Connection in refused in nodeJs - node.js

I try MongoDB connect to My chat application with node.js. I have google and read lot's of article but I cant figure it out.
it's throw's arror like:
{ [MongoError: connect ECONNREFUSED] name: 'MongoError', message: 'connect ECONNREFUSED' }
Following my code :
var app = require('express')();
var http = require('http').Server(app);
var https = require('http')
var io = require('socket.io')(http);
var sockets = new Array;
var clients = new Array;
var webSockets = {}; // userID: webSocket
var userlist = {};
var allClients = [];
app.get('/', function (req, res) {
res.sendFile(__dirname + '/index.html');
});
var MongoClient = require('mongodb').MongoClient;
var url = 'mongodb://localhost:27017/products';
// Use connect method to connect to the Server
MongoClient.connect(url, function (err, db) {
if (err) {
console.log(err);
} else {
//HURRAY!! We are connected. :)
console.log('Connection established to', url);
//Close connection
db.close();
}
});

I had this problem and it turned out I had to replace localhost with 127.0.0.1 and it worked

Related

Access Mongodb's 'db' in routers, NodeJS/Express

I'm unable to export the db object for using in my routers (controller). Heres the file where i connect to the database and attempt to export db object:
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/database';
// Use connect method to connect to the server
var database;
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected successfully to server");
database = db;
module.exports = database;
});
and where i try using it in one of my routers:
var db = require('../path/to/file/above');
// Redirect to application
router.get('/', function(req, res, next) {
try {
db.close();
} catch (err) {
console.log(err);
}
res.render('index',{});
});
"console.log(err)" says "db.close() is not a function".
Q: How do i properly export the db object so i can use it in my routers?
i think there is some problem with your module.exports try this
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/database';
// Use connect method to connect to the server
var database;
function connectMongo(cb){
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected successfully to server");
cb(db);
});
}
module.exports = connectMongo;
You can use mongoskin to access the mongodb and can export the db object.
e.g.
var mongo = require('mongoskin');
var url = 'mongodb://localhost:27017/database';
var db = mongo.db(url, {native_parser:true});
module.exports = db;
And, in your router,
var db = require('../path/to/file/above');
// Redirect to application
router.get('/', function(req, res, next) {
try {
//some db operations
} catch (err) {
console.log(err);
}
res.render('index',{});
});
Other solution is to pass the callback as suggested by #Asif.
This is what my database file (database.js) ended up to be:
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
var express = require('express');
var app = express();
// Connection URL
var url = 'mongodb://localhost:27017/database';
// Use connect method to connect to the server
var database;
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
database = db;
});
// Returns DB object when called
module.exports.get = function() {
return database;
}
and using it like this (note that you have to call the get function in a router.get() for example, calling it directly won't work since the connection won't be open yet):
var database = require('./database.js');
var assert = require('assert');
var express = require('express');
var router = express.Router();
// Redirect to application
router.get('/', function(req, res, next) {
var db = database.get();
// Mongo Query here
res.render('index',{});
});

c9.io mongodb connection url example

Can anyone give me an example of a mongodb connection URL in c9.io? I'm wanting to connect to their local instance of mongodb and I have mongod running in the background.
Here is what I'm trying to use:
var mongodb = require('mongodb');
function ConnectToDB(mongoUrl){
var MongoClient = mongodb.MongoClient;
//var url = 'mongodb://localhost:27017/my_database_name';
var url = mongoUrl || 'mongodb://' + process.env.IP + ":27017/test";
// Use connect method to connect to the Server
MongoClient.connect(url, function(err, db) {
if(err){
console.log(err);
}
console.log("Connected correctly to server");
return db;
});
}
It doesn't even log, any help would be much appreciated.
I got this to work my logic was off a bit :p
function OpenDB(mongoUrl, callBack){
var MongoClient = mongodb.MongoClient;
//var url = 'mongodb://localhost:27017/my_database_name';
var url = mongoUrl || "mongodb://" + process.env.IP + "/test";
console.log(url.bgWhite.blue);
// Use connect method to connect to the Server
MongoClient.connect(url, function(err, db) {
if(err){
console.log(err);
}
console.log("Connected correctly to server");
callBack(db);
db.close();
});
}

Nodejs websocket communication with external system

I'm new to nodejs and I'm trying to solve communication issue with external system.
There is a gateway to external system which can handle websocket requests on port 5000. In the example below, when you request homepage, the nodejs opens websocket connection, then on websocket open event it sends request and waits for response which is used for the HTTP response.
Do you know how to open websocket to external system only once and handle requests based on request id?
var ws = require('ws');
var express = require('express');
var async = require('async');
var uuid = require('node-uuid');
app = express();
app.get('/', function (req, res) {
var webSocket = new ws('ws://localhost:5000/');
async.series([
function (callback) {
webSocket.on('open', function () {
webSocket.send(JSON.stringify({query:'data query', requestid: uuid.v4()}));
callback(null, 'data query');
});
},
function (callback) {
webSocket.on('message', function (data, flags) {
callback(null, data);
})
}
], function (err, results) {
res.setHeader('content-type', 'text/javascript');
res.send(results[1]);
webSocket.terminate();
});
});
var server = app.listen(3000, function () {
var port = server.address().port
console.log('Listening at %s', port)
});
Thanks for the hints. I ended with the following solution which does what I expect:
var ws = require('ws');
var express = require('express');
var uuid = require('node-uuid');
var requests = {};
app = express();
var webSocket = new ws('ws://localhost:5000/');
webSocket.on('open', function () {
console.log('Connected!');
});
webSocket.on('message', function (data, flags) {
var json = JSON.parse(data);
console.log(json.requestId);
var res = requests[json.requestId];
res.setHeader('content-type', 'text/javascript');
res.send(json.data);
delete requests[json.requestId];
});
app.get('/', function (req, res) {
var rid = uuid.v4();
requests[rid] = res;
webSocket.send(JSON.stringify({query:'data query', requestId: rid}));
});
var server = app.listen(3000, function () {
var port = server.address().port
console.log('Listening at %s', port)
});

Inserting in mongodb with nodejs

I'm trying to insert some data in my mongodb with nodejs whenever a socket is emitted. Here is the code:
io.sockets.on( "connection",function( socket ){
socket.on( "send", function( data ) {
console.log(data.name + " and the content is: " + data.content);
mongodb.connect( "mongodb://127.0.0.1", function( err, db ) {
if(err) throw err;
var to_be_inserted = {name: data.name,content: data.content};
db.collection("chat").insert(to_be_inserted,function(err,objects){
if(err) throw err;
});
})
})
})
However whenever I go to my mongo console and type
db.chat.find()
I cannot find the inserted record. I'm sure that I have mongod open and I'm sure that the socket is emitted. Moreover the consoloe.log before the insertion does work.
Here is my mongo client
var mongodb = require("mongodb").MongoClient;
My console which runs the nodejs server does not log any error.
You should specify a database name (here: myDatabase ) and a port number (for safety).
mongodb.connect("mongodb://127.0.0.1:27017/myDatabase", function( err, db ) {
When searching the record in the mongo shell try:
use myDatabase
db.chat.find()
You forget to include the port number and database of mongodb,
MongoClient.connect('mongodb://127.0.0.1:27017/test', function(err, db) {
if (err) throw err;
console.log("Connected to Database");
}
try this code
var MongoClient=require('mongodb').MongoClient;
var Server=require('mongodb').Server;
var mongoc=new MongoClient(new Server("localhost",27017));
mongoc.open(function(err)
{
db.collection(<collection_name>).insert(<query>,function(err,result)
{
});
const http = require('http');
const hostname = '127.0.0.1';
const port = 8081;
var express = require("express");
var bodyParser = require('body-parser');
var app = express();
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017";
app.use(bodyParser.json());
app.get('/get', function (req, res) {
res.send('Hello World')
})
var data = {
title: 'my title',
content: 'my content'
};
// This responds a POST request for the homepage
app.post('/say/:userid', function (req, res) {
var queryParameter=JSON.stringify(req.query);
res.send('Hello POST'+req.params.userid+""+queryParameter);
})
app.post('/insert', function (req, res) {
console.log(req.body);
res.send('Hello POST'+JSON.stringify(req.body));
/* var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017"; */
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbase = db.db("mydb");
var myobj = { name: JSON.stringify(req.body.name), address:JSON.stringify(req.body.address) };
dbase.collection("student").insertOne(myobj, function(err, res) {
if (err) throw err;
console.log("1 document inserted");

How to create a simple socket in node.js?

I'm trying to create a dummy socket for use in some of my tests
var net = require("net");
var s = new net.Socket();
s.on("data", function(data) {
console.log("data received:", data);
});
s.write("hello!");
Getting this error
Error: This socket is closed.
I've also tried creating the socket with
var s = new net.Socket({allowHalfOpen: true});
What am I doing wrong?
For reference, the complete test looks like this
it("should say hello on connect", function(done) {
var socket = new net.Socket();
var client = Client.createClient({socket: socket});
socket.on("data", function(data){
assert.equal("hello", data);
done();
});
client.connect();
// writes "hello" to the socket
});
I don't think the server is put into listening state. This what I use..
// server
require('net').createServer(function (socket) {
console.log("connected");
socket.on('data', function (data) {
console.log(data.toString());
});
})
.listen(8080);
// client
var s = require('net').Socket();
s.connect(8080);
s.write('Hello');
s.end();
Client only..
var s = require('net').Socket();
s.connect(80, 'google.com');
s.write('GET http://www.google.com/ HTTP/1.1\n\n');
s.on('data', function(d){
console.log(d.toString());
});
s.end();
Try this.
The production code app.js:
var net = require("net");
function createSocket(socket){
var s = socket || new net.Socket();
s.write("hello!");
}
exports.createSocket = createSocket;
The test code: test.js: (Mocha)
var sinon = require('sinon'),
assert = require('assert'),
net = require('net'),
prod_code=require('./app.js')
describe('Example Stubbing net.Socket', function () {
it("should say hello on connect", function (done) {
var socket = new net.Socket();
var stub = sinon.stub(socket, 'write', function (data, encoding, cb) {
console.log(data);
assert.equal("hello!", data);
done();
});
stub.on = socket.on;
prod_code.createSocket(socket);
});
});
We can create socket server using net npm module and listen from anywhere. after creating socket server we can check using telnet(client socket) to interact server.
server.js
'use strict';
const net = require('net');
const MongoClient= require('mongodb').MongoClient;
const PORT = 5000;
const ADDRESS = '127.0.0.1';
const url = 'mongodb://localhost:27017/gprs';
let server = net.createServer(onClientConnected);
server.listen(PORT, ADDRESS);
function onClientConnected(socket) {
console.log(`New client: ${socket.remoteAddress}:${socket.remotePort}`);
socket.destroy();
}
console.log(`Server started at: ${ADDRESS}:${PORT}`);
function onClientConnected(socket) {
let clientName = `${socket.remoteAddress}:${socket.remotePort}`;
console.log(`${clientName} connected.`);
socket.on('data', (data) => {
let m = data.toString().replace(/[\n\r]*$/, '');
var d = {msg:{info:m}};
insertData(d);
console.log(`${clientName} said: ${m}`);
socket.write(`We got your message (${m}). Thanks!\n`);
});
socket.on('end', () => {
console.log(`${clientName} disconnected.`);
});
}
function insertData(data){
console.log(data,'data');
MongoClient.connect(url, function(err, db){
console.log(data);
db.collection('gprs').save(data.msg , (err,result)=>{
if(err){
console.log("not inserted");
}else {
console.log("inserted");
}
});
});
}
using telnet:
$ telnet localhost 5000
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
hi
We got your message (hi). Thanks!
you need to connect your socket before you can write to it:
var PORT = 41443;
var net = require("net");
var s = new net.Socket();
s.on("data", function(data) {
console.log("data received:", data);
});
s.connect(PORT, function(){
s.write("hello!");
});
It will useful code for websocket
'use strict';
const express = require('express');
const { Server } = require('ws');
const bodyParser = require('body-parser');
const cors = require('cors');
const PORT = process.env.PORT || 5555;
const INDEX = '/public/index.html';
const router = express.Router();
var urlencodedParser = bodyParser.urlencoded({ extended: false });
router.get('/', function(req, res) {
res.sendFile(INDEX, { root: __dirname });
});
const server = express()
.use(router)
.use(bodyParser.json())
.use(cors)
.listen(PORT, () => {
console.log(`Listening on ${PORT}`)
});
const wss = new Server({ server });
wss.on('connection', (ws) => {
ws.on('message', message => {
var current = new Date();
console.log('Received '+ current.toLocaleString()+': '+ message);
wss.clients.forEach(function(client) {
client.send(message);
var getData = JSON.parse(message);
var newclip = getData.clipboard;
var newuser = getData.user;
console.log("User ID : "+ newuser);
console.log("\nUser clip : "+ newclip);
});
});
});

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