Firebase Auth JS/PHP - php

Question

I've been tasked to build a web interface for an Android app based on firebase.
I've got a handful of endpoints, that interact with the database (Cloud functions). To access those endpoints I need to authenticate an user with email and password[1], retrieve an accessToken[2] und authorize every request to the endpoints with an Authorization: Bearer {accessToken} header.
I use php and struggle to wrap my mind around how to manage authenticated user in my app.
TL;DR please see my final solution in php only. https://stackoverflow.com/a/52119600/814031
I transfer the accessToken via ajax in a php session, to sign the cURL requests to the endpoints.
Apparently there is no other way around than use the firebase JS auth (not as far as I understand[4]).
My question is: Is it enough to save the accessToken in a php session and compare it with every page load via an ajax POST request (see code below)?
What would be a more robust strategy to handle that in php?
Edit: A user pointed out that using classic php sessions with JWT tokens don't make much sense and I read up about that topic.
So regarding Firebase - is this something to consider?
https://firebase.google.com/docs/auth/admin/manage-cookies
Firebase Auth provides server-side session cookie management for traditional websites that rely on session cookies. This solution has several advantages over client-side short-lived ID tokens, which may require a redirect mechanism each time to update the session cookie on expiration:
Here is what I got:
1. Login Page
As described in the Firebase examples[3]
function initApp() {
firebase.auth().onAuthStateChanged(function (user) {
if (user) {
// User is signed in.
// obtain token, getIdToken(false) = no forced refresh
firebase.auth().currentUser.getIdToken(false).then(function (idToken) {
// Send token to your backend via HTTPS
$.ajax({
type: 'POST',
url: '/auth/check',
data: {'token': idToken},
complete: function(data){
// data = {'target' => '/redirect/to/route'}
if(getProperty(data, 'responseJSON.target', false)){
window.location.replace(getProperty(data, 'responseJSON.target'));
}
}
});
// ...
}).catch(function (error) {
console.log(error);
});
} else {
// User Signed out
$.ajax({
type: 'POST',
url: '/auth/logout',
complete: function(data){
// data = {'target' => '/redirect/to/route'}
if(getProperty(data, 'responseJSON.target', false)){
// don't redirect to itself
// logout => /
if(window.location.pathname != getProperty(data, 'responseJSON.target', false)){
window.location.replace(getProperty(data, 'responseJSON.target'));
}
}
}
});
// User is signed out.
}
});
}
window.onload = function () {
initApp();
};
2. a php controller to handle the auth requests
public function auth($action)
{
switch($action) {
// auth/logout
case 'logout':
unset($_SESSION);
// some http status header and mime type header
echo json_encode(['target' => '/']); // / => index page
break;
case 'check':
// login.
if(! empty($_POST['token']) && empty($_SESSION['token'])){
// What if I send some bogus data here? The call to the Endpoint later would fail anyway
// But should it get so far?
$_SESSION['token'] = $_POST['token'];
// send a redirect target back to the JS
echo json_encode(['target' => '/dashboard']);
break;
}
if($_POST['token'] == $_SESSION['token']){
// do nothing;
break;
}
break;
}
}
3. the Main controller
// pseudo code
class App
{
public function __construct()
{
if($_SESSION['token']){
$client = new \GuzzleHttp\Client();
// $user now holds all custom access rights within the app.
$this->user = $client->request(
'GET',
'https://us-centralx-xyz.cloudfunctions.net/user_endpoint',
['headers' =>
[
'Authorization' => "Bearer {$_SESSION['token']}"
]
]
)->getBody()->getContents();
}else{
$this->user = null;
}
}
public function dashboard(){
if($this->user){
var_dump($this->user);
}else{
unset($_SESSION);
// redirect to '/'
}
}
}
Note: I'm aware of this sdk https://github.com/kreait/firebase-php and I read a lot in the issues there and in posts here on SO, but I got confused, since there is talk about full admin rights etc. and I really only interact with the endpoints that build upon firebase (plus firebase auth and firestore). And I'm still on php 5.6 :-/
Thanks for your time!
[1]: https://firebase.google.com/docs/auth/web/password-auth
[2]: https://firebase.google.com/docs/reference/js/firebase.User#getIdToken
[3]: https://github.com/firebase/quickstart-js/blob/master/auth/email-password.html
[4]: https://github.com/kreait/firebase-php/issues/159#issuecomment-360225655

Answer 1

I have to admit, the complexity of the firebase docs and examples and different services, got me so confused, that I thought, authentication for the web is only possible via JavaScript. That was wrong. At least for my case, where I just login with email and password to retrieve a Json Web Token (JWT), to sign all calls to the Firebase cloud functions. Instead of juggling with weird Ajax requests or set the token cookie via JavaScript, I just needed to call the Firebase Auth REST API
Here is a minimal case using the Fatfreeframework:
Login form
<form action="/auth" method="post">
<input name="email">
<input name="password">
<input type="submit">
</form>
Route
$f3->route('POST /auth', 'App->auth');
Controller
class App
{
function auth()
{
$email = $this->f3->get('POST.email');
$password = $this->f3->get('POST.password');
$apiKey = 'API_KEY'; // see https://firebase.google.com/docs/web/setup
$auth = new Auth($apiKey);
$result = $auth->login($email,$password);
if($result['success']){
$this->f3->set('COOKIE.token',$result['idToken']);
$this->f3->reroute('/dashboard');
}else{
$this->f3->clear('COOKIE.token');
$this->f3->reroute('/');
}
}
}
Class
<?php
use GuzzleHttp\Client;
class Auth
{
protected $apiKey;
public function __construct($apiKey){
$this->apiKey = $apiKey;
}
public function login($email,$password)
{
$client = new Client();
// Create a POST request using google api
$key = $this->apiKey;
$responsee = $client->request(
'POST',
'https://www.googleapis.com/identitytoolkit/v3/relyingparty/verifyPassword?key=' . $key,
[
'headers' => [
'content-type' => 'application/json',
'Accept' => 'application/json'
],
'body' => json_encode([
'email' => $email,
'password' => $password,
'returnSecureToken' => true
]),
'exceptions' => false
]
);
$body = $responsee->getBody();
$js = json_decode($body);
if (isset($js->error)) {
return [
'success' => false,
'message' => $js->error->message
];
} else {
return [
'success' => true,
'localId' => $js->localId,
'idToken' => $js->idToken,
'email' => $js->email,
'refreshToken' => $js->refreshToken,
'expiresIn' => $js->expiresIn,
];
}
}
}
Credits

Answer 2

Sounds like #Chad K is getting you on the right track (cookies and ajax - breakfast of champions... :), though I thought to share my code from my working system (with some 'privacy' things, of course!)
Look for /**** type comments for things you need to set up yourself (you may want to do some other firebase things differently as well - see the docs...)
LOGIN.php page (I found it simpler overall to keep this separate - see notes to learn why....)
<script>
/**** I picked this up somewhere off SO - kudos to them - I use it a lot!.... :) */
function setCookie(name, value, days = 7, path = '/') {
var expires = new Date(Date.now() + days * 864e5).toUTCString();
document.cookie = name + '=' + encodeURIComponent(value) + '; expires=' + expires + '; path=' + path;
}
function getCookie(c_name) {
if (document.cookie.length > 0) {
c_start = document.cookie.indexOf(c_name + "=");
if (c_start !== -1) {
c_start = c_start + c_name.length + 1;
c_end = document.cookie.indexOf(";", c_start);
if (c_end === -1) {
c_end = document.cookie.length;
}
return unescape(document.cookie.substring(c_start, c_end));
}
}
return "";
}
</script>
<script>
var config = {
apiKey: "your_key",
authDomain: "myapp.firebaseapp.com",
databaseURL: "https://myapp.firebaseio.com",
projectId: "myapp",
storageBucket: "myapp.appspot.com",
messagingSenderId: "the_number"
};
firebase.initializeApp(config);
</script>
<script src="https://cdn.firebase.com/libs/firebaseui/2.7.0/firebaseui.js"></script>
<link type="text/css" rel="stylesheet" href="https://cdn.firebase.com/libs/firebaseui/2.7.0/firebaseui.css"/>
<script type="text/javascript">
/**** set this url to the 'logged in' page (mine goes to a dashboard) */
var url = 'https://my.app/index.php#dashboard';
/**** by doing this signOut first, then it is simple to send any 'logout' request in the app to 'login.php' - one page does it.... :) */
firebase.auth().signOut().then(function () {
}).catch(function (error) {
console.log(error);
});
var signInFlow = 'popup';
if (('standalone' in window.navigator)
&& window.navigator.standalone) {
signInFlow = 'redirect';
}
var uiConfig = {
callbacks: {
signInSuccessWithAuthResult: function (authResult, redirectUrl) {
/**** here you can see the logged in user */
var firebaseUser = authResult.user;
var credential = authResult.credential;
var isNewUser = authResult.additionalUserInfo.isNewUser;
var providerId = authResult.additionalUserInfo.providerId;
var operationType = authResult.operationType;
/**** I like to force emailVerified...... */
if (firebaseUser.emailVerified !== true) {
firebase.auth().currentUser.sendEmailVerification().then(function () {
/**** if using this, you can set up your own usermgmt.php page for the user verifications (see firebase docs) */
window.location.replace("https://my.app/usermgmt.php?mode=checkEmail");
}).catch(function (error) {
console.log("an error has occurred in sending verification email " + error)
});
}
else {
var accessToken = firebaseUser.qa;
/**** set the Cookie (yes, I found this best, too) */
setCookie('firebaseRegistrationID', accessToken, 1);
/**** set up the AJAX call to PHP (where you will store this data for later lookup/processing....) - I use "function=....." and "return=....." to have options for all functions and what to select for the return so that ajax.php can be called for 'anything' (you can just call a special page if you like instead of this - if you use this idea, be sure to secure the ajax.php 'function' call to protect from non-authorized use!) */
var elements = {
function: "set_user_data",
user: JSON.stringify(firebaseUser),
return: 'page',
accessToken: accessToken
};
$.ajaxSetup({cache: false});
$.post("data/ajax.php", elements, function (data) {
/**** this calls ajax and gets the 'page' to set (this is from a feature where I store the current page the user is on, then when they log in again here, we go back to the same page - no need for cookies, etc. - only the login cookie is needed (and available for 'prying eyes' to see!) */
url = 'index.php#' + data;
var form = $('<form method="post" action="' + url + '"></form>');
$('body').append(form);
form.submit();
});
}
return false;
},
signInFailure: function (error) {
console.log("error - signInFailure", error);
return handleUIError(error);
},
uiShown: function () {
var loader = document.getElementById('loader');
if (loader) {
loader.style.display = 'none';
}
}
},
credentialHelper: firebaseui.auth.CredentialHelper.ACCOUNT_CHOOSER_COM,
queryParameterForWidgetMode: 'mode',
queryParameterForSignInSuccessUrl: 'signInSuccessUrl',
signInFlow: signInFlow,
signInSuccessUrl: url,
signInOptions: [
firebase.auth.GoogleAuthProvider.PROVIDER_ID,
// firebase.auth.FacebookAuthProvider.PROVIDER_ID,
// firebase.auth.TwitterAuthProvider.PROVIDER_ID,
{
provider: firebase.auth.EmailAuthProvider.PROVIDER_ID,
requireDisplayName: true,
customParameters: {
prompt: 'select_account'
}
}
/* {
provider: firebase.auth.PhoneAuthProvider.PROVIDER_ID,
// Invisible reCAPTCHA with image challenge and bottom left badge.
recaptchaParameters: {
type: 'image',
size: 'invisible',
badge: 'bottomleft'
}
}
*/
],
tosUrl: 'https://my.app/login.php'
};
var ui = new firebaseui.auth.AuthUI(firebase.auth());
(function () {
ui.start('#firebaseui-auth-container', uiConfig);
})();
</script>
Now, on every page you want the user to see (in my case, it all goes through index.php#something - which makes it easier.... :)
<script src="https://www.gstatic.com/firebasejs/4.12.0/firebase.js"></script>
<script>
// Initialize Firebase - from https://github.com/firebase/firebaseui-web
var firebaseUser;
var config = {
apiKey: "your_key",
authDomain: "yourapp.firebaseapp.com",
databaseURL: "https://yourapp.firebaseio.com",
projectId: "yourapp",
storageBucket: "yourapp.appspot.com",
messagingSenderId: "the_number"
};
firebase.initializeApp(config);
initFBApp = function () {
firebase.auth().onAuthStateChanged(function (firebaseuser) {
if (firebaseuser) {
/**** here, I have another ajax call that sets up some select boxes, etc. (I chose to call it here, you can call it anywhere...) */
haveFBuser();
firebaseUser = firebaseuser;
// User is signed in.
var displayName = firebaseuser.displayName;
var email = firebaseuser.email;
var emailVerified = firebaseuser.emailVerified;
var photoURL = firebaseuser.photoURL;
if (firebaseuser.photoURL.length) {
/**** set the profile picture (presuming you are showing it....) */
$(".profilepic").prop('src', firebaseuser.photoURL);
}
var phoneNumber = firebaseuser.phoneNumber;
var uid = firebaseuser.uid;
var providerData = firebaseuser.providerData;
var string = "";
firebaseuser.getIdToken().then(function (accessToken) {
// document.getElementById('sign-in-status').textContent = 'Signed in';
// document.getElementById('sign-in').textContent = 'Sign out';
/**** set up another ajax call.... - to store things (yes, again.... - though this time it may be due to firebase changing the token, so we need it twice...) */
string = JSON.stringify({
displayName: displayName,
email: email,
emailVerified: emailVerified,
phoneNumber: phoneNumber,
photoURL: photoURL,
uid: uid,
accessToken: accessToken,
providerData: providerData
});
if (accessToken !== '<?php echo $_COOKIE['firebaseRegistrationID']?>') {
console.log("RESETTING COOKIE with new accessToken ");
setCookie('firebaseRegistrationID', accessToken, 1);
var elements = 'function=set_user_data&user=' + string;
$.ajaxSetup({cache: false});
$.post("data/ajax.php", elements, function (data) {
<?php
/**** leave this out for now and see if anything weird happens - should be OK but you might want to use it (refreshes the page when firebase changes things..... I found it not very user friendly as they reset at 'odd' times....)
/*
// var url = 'index.php#<?php echo(!empty($user->userNextPage) ? $user->userNextPage : 'dashboard'); ?>';
// var form = $('<form action="' + url + '" method="post">' + '</form>');
// $('body').append(form);
// console.log('TODO - leave this form.submit(); out for now and see if anything weird happens - should be OK');
// form.submit();
*/
?>
});
}
});
} else {
console.log("firebase user CHANGED");
document.location.href = "../login.php";
}
}, function (error) {
console.log(error);
}
);
};
window.addEventListener('load', function () {
initFBApp();
});
</script>
Hope this helps. It is from my working system, which includes some extra features I've put in there along the way, but mostly it is directly from firebase so you should be able to follow along well enough.
Seems a much simpler route to take than your original one.

Answer 3

You really aren't supposed to use sessions in PHP when using tokens. Tokens should be sent in the header on every request (or a cookie works too).
Tokens work like this:
1. You sign in, the server mints a token with some information encoded
2. You send that token back on every request
Based on the information encoded in the token, the server can get information about the user. Typically a User ID of some sort is encoded in it. The server knows it's a valid token because of the way it's encoded.
Send the token on every request you need to make, then in PHP you can just pass that token to the other API