getDoc(doc(db, "users", userId));
+			if (!docUser.exists()) {
+				res.status(401).json({error: 401, message: "User does not exist!"});
+				return;
+			}
+
+			const user = docUser.data() as User;
+
+			req.session.user = user;
+			await req.session.save();
+
+			res.status(200).json({user: {...user, id: userId}});
+		})
+		.catch((error) => {
+			console.log(error);
+			res.status(401).json({error});
+		});
+}