There is a nice official example on it using Express - may be handy in future: https://github.com/firebase/functions-samples/blob/master/authorized-https-endpoint/functions/index.js (pasted below just for sure)
Keep in mind that exports.app makes your functions available under /app slug (in this case there is only one function and is available under <you-firebase-app>/app/hello. To get rid of it you actually need to rewrite Express part a bit (middleware part for validation stays the same - it works very good and is quite understandable thanks to comments).
/**
* Copyright 2016 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
const express = require('express');
const cookieParser = require('cookie-parser')();
const cors = require('cors')({origin: true});
const app = express();
// Express middleware that validates Firebase ID Tokens passed in the Authorization HTTP header.
// The Firebase ID token needs to be passed as a Bearer token in the Authorization HTTP header like this:
// `Authorization: Bearer <Firebase ID Token>`.
// when decoded successfully, the ID Token content will be added as `req.user`.
const validateFirebaseIdToken = async (req, res, next) => {
console.log('Check if request is authorized with Firebase ID token');
if ((!req.headers.authorization || !req.headers.authorization.startsWith('Bearer ')) &&
!(req.cookies && req.cookies.__session)) {
console.error('No Firebase ID token was passed as a Bearer token in the Authorization header.',
'Make sure you authorize your request by providing the following HTTP header:',
'Authorization: Bearer <Firebase ID Token>',
'or by passing a "__session" cookie.');
res.status(403).send('Unauthorized');
return;
}
let idToken;
if (req.headers.authorization && req.headers.authorization.startsWith('Bearer ')) {
console.log('Found "Authorization" header');
// Read the ID Token from the Authorization header.
idToken = req.headers.authorization.split('Bearer ')[1];
} else if(req.cookies) {
console.log('Found "__session" cookie');
// Read the ID Token from cookie.
idToken = req.cookies.__session;
} else {
// No cookie
res.status(403).send('Unauthorized');
return;
}
try {
const decodedIdToken = await admin.auth().verifyIdToken(idToken);
console.log('ID Token correctly decoded', decodedIdToken);
req.user = decodedIdToken;
next();
return;
} catch (error) {
console.error('Error while verifying Firebase ID token:', error);
res.status(403).send('Unauthorized');
return;
}
};
app.use(cors);
app.use(cookieParser);
app.use(validateFirebaseIdToken);
app.get('/hello', (req, res) => {
res.send(`Hello ${req.user.name}`);
});
// This HTTPS endpoint can only be accessed by your Firebase Users.
// Requests need to be authorized by providing an `Authorization` HTTP header
// with value `Bearer <Firebase ID Token>`.
exports.app = functions.https.onRequest(app);
My rewrite to get rid of /app:
const hello = functions.https.onRequest((request, response) => {
res.send(`Hello ${req.user.name}`);
})
module.exports = {
hello
}
