node.js http 'get' request with query string parameters

No need for a 3rd party library. Use the nodejs url module to build a URL with query parameters:

const requestUrl = url.parse(url.format({
    protocol: 'https',
    hostname: 'yoursite.com',
    pathname: '/the/path',
    query: {
        key: value
    }
}));

Then make the request with the formatted url. requestUrl.path will include the query parameters.

const req = https.get({
    hostname: requestUrl.hostname,
    path: requestUrl.path,
}, (res) => {
   // ...
})

If you don't want use external package , Just add the following function in your utilities :

var params=function(req){
  let q=req.url.split('?'),result={};
  if(q.length>=2){
      q[1].split('&').forEach((item)=>{
           try {
             result[item.split('=')[0]]=item.split('=')[1];
           } catch (e) {
             result[item.split('=')[0]]='';
           }
      })
  }
  return result;
}

Then , in createServer call back , add attribute params to request object :

 http.createServer(function(req,res){
     req.params=params(req); // call the function above ;
      /**
       * http://mysite/add?name=Ahmed
       */
     console.log(req.params.name) ; // display : "Ahmed"

})

I have been struggling with how to add query string parameters to my URL. I couldn't make it work until I realized that I needed to add ? at the end of my URL, otherwise it won't work. This is very important as it will save you hours of debugging, believe me: been there...done that.

Below, is a simple API Endpoint that calls the Open Weather API and passes APPID, lat and lon as query parameters and return weather data as a JSON object. Hope this helps.

//Load the request module
var request = require('request');

//Load the query String module
var querystring = require('querystring');

// Load OpenWeather Credentials
var OpenWeatherAppId = require('../config/third-party').openWeather;

router.post('/getCurrentWeather', function (req, res) {
    var urlOpenWeatherCurrent = 'http://api.openweathermap.org/data/2.5/weather?'
    var queryObject = {
        APPID: OpenWeatherAppId.appId,
        lat: req.body.lat,
        lon: req.body.lon
    }
    console.log(queryObject)
    request({
        url:urlOpenWeatherCurrent,
        qs: queryObject
    }, function (error, response, body) {
        if (error) {
            console.log('error:', error); // Print the error if one occurred

        } else if(response && body) {
            console.log('statusCode:', response && response.statusCode); // Print the response status code if a response was received
            res.json({'body': body}); // Print JSON response.
        }
    })
})  

Or if you want to use the querystring module, make the following changes

var queryObject = querystring.stringify({
    APPID: OpenWeatherAppId.appId,
    lat: req.body.lat,
    lon: req.body.lon
});

request({
   url:urlOpenWeatherCurrent + queryObject
}, function (error, response, body) {...})

If you ever need to send GET request to an IP as well as a Domain (Other answers did not mention you can specify a port variable), you can make use of this function:

function getCode(host, port, path, queryString) {
    console.log("(" + host + ":" + port + path + ")" + "Running httpHelper.getCode()")

    // Construct url and query string
    const requestUrl = url.parse(url.format({
        protocol: 'http',
        hostname: host,
        pathname: path,
        port: port,
        query: queryString
    }));

    console.log("(" + host + path + ")" + "Sending GET request")
    // Send request
    console.log(url.format(requestUrl))
    http.get(url.format(requestUrl), (resp) => {
        let data = '';

        // A chunk of data has been received.
        resp.on('data', (chunk) => {
            console.log("GET chunk: " + chunk);
            data += chunk;
        });

        // The whole response has been received. Print out the result.
        resp.on('end', () => {
            console.log("GET end of response: " + data);
        });

    }).on("error", (err) => {
        console.log("GET Error: " + err);
    });
}

Don't miss requiring modules at the top of your file:

http = require("http");
url = require('url')

Also bare in mind that you may use https module for communicating over secured network.

const { URL } = require('url');
const reqUrl = new URL(req.url, `http://${req.headers.host}`);
const query = reqUrl.searchParams;