在Express / Angular中调用Post请求两次（不确定是express还是angular）

Question

这是我的角色代码

组件

    onSubmit(formValue: any) {
        console.log("Form Value = " + JSON.stringify(formValue, null, 4));
        let newRegisterdUser = {
            firstName : formValue.firstName,
            lastName : formValue.lastName,
            email : formValue.email,
            password : formValue.password,
            phone : formValue.phone,
            location : formValue.location
        };
        console.log('Registered user in Angular : '+JSON.stringify(newRegisterdUser, null, 4));
        this._registrationService.saveRegisteredUser(newRegisterdUser).subscribe(
            (test : any)=> this.router.navigate(['registrationsuccess']),
            err => console.log(err)
          );
      }

服务

import { Injectable } from "@angular/core";
import { HttpClient, HttpClientModule } from '@angular/common/http';
import { Router } from '@angular/router';

@Injectable()
export class RegistrationService{

    constructor(private _http : HttpClient){}

    saveRegisteredUser(newRegisterdUser : any){
      console.log('test user : '+newRegisterdUser.firstName);
      return this._http.post('http://localhost:3000/register/save',newRegisterdUser);
    }
}

快递代码

var RegisteredUserApi = require('../data/FoodCourtApi');
var express = require('express');
var router = express.Router();

router.get('/', function(req,res){
    res.json({Hi : 'karthik'}); 
});

router.post('/save', function (req, res) {
    var registeredUser = {};
    registeredUser.firstName = req.body.firstName;
    registeredUser.lastName = req.body.lastName;
    registeredUser.email = req.body.email;
    registeredUser.password = req.body.password;
    registeredUser.phone = req.body.phone;
    registeredUser.location = req.body.location;
   // console.log('Registered user in Node : '+JSON.stringify(registeredUser, null, 4));
    RegisteredUserApi.saveRegisteredUser(registeredUser, function (err, registeredUser) {
        // res.end();
        if(err){
            console.log('Hii');
            console.log(err);
            res.status(500).json({ error: "save failed", err: err});    
        }else{
            res.json([{ statusSave: 'success' }]);
        }
    });
});

MongoDB - API代码

var RegisteredUserApi = {
    saveRegisteredUser: function(registeredUser, callback) {
        var newUser = new RegisteredUser(registeredUser);
        newUser.save({}, function (err, registeredUser) {
            if (err) {
                return console.log(err);
            } else {
               return console.log('RegisteredUser inserted successfully.....!!!');
            }
        });
    }
}

触发两个网络呼叫，一个使用OPTIONS，另一个使用POST。选项网络呼叫状态代码为204，没有请求有效负载且没有响应内容。 POST网络呼叫正在接收请求有效负载，并在一段时间后（大多数在3分钟后）失败。但是在后端（Node＆amp; Mongo）中，我看到正在插入2倍的记录。

Answer 1

在

saveRegisteredUser: function(regis... 

保存用户后需要调用callback函数。

而不是return console.log(err);和return console.log('RegisteredUser inserted successfully.....!!!');中的console.log使用callback(....)

您的快递应用根本没有回复/save路线的任何请求。此代码res.status(500).json({ error..或此res.json([{ statu....均未被调用。

var RegisteredUserApi = {
    saveRegisteredUser: function(registeredUser, callback) {
        var newUser = new RegisteredUser(registeredUser);
        newUser.save({}, function (err, registeredUser) {
            if (err) {
                return callback(err);  // <---
            } else {
               return callback('RegisteredUser inserted successfully.....!!!'); // <---
            }
        });
    }
}