我如何在Backbone.js的错误消息？ [英] How do I get the error messages in Backbone.js?

问题描述

我就在Backbone.js的方法成功/错误回调的问题。由于我是新来这个，我的问题似乎是简单的或类似的东西。

I got a question regarding success/error callbacks of the methods in Backbone.js. As I am new to this , my question might seem to be simple or something like that.

据我所知，保存（）或取（）模型火灾方法成功，如果没有的<​​em>错误的（比如除外）在服务器上。现在的问题是，我应该扔在服务器上的异常，以得到一个错误的在客户端的类型？让我给你我的意思的例子：

As far as I know, save() or fetch() methods of a model fires success, if there is no error (say, exception) on the server. The question is, should I throw an exception on the server in order to get the type of an error on the client side? Let me give you an example of what I mean:

我有创建应用程序的新用户，比如在网络上的UI。我的客户端会是这个样子：

I have a UI on the web which creates a new user for the app, for instance. My client-side would look something like this:

var userView = Backbone.View.extend({

   initialize:function(){ ... },
   events: {
     'click #sign_up': 'createAccount'
   },
    createAccount: function() { 
      login = $('#login').val();
      password = $('#password').val();
      var user = new User(); // User is a model
      user.save({login: login, password: password},{
            success: function(data) {
               if (data != null) {
                  alert('success');                       
               } else {
                   alert('fail');
               }

            },
            error : function() {
                alert('error');     
            }
   }
});

因此​​，服务器端将是：

Accordingly, server side would be:

@Controller
@RequestMapping("/users")
public class UsersController {

@RequestMapping(method = RequestMethod.POST)
public @ResponseBody User createUser(@RequestBody User user) throws Exception {


    if (user == null || !user.isValid()) {
        return null;// not valid - error message 1
    }
    if (userDao.getUserByLogin(user.getLogin()) != null) {
        return null;// such user already exists! - error message 2
    }

    userDao.saveUser(user);

    return user;
}

我想是能够相应地发送正确的错误信息是什么。如果我回到空，那么数据的成功在的回调将是模型，我刚刚打开填充之前发送请求。如果我抛出一个异常，那么它会火错误。在这一点上，我应该采取什么样的方式来满足我的需求。

What I want is being able to send proper error messages accordingly. If I return null, then the data inside success callback will be the model that I've just populated before send the request. If I throw an exception, then it will fire error. At this point, what approach should I take to meet my needs.

推荐答案

您不应该抛出异常。那么你可以，但你应该处理在服务器端异常，并只返回正确的HTTP codeS。

You should not throw an exception. Well you can but then you should handle the exception on the server-side and only return correct HTTP codes.

例如。

如果在服务器端没有找到用户，通常你返回404 HTTP状态code。 404将触发错误回调。

If a user is not found on the server side, normally you return a 404 HTTP Status Code. 404 will fire the error callback.

错误回调在个案多个参数，你要传递的服务器（如错误​​消息）上的一些数据。根据文档：

The error call back has multiple arguments in case you want to pass some data on the server (like error message). According to docs:

"error" (model, xhr, options) — when a model's save call fails on the server.

您可以在XHR对象访问的错误消息。

You can access the error message in xhr object.

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