oauth-passport-facebook

• By using the Passport OAuth support through the passport-facebook module together with Facebook's OAuth support to enable user authentication within your server.
  • Configure your server to support user authentication based on OAuth providers
  • Use Passport OAuth support through the passport-facebook module to support OAuth based authentication with Facebook for your users.

Installing passport-facebook Module

In the project folder, install passport-facebook module by typing the following at the prompt:

     npm install passport-facebook --save

• Refactoring Authentication Code
  • Create a new file named authenticate.js and add the following code to it:

var passport = require('passport');
var LocalStrategy = require('passport-local').Strategy;
var User = require('./models/user');
var config = require('./config');

exports.local = passport.use(new LocalStrategy(User.authenticate()));
passport.serializeUser(User.serializeUser());
passport.deserializeUser(User.deserializeUser());

• Updating app.js
  • Update app.js to include authenticate.js module:

var authenticate = require('./authenticate');

• Remove the following line:

var LocalStrategy = require('passport-local').Strategy;

• Also, remove the following lines from the passport configuration part of app.js:

var User = require('./models/user');passport.use(new LocalStrategy(User
  .authenticate()));
passport.serializeUser(User.serializeUser());
passport.deserializeUser(User.deserializeUser());

• Updating config.js
  • Update config.js as follows:

module.exports = {
    'secretKey': '12345-67890-09876-54321',
    'mongoUrl' : 'mongodb://localhost:27017/dbname',
    'facebook': {
        clientID: 'YOUR FACEBOOK APP ID',
        clientSecret: 'YOUR FACEBOOK SECRET',
        callbackURL: 'https://localhost:3443/users/facebook/callback'
    }
}

• Updating User Model
  • Open user.js from the models folder and update the User schema as follows:

var User = new Schema({
    username: String,
    password: String,
    OauthId: String,
    OauthToken: String,
    firstname: {
      type: String,
      default: ''
    },
    lastname: {
      type: String,
      default: ''
    },
    admin:   {
        type: Boolean,
        default: false
    }
});

• Setting up Facebook Authentication
  • Open authenticate.js and add in the following line to add Facebook strategy:

var FacebookStrategy = require('passport-facebook').Strategy;

Then add the following code to initialize and set up Facebook authentication strategy in Passport:

exports.facebook = passport.use(new FacebookStrategy({
  clientID: config.facebook.clientID,
  clientSecret: config.facebook.clientSecret,
  callbackURL: config.facebook.callbackURL
  },
  function(accessToken, refreshToken, profile, done) {
    User.findOne({ OauthId: profile.id }, function(err, user) {
      if(err) {
        console.log(err); // handle errors!
      }
      if (!err && user !== null) {
        done(null, user);
      } else {
        user = new User({
          username: profile.displayName
        });
        user.OauthId = profile.id;
        user.OauthToken = accessToken;
        user.save(function(err) {
          if(err) {
            console.log(err); // handle errors!
          } else {
            console.log("saving user ...");
            done(null, user);
          }
        });
      }
    });
  }
));

• Updating users.js
  • Open users.js and add the following code to it:

router.get('/facebook', passport.authenticate('facebook'),
  function(req, res){});

router.get('/facebook/callback', function(req,res,next){
  passport.authenticate('facebook', function(err, user, info) {
    if (err) {
      return next(err);
    }
    if (!user) {
      return res.status(401).json({
        err: info
      });
    }
    req.logIn(user, function(err) {
      if (err) {
        return res.status(500).json({
          err: 'Could not log in user'
        });
      }
              var token = Verify.getToken(user);
              res.status(200).json({
        status: 'Login successful!',
        success: true,
        token: token
      });
    });
  })(req,res,next);
});

• Registering your app on Facebook
  • Go to https://developers.facebook.com/apps/ and register your app by following the instructions there and obtain your App ID and App Secret, and then update config.js with the information.
• Start your server and test your application. You can log in using Facebook by accessing https://localhost:3443/users/facebook which will redirect you to Facebook for authentication and return to your server.
• Conclusions

• Using the Facebook OAuth support to enable authentication of your users and allowing them access to your server.