angular2 http.post() 到本地 json 文件

Question

little help?

I am trying to write pure JSON to a file inside my project, my project tree looks like this:

src
->app
-->components
--->people.component.ts
--->(other irrelevant components)
-->services
--->people.service.ts
-->data
--->JSON.json
->(other irrelevant src files)

The code in my people.component.ts is just used to call and subscribe to a function inside my people.service.ts , passing the newPerson property which is data-binded from the DOM using angular2 magic; this is the function inside name.service.ts :

public addPerson(newPerson) {
        let headers = new Headers();
        headers.append('Content-Type', 'application/json');
        return this.http.post('app/data/PEOPLE.json', newPerson, { header: headers })
        .map(res => res.json())
}

My objective is to write (if necessary replace) the newPerson property (or the entire file) inside PEOPLE.json . of course, the current addPerson() function returns an error.

I've also tried the put method, it errors slightly differently, but i haven't found solutions to either method.

I know categorically it's not an error with the format/type of data i'm trying to put in PEOPLE.json file.

Answer 1

Unfortunately, you can not PUT or POST directly to a file on your local filesystem using client side (browser) JavaScript.

Consider building a simple server to handle a POST request. If you are most comfortable with JavaScript, try Express with Node.js

// server.js
'use strict'

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

const app = express()
app.use(bodyParser.json());

app.use(function(req, res, next) {
  res.header('Access-Control-Allow-Origin', 'http://localhost:8000');
  res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
  res.header('Access-Control-Allow-Methods', 'POST');
  next();
});

app.post('/', (req, res) => {
  console.log('Received request');
  fs.writeFile('json.json', JSON.stringify(req.body), (err) => {
    if (err) throw err;
    console.log('File written to JSON.json');
    res.send('File written to JSON.json')
  })
});

app.listen(3000, ()=>{
  console.log('Listening on port 3000. Post a file to http://localhost:3000 to save to /JSON.json');
});

Answer 2

You cannot write to files from Browser. Period. Even if such action is possible it will be stored on User side, not your server. If your task is indeed to write something on user end, please refer to localStorage documentation (or couple other API implementations). But if you are going to user that file for some purpose outside of your browser, it will be non-trivial task.

If you want to save file on server, then you need to hande it on back end.