Multiple Requests with Request (Node.js)

__request

var request = require('request')

/**
 * Handle multiple requests at once
 * @param urls [array]
 * @param callback [function]
 * @requires request module for node ( https://github.com/mikeal/request )
 */
var __request = function (urls, callback) {

	'use strict';

	var results = {}, t = urls.length, c = 0,
		handler = function (error, response, body) {

			var url = response.request.uri.href;

			results[url] = { error: error, response: response, body: body };

			if (++c === urls.length) { callback(results); }

		};

	while (t--) { request(urls[t], handler); }
};

example

/* 
* How to use __request()
* step by step
*/

// create an array of URLs
var urls = ["http://www.example.com/firts", "http://www.example.com/second", "http://www.example.com/third"];

// execute the request
// and assign a callback
__request(urls, function(responses) {

	// When all the requests are ready
	// this callback will be called
	// you will get an argument, is
	// a map with all the responses
	// of the request you made,
	// something like this:
	/*
		responses = {
			"http://www.example.com/firts": {
				error: [object Object],
				response: [object Object],
				body: [object Object]
			},
			"http://www.example.com/second": {
				error: [object Object],
				response: [object Object],
				body: [object Object]
			},
			"http://www.example.com/third": {
				error: [object Object],
				response: [object Object],
				body: [object Object]
			}
		}
	*/


	// Acces to a response:

	// direct reference
	var first_response = response["http://www.example.com/first"];
		// check for errors of the first response
		console.log(first_response.error);
		// access to the body of the first response
		console.log(first_response.body);

	// also you can reuse the reference on the original array
	var first_response = response[urls[0]];


	// Iterate responses:

	// You can simply iterate all responses
	// to find errors or process the response
	var url, response;

	for (url in responses) {
		// reference to the response object
		response = responses[url];

		// find errors
		if (response.error) {
			console.log("Error", url, response.error);
			return;
		}

		// render body
		if (response.body) {
			console.log("Render", url, response.body);
		}
	}

});

this works, i wouldn't use arguments.callee tho.

you might want to check out async or another flow control library, that have more generic APIs for handling this kind of stuff, but if this works for you it looks fine.

Thanks for the feedback, I've made some changes according to JSLint parser and your suggestions.

Great Gist. Is there any chance you could show an example of how this looks in an actual request? Having trouble figuring out the syntax and/or format. Right now I'm storing my urls in an array like this:

var URLStoRequest = [http://www.foo1.com, http://www.foo2.com]
//executing
request({
uri:URLStoRequest
},
callback function

@sushidub I've created an example file, check it out and let me know if you need any help.

sweet. I'll give it a shot

Natos - It works! I understood what was happening in the Gist but the example clears up a few ambiguities. Very helpful. Thanks for the quick reply.

Cool, let me know if you need more hints.

I've got something error like this, any idea?

var first_response = response["http://cookingdiets.com"];
                                 ^
TypeError: Cannot read property 'http://cookingdiets.com' of undefined

ah, seems like in your example gist #43 you need to replace response with responses :)

What if the url is not reachable or if the url doesn't exists. Then how will we come to know that which url was not reachable because in that that case we get response as undefined.

When I use request 2.66, it can't find response.request

Unfortunately doesn't work. My code is this -

      var links              = [urls.singleMovieInfo +body.results[0].id+'?api_key='+apiKey,
                                urls.singleMovieInfo +body.results[0].id+'/credits?api_key='+apiKey,
                                urls.nowPlaying +apiKey];
        request(links, function(err, responses){
            if(err){
              console.log(err);
            } else {
              console.log(responses);

It gives me the Error: options.uri is a required argument.

Cool @natos

I re-wrote a promised version, check it out here: https://gist.github.com/serganus/ebea6717ce92df88061b0b96bef7c63e

Nice work 👍

Hi,

I have multiple GET/POST API's and in that i have to set the body, header content-type and then I need to post it with http method.
Can you please share an example how this could be done.
var options = { method: 'POST',
url: 'http://sdsdksdlas.com/api',
headers:
{
'content-type': 'application/json' },
body:
{ header: 'networork=verizon,asnum=1sfa000+11dasd6,location_id=0',
ip: 'NULL' },
json: true };

$http(options, function (error, response, body) {
console.log('Response code: ' + response.statusCode);

        if (!error && response.statusCode == 200) {
          console.log('GET authentication was successful');                 
          console.log(body);
        }
        else
        {
            console.log('GET failed');
            throw new Error(response.statusCode + ' response code received');
        }

});

how if the process is post and contain json file?

how if the process is post and contain json file?

Change:
while (t--) { request(urls[t], handler); }
to
while (t--) { request(urls[t], { json: true }, handler); }

and:

if (response.body) {
                        console.log("Render", url, response.body);
 }

to:

if (response.body) {
                       Object.keys(response.body).forEach(e => result=`${response.body[e]}`);
                        console.log(result);
}