无法将数据从React Js发布到Node js

Question

我无法将我的数据从React Js发布到Node Js，我一直在寻找几种资源，但无法解决

这是我完整的代码。

这是我的反应文件“ Register.js”，运行在端口3000（http://localhost:3000/register）

import React, { Component } from 'react';
import axios from 'axios';

class Register extends Component {
  //takes user input
  constructor(){
    super();
    this.state={
      name:'',
      email:'',
      password:'',
      password2:'',
      errors:{}
    }
    //joins it to onChange fun
    this.onChange=this.onChange.bind(this);
    this.onSubmit=this.onSubmit.bind(this);
  }

  onChange(e){
    this.setState({[e.target.name]:e.target.value});

  }
  onSubmit(s){
    s.preventDefault();

    const newUser={
      name:this.state.name,
      email:this.state.email,
      password:this.state.password,
      password2:this.state.password2
    }

    axios.post('/api/users/register',newUser)
    .then(res=> console.log(res.data))
    .catch(err=>console.log(err.response.data));
    }
  render() {
    return (

        <div className="home">


    <div className="dark-overlay landing-inner text-light">
      <div className="container">


        <div className="row">
          <div className="col-md-12 text-center">
               <h1 className="display-4 text-center">Sign Up</h1>
               <p className="lead text-center">Create your Profile and start getting noticed by Employers!</p>

              <div className="form-group">
              <form onSubmit={this.onSubmit}>
                    <div className="form-group">
                            <input type="name" placeholder="Name" className="form-control" name="name" value={this.state.name} onChange={this.onChange}/>
                        </div>
                    <div className="form-group">
                        <input type="email" placeholder="Email" className="form-control" name="email" value={this.state.email} onChange={this.onChange}/>
                    </div>
                    <div className="form-group">
                            <input type="password" placeholder="Password" className="form-control" name="password" value={this.state.password} onChange={this.onChange} />
                    </div>
                    <div className="form-group">
                            <input type="password" placeholder=" Confirm Password" className="form-control" name="password2" value={this.state.password2} onChange={this.onChange}/>
                    </div>
                    <hr />
                    <input type="submit" className="btn btn-lg btn-success"/>
                    </form>


          </div>
        </div>
        </div>
      </div>
      </div>
    </div>



    )
  }
}

export default Register;

这是“ server.js”代码：

const express = require('express');
const mongoose = require('mongoose');
const bodyParser = require('body-parser');
const passport = require('passport');

const users=require('./routes/api/users');
const userprofile=require('./routes/api/userprofile');

const app=express();

//body parser middleware
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

//db config
const db = require('./config/keys').mongoURI;

//connecting to database
mongoose
  .connect(db)
  .then(() => console.log('mongo is successfully Connected'))
  .catch(err => console.log(err));

//passport middleware
app.use(passport.initialize());
//passsport config
require('./config/passport')(passport);

//testing the server
app.get('/',(req,res)=>res.send('working'));

//using routes for users and userprofile
app.use('/api/users',users);
app.use('/api/userprofile',userprofile);
//to connect to localhost
const port=process.env.PORT || 5000;

app.listen(port,()=> console.log('server running on ${port}'));

这是我的节点文件'users.js'，在端口5000上运行

const express = require('express');
const router = express.Router();
const bcrypt = require('bcryptjs');
const jwt = require('jsonwebtoken');
const keys = require('../../config/keys');
const passport = require('passport');

//bringing input validation
const validatingregister=require('../../validation/register');
const validatingrlogin=require('../../validation/login');


//loading User schema
const User=require('../../models/User');
router.get('/demo', (req, res) => res.json({ msg: 'user api Works' }));

//will check email address if exists or not
router.post('http://localhost:5000/api/users/register',(req,res)=>{
    const { errors, isValid } = validatingregister(req.body);
  // Checking Validation
  if (!isValid) {
    return res.status(400).json(errors);
  }

    User.findOne({email:req.body.email})
    .then(user=>{
        if(user){
            return res.status(400).json({email:"email already registered"});

        }
//if not then will create newuser
        else{
            const newUser=new User({
                name:req.body.name,
                email:req.body.email,
                password:req.body.password
            });
//bcrypt is for hashing the password of the user
            bcrypt.genSalt(10, (err, salt) => {
                bcrypt.hash(newUser.password, salt, (err, hash) => {
                  if (err) throw err;
                  newUser.password = hash;
                  newUser
                    .save()
                    .then(user => res.json(user))
                    .catch(err => console.log(err));
                });

            }
    )}
    })

})

//login route
router.post('/login', (req, res) => {
    const { errors, isValid } = validatingrlogin(req.body);
  // Check Validation for login
  if (!isValid) {
    return res.status(400).json(errors);
  }
    const email = req.body.email;
    const password = req.body.password;
//finding user by email
User.findOne({ email }).then(user => {
                //if no user with this email
                if(!user){
                    return res.status(400).json("No user with this email");
                }
                //checking pass
                bcrypt.compare(password, user.password).then(isMatch => {
                    if (isMatch) {
                      // User Matched
                      const payload = { id: user.id, name: user.name, avatar: user.avatar }; // Create JWT Payload

                      // Sign Token
                      jwt.sign(
                        payload,
                        keys.secretOrKey,
                        { expiresIn: 3600 },
                        (err, token) => {
                          res.json({
                            success: true,
                            token: 'Bearer ' + token
                          });
                        }
                      );
                    } 
                    else{
                        res.status(400).json({password:"incorrect password"});
                    }

                })
            });
        })

        router.get(
            '/current',
            passport.authenticate('jwt', { session: false }),
            (req, res) => {
              res.json({
                id: req.user.id,
                name: req.user.name,
                email: req.user.email
            });
})
module.exports = router;

我正在尝试注册用户，但出现错误：

    Unhandled Rejection (TypeError): Cannot read property 'data' of undefined
(anonymous function)
src/components/auth/Register.js:36
  33 |   
  34 |   axios.post('http://localhost:5000/api/users/register',newUser)
  35 |   .then(res=> console.log(res.data))
> 36 |   .catch(err=>console.log(err.response.data));
  37 |   }
  38 | render() {
  39 |   return (

Answer 1

从网络请求中您可以看到：

xhr.js:178 POST http://localhost:3000/api/users/register 404 (Not Found)

您正在将请求发送到localhost:3000。如前所述，您的节点服务器在端口5000上运行。这意味着您的请求应该发送到那里。

现在在这种情况下您有多种选择。

1）启用Cross-Origin Resource Sharing。 这样您就可以将请求从一个来源发送到另一个来源。

2）让您的Node服务器提供您的前端代码，这样您就无需处理单独的源了。

我个人更喜欢选项1，因为它可以帮助我分开关注点。

由于您使用快递，因此需要将其添加到服务器代码中：

app.use((req, res, next) => {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
});

有关启用CORS支票Enable CORS

的更多信息

您的客户代码（反应）应进行更新以调用正确的来源

onSubmit(s){
  // your code ...
  axios.post('//localhost:5000/api/users/register', newUser)
    .then(res=> console.log(res.data))
    .catch(err=>console.log(err.response.data));
  }
}