How is an HTTP POST request made in node.js?

Here's an example of using node.js to make a POST request to the Google Compiler API:

// We need this to build our post string
var querystring = require('querystring');
var http = require('http');
var fs = require('fs');

function PostCode(codestring) {
  // Build the post string from an object
  var post_data = querystring.stringify({
      'compilation_level' : 'ADVANCED_OPTIMIZATIONS',
      'output_format': 'json',
      'output_info': 'compiled_code',
        'warning_level' : 'QUIET',
        'js_code' : codestring
  });

  // An object of options to indicate where to post to
  var post_options = {
      host: 'closure-compiler.appspot.com',
      port: '80',
      path: '/compile',
      method: 'POST',
      headers: {
          'Content-Type': 'application/x-www-form-urlencoded',
          'Content-Length': Buffer.byteLength(post_data)
      }
  };

  // Set up the request
  var post_req = http.request(post_options, function(res) {
      res.setEncoding('utf8');
      res.on('data', function (chunk) {
          console.log('Response: ' + chunk);
      });
  });

  // post the data
  post_req.write(post_data);
  post_req.end();

}

// This is an async file read
fs.readFile('LinkedList.js', 'utf-8', function (err, data) {
  if (err) {
    // If this were just a small part of the application, you would
    // want to handle this differently, maybe throwing an exception
    // for the caller to handle. Since the file is absolutely essential
    // to the program's functionality, we're going to exit with a fatal
    // error instead.
    console.log("FATAL An error occurred trying to read in the file: " + err);
    process.exit(-2);
  }
  // Make sure there's data before we post it
  if(data) {
    PostCode(data);
  }
  else {
    console.log("No data to post");
    process.exit(-1);
  }
});

I've updated the code to show how to post data from a file, instead of the hardcoded string. It uses the async fs.readFile command to achieve this, posting the actual code after a successful read. If there's an error, it is thrown, and if there's no data the process exits with a negative value to indicate failure.

Simple and dependency-free. Uses a Promise so that you can await the result. It returns the response body and does not check the response status code.

const https = require('https');

function httpsPost({body, ...options}) {
    return new Promise((resolve,reject) => {
        const req = https.request({
            method: 'POST',
            ...options,
        }, res => {
            const chunks = [];
            res.on('data', data => chunks.push(data))
            res.on('end', () => {
                let resBody = Buffer.concat(chunks);
                switch(res.headers['content-type']) {
                    case 'application/json':
                        resBody = JSON.parse(resBody);
                        break;
                }
                resolve(resBody)
            })
        })
        req.on('error',reject);
        if(body) {
            req.write(body);
        }
        req.end();
    })
}

Usage:

async function main() {
    const res = await httpsPost({
        hostname: 'sentry.io',
        path: `/api/0/organizations/org/releases/${changesetId}/deploys/`,
        headers: {
            'Authorization': `Bearer ${process.env.SENTRY_AUTH_TOKEN}`,
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({
            environment: isLive ? 'production' : 'demo',
        })
    })
}

main().catch(err => {
    console.log(err)
})

You can use request library. https://www.npmjs.com/package/request

var request = require('request');

To post JSON data:

var myJSONObject = { ... };
request({
    url: "http://josiahchoi.com/myjson",
    method: "POST",
    json: true,   // <--Very important!!!
    body: myJSONObject
}, function (error, response, body){
    console.log(response);
});

To post xml data:

var myXMLText = '<xml>...........</xml>'
request({
    url: "http://josiahchoi.com/myjson",
    method: "POST",
    headers: {
        "content-type": "application/xml",  // <--Very important!!!
    },
    body: myXMLText
}, function (error, response, body){
    console.log(response);
});

---

EDIT: As of February 2020 request has been deprecated.

request is now deprecated. It is recommended you use an alternative

In no particular order and dreadfully incomplete:

• native HTTP/S, const https = require('https');
• node-fetch
• axios
• got
• superagent
• bent
• make-fetch-happen
• unfetch
• tiny-json-http
• needle
• urllib

Stats comparision Some code examples

Original answer:

This gets a lot easier if you use the request library.

var request = require('request');

request.post(
    'http://www.yoursite.com/formpage',
    { json: { key: 'value' } },
    function (error, response, body) {
        if (!error && response.statusCode == 200) {
            console.log(body);
        }
    }
);

Aside from providing a nice syntax it makes json requests easy, handles oauth signing (for twitter, etc.), can do multi-part forms (e.g. for uploading files) and streaming.

To install request use command npm install request