HTTP GET Request in Node.js Express

HTTP GET Request in Node.js Express

How can I make an HTTP request from within Node.js or Express.js? I need to connect to another service. I am hoping the call is asynchronous and that the callback contains the remote server’s response.

Solutions/Answers:

Solution 1:

Here is a snippet of some code from a sample of mine. It’s asynchronous and returns a JSON object. It can do any form of GET request.

Note that there are more optimal ways (just a sample) – for example, instead of concatenating the chunks you put into an array and join it etc… Hopefully, it gets you started in the right direction:

const http = require('http');
const https = require('https');

/**
 * getJSON:  RESTful GET request returning JSON object(s)
 * @param options: http options object
 * @param callback: callback to pass the results JSON object(s) back
 */

module.exports.getJSON = (options, onResult) => {
  console.log('rest::getJSON');
  const port = options.port == 443 ? https : http;

  let output = '';

  const req = port.request(options, (res) => {
    console.log(`${options.host} : ${res.statusCode}`);
    res.setEncoding('utf8');

    res.on('data', (chunk) => {
      output += chunk;
    });

    res.on('end', () => {
      let obj = JSON.parse(output);

      onResult(res.statusCode, obj);
    });
  });

  req.on('error', (err) => {
    // res.send('error: ' + err.message);
  });

  req.end();
};

It’s called by creating an options object like:

const options = {
  host: 'somesite.com',
  port: 443,
  path: '/some/path',
  method: 'GET',
  headers: {
    'Content-Type': 'application/json'
  }
};

And providing a callback function.

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For example, in a service, I require the REST module above and then do this:

rest.getJSON(options, (statusCode, result) => {
  // I could work with the resulting HTML/JSON here. I could also just return it
  console.log(`onResult: (${statusCode})\n\n${JSON.stringify(result)}`);

  res.statusCode = statusCode;

  res.send(result);
});

UPDATE

If you’re looking for async/await (linear, no callback), promises, compile time support and intellisense, we created a lightweight HTTP and REST client that fits that bill:

Microsoft typed-rest-client

Solution 2:

Try using the simple http.get(options, callback) function in node.js:

var http = require('http');
var options = {
  host: 'www.google.com',
  path: '/index.html'
};

var req = http.get(options, function(res) {
  console.log('STATUS: ' + res.statusCode);
  console.log('HEADERS: ' + JSON.stringify(res.headers));

  // Buffer the body entirely for processing as a whole.
  var bodyChunks = [];
  res.on('data', function(chunk) {
    // You can process streamed parts here...
    bodyChunks.push(chunk);
  }).on('end', function() {
    var body = Buffer.concat(bodyChunks);
    console.log('BODY: ' + body);
    // ...and/or process the entire body here.
  })
});

req.on('error', function(e) {
  console.log('ERROR: ' + e.message);
});

There is also a general http.request(options, callback) function which allows you to specify the request method and other request details.

Solution 3:

Request and Superagent are pretty good libraries to use.

Using request:

var request=require('request');

request.get('https://someplace',options,function(err,res,body){
  if(err) //TODO: handle err
  if(res.statusCode !== 200 ) //etc
  //TODO Do something with response
});

Solution 4:

You can also use Requestify, a really cool and very simple HTTP client I wrote for nodeJS + it supports caching.

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Just do the following for GET method request:

var requestify = require('requestify');

requestify.get('http://example.com/api/resource')
  .then(function(response) {
      // Get the response body (JSON parsed or jQuery object for XMLs)
      response.getBody();
  }
);

Solution 5:

This version is based on the initially proposed by bryanmac function which uses promises, better error handling, and is rewritten in ES6.

let http = require("http"),
    https = require("https");

/**
 * getJSON:  REST get request returning JSON object(s)
 * @param options: http options object
 */
exports.getJSON = function(options)
{
    console.log('rest::getJSON');
    let reqHandler = +options.port === 443 ? https : http;

    return new Promise((resolve, reject) => {
        let req = reqHandler.request(options, (res) =>
        {
            let output = '';
            console.log('rest::', options.host + ':' + res.statusCode);
            res.setEncoding('utf8');

            res.on('data', function (chunk) {
                output += chunk;
            });

            res.on('end', () => {
                try {
                    let obj = JSON.parse(output);
                    // console.log('rest::', obj);
                    resolve({
                        statusCode: res.statusCode,
                        data: obj
                    });
                }
                catch(err) {
                    console.error('rest::end', err);
                    reject(err);
                }
            });
        });

        req.on('error', (err) => {
            console.error('rest::request', err);
            reject(err);
        });

        req.end();
    });
};

As a result you don’t have to pass in a callback function, instead getJSON() returns a promise. In the following example the function is used inside of an ExpressJS route handler

router.get('/:id', (req, res, next) => {
    rest.getJSON({
        host: host,
        path: `/posts/${req.params.id}`,
        method: 'GET'
    }).then(({status, data}) => {
        res.json(data);
    }, (error) => {
        next(error);
    });
});

On error it delegates the error to the server error handling middleware.

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Solution 6:

Unirest is the best library I’ve come across for making HTTP requests from Node. It’s aiming at being a multiplatform framework, so learning how it works on Node will serve you well if you need to use an HTTP client on Ruby, PHP, Java, Python, Objective C, .Net or Windows 8 as well. As far as I can tell the unirest libraries are mostly backed by existing HTTP clients (e.g. on Java, the Apache HTTP client, on Node, Mikeal’s Request libary) – Unirest just puts a nicer API on top.

Here are a couple of code examples for Node.js:

var unirest = require('unirest')

// GET a resource
unirest.get('http://httpbin.org/get')
  .query({'foo': 'bar'})
  .query({'stack': 'overflow'})
  .end(function(res) {
    if (res.error) {
      console.log('GET error', res.error)
    } else {
      console.log('GET response', res.body)
    }
  })

// POST a form with an attached file
unirest.post('http://httpbin.org/post')
  .field('foo', 'bar')
  .field('stack', 'overflow')
  .attach('myfile', 'examples.js')
  .end(function(res) {
    if (res.error) {
      console.log('POST error', res.error)
    } else {
      console.log('POST response', res.body)
    }
  })

You can jump straight to the Node docs here