I'm working with net in node.js and I'm sending packet to a server and listening to the response, but I can't manage to return it. Here's my code:
function packetsend (sockeT, packeT) {
var resp = null;
if(sockeT) {
sockeT.write(packeT);
sockeT.on('data', (data) => {
resp = data.toString()
})
}
return resp;
}
const socket = new net.Socket();
socket.connect({host: server, port: port}, function() {
console.log('Connected');
var packetRecv = packetsend(socket, 'some packet');
if (packetRecv === 'some') {
console.log("ok");
}
})
I don't understand why packetsend() function is not returning the updated resp variable, and sends undefined object instead. When I do console.log(data) inside the sockeT.on() I see that it receives data.
Try transforming your packetsend() function in an async function. Maybe it's not returning the resp because you return it before the event 'data' is invoked.
This is just an example of a possible implementation:
function packetsend (sockeT, packeT) {
return new Promise((resolve, reject) => {
if (sockeT) {
sockeT.write(packeT);
sockeT.on('data', (data) => {
resolve(data.toString());
});
//WARNING: I don't know this 'socketT' object, don't know if there is an 'error' event.
//but it's recommended to handle errors. This is just an example.
sockeT.on('error', (error) => {
reject(error);
});
}
else{
reject('Missing sockeT');
}
});
}
const socket = new net.Socket();
socket.connect({ host: server, port: port }, function () {
console.log('Connected');
packetsend(socket, 'some packet').then(packetRecv => {
console.log('Received data => '+ packetRecv);
if (packetRecv === 'some') {
console.log("ok");
}
}).catch(error => console.log(error));
})
Update: you can also use the async/await
const socket = new net.Socket();
socket.connect({ host: server, port: port }, async function () {
try {
console.log('Connected');
let packetRecv = await packetsend(socket, 'some packet');
console.log('Received data => '+ packetRecv);
if (packetRecv === 'some') {
console.log("ok");
}
}
catch (error) {
console.log(error);
}
});
Tips: