将传递给猫鼬中间件 next() 方法的错误消息传递给客户端控制器

Question

我是 MEAN 堆栈的新手，所以请原谅我幼稚的问题，但我无法弄清楚如何将自定义错误消息从我的 Mongoose 预保存钩子中间件传递到我的 Angularjs 控制器。

我正在使用预保存钩子来检查以前是否保存过文档。如果有，那么我想取消保存尝试，而是更新文档。我使用了next(new Error('Error message'))方法来防止save操作。下面是我的代码：在我的后端：

VoteSchema.pre('save',function(next){
var self = this;
self.constructor.findOneAndUpdate(
{'choice._id':self.choice._id},
{$inc:{'choice.count':1}},
{new:true},
function(err,doc){
if(err) return next(err);
if(doc!==null){
//I want to be able to pass a type like this {x:1, y:2}
//to my angular controller from here. How do I do this?
return next(new Error("Canceled save attempt!")); //this cancels the save
} 
return next();
});
});

在我的客户端控制器上：

vote.$save(function (response) {
console.log(response);
},
function (errorResponse) {
//I want to get my custom type from the pre-save 
//middleware hook here which was equals to {x:1, y:2}
//or at least the message "Canceled save attempt!"
//Note that I checked the 'errorResponse' object but
//it isn't anywhere there
console.log(errorResponse);
}
);

换句话说，如何将自定义对象从猫鼬中间件(预保存钩子(传递给 Angular 控制器？

Answer 1

我在项目中所做的是，我创建了一个错误.js文件，并且还创建了许多可能的错误，当需要发送时，我只需要我的错误.js并发送错误，如以下代码：

错误.js：

var errors = {};
var util = require('util');
/**
* Used to create errors
* @Param {Number} httpCode - http response code
* @Param {String} message - Error message
*/
function ApiError(httpCode, httpMessage, description) {
this.httpCode = httpCode;
this.httpMessage = httpMessage;
this.description = description;
this.details = null;
}
// inherit the Error class
util.inherits(ApiError, Error);
// exporting error Object
module.exports = errors;
errors.ApiError = ApiError;
/**
* Sends httpCode and message to user
* @Param {Response} res - http response
*/
ApiError.prototype.send = function (res) {
res.status(this.httpCode);
res.json({ httpCode: this.httpCode, httpMessage: this.httpMessage, description: this.description, details: this.details })
}
ApiError.prototype.withDetails = function (details) {
this.details = details;
return this;
};
errors.not_registeration = new ApiError(404, 'NOT_REGISTERATION',
'User not registered with this email/mobile.');

errors.invalid_login = new ApiError(400, 'INVALID_LOGIN',
'Login credentials do not match any registered user.');

您可以在此处使用代码创建自己的错误，就像我已经创建的那样。

如何使用文件中的错误：

var errors = require('../../library/errors');
.....
.....
.....
VoteSchema.pre('save',function(next){
var self = this;
self.constructor.findOneAndUpdate(
{'choice._id':self.choice._id},
{$inc:{'choice.count':1}},
{new:true},
function(err,doc){
if(err) return next(err);
if(doc!==null){
return next(errors.not_registeration)  // Here  i am sending errors.
or
return next(errors.invalid_input.withDetails("This  is extra details"));
} 
return next();
});
});

每次响应都是：

如果返回下一个(errors.not_registeration(-

{
"httpCode": 404,
"httpMessage": "NOT_REGISTERATION",
"description": "User not registered with this email/mobile.",
"details": null
}

如果返回 next(errors.invalid_input.withDetails("这是额外的细节"((-

{
"httpCode": 400,
"httpMessage": "INVALID_INPUT",
"description": "The request input is not as expected by API. Please provide valid input.",
"details": "This  is extra details"
}

**据我了解，您希望将数据传递给下一个中间件。然后你可以在当前的中间件中执行此操作：

res.locals.result={ X:1,Y:1};

在下一个中间件中，您将能够获得这样的 X，Y：console.log(res.locals.result);您可以使用res.locals在下一个中间件中传递任何内容。