Google OAuth Passport Sample

gistfile1.txt

/**
 * Sign in with Google.
 */
passport.use(new GoogleStrategy({
  clientID: process.env.GOOGLE_ID,
  clientSecret: process.env.GOOGLE_SECRET,
  callbackURL: '/auth/google/callback',
  passReqToCallback: true
}, function(req, accessToken, refreshToken, profile, done) {

  if (req.user) {
    User.findOne({ google: profile.id }, function(err, existingUser) {
      if (existingUser) {
        req.flash('errors', { msg: 'There is already a Google account that belongs to you. Sign in with that account or delete it, then link it with your current account.' });
        done(err);
      } else {
        User.findById(req.user.id, function(err, user) {
          user.google = profile.id;
          user.tokens.push({ kind: 'google', accessToken: accessToken, refreshToken: refreshToken });
          user.profile.name = user.profile.name || profile.displayName;
          user.profile.gender = user.profile.gender || profile._json.gender;
          user.profile.picture = user.profile.picture || profile._json.image.url;
          user.save(function(err) {
            req.flash('info', { msg: 'Google account has been linked.' });
            done(err, user);
          });
        });
      }
    });
  } else {
    console.log(accessToken+" "+refreshToken);

    User.findOne({ google: profile.id }, function(err, existingUser) {
      if (existingUser) {
        return done(null, existingUser);
      }
      User.findOne({ email: profile.emails[0].value }, function(err, existingEmailUser) {
        if (existingEmailUser) {
          req.flash('errors', { msg: 'There is already an account using this email address. Sign in to that account and link it with Google manually from Account Settings.' });
          done(err);
        } else {
          var user = new User();
          user.email = profile.emails[0].value;
          user.google = profile.id;
          user.tokens.push({ kind: 'google', accessToken: accessToken, refreshToken: refreshToken });
          user.profile.name = profile.displayName;
          user.profile.gender = profile._json.gender;
          user.profile.picture = profile._json.image.url;
          user.save(function(err) {
            done(err, user);
          });
        }
      });
    });
  }
}));