在你的验证回调中，我会改变一切 findOrCreateUser 函数将实际记录提供给回调，然后将其传递到 done（），如此：

In your verify callback, I would change things up so that the findOrCreateUser function supplies the actual record to the callback, and then pass that through to done(), like so:

Models_User.findOrCreateUser(profile, function(user){
  console.log("auth type:" + msg);
  return done(null, user);
});

// take this out, use the actual model above
//return done(null, profile);

现在，在验证后处理回调URL时，您可以检查此用户记录，看看是否new（我假设它有一个isNew属性在这里）：

Now, when handling the callback URL after authentication, you can check this user record and see if it was new (I'm assuming it has an isNew property here):

app.get('/auth/github/callback', 
  passport.authenticate('github', { failureRedirect: '/login' }),
  function(req, res) {
    // successful auth, user is set at req.user.  redirect as necessary.
    if (req.user.isNew) { return res.redirect('/back_again'); }
    res.redirect('/welcome');
  });