ASYNC/AWAIT for Chaining multiple http.requests

Question

How would I go about chaining an http.request within the response of another http.request and then push them into an array before going to the front end?

router.get("/:team", (req, res) => {


  let teamParams = teams[req.params.team];
  twitter.get("search/tweets", teamParams, (err, data, resp) => {
    let tweetArr = [];
    let text = data.statuses;
    text.map((dat) => {
      let im = dat.entities.urls[0].url
      dat.links = im;
      tweetArr.push(dat);
    });
  

   res.json({ message: "Success", tweets: tweetArr });
  });
});

Currently I get my data object loop through it and add a url as a property. Now I want to chain another http request to make an API call to another API and get a response, before I use res.json. I've tried a workaround with promises but I can never return the full object with the response from the second api call.

This is what I have so far, I have managed to get to a point where my object contains the requests from the second link. How can I return all the tweets into an array I can finally resolve?

require("dotenv").config();
const Twitter = require("twitter");
const API_IMAGE_PREV = "http://api.linkpreview.net/";
const request = require("request");
const key = process.env.IM_PREV_KEY;

let twitter = new Twitter({
  consumer_key: process.env.TWITTER_CONSUMER_KEY,
  consumer_secret: process.env.TWITTER_CONSUMER_SECRET,
  bearer_token: process.env.TWITTER_BEARER_TOKEN
});
let teamParams = {
  q: "from:ManUtdMEN MUFC",
  count: 2,
  result_type: "recent"
};


var third = function thirdUrl(next) {
  var promise = new Promise(function(resolve, reject) {
    next.forEach(x => {
      let ln = x.links;
      const options = {
        url: "http://api.linkpreview.net/?key=" + key + "&q=" + ln,
        method: "get"
      };
      request.get(options, (err, req, res) => {
        if (err) {
          console.log(err);
        } else {
          x.desc = res;
        }
      });
    });
  });
};

var second = function secondUrl(previous) {
  var promise = new Promise(function(resolve, reject) {
    let p = previous.statuses;
    let links = [];
    p.forEach(t => {
      let l = t.entities.urls[0].url;
      t.links = l;
    });

    resolve(p);
  });
  return promise;
};

twitter
  .get("search/tweets", teamParams)
  .then(second)
  .then(third)
  .catch(function(error) {
    throw error;
  });

What other requests are you looking to make? Presumably one per URL being fetched out each Tweet? — James
– James, Commented Jul 9, 2018 at 22:09
Yup just the one for each tweet, i’m sending it through to another API to generate a preview — Pari Baker
– Pari Baker, Commented Jul 9, 2018 at 22:20
Ok so after we've fetched info from each tweet, what goes into the response to the client? This should be fairly trivial to write using async / await — James
– James, Commented Jul 9, 2018 at 22:23
Well the res.json at the moment just sends the full tweet object plus the added link that I want to make the subsequent request on, but then once angular picks it up for the time being I just have card with the tweet ID created date the text and that link. — Pari Baker
– Pari Baker, Commented Jul 9, 2018 at 22:27
The second API I want to pass that dat.link to, will follow the link and return an object with the title, a short description, a url and an image. So ideally I would present my user with the image A title, description and the user’s tweet — Pari Baker
– Pari Baker, Commented Jul 9, 2018 at 22:29

user835611 · Accepted Answer · 2018-07-09 23:22:39Z

1

What module are you using for the http requests? Here's an example with axios.

const axios = require('axios');

router.get("/:team", (req, res) => {
  let teamParams = teams[req.params.team];
  twitter.get("search/tweets", teamParams, async (err, data, resp) => {
    let tweetArr = [];
    let text = data.statuses;
    text.map((dat) => {
      let im = dat.entities.urls[0].url
      dat.links = im;
      tweetArr.push(dat);
    });
    let res = await Promise.all(tweetArr.map(dat => axios.get(dat.links));
    res.json({ message: "Success", tweets: res });
  });
})

answered Jul 9, 2018 at 23:22

user835611

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4 Comments

Pari Baker Over a year ago

Was just using the requests library and express Js, but I could try axios. I will let you know how it goes.

user835611 Over a year ago

Then you need to promisify request as it does not return promises by default

Pari Baker Over a year ago

getting this error, ReferenceError: tweetArr is not defined

Pari Baker Over a year ago

is that because I need to promisify first?

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