在Firefox中发布端点404，在chrome中发布

Question

Following this quick guide ( React and PostgreSQL ), the following app should print the JSON fetch to the bash terminal (at ~37min of video).

However this does not happen. There is no feedback on the npm or nodemon servers.

When adding a value via the front-end, firefox instantly sends back a 404 status (observed in console:network). In chrome, the thread hangs as pending until the nodemon server is shut down (and then fails with a connection reset error)(again in console:network).

npm is running app and nodemon is running the server.

app.js

import React, { Component } from 'react';
import './App.css';

class App extends Component {
  constructor(props) {
        super();  
        this.state = {
          title: 'Simple postgres app',
          treatments: []
        }
  }

  componentDidMount(){
        console.log('COMPONENT HAS MOUNTED')
  }   

  addStuff(event){
    event.preventDefault()
    // console.log('in method');

    let data = {
            test_field: this.refs.test_field.value,
    };

    var request = new Request('http://localhost:3000/api/new-thing', {
            method: 'POST', 
            headers: new Headers({ 'Content-Type': 'application/json' }),
            body: JSON.stringify(data), 
            message: console.log('JSON output: ', JSON.stringify(data))
    }); 

    fetch(request)
      .then((response) => {
        response.json()
          .then((data) => {
            console.log(data)
          })
      })
  }

  render() {
    let title = this.state.title;
    return (
      <div className="App">
        <h1> { title } </h1>  
        <form ref = "testForm">
                        <input type="text" ref="test_field" placeholder="test_field"/> 
                        <button onClick={this.addStuff.bind(this)}>Add This</button>
                </form>
      </div>
    );
  }
}

export default App;

server.js

let express = require('express');
let bodyParser = require('body-parser');
let morgan = require('morgan');
let pg = require('pg');
const PORT = 3000;

// let pool = new pg.Pool({
//         port: 5432,
//         user: 'postgres',
//         password: 'postgres',
//         database: 'po1dev_v0.0.1',
//         max: 10, //max connections
//         host: 'localhost'
// })

let app = express();

app.use(bodyParser.json);
app.use(bodyParser.urlencoded({ extended:true }));

app.use(morgan('dev')); 

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

// app.post('/api/new-thing', (request,response) => {
//     console.log(request.body)
// })
app.post('/api/new-thing', function(request,response){
    console.log(request.body);
})

app.listen(PORT, () => console.log('Listening on port ' + PORT));

Any ideas on what may be causing the 404/hang problems in firefox/chrome and how to go about fixing it?

Cheers

Answer 1

That's because the route you're creating doen't return any response so it waits indefinitely for a response then gets timed out.

The route should return some response,

app.post('/api/new-thing', function(request,response){
    console.log(request.body);
    return response.json({"data": "Hello World"})
})

Which will return the {"data": "Hello World"} from the /api/new-thing route.

Also, bodyParser.json is a function not property. Change it to

app.use(bodyParser.json())

If you are using create-react-app try another port for the backend server. Because by default it uses 3000 for the react app.