Node.js + Passport – Local Authentication Strategy – Deserialising the user

When using Node.js with Passport for local authentication strategy, deserialising the user is an important step in the authentication process.

Deserialising the user means converting the user data from a serialized format (such as a cookie or session data) back into a user object.

Here’s how you can deserialise the user in a Node.js application using Passport:

        
            const passport = require('passport');
            const User = require('./models/user');

            passport.deserializeUser((id, done) => {
                User.findById(id, (err, user) => {
                    done(err, user);
                });
            });
        
    

In the above code, we are using the deserializeUser method provided by Passport to deserialise the user. This method takes a callback function as a parameter, which is called with the user’s id and a callback function (done) when Passport needs to fetch the user data from the database.

Inside the callback function, we are using the User model to find the user by their id in the database. Once we have the user object, we call the done function with the user as the second argument.

By deserialising the user, we can retrieve the user’s data from the serialized format and use it for the authentication process. This is a crucial step in the local authentication strategy with Passport in Node.js applications.

With the above code, you can effectively deserialise the user in your Node.js application using Passport, ensuring that the user data is retrieved and made available for authentication.