检查是否使用了用户名-PassportJS [英] Check if username is taken - PassportJS

问题描述

我需要在用户创建帐户之前检查用户名是否未占用.我正在尝试使用AJAX和通行证构建一个一页应用程序.

I am needing to check that the username is not taken before a user creates an account. I am attempting to build a one page application with AJAX and passport.

当用户使用护照进行注册时，我该如何检查是否在发布之前取走了用户名?

How would I go about checking to see if the username is taken BEFORE posting when a user is registering using passport?

不确定从哪里开始.

谢谢！

app.post("/quiz", function(req, res){

    var newUser = new User({username: req.body.username, datapoint: req.body.datapoint});
    User.register(newUser, req.body.password, function(err, user){


        // if(res.error){

          if(err){
            req.flash("error", err.message);
            res.redirect('back')
            return res.render("quiz");

        } else {

        passport.authenticate("local")(req, res, function(){
        //   req.flash("success", "Welcome to JobQuiz " + user.username);
          res.redirect("jobquiz");
          console.log(req.body.datapoint)
        });
        }
    });

});

推荐答案

使用findOne函数首先查找用户是否存在.如果用户存在，那么您就可以返回错误

First find if the user exists using findOne function. If user exists then you can just return an error

app.post("/quiz", function(req, res){
    User.findOne({username: req.body.username}, function(err, user){
       if(err) {//error handling... }
       if(user) { //user already exists. throw error accordingly}

       //continue with your registration logic
       var newUser = new User({username: req.body.username, datapoint: req.body.datapoint});
         User.register(newUser, req.body.password, function(err, user){


        // if(res.error){

             if(err){
               req.flash("error", err.message);
               res.redirect('back')
               return res.render("quiz");

           } else {

           passport.authenticate("local")(req, res, function(){
           //   req.flash("success", "Welcome to JobQuiz " + user.username);
             res.redirect("jobquiz");
             console.log(req.body.datapoint)
           });
           }
       });
    });


});

上面的代码在回调中处理.如果您想避免回调地狱，可以使用promises

The above code is handled in a callback. If you want to avoid callback hell you can use promises

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