NodeJS在下一个请求之前等待HTTP响应

Question

I'm totally failing with my NodeJS code. I need to make a HTTP Request to an REST API - that API sends me a new URL as response. After receiving that URL, I need to make an Request to that URL and so on.

I'm using the

var request = require('request');

package. The response looks like this:

{
    "nextURL": "http:// ..."
}

How can I do this? I'm new to the NodeJS world but I already have a lot of experience with JavaScript. So therefore it shouldn't be a big problem for me.

I heard and read something about Promises but I don't know if that's the right thing for that. Please help me!

Answer 1

Igues u can make it like this

const request = require('request');

    request('https://api.xxx', { json: true }, (err, 
    res, body) => {
      if(response.statusCode === 200) {

         nextUrl(body['nextURL']);
      }

      else (err) {
       return console.log(err); 
      }

    });

    function nextUrl(url){
       request(url, { json: true }, (err, 
       res, body) => {
      if(response.statusCode === 200) {

        //your logic
      }

      else (err) {
       return console.log(err); 
      }

      });
    }

Answer 2

I think you are looking for this

A Promise is a proxy for a value not necessarily known when the promise is created. It allows you to associate handlers to an asynchronous action's eventual success value or failure reason. This lets asynchronous methods return values like synchronous methods: instead of the final value, the asynchronous method returns a promise for the value at some point in the future.

var request = require('request-promise');

var baseUrl = 'http://111.111.111.111:8080';

request.post(baseUrl + '/api/auth/login')
.then(function(body) {
    console.log("login OK: " + body);
}).then(function() {
    return request.post(baseUrl + '/api/auth/login'); // <-- inside a function
}).then(function(body) {
    console.log("login OK again: " + body);
}).catch(function (err) {
    console.error(err);
});

Answer 3

I would suggest that you use promisified http client such as axios in the following form

const axios = require('axios');
axios.get('firstURL')
     .then(firstRes=>{
           return axios.get(firstRes.data.nextURL)
     })
     .then(secondRes=>{
           console.log(secondRes.data)
     })
     .catch(err=>{

     console.log('something went wrong', err);

   })