I have some code that opens and reads a SQL script file and opens a connection to the database in parallel, when they are done it executes the contents of the file on the connection. However, the connection result needs to be 'closed'. I need to be able to handle the case where the database connection succeeds and reading the file fails (wrong filename perhaps) and still close the connection in either case.
Here is the code I am currently using, it has a finally() handler to close the client if the query succeeds or fails, but if the file read fails the client will not be closed.
function execFile(db, file) {
console.log('Connecting to ' + db);
return Promise.all([
connect('postgres://' + credentials + host + '/' + db),
fs.readFileAsync(file, 'utf8')
]).spread(function(client, initSql) {
console.log('Connected to ' + db);
console.log('Running init script ' + file);
return client.queryAsync(initSql).finally(client.end);
});
}
I played a little with the bind() function to pass the client into the finally block but I'm not very happy with the complexity that it introduces. I have a feeling that settle() could be useful here and I'm playing with that now.
What is the best way to handle this?
function execFile(db, file) {
console.log('Connecting to ' + db);
var client = connect('postgres://' + credentials + host + '/' + db);
var initSql = fs.readFileAsync(file, 'utf8');
return Promise.all([client, initSql]).spread(function(client, initSql) {
console.log('Connected to ' + db);
console.log('Running init script ' + file);
return client.queryAsync(initSql);
}).finally(function() {
if (client.isFulfilled()) client.inspect().value().end();
});
}
Related
I'm trying to build a TCP server on node JS. The idea is to have multiple TCP clients connect and send / receive data(from server to client / client to server) and to have some sort of authentication (at least to enter a strong password) Also not sure if this approach is worth it. But, I've come up with something (most from online sources and docs) and crated below code.
Code runs and I can connect, but if I send data from client to server, the "password" check function fires up and each time I enter the correct password, a new (duplicate connection) is created. Seems like it keeps calling the same function on each input.
Desired behavior would be ; once client try's to connect, needs to provide the password and then start sending date. Also could someone give me a hint on how to send data back from server, or is it even possible. Or do I need to create a separate function for server.createConnection()
thanks in advance
UPDATE :I've changed the code a bit, but the main issue remains. this bit was supposed to check whether "clientAddress" exists and if so skip the auth part all together.
server.on('connection', (socket) => {
let clientAddress = `${socket.remoteAddress}:${socket.remotePort}`;
console.log(clientAddress)
if(sock.indexOf(clientAddress) !== -1){
console.log('devie found, opening communication')
newConnectionHandler(socket,clientAddress)
} else {
console.log('devie not found, need to authenticate')
userAuth(socket,clientAddress)
}
but as you can guess, it's not working :) if I manually specify the "clientAddress" it works , if I place "sock.push(clientAddress);" within the first block of code, it also works. No auth is asked. But when it's placed within
function userAuth(socket,clientAddress){
socket.write('password : ' )
socket.on('data', function (data) {
let pass = data.toString()
if (pass == password) {
sock.push(clientAddress);
console.log(sock)
newConnectionHandler(socket,clientAddress)
return;
} else {
//console.log(pass)
socket.write('Sorry, you cannot access the server \n')
console.log('acess denied for ' + socket.remoteAddress + ':' + socket.remotePort + '\n')
socket.write('connection closed')
socket.destroy()
}
})
}
code does run as expected and goes all the way till
function newConnectionHandler(socket,clientAddress){
//console.log(sock)
socket.write('Welcome \n')
socket.on('data', function(data1){
console.log("Client Sent: " + data1);
});
but as soon as I send a new message from the client, it goes back as if it was never authenticated and treats my input as the password and because it does not match with the actual password,it destroys the connection.
can someone please give me a hand...
const net = require('net');
const port = 3001;
const host = '192.168.0.165';
const server = net.createServer()
let sock = [];
let password = 123
//server.on('listening',createConnection);
server.on('connection', (socket) => {
let clientAddress = `${socket.remoteAddress}:${socket.remotePort}`;
console.log(clientAddress)
if(sock.indexOf(clientAddress) !== -1){
console.log('devie found, opening communication')
newConnectionHandler(socket,clientAddress)
} else {
console.log('devie not found, need to authenticate')
userAuth(socket,clientAddress)
}
server.on('error', errorHandler);
function errorHandler(err){
console.log(`Error occurred in ${clientAddress}: ${err.message}`);
}
function userAuth(socket,clientAddress){
socket.write('password : ' )
socket.on('data', function (data) {
let pass = data.toString()
if (pass == password) {
sock.push(clientAddress);
console.log(sock)
newConnectionHandler(socket,clientAddress)
return;
} else {
//console.log(pass)
socket.write('Sorry, you cannot access the server \n')
console.log('acess denied for ' + socket.remoteAddress + ':' + socket.remotePort + '\n')
socket.write('connection closed')
socket.destroy()
}
})
}
function newConnectionHandler(socket,clientAddress){
//console.log(sock)
socket.write('Welcome \n')
socket.on('data', function(data1){
console.log("Client Sent: " + data1);
});
socket.once('close', (data) => {
let index = sock.findIndex((o) => {
return o.remoteAddress === socket.remoteAddress && o.remotePort === socket.remotePort;
})
if (index !== -1) sock.splice(index, 1);
sock.forEach((sock) => {
socket.write(`${clientAddress} disconnected\n`);
});
console.log(`connection closed: ${clientAddress}`);
});
}
/* function createConnection(){
// Start a connection to the server
var socket = server.on('connect',function(){
// Send the initial message once connected
socket.write({question: "Hello, world?"});
});
// Whenever the server sends us an object...
socket.on('data', function(data){
// Output the answer property of the server's message to the console
console.log("Server's answer: " + data.answer);
});
} */
})
server.listen(port, host, () => {
console.log('TCP Server is running on port ' + port + '.');
});
so it appears as the only bit of code that was causing the authentication loop was the
function userAuth(socket,clientAddress){
socket.write('password : ' )
**socket.on('data', function (data) {**
let pass = data.toString()
after changing "on" with "once" it is now functioning properly. I tested with two TCP clients, both connected and was asked to enter a password. They can both actively send messages to the server and both disconnected properly in the end.
this is the code if anyone finds any use for it :) the connection it's self is still unencrypted so not good for sending/receiving sensitive data.
const net = require('net');
const port = 3001;
const host = '192.168.0.165';
const server = net.createServer()
let sock = [];
let password = 123
//server.on('listening',createConnection);
server.on('connection', (socket) => {
let clientAddress = `${socket.remoteAddress}:${socket.remotePort}`;
console.log(clientAddress)
if(sock.indexOf(clientAddress) !== -1){
console.log('devie found, opening communication')
newConnectionHandler(socket,clientAddress)
} else {
console.log('devie not found, need to authenticate')
userAuth(socket,clientAddress)
}
})
server.on('error', errorHandler);
function errorHandler(err){
console.log(`Error occurred in ${clientAddress}: ${err.message}`);
}
function userAuth(socket,clientAddress){
socket.write('password : ' )
socket.once('data', function (data) {
let pass = data.toString()
if (pass == password) {
sock.push(clientAddress);
console.log(sock)
newConnectionHandler(socket,clientAddress)
return;
} else {
//console.log(pass)
socket.write('Sorry, you cannot access the server \n')
console.log('acess denied for ' + socket.remoteAddress + ':' + socket.remotePort + '\n')
socket.write('connection closed')
socket.destroy()
}
})
}
function newConnectionHandler(socket,clientAddress){
//console.log(sock)
socket.write('Welcome \n')
socket.on('data', function(data1){
console.log("Client Sent: " + data1);
});
socket.on('close', function(data) {
let index = sock.findIndex(function(o) {
return o.remoteAddress === sock.remoteAddress && o.remotePort === sock.remotePort;
})
if (index !== -1) sock.splice(index, 1);
console.log('CLOSED: ' + socket.remoteAddress + ' ' + socket.remotePort);
});
}
/* function createConnection(){
// Start a connection to the server
var socket = server.on('connect',function(){
// Send the initial message once connected
socket.write({question: "Hello, world?"});
});
// Whenever the server sends us an object...
socket.on('data', function(data){
// Output the answer property of the server's message to the console
console.log("Server's answer: " + data.answer);
});
} */
server.listen(port, host, () => {
console.log('TCP Server is running on port ' + port + '.');
});
var net = require('net');
var HOST = '0.0.0.0';
var PORT = 5000;
// Create a server instance, and chain the listen function to it
// The function passed to net.createServer() becomes the event handler for the 'connection' event
// The sock object the callback function receives UNIQUE for each connection
net.createServer(function(sock) {
// We have a connection - a socket object is assigned to the connection automatically
console.log('CONNECTED: ' + sock.remoteAddress +':'+ sock.remotePort);
// Add a 'data' event handler to this instance of socket
sock.on('data', function(data) {
console.log('DATA ' + sock.remoteAddress + ': ' + data);
// Write the data back to the socket, the client will receive it as data from the server
if (data === "exit") {
console.log('exit message received !')
}
});
// Add a 'close' event handler to this instance of socket
sock.on('close', function(data) {
console.log('CLOSED: ' + sock.remoteAddress +' '+ sock.remotePort);
});
}).listen(PORT, HOST);
console.log('Server listening on ' + HOST +':'+ PORT);
No matter what I try, I cannot get:
if (data === "exit") {
console.log('exit message received !')
}
working, it's always false.
I'm connecting via telnet and sending "exit", the server should then go into the "if" loop and say "exit message received". This never happens, can someone shed some light ? thanks
That's because data is not a string, if you try to compare with === you will get false because types don't match.
To solve it you should compare the data object with a simple == or use socket.setEncoding('utf8') previous to binding the data event.
https://nodejs.org/api/net.html#net_event_data
var net = require('net');
var HOST = '0.0.0.0';
var PORT = 5000;
net.createServer(function(sock) {
console.log('CONNECTED:',sock.remoteAddress,':',sock.remotePort);
sock.setEncoding("utf8"); //set data encoding (either 'ascii', 'utf8', or 'base64')
sock.on('data', function(data) {
console.log('DATA',sock.remoteAddress,': ',data,typeof data,"===",typeof "exit");
if(data === "exit") console.log('exit message received !');
});
}).listen(PORT, HOST, function() {
console.log("server accepting connections");
});
Note.
If the data received is going to be big you should concatenate and handle the message comparison at the end of it. Check other questions to handle those cases:
Node.js net library: getting complete data from 'data' event
I am aware this is quite an old post, when I tried to implement the code in the answer to this question I came across the same problem regardless of having used "==" or utf8 encoding. The issue for me turned out to be that the client I was using was appending a '\n' character to the end of the exit message thus causing the string comparison to fail on the server. Perhaps this is not an issue with telnet and the like but this was the case with netcat. Hopefully this sheds some light for anyone else who comes across this post and has the same problem that I did.
I made an application to the control of simultaneous logins, in starts everything works perfectly, however after a few hours i can not longer connect to the server, my client returns me the following error: net :: ERR_CONNECTION_TIMED_OUT and on the server side does not happen any error like it was running correctly... code below:
CLIENT SIDE:
var socket;
function connect(id) {
socket = io.connect('http://IP:4200');
socket.on('connect', function (data) {
socket.emit('join', id);
});
socket.on('messages', function (data) {
console.log('MSG: ' + data.toString());
switch (data.toString()) {
case "kick":
socket.close();
console.log("KICK!");
break;
case "duplicate_entry":
socket.close();
console.log("Another user connection!");
break;
}
});
}
SERVER SIDE:
var express = require('express');
var app = express();
var server = require('http').createServer(app);
var io = require('socket.io')(server);
var clients = [];
app.use(express.static(__dirname + '/bower_components'));
function logtimestamp() {
var log_date = new Date();
log_date = '[' + log_date.getFullYear() + '/' + (log_date.getMonth() + 1) + '/' + log_date.getDate() + ' ' + log_date.getHours() + ':' + log_date.getMinutes() + ':' + log_date.getSeconds() + ']';
return log_date;
}// FUNCTION logtimestamp
console.log("Start time: " + logtimestamp());
console.log("Server port 4200")
console.log("websocket server created!");
try {
io.on('connection', function (client) {
try {
var id;
var conexao;
client.on('join', function (data) {
try {
console.log('Client connected...'+logtimestamp()+' ID:' + data);
id = data;
conexao = {
ws: client,
id_user: data
};
clients.push(conexao);
for (var x = 0; x < clients.length; x++) {
//desconect previous user
try {
if (clients[x].id_user == id) {
if (clients[x].ws != conexao.ws) {
clients[x].ws.emit('messages', 'duplicate_entry');
clients.splice(x, 1);
}
}
} catch (err) {
console.log("ERROR 1: " + err.message);
}
}
} catch (err) {
console.log("ERROR 2: " + err.message);
}
});
} catch (err) {
console.log("ERROR 3: " + err.message);
}
});
} catch (err) {
console.log("ERROR 4: " + err.message);
}
server.listen(4200);
I see a couple possible issues. It is hard for us to know by just inspecting code which issues actually are the cause of your issue. In any case, you should clean up these issues and see if it improves the situation:
You should respond the the disconnect event and immediately remove any socket from your clients array when it disconnects.
In your loop where you are looking to removing any prior instances of a given user, your for loop will not work properly when you are doing .splice(x, 1) in the middle of the for loop. This will move all items after it does one in the array causing you to skip the comparison of the next element in the array. One simple way to get around this is to iterate the array backwards: for (var x = clients.length - 1; x >= 0; x--) because then the elements who's position are affected after the .splice() are elements you have already looked at. None will be missed.
Beyond this, you should examine the memory usage of the nodejs process, the open sockets by the nodejs process and the CPU usage of the nodejs process to see if any of those point to any possible issues.
And, what is your deployment environment? Is there a proxy server in front of your web server?
I am in a trouble while coding ssh2 module in my project. I tried to run multiple commands on one terminal for ruling remote Linux system. For example "bc" command provides you a basic calculator and you can run it for basic operations. but that kind of processes need to be awake when you are using (it will accepts two or more input and it will give a response as a result).
I need to create a system like work with websocket and ssh. When a websocket received a command ,ssh node need to execute this message and Module need to send it's response via websocket.send()
I am using Node.js websocket,ssh2 client.
Here my code :
#!/usr/bin/node
var Connection = require('ssh2');
var conn = new Connection();
var command="";
var http = require('http');
var WebSocketServer = require('websocket').server;
var firstcom=true;
conn.on('ready', function() {
console.log('Connection :: ready');
// conn.shell(onShell);
});
var onShell = function(err, stream) {
// stream.write(command+'\n');
stream.on('data', function(data) {
console.log('STDOUT: ' + data);
});
stream.stderr.on('data', function(data) {
console.log('STDERR: ' + data);
});
}
var webSocketsServerPort=5000;
var ssh2ConnectionControl=false;
var server = http.createServer(function (req, res) {
//blahbalh
}).listen(webSocketsServerPort, function() {
console.log((new Date()) + " Server is listening on port:: " + webSocketsServerPort);
});
//console.log((new Date()) + 'server created');
wsServer = new WebSocketServer({
httpServer: server,
// autoAcceptConnections: false
});
wsServer.on('request', function(request) {
console.log((new Date()) + ' Connection from origin ' + request.origin + '.');
var wsconnection = request.accept('echo-protocol', request.origin);
console.log((new Date()) + ' Connection accepted.');
if(!ssh2ConnectionControl){
conn.connect({
host: 'localhost',
port: 22,
username: 'attilaakinci',
password: '1'
});
ssh2ConnectionControl=true;
console.log('SSH Connected.');
}
wsconnection.on('message', function(message) {
if (message.type === 'utf8') {
console.log('Received Message: ' + message.utf8Data);
command=message.utf8Data;
//if(firstcom){
// conn.shell(onShell);
// firstcom=false;
//}else{
conn.exec(message.utf8Data,onShell);
//}
wsconnection.send(message.utf8Data);
}
else{
console.log('Invalid message');
}
});
wsconnection.on('close', function(reasonCode, description) {
console.log((new Date()) + ' Peer ' + wsconnection.remoteAddress + ' disconnected.');
});
});
You should use conn.shell() instead of conn.exec() if you want a real interactive shell. conn.exec() is typically for executing one-liner commands, so it does not persist "shell state" between conn.exec() calls (e.g. working directory, etc.).
You should also be aware of possible limits by your SSH server has set up as far as how many simultaneous shell/exec requests are allowed per connection. I think the default limit for this on OpenSSH's server is 10.
This is an old question but I wanted to provide a alternative method usings sh2shell which wraps ssh2.shell by mscdex, used above. The example below only covers making the ssh connection, running the commands and processing the result.
Using ssh2shel it is possible to run any number of commands sequentually in the context of the previous commands in the same shell session and then return the output for each command (onCommandComplete event) and/or return all session text on disconnection using a callback function.
See the ssh2shell readme for examples and lots of info. There are also tested scripts for working code examples.
var host = {
//ssh2.client.connect options
server: {
host: 120.0.0.1,
port: 22,
userName: username,
password: password
},
debug: false,
//array of commands run in the same session
commands: [
"echo $(pwd)",
command1,
command2,
command3
],
//process each command response
onCommandComplete: function( command, response, sshObj) {
//handle just one command or do it for all of the each time
if (command === "echo $(pwd)"){
this.emit("msg", response);
}
}
};
//host object can be defined earlier and host.commands = [....] set repeatedly later with each reconnection.
var SSH2Shell = require ('ssh2shell');
var SSH = new SSH2Shell(host),
callback = function( sessionText ){
console.log ( "-----Callback session text:\n" + sessionText);
console.log ( "-----Callback end" );
}
SSH.connect(callback)
To see what is happening at process level set debug to true.
I'm trying to change a working code that doesn't have any control flow to display when everything is done how much change were done. WIthout control flow, it's not possible.
To do so, I'm trying async, but I'm a bit confused here.
Old code:
public static populate(){
// Read all files inside the populate folder.
fs.readdir(__config.path.populate, function(err, files){
if(err){
consoleDev(err);
}else{
// For each file, get the data to populate stored in the file.
_.each(files, function(file){
_.each(require(__config.path.base + __config.path.populate + file), function(documents){
// The file name must be the same as the targeted model.
var Model = __Dao.getModel(file.split('.')[0]);// Filter the extension.
if(Model){
// For each data, try to add it if it does not exist in the DB.
Model.findOrCreate(documents, function(err, doc, created){
if(created){
consoleDev('The following document was created in the [' + Model.modelName + '] collection: ' + JSON.stringify(doc));
}
});
}else{
consoleDev('Unable to populate the file: ' + file + '. The model was not found.')
}
});
});
}
});
}
New code:
public static populate(){
// Read all files inside the populate folder.
fs.readdir(__config.path.populate, function(err, files){
if(err){
consoleDev(err);
}else{
_.each(files, function(file){
// Read all files in async mode with control flow.
async.each(require(__config.path.base + __config.path.populate + file), function(documents, callback){
// The file name must be the same as the targeted model.
var Model = __Dao.getModel(file.split('.')[0]);// Filter the extension.
if(Model){
// For each data, try to add it if it does not exist in the DB.
Model.findOrCreate(documents, function(err, doc, created){
if(created){
consoleDev('The following document was created in the [' + Model.modelName + '] collection: ' + JSON.stringify(doc));
Populate._added++;
}else{
Populate._read++;
}
callback();
});
}else{
callback('Unable to populate the file: ' + file + '. The model was not found.')
}
});
}, function(err){
if(err){
console.log(err);
}
consoleDev(Populate._added + ' documents were added. There are now ' + Populate._read + ' + ' + Populate._added + ' = ' + (Populate._read + Populate._added) + ' documents populated.');
});
}
});
}
Nothing is showed on the console at the end and I don't have any error on the console. The script still works and add documents that wasn't present in the DB before. But I still don't have a message saying me how much were added.
I tried to do async.each(files, function(file, callback){ instead but I get the error Error: Callback was already called..
What am I missing here?