Node EventEmitter manage listener pool - node.js

I'm trying to notify periodically all clients about changes in sports matches, for which I use Eventemitter in node. The notification works fine, the issue I have is that if the client closes/refreshes the browser window, I should remove the listener on the server and decrease the pool of listeners, otherwise I could easily bump into memory leak warnings.
Code:
const EventEmitter = require('events');
const Stream = new EventEmitter();
exports.getScheduleUpdates = async (req, res) => {
res.writeHead(200, {
'Content-Type': 'text/event-stream',
'Cache-Control': 'no-cache',
Connection: 'keep-alive'
});
Stream.on('push', (data) => {
let isAlive = res.write(`data: ${JSON.stringify(data)}\n\n`);
if (!isAlive) {
console.log("Should terminate");
}
console.log(isAlive);
});
}
setInterval(() => {
Stream.emit('push', { match: 'sending some data' });
}, 10000);
When I run it locally and refresh the browser for example 2 times, the event fires for 3 clients, 2 of which are closed and the res.write returned false.
I got this far with the help of Google, but I can't figure out how to handle the listener pool for the event and remove them if the isAlive flag is false. Not 100% sure if relying on res.write return value is correct.
Thank you

In the end, I found this tutorial:
https://alligator.io/nodejs/server-sent-events-build-realtime-app/
Which ended up working well for my case.
let connectedClients = [];
exports.getScheduleUpdates = async (req, res) => {
res.writeHead(200, {
'Content-Type': 'text/event-stream',
'Cache-Control': 'no-cache',
Connection: 'keep-alive'
});
const clientId = Date.now();
const newclient = {
id: clientId,
res
}
connectedClients.push(newclient);
req.on('close', () => {
connectedClients = connectedClients.filter(c => c.id !== clientId);
});
}
function sendScheduleUpdates(changesToSend) {
connectedClients.forEach(client => {
client.res.write(`data: ${JSON.stringify(changesToSend)}\n\n`);
});
}
setInterval(() => {
sendScheduleUpdates([{ match: 'sending some data' }]);
}, 10000);
Closing of old, unused responses is done in res.on('close', () => {...}) part.

Related

server sent events: how to detect client disconnection from Node.js server

I've setup a simple server-sent-event for testing which sends data periodically once client gets connected. When client reloads the page or move to another page, browser closes the connection and stops receiving the events.
app.get("/stream", (req, res) =>{
res.writeHead(200, {
'Content-Type': 'text/event-stream',
'Cache-Control': 'no-cache',
'Connection': 'keep-alive'
});
const data = JSON.parse(fs.readFileSync("./data/group_list.json"))
let i = 0;
const intervalId = setInterval(function() {
++i;
console.log('iteration', i);
if ( i === 5 ) {
clearInterval(intervalId);
res.end();
return 1
}
res.write('data:' + JSON.stringify(data) + '\n\n');
res.flush();
}, 3000);
})
Here's my event handler in React.
handleSSE = () => {
console.log('here');
const url = "/test/stream"
//url can be your server url
if ('EventSource' in window) {
let source = new EventSource(url)
source.onopen = (e) => console.log('cnx successful', e);
source.onmessage = (e) => console.log('data-', JSON.parse(e.data));
source.onerror = (e) => {
console.log('cnx failed', e);
source.close();
};
}
}
The SSE only stops emitting the data once "i" reaches a certain number, I'd like the SSE to detect & stop emitting data when client closes the connection. what I specifically need is a way for setInterval() in my server to stop when the client closes the connection.
I think you need to add windows unload event inside handleSSE function for check the connection.
For that you need to add Event Listener of beforeunload inside handleSSE function.
So your final handleSSE function will be:
handleSSE = () => {
console.log('here');
const url = "/test/stream"
//url can be your server url
if ('EventSource' in window) {
let source = new EventSource(url)
source.onopen = (e) => console.log('cnx successful', e);
source.onmessage = (e) => console.log('data-', JSON.parse(e.data));
source.onerror = (e) => {
console.log('cnx failed', e);
source.close();
};
window.addEventListener("beforeunload", () => {
if (source.readyState !== EventSource.CLOSED) {
source.close();
}
});
}
}

Server Sent Event; `EventSource.onmessage` not firing

I'm trying to use the following example of Server Sent Events. Seems like the server is emitting the data, but the event is not firing and no data is recorded in the event stream (through the developer tools).
Angular code (service):
getAlertsEvent(fieldIds: Guid[]): Observable<responseModel.LoanAlert> {
return new Observable(obs => {
fieldIds.forEach(fieldId => {
const source = new EventSource(`http://localhost:3000/loan/alerts/${fieldId}`);
alert('Succesfully creates the EventSource, I see reuslt 200 in Networking tab but with 0 events');
source.onmessage = (ev): void => {
this.zone.run(() => {
alert('This alert will not happen');
obs.next(ev.data);
});
};
source.onerror = (err): void => this.zone.run(() => obs.error(err));
// Also tried this way with no luck:
// source.addEventListener('message', (event) => {
// obs.next(event.data);
// });
});
});
}
Component:
this.loansService.getAlertsEvent(this.fields.map(field => field.fieldId)).subscribe(alert => {
console.log(alert);
});
Node.js code:
const express = require('express');
const parser = require('body-parser');
const app = express();
const EventEmitter = require('events');
const Stream = new EventEmitter();
app.unsubscribe(parser.json());
app.use(
parser.urlencoded({
extended: true,
})
);
app.get('/loan/alerts/:fieldId', function(req, res) {
res.writeHead(200, {
'Content-Type': 'text/event-stream',
'Cache-Control': 'no-cache',
'Access-Control-Allow-Origin': "*",
Conection: 'keep-alive'
});
Stream.on(req.params.fieldId, function(event, data) {
res.write(JSON.stringify(data));
});
});
setInterval(function() {
const item = {
formId: 51415,
alertId: 'asdfasdfasdf',
messageStatus: 'NEW',
messageType: 'ACTION_MESSAGE_FROM_SERVER',
actionType: 'NAVIGATION',
message: 'New Message!',
archiverId: '12345',
documentCode: 3,
from: 'Internal Server Message',
messageTimestamp: new Date().toJSON(),
markedAsRead: false,
};
Stream.emit('aed29580-09fd-e411-b8e1-e61f13cf5d4b', 'message', item);
}, 5000);
app.listen(3000);
console.log('Express E2e Mock server is running');
When manually going to http://localhost:3000/loan/alerts/aed29580-09fd-e411-b8e1-e61f13cf5d4b I'm seeing the messages printed to the screen, so I guess that this is either an Angular or a missing security header.
Thanks!
I just realized, thanks to this answer, that events must be formatted in a specific way. I changed the value of res.write accordingly:
Stream.on(req.params.fieldId, function(event, data) {
res.write('event: ' + String(event) + '\n' + 'data: ' + JSON.stringify(data) + '\n\n');
});

Issue posting API request from AWS Lambda with nodejs

completely beginner question here, but im stuck for hours, hope someone can help!
I'm building some thing over AWS API Gateway + Lambda, where I receive a POST request on AWS and I send some data to another API.
I'm using https from NodeJS (from examples i found here on stackoverflow) but it doesnt seem to be working...I'm testing by sending it to a webhook inbox in beeceptor
Could you give me some light?
exports.handler = async (event) => {
if(event.httpMethod == 'POST'){
return pedido(event);
}
};
var aid = '';
var cep = '';
const pedido = event => {
let body = JSON.parse(event.body);
var aid = body.cid;
//var sku = body.items.id
var cep = body.cep;
callapi(cep,aid);
console.log("teste cep ", body.cep);
return{
statusCode: 200,
body: JSON.stringify({
message: body.cep,
convid: aid
})
};
};
function callapi(cep,aid){
const https = require('https');
const data = JSON.stringify({
message: cep,
convid: aid,
test: 123
});
console.log("data is ", data);
const options = {
hostname: 'testbot.free.beeceptor.com',
//port: 443,
path: '/',
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': data.length
}
};
console.log("code was here ");
var req = https.request(options, (res) => {
console.log('req:', req);
console.log('res:', res);
console.log('statusCode:', res.statusCode);
console.log('headers:', res.headers);
res.on('data', (d) => {
process.stdout.write(d);
});
});
console.log('req:', req);
req.on('error', (e) => {
console.error(e);
});
req.write(data);
req.end();
}
There's at least one problem with your code:
The callapi function is making a request and this request is using a callback to notify you about a response. However, you are not waiting for it in your Lambda code and hence you won't see its response in your logs. Add appropriate awaits or Promises to it, so your code won't return before you've received a response.
The structure of your code could look similar to this:
exports.handler = async (event) => {
if (event.httpMethod === 'POST') {
return await pedido(event);
}
};
async function pedido(event) {
// init vars...
// wait for your API call
await callapi(cep, aid);
// then return a response
return {...}
}
async function callapi(cep, aid) {
// init vars like https and others...
// then use a promise and resolve it when you receive the request's callback (= response) or an error
return new Promise((resolve, reject) => {
const req = https.request(options, (res) => {
// handle response however you like ...
// then resolve the promise when you're done
resolve();
});
req.on('err', (e) => {
// reject in case the request fails
reject(e);
});
});
}
Does this solve your problem? If not, having some more logs of your method and a simplified code example would help a lot!

How to wait for the pipe to finish in form-data node.js module?

Using the form-data module in node.js, you can do this
form.pipe(request)
to put the form data to the request. But how can you wait until it is complete? Is there a callback like this
form.pipe(request).done(function(err) {});
Does anyone know?
Thanks
In the docs, they use:
form.pipe(request);
request.on('response', function(res) {
console.log(res.statusCode);
});
What I ended up doing to get my tests to work:
app.js
// form is declared
return await new Promise((resolve, reject) => {
const req = https.request(
process.env.HOST,
{
method: 'POST',
headers: form.getHeaders()
},
(res) => {
let data = '';
res.on('data', (d) => {
data += d;
});
res.on('end', () => {
resolve({
statusCode: res.statusCode,
body: data,
});
});
},
).on('error', reject);
form.pipe(req);
});
and
test-handler.js
sinon.replace(https, 'request', (url, options, callback) => {
const request = new EventEmitter();
request.on('pipe', () => {
const res = new EventEmitter();
res.statusCode = 200;
callback(res);
res.emit(
'data',
JSON.stringify({}),
);
res.emit('end');
});
return request;
});
I understand that it doesn't strictly answer your question in that the "pipe" event fires when the pipe begins and not when it's complete, but in terms of testing I don't know how to otherwise make the response finish.

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

How can I make an outbound HTTP POST request, with data, in node.js?
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
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.
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.
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)
})
There are dozens of open-source libraries available that you can use to making an HTTP POST request in Node.
1. Axios (Recommended)
const axios = require('axios');
const data = {
name: 'John Doe',
job: 'Content Writer'
};
axios.post('https://reqres.in/api/users', data)
.then((res) => {
console.log(`Status: ${res.status}`);
console.log('Body: ', res.data);
}).catch((err) => {
console.error(err);
});
2. Needle
const needle = require('needle');
const data = {
name: 'John Doe',
job: 'Content Writer'
};
needle('post', 'https://reqres.in/api/users', data, {json: true})
.then((res) => {
console.log(`Status: ${res.statusCode}`);
console.log('Body: ', res.body);
}).catch((err) => {
console.error(err);
});
3. Request
const request = require('request');
const options = {
url: 'https://reqres.in/api/users',
json: true,
body: {
name: 'John Doe',
job: 'Content Writer'
}
};
request.post(options, (err, res, body) => {
if (err) {
return console.log(err);
}
console.log(`Status: ${res.statusCode}`);
console.log(body);
});
4. Native HTTPS Module
const https = require('https');
const data = JSON.stringify({
name: 'John Doe',
job: 'Content Writer'
});
const options = {
hostname: 'reqres.in',
path: '/api/users',
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': data.length
}
};
const req = https.request(options, (res) => {
let data = '';
console.log('Status Code:', res.statusCode);
res.on('data', (chunk) => {
data += chunk;
});
res.on('end', () => {
console.log('Body: ', JSON.parse(data));
});
}).on("error", (err) => {
console.log("Error: ", err.message);
});
req.write(data);
req.end();
For details, check out this article.
I use Restler and Needle for production purposes.
They are both much more powerful than native httprequest. It is possible to request with basic authentication, special header entry or even upload/download files.
As for post/get operation, they also are much simpler to use than raw ajax calls using httprequest.
needle.post('https://my.app.com/endpoint', {foo:'bar'},
function(err, resp, body){
console.log(body);
});
Update 2020:
I've been really enjoying phin - The ultra-lightweight Node.js HTTP client
It can be used in two different ways. One with Promises (Async/Await) and the other with traditional callback styles.
Install via: npm i phin
Straight from it's README with await:
const p = require('phin')
await p({
url: 'https://ethanent.me',
method: 'POST',
data: {
hey: 'hi'
}
})
Unpromisifed (callback) style:
const p = require('phin').unpromisified
p('https://ethanent.me', (err, res) => {
if (!err) console.log(res.body)
})
As of 2015 there are now a wide variety of different libraries that can accomplish this with minimal coding. I much prefer elegant light weight libraries for HTTP requests unless you absolutely need control of the low level HTTP stuff.
One such library is Unirest
To install it, use npm.
$ npm install unirest
And onto the Hello, World! example that everyone is accustomed to.
var unirest = require('unirest');
unirest.post('http://example.com/helloworld')
.header('Accept', 'application/json')
.send({ "Hello": "World!" })
.end(function (response) {
console.log(response.body);
});
Extra:
A lot of people are also suggesting the use of request [ 2 ]
It should be worth noting that behind the scenes Unirest uses the request library.
Unirest provides methods for accessing the request object directly.
Example:
var Request = unirest.get('http://mockbin.com/request');
You can also use Requestify, a really cool and simple HTTP client I wrote for nodeJS + it supports caching.
Just do the following:
var requestify = require('requestify');
requestify.post('http://example.com', {
hello: 'world'
})
.then(function(response) {
// Get the response body (JSON parsed or jQuery object for XMLs)
response.getBody();
});
var https = require('https');
/**
* HOW TO Make an HTTP Call - POST
*/
// do a POST request
// create the JSON object
jsonObject = JSON.stringify({
"message" : "The web of things is approaching, let do some tests to be ready!",
"name" : "Test message posted with node.js",
"caption" : "Some tests with node.js",
"link" : "http://www.youscada.com",
"description" : "this is a description",
"picture" : "http://youscada.com/wp-content/uploads/2012/05/logo2.png",
"actions" : [ {
"name" : "youSCADA",
"link" : "http://www.youscada.com"
} ]
});
// prepare the header
var postheaders = {
'Content-Type' : 'application/json',
'Content-Length' : Buffer.byteLength(jsonObject, 'utf8')
};
// the post options
var optionspost = {
host : 'graph.facebook.com',
port : 443,
path : '/youscada/feed?access_token=your_api_key',
method : 'POST',
headers : postheaders
};
console.info('Options prepared:');
console.info(optionspost);
console.info('Do the POST call');
// do the POST call
var reqPost = https.request(optionspost, function(res) {
console.log("statusCode: ", res.statusCode);
// uncomment it for header details
// console.log("headers: ", res.headers);
res.on('data', function(d) {
console.info('POST result:\n');
process.stdout.write(d);
console.info('\n\nPOST completed');
});
});
// write the json data
reqPost.write(jsonObject);
reqPost.end();
reqPost.on('error', function(e) {
console.error(e);
});
This is the simplest way I use to make request: using 'request' module.
Command to install 'request' module :
$ npm install request
Example code:
var request = require('request')
var options = {
method: 'post',
body: postData, // Javascript object
json: true, // Use,If you are sending JSON data
url: url,
headers: {
// Specify headers, If any
}
}
request(options, function (err, res, body) {
if (err) {
console.log('Error :', err)
return
}
console.log(' Body :', body)
});
You can also use Node.js's built-in 'http' module to make request.
I like the simplicity of superagent (https://github.com/visionmedia/superagent). Same API on both node and browser.
;(async function() {
var response = await superagent.post('http://127.0.0.1:8125/', {age: 2})
console.log(response)
})
There is also node-fetch (https://www.npmjs.com/package/node-fetch), which has an API that matches fetch from the browsers - however this requires manual query string encoding, does not automatically handle content types, or so any of the other work superagent does.
In Node.js 18
Fetch
The fetch() method in JavaScript is used to request data from a
server. The request can be of any type of API that returns the data in
JSON or XML.
Say goodbye to the node-fetch package ,axios and request ,... now the fetch API is available on the global scope by default.
app.get('/', (req, res, next) => {
// Make a post Request.
fetch('https://jsonplaceholder.typicode.com/posts', {
method: 'POST',
body: JSON.stringify({
title: 'foo',
body: 'bar',
userId: 1,
}),
headers: {
'Content-type': 'application/json; charset=UTF-8',
},
})
.then((response) => response.json())
.then((json) => console.log(json))
.catch(error => {
console.log(error)
})
res.send('Fetch API is available on the global scope by default')
})
We can make requests as we do in browsers.
For More Information
If you are looking for promise based HTTP requests, axios does its job nicely.
const axios = require('axios');
axios.post('/user', {firstName: 'Fred',lastName: 'Flintstone'})
.then((response) => console.log(response))
.catch((error) => console.log(error));
OR
await axios.post('/user', {firstName: 'Fred',lastName: 'Flintstone'})
To Post Rest/JSON Request
We can simply use request package and save the values we have to send in Json variable.
First install the require package in your console by
npm install request --save
var request = require('request');
var options={
'key':'28',
'key1':'value',
'key2':'value'
}
request({
url:"http://dev.api.ean.com/ean-services/rs/hotel/v3/ping?
minorRev="+options.key+
"&cid="+options.key1+
"&apiKey="+options.key2,
method:"POST",
json:true},function(error,response,body){
console.log(body)
}
);
This my solution for POST and GET.
About the Post method:
If the body is a JSON object, so it's important to deserialize it with JSON.stringify and possibly set the Content-Lenght header accordingly:
var bodyString=JSON.stringify(body)
var _headers = {
'Content-Length': Buffer.byteLength(bodyString)
};
before writing it to the request:
request.write( bodyString );
About both Get and Post methods:
The timeout can occur as a socket disconnect, so you must register its handler like:
request.on('socket', function (socket) {
socket.setTimeout( self.timeout );
socket.on('timeout', function() {
request.abort();
if(timeout) return timeout( new Error('request timed out') );
});
});
while the request handler is
request.on('timeout', function () {
// Timeout happend. Server received request, but not handled it
// (i.e. doesn't send any response or it took to long).
// You don't know what happend.
// It will emit 'error' message as well (with ECONNRESET code).
req.abort();
if(timeout) return timeout( new Error('request timed out') );
});
I strongly suggest to register both the handlers.
The response body is chunked, so you must concat chunks at the data handler:
var body = '';
response.on('data', function(d) {
body += d;
});
At the end the body will contain the whole response body:
response.on('end', function() {
try {
var jsonResponse=JSON.parse(body);
if(success) return success( jsonResponse );
} catch(ex) { // bad json
if(error) return error(ex.toString());
}
});
It is safe to wrap with a try...catchtheJSON.parse` since you cannot be sure that it is a well-formatted json actually and there is no way to be sure of it at the time you do the request.
Module: SimpleAPI
/**
* Simple POST and GET
* #author Loreto Parisi (loretoparisi at gmail dot com)
*/
(function() {
var SimpleAPI;
SimpleAPI = (function() {
var qs = require('querystring');
/**
* API Object model
* #author Loreto Parisi (loretoparisi at gmail dot com)
*/
function SimpleAPI(host,port,timeout,ssl,debug,json) {
this.host=host;
this.port=port;
this.timeout=timeout;
/** true to use ssl - defaults to true */
this.ssl=ssl || true;
/** true to console log */
this.debug=debug;
/** true to parse response as json - defaults to true */
this.json= (typeof(json)!='undefined')?json:true;
this.requestUrl='';
if(ssl) { // use ssl
this.http = require('https');
} else { // go unsafe, debug only please
this.http = require('http');
}
}
/**
* HTTP GET
* #author Loreto Parisi (loretoparisi at gmail dot com)
*/
SimpleAPI.prototype.Get = function(path, headers, params, success, error, timeout) {
var self=this;
if(params) {
var queryString=qs.stringify(params);
if( queryString ) {
path+="?"+queryString;
}
}
var options = {
headers : headers,
hostname: this.host,
path: path,
method: 'GET'
};
if(this.port && this.port!='80') { // port only if ! 80
options['port']=this.port;
}
if(self.debug) {
console.log( "SimpleAPI.Get", headers, params, options );
}
var request=this.http.get(options, function(response) {
if(self.debug) { // debug
console.log( JSON.stringify(response.headers) );
}
// Continuously update stream with data
var body = '';
response.on('data', function(d) {
body += d;
});
response.on('end', function() {
try {
if(self.json) {
var jsonResponse=JSON.parse(body);
if(success) return success( jsonResponse );
}
else {
if(success) return success( body );
}
} catch(ex) { // bad json
if(error) return error( ex.toString() );
}
});
});
request.on('socket', function (socket) {
socket.setTimeout( self.timeout );
socket.on('timeout', function() {
request.abort();
if(timeout) return timeout( new Error('request timed out') );
});
});
request.on('error', function (e) {
// General error, i.e.
// - ECONNRESET - server closed the socket unexpectedly
// - ECONNREFUSED - server did not listen
// - HPE_INVALID_VERSION
// - HPE_INVALID_STATUS
// - ... (other HPE_* codes) - server returned garbage
console.log(e);
if(error) return error(e);
});
request.on('timeout', function () {
// Timeout happend. Server received request, but not handled it
// (i.e. doesn't send any response or it took to long).
// You don't know what happend.
// It will emit 'error' message as well (with ECONNRESET code).
req.abort();
if(timeout) return timeout( new Error('request timed out') );
});
self.requestUrl = (this.ssl?'https':'http') + '://' + request._headers['host'] + request.path;
if(self.debug) {
console.log("SimpleAPI.Post",self.requestUrl);
}
request.end();
} //RequestGet
/**
* HTTP POST
* #author Loreto Parisi (loretoparisi at gmail dot com)
*/
SimpleAPI.prototype.Post = function(path, headers, params, body, success, error, timeout) {
var self=this;
if(params) {
var queryString=qs.stringify(params);
if( queryString ) {
path+="?"+queryString;
}
}
var bodyString=JSON.stringify(body)
var _headers = {
'Content-Length': Buffer.byteLength(bodyString)
};
for (var attrname in headers) { _headers[attrname] = headers[attrname]; }
var options = {
headers : _headers,
hostname: this.host,
path: path,
method: 'POST',
qs : qs.stringify(params)
};
if(this.port && this.port!='80') { // port only if ! 80
options['port']=this.port;
}
if(self.debug) {
console.log( "SimpleAPI.Post\n%s\n%s", JSON.stringify(_headers,null,2), JSON.stringify(options,null,2) );
}
if(self.debug) {
console.log("SimpleAPI.Post body\n%s", JSON.stringify(body,null,2) );
}
var request=this.http.request(options, function(response) {
if(self.debug) { // debug
console.log( JSON.stringify(response.headers) );
}
// Continuously update stream with data
var body = '';
response.on('data', function(d) {
body += d;
});
response.on('end', function() {
try {
console.log("END", body);
var jsonResponse=JSON.parse(body);
if(success) return success( jsonResponse );
} catch(ex) { // bad json
if(error) return error(ex.toString());
}
});
});
request.on('socket', function (socket) {
socket.setTimeout( self.timeout );
socket.on('timeout', function() {
request.abort();
if(timeout) return timeout( new Error('request timed out') );
});
});
request.on('error', function (e) {
// General error, i.e.
// - ECONNRESET - server closed the socket unexpectedly
// - ECONNREFUSED - server did not listen
// - HPE_INVALID_VERSION
// - HPE_INVALID_STATUS
// - ... (other HPE_* codes) - server returned garbage
console.log(e);
if(error) return error(e);
});
request.on('timeout', function () {
// Timeout happend. Server received request, but not handled it
// (i.e. doesn't send any response or it took to long).
// You don't know what happend.
// It will emit 'error' message as well (with ECONNRESET code).
req.abort();
if(timeout) return timeout( new Error('request timed out') );
});
self.requestUrl = (this.ssl?'https':'http') + '://' + request._headers['host'] + request.path;
if(self.debug) {
console.log("SimpleAPI.Post",self.requestUrl);
}
request.write( bodyString );
request.end();
} //RequestPost
return SimpleAPI;
})();
module.exports = SimpleAPI
}).call(this);
Usage:
// Parameters
// domain: example.com
// ssl:true, port:80
// timeout: 30 secs
// debug: true
// json response:true
var api = new SimpleAPI('posttestserver.com', 80, 1000 * 10, true, true, true);
var headers = {
'Content-Type' : 'application/json',
'Accept' : 'application/json'
};
var params = {
"dir" : "post-test"
};
var method = 'post.php';
api.Post(method, headers, params, body
, function(response) { // success
console.log( response );
}
, function(error) { // error
console.log( error.toString() );
}
, function(error) { // timeout
console.log( new Error('timeout error') );
});
I found a video which explains on how to achieve this: https://www.youtube.com/watch?v=nuw48-u3Yrg
It uses default "http" module together with "querystring" and "stringbuilder" modules. The application takes two numbers (using two textboxes) from a web page and upon submit, returns sum of those two (along with persisting the values in the textboxes). This is the best example I could find anywhere else.
var http = require("http");
var qs = require("querystring");
var StringBuilder = require("stringbuilder");
var port = 9000;
function getCalcHtml(req, resp, data) {
var sb = new StringBuilder({ newline: "\r\n" });
sb.appendLine("<html>");
sb.appendLine(" <body>");
sb.appendLine(" <form method='post'>");
sb.appendLine(" <table>");
sb.appendLine(" <tr>");
sb.appendLine(" <td>Enter First No: </td>");
if (data && data.txtFirstNo) {
sb.appendLine(" <td><input type='text' id='txtFirstNo' name='txtFirstNo' value='{0}'/></td>", data.txtFirstNo);
}
else {
sb.appendLine(" <td><input type='text' id='txtFirstNo' name='txtFirstNo' /></td>");
}
sb.appendLine(" </tr>");
sb.appendLine(" <tr>");
sb.appendLine(" <td>Enter Second No: </td>");
if (data && data.txtSecondNo) {
sb.appendLine(" <td><input type='text' id='txtSecondNo' name='txtSecondNo' value='{0}'/></td>", data.txtSecondNo);
}
else {
sb.appendLine(" <td><input type='text' id='txtSecondNo' name='txtSecondNo' /></td>");
}
sb.appendLine(" </tr>");
sb.appendLine(" <tr>");
sb.appendLine(" <td><input type='submit' value='Calculate' /></td>");
sb.appendLine(" </tr>");
if (data && data.txtFirstNo && data.txtSecondNo) {
var sum = parseInt(data.txtFirstNo) + parseInt(data.txtSecondNo);
sb.appendLine(" <tr>");
sb.appendLine(" <td>Sum: {0}</td>", sum);
sb.appendLine(" </tr>");
}
sb.appendLine(" </table>");
sb.appendLine(" </form>")
sb.appendLine(" </body>");
sb.appendLine("</html>");
sb.build(function (err, result) {
resp.write(result);
resp.end();
});
}
function getCalcForm(req, resp, data) {
resp.writeHead(200, { "Content-Type": "text/html" });
getCalcHtml(req, resp, data);
}
function getHome(req, resp) {
resp.writeHead(200, { "Content-Type": "text/html" });
resp.write("<html><html><head><title>Home</title></head><body>Want to some calculation? Click <a href='/calc'>here</a></body></html>");
resp.end();
}
function get404(req, resp) {
resp.writeHead(404, "Resource Not Found", { "Content-Type": "text/html" });
resp.write("<html><html><head><title>404</title></head><body>404: Resource not found. Go to <a href='/'>Home</a></body></html>");
resp.end();
}
function get405(req, resp) {
resp.writeHead(405, "Method not supported", { "Content-Type": "text/html" });
resp.write("<html><html><head><title>405</title></head><body>405: Method not supported</body></html>");
resp.end();
}
http.createServer(function (req, resp) {
switch (req.method) {
case "GET":
if (req.url === "/") {
getHome(req, resp);
}
else if (req.url === "/calc") {
getCalcForm(req, resp);
}
else {
get404(req, resp);
}
break;
case "POST":
if (req.url === "/calc") {
var reqBody = '';
req.on('data', function (data) {
reqBody += data;
if (reqBody.length > 1e7) { //10MB
resp.writeHead(413, 'Request Entity Too Large', { 'Content-Type': 'text/html' });
resp.end('<!doctype html><html><head><title>413</title></head><body>413: Request Entity Too Large</body></html>');
}
});
req.on('end', function () {
var formData = qs.parse(reqBody);
getCalcForm(req, resp, formData);
});
}
else {
get404(req, resp);
}
break;
default:
get405(req, resp);
break;
}
}).listen(port);
After struggling a lot while creating a low level utility to handle the post and get requests for my project, I decided to post my effort here. Much on the lines of accepted answer, here is a snippet for making http and https POST requests for sending JSON data.
const http = require("http")
const https = require("https")
// Request handler function
let postJSON = (options, postData, callback) => {
// Serializing JSON
post_data = JSON.stringify(postData)
let port = options.port == 443 ? https : http
// Callback function for the request
let req = port.request(options, (res) => {
let output = ''
res.setEncoding('utf8')
// Listener to receive data
res.on('data', (chunk) => {
output += chunk
});
// Listener for intializing callback after receiving complete response
res.on('end', () => {
let obj = JSON.parse(output)
callback(res.statusCode, obj)
});
});
// Handle any errors occurred while making request
req.on('error', (err) => {
//res.send('error: ' + err.message)
});
// Request is made here, with data as string or buffer
req.write(post_data)
// Ending the request
req.end()
};
let callPost = () => {
let data = {
'name': 'Jon',
'message': 'hello, world'
}
let options = {
host: 'domain.name', // Your domain name
port: 443, // 443 for https and 80 for http
path: '/path/to/resource', // Path for the request
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': Buffer.byteLength(data)
}
}
postJSON(options, data, (statusCode, result) => {
// Handle response
// Process the received data
});
}
Axios is a promise based HTTP client for the browser and Node.js. Axios makes it easy to send asynchronous HTTP requests to REST endpoints and perform CRUD operations. It can be used in plain JavaScript or with a library such as Vue or React.
const axios = require('axios');
var dataToPost = {
email: "your email",
password: "your password"
};
let axiosConfiguration = {
headers: {
'Content-Type': 'application/json;charset=UTF-8',
"Access-Control-Allow-Origin": "*",
}
};
axios.post('endpoint or url', dataToPost, axiosConfiguration)
.then((res) => {
console.log("Response: ", res);
})
.catch((err) => {
console.log("error: ", err);
})
let request = require('request');
let jsonObj = {};
request({
url: "https://myapii.com/sendJsonData",
method: "POST",
json: true,
body: jsonObj
}, function (error, resp, body){
console.log(resp);
});
Or you could use this library:
let axios = require("axios");
let jsonObj = {};
const myJsonAPI = axios.create({
baseURL: 'https://myapii.com',
timeout: 120*1000
});
let response = await myJsonAPI.post("sendJsonData",jsonobj).catch(e=>{
res.json(e);
});
console.log(response);
Posting another axios example of an axios.post request that uses additional configuration options and custom headers.
var postData = {
email: "test#test.com",
password: "password"
};
let axiosConfig = {
headers: {
'Content-Type': 'application/json;charset=UTF-8',
"Access-Control-Allow-Origin": "*",
}
};
axios.post('http://<host>:<port>/<path>', postData, axiosConfig)
.then((res) => {
console.log("RESPONSE RECEIVED: ", res);
})
.catch((err) => {
console.log("AXIOS ERROR: ", err);
})
By using request dependency.
Simple solution :
import request from 'request'
var data = {
"host":"127.1.1.1",
"port":9008
}
request.post( baseUrl + '/peers/connect',
{
json: data, // your payload data placed here
headers: {
'X-Api-Key': 'dajzmj6gfuzmbfnhamsbuxivc', // if authentication needed
'Content-Type': 'application/json'
}
}, function (error, response, body) {
if (error) {
callback(error, null)
} else {
callback(error, response.body)
}
});
Request-Promise Provides promise based response.
http response codes other than 2xx will cause the promise to be rejected. This can be overwritten by setting options.simple = false
var options = {
method: 'POST',
uri: 'http://api.posttestserver.com/post',
body: {
some: 'payload'
},
json: true // Automatically stringifies the body to JSON
};
rp(options)
.then(function (parsedBody) {
// POST succeeded...
})
.catch(function (err) {
// POST failed...
});
In case you need an XML request I'll share my codes with axios library.
const {default: axios} = require('axios');
let xmlString = '<XML>...</XML>';
axios.post('yourURL', xmlString)
.then((res) => {
console.log("Status: ", res.status);
console.log("Body: ", res.data);
})
.catch((err) => {
console.error("Error: ", err);
});
Make arbitrary HTTP requests with the Node.js http library.
Don't use third-party packages that don't provide any new functionality.
Use the Node.js built-ins.
https://nodejs.org/api/http.html#httprequesturl-options-callback
The example from the documentation for http.request shows you how to make a "hello world" POST request.
Here is the example. Ask questions in the comments, e.g., if you are learning Node.js and want more resources.
const http = require('node:http');
const postData = JSON.stringify({
'msg': 'Hello World!',
});
const options = {
hostname: 'www.google.com',
port: 80,
path: '/upload',
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': Buffer.byteLength(postData),
},
};
const req = http.request(options, (res) => {
console.log(`STATUS: ${res.statusCode}`);
console.log(`HEADERS: ${JSON.stringify(res.headers)}`);
res.setEncoding('utf8');
res.on('data', (chunk) => {
console.log(`BODY: ${chunk}`);
});
res.on('end', () => {
console.log('No more data in response.');
});
});
req.on('error', (e) => {
console.error(`problem with request: ${e.message}`);
});
// Write data to request body
req.write(postData);
req.end();
~
~
~

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