Added the FBAuth middleman function for authentication.

functions/index.js

@@ -3,6 +3,7 @@ const functions = require('firebase-functions');
 const admin = require('firebase-admin');
 const app = require('express')();
 admin.initializeApp();
+const db = admin.firestore();
 
 const firebaseConfig = {
     apiKey: "AIzaSyCvsWetg4qFdsPGfJ3LCw_QaaYzoan7Q34",
@@ -13,9 +14,42 @@ const firebaseConfig = {
     messagingSenderId: "20131817365",
     appId: "1:20131817365:web:633c95fb08b16d4526b89c"
 };
+
 const firebase = require('firebase');
 firebase.initializeApp(firebaseConfig);
 
+// Acts as a middleman between the client and any function that you use it with
+// The function will only execute if the user is logged in, or rather, they have
+// a valid token
+const FBAuth = (req, resp, next) => {
+    let idToken;
+
+    if (req.headers.authorization && req.headers.authorization.startsWith('Bearer ')) {
+        idToken = req.headers.authorization.split('Bearer ')[1];
+    } else {
+        console.error('No token found');
+        return resp.status(403).json({ error: 'Unauthorized' });
+    }
+
+    admin.auth().verifyIdToken(idToken)
+        .then(decodedToken => {
+            req.user = decodedToken;
+            console.log(decodedToken);
+            return db.collection('users')
+                .where('userId', '==', req.user.uid)
+                .limit(1)
+                .get();
+        })
+        .then(data => {
+            req.user.handle = data.docs[0].data().handle;
+            return next();
+        })
+        .catch(err => {
+            console.error('Error verifying token', err);
+            return res.status(403).json(err);
+        })
+}
+
 app.get('/getUsers', (req, res) => {
     admin.firestore().collection('users').get().then(data => {
         let users = [];
@@ -40,4 +74,5 @@ app.post('/postUser', (req, res) => {
         console.error(err);
     });
 });
+
 exports.api = functions.https.onRequest(app);