Develop Reference

Node.js — Google OAuth 2.0 for Web Server Applications -> How to use the token event

I'm trying to figure out how to use the token event as specified in Google's OAuth 2.0 documentation for server side applications (using Node.js):
Here's the code for the token event:
oauth2Client.on('tokens', (tokens) => {
if (tokens.refresh_token) {
// store the refresh_token in your secure persistent database
console.log(tokens.refresh_token);
}
console.log(tokens.access_token);
});
I actually get this event to fire, but am unsure about when to check for a valid token. If I do this one every request (let's say Google Docs API request), the token event fires after I'm requesting the API, so credentials are not set correctly.
How would you go about making sure that the correct access token is set BEFORE making a request?
Google says "Once the client has a refresh token, access tokens will be acquired and refreshed automatically in the next call to the API.", which is also kind of the case, but too late.
So my question once again: How do I, in my call, wait for the token event to finish updating my access token in order to set credentials BEFORE making the request?
Thank you!

#AskFirebase FCM web push token invalidation time

Do FCM tokens generated using Firebase JS SDK ever expire when user is offline too long?
For example, after calling the following code:
messaging.getToken().then((currentToken) => {
if (currentToken) {
sendTokenToServer(currentToken);
updateUIForPushEnabled(currentToken);
} else {
// Show permission request.
console.log('No Instance ID token available. Request permission to generate one.');
// Show permission UI.
updateUIForPushPermissionRequired();
setTokenSentToServer(false);
}
}).catch((err) => {
console.log('An error occurred while retrieving token. ', err);
showToken('Error retrieving Instance ID token. ', err);
setTokenSentToServer(false);
});
The server has the client token. If the user clears the site data, the client no longer knows of this registration, and no one updates the server that the client is gone. So does it ever invalidates the token? If so, how long does it take to invalidate? I understand that FCM can save messages up to 28 days, so I'm assuming no less than that amount of time?

Tokens might be invalidated for a number of reasons. According to the documentation:
The registration token may change when:
The web app deletes the registration token.
The user clears browser data. In this case, call getToken to retrieve the new token.
The documentation doesn't say anything about expiration times, but your code should be prepared to handle these cases by detecting the change and sending the new token to your backend.

Firebase ID token to secure API (Google Cloud Endpoints)

I have an API that I want to secure, I'm thinking of use Firebase ID tokens and include a token in every request, using:
firebase.auth().currentUser.getToken(/* forceRefresh */ true).then(function(idToken) {
// Send token to your backend via HTTPS
}).catch(function(error) {
// Handle error
});
and then verify the token.
Could this slow down the request to the API?

The answer is of course, yes, authentication will always slow down the request to the API. But it should be pretty minimal.

Token based authorization in nodejs/ExpressJs and Angular(Single Page Application)

In my application,while registering the users i am saving username,password and jwt generated token with these fields in MONGO DB.When user tries to login with correct credentials then i will send the response with stored token.Then at client side(In my controller) i am using the localstorage to store the token so that i can send the same token for each and every request sent by the client.But I found some issues regarding this procedure:
I am generating same token for one user every time.So if any third person is able to get the token then he can access the restricted page.
Am i wasting space in db by storing the generated token in MONGODB
Can Anyone access the token stored in localstorage other than the user.
for each and every request in my single page application,I am again querying mongodb to get the token for that user and validating.Here,I am checking both client side and server side.
I am using jwt to generate tokens,Node,Express,Mongoose in my application
Am i following the good procedure.If not,can you please provide the solution for my approach or any new approach.
I have searched many sites for token based authorization and session based authorization,But nothing worked for me.
Note:I am beginner for Nodejs,AngularjS

You should store token in advanced key-value cache tool like: Redis
That would improve performance remarkably.
You will get token from database for 1st time then it should be stored in Redis. I used to set token as key and username as value. Next request , the token will be given from cache. with Redis you can set expire for token.

When a user registers, you would need to generate a JWT like you're doing now. That's OK. You don't need to save it to the database however. You didn't ask but I assume that the password should not be stored in clear text. You can use something bcrypt to encrypt before saving it to the database.
When user tries to login with correct credentials then i will send the response with stored token
Yes, that's correct way to do.
Then at client side(In my controller) i am using the localstorage to store the token so that i can send the same token for each and every request sent by the client.
Yes, on the client side, you can save the JWT to local storage and send it in subsequent requests to the server.
Now your bullet points:
So that you won't have the same JWT each time, you can include an "exp" claim in the payload (I'm assuming you're using something like jwt-simple to generate a JWT). Something like:
var payload = {
sub: account.username,
exp: moment().add(10, 'days').unix()
};
var token = jwt.encode(payload, "secret");
You don't need to store the JWTs in the database. In some cases, the token issuers (the authorization servers) are not the same as the resource servers. The resource servers only receives the JWTs in a request but there's no way for the resource servers to touch the database used by the authorization servers. Side note: If you eventually need to support refresh tokens, i.e. the JWTs that you hand to the clients will need to eventually expire, then you can store the refresh token in a database. Refresh tokens are not the same as JWTs (access tokens). The complexity to support refresh tokens will increase.
Local storage is not where you store passwords, but it can be used to store JWTs. For that very reason, a JWT must and should expire after a certain time.
Not sure what you mean by saying you check both client side and server side. When the client needs to access a resource (again it's fair to assume that the resource server might not be the same as the authorization server), the only thing that the resource server is passed is the JWT. Anyone can decode a JWT. For example, try to paste your JWT on this site http://jwt.io/. That's why a JWT should not contain any sensitive data. But if the resource server knows the secret that the authorization server uses when it encode the JWT, the resource server can verify the signature. Back to your third bullet, that's why it's OK to store the JWT in local storage of the client.
Update I'm updating this to answer to some of your questions in the comment box.
User clicks on 'Login' button triggers the Angular controller to post a request to the server, something like:
$http.post(url, {
username: $scope.username,
password: $scope.password
}).success(function(res) { ... })
Server receives the POST request, it checks username/password, then it generates a JWT, and sends back to the browser. Note that it does not have to save the JWT to the database. The code would be something like
var payload = {
sub: account.username,
exp: moment().add(10, 'days').unix()
};
var token = jwt.encode(payload, "secret");
res.status(200).json({
token: token
});
Back on the client side, in the success() callback above, now you can save the JWT in local storage:
.success(function(res) { $window.localStorage.setItem('accessJWT', res.token) })
The user is now authenticated. Now when user wants to access a protected resource, user don't have to provide username/password. With the JWT which can be retrieved from local storage, the client can now put the JWT in the Authorization header of the request using the bearer scheme, and sends the request to the server. In code, it would like:
headers.Authorization = 'Bearer ' + token;
The server receives the request. Again, this server receiving this request does not have to be the same as the server which generates the JWT above. The 2 servers can be in 2 different continents. Even if you save the JWT above, that does not do any good to this server which can not access the database where the JWT is stored. But this server can pull out the bearer token from the header of the request, validates the token and carries on with the normal tasks.
Hope this helps.

You do not want to store the JWT in mongoose because it appears in headers when logging in. You first generate a token then hash it using a module like crypto.
There are different ways to do this and they all use Passport which handles the tokens. Here's an example project Satellizer
I would recommend you generate the angular-fullstack project. Then go through the server/auth folder and the client/account folder. You will see how to securely handle authentication in a MEAN based app.

Facebook login with Parse client site, use user object with Express js

I am trying to create a login procedure with the Parse and Facebook Javascript SDK. The authentication works without a problem on the client side, but I need to access the user object (created by Parse SDK) on the server side too. How can I do this the most elegant way? I thought when I log in into Facebook via Parse a cookie is set and so I can access the user object from the server. Or should I do the login process server side? Any recommendations?

I'm facing the same problem. Turns out that you can use either server-side auth or client-side auth. You cannot mix-and-match the two. Have a look at their official blog post about sessions.
var parseExpressCookieSession = require('parse-express-cookie-session');
// In your middleware setup...
app.use(express.cookieParser('YOUR_SIGNING_SECRET'));
app.use(parseExpressCookieSession({ cookie: { maxAge: 3600000 } }));
// Making a "login" endpoint is SOOOOOOOO easy.
app.post("/login", function(req, res) {
Parse.User.logIn(req.body.username, req.body.password).then(function() {
// Login succeeded, redirect to homepage.
// parseExpressCookieSession will automatically set cookie.
res.redirect('/');
},
function(error) {
// Login failed, redirect back to login form.
res.redirect("/login");
});
});
Also, I came across this when digging through the doc:
You can add Parse.User authentication and session management to your
Express app using the parseExpressCookieSession middleware. You just
need to call Parse.User.logIn() in Cloud Code, and this middleware
will automatically manage the user session for you.
You can use a web form to ask for the user's login credentials, and
log in the user in Cloud Code when you receive data from this form.
After you call Parse.User.logIn(), this middleware will automatically
set a cookie in the user's browser. During subsequent HTTP requests
from the same browser, this middleware will use this cookie to
automatically set the current user in Cloud Code.
...
When you work with user data, you should use HTTPS whenever possible.
To protect your app and your users, the parseExpressCookieSession
middleware requires you to use HTTPS. For your convenience, we also
provide a parseExpressHttpsRedirect middleware for redirecting all
HTTP requests to HTTPS.