Return accesstoken after Oauth Authentication in passport.js - passport.js

Question

I want the following flow in my app
User selects authenticate with google
I redirect to google and get the callback (This happens using Passport)
I now want to return an auth token that is specific to my application in the form of response to user.
var GoogleStrategy = require('passport-google-oauth').OAuth2Strategy;
passport.use(new GoogleStrategy({
clientID: GOOGLE_CLIENT_ID,
clientSecret: GOOGLE_CLIENT_SECRET,
callbackURL: "http://127.0.0.1:3000/auth/google/callback"
},
function(accessToken, refreshToken, profile, done) {
// RETURN ACCESS TOKEN IN THE RESPONSE
}
));
I do get the success callback, but I don know how to return a custom access token/response from the callback function.
I guess the answer related to using of done(), or serialization or deserialization which I am not clear from the docs or any examples. Can you please also explain how done(), or serialization or deserialization are used.

Answer 1

You can do this in serialization and deserialization. See this passport example
userSchema.methods.generateRandomToken = function () {
var user = this,
chars = "_!abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890",
token = new Date().getTime() + '_';
for ( var x = 0; x < 16; x++ ) {
var i = Math.floor( Math.random() * 62 );
token += chars.charAt( i );
}
return token;
};
var User = mongoose.model('User', userSchema);
//serialize
passport.serializeUser(function (user, done){
var createAccessToken = function() {
var token = user.generateRandomToken()
User.findOne({
accessToken: token
}, function(err, existingUser){
if (err) { return done(err) }
if (existingUser) {
createAccessToken()
} else {
user.set('accessToken', token)
user.save(function(err){
if (err) { return done(err) }
return done(null, user.get('accessToken'))
})
}
})
}
if (user._id) {
createAccessToken()
}
})
//deserialize
passport.deserializeUser(function(token, done){
User.findOne({
accessToken : token
}, function(err, user){
done(err, user)
})
})