tcp-base
v3.2.0
Published
A base class for tcp client with basic functions
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tcp-base
A base class for tcp client with basic functions
Install
npm install tcp-base --save
Node.js >= 6.0.0 required
Usage
A quick guide to implement a tcp echo client
Client:
const TCPBase = require('tcp-base');
/**
* A Simple Protocol:
* (4B): request id
* (4B): body length
* ------------------------------
* body data
*/
class Client extends TCPBase {
getHeader() {
return this.read(8);
}
getBodyLength(header) {
return header.readInt32BE(4);
}
decode(body, header) {
return {
id: header.readInt32BE(0),
data: body,
};
}
// heartbeat packet
get heartBeatPacket() {
return Buffer.from([ 255, 255, 255, 255, 0, 0, 0, 0 ]);
}
}
const client = new Client({
host: '127.0.0.1',
port: 8080,
});
const body = Buffer.from('hello');
const data = Buffer.alloc(8 + body.length);
data.writeInt32BE(1, 0);
data.writeInt32BE(body.length, 4);
body.copy(data, 8, 0);
client.send({
id: 1,
data,
timeout: 5000,
}, (err, res) => {
if (err) {
console.error(err);
}
console.log(res.toString()); // should echo 'hello'
});
Server:
'use strict';
const net = require('net');
const server = net.createServer(socket => {
let header;
let bodyLen;
function readPacket() {
if (bodyLen == null) {
header = socket.read(8);
if (!header) {
return false;
}
bodyLen = header.readInt32BE(4);
}
if (bodyLen === 0) {
socket.write(header);
} else {
const body = socket.read(bodyLen);
if (!body) {
return false;
}
socket.write(Buffer.concat([ header, body ]));
}
bodyLen = null;
return true;
}
socket.on('readable', () => {
try {
let remaining = false;
do {
remaining = readPacket();
}
while (remaining);
} catch (err) {
console.error(err);
}
});
});
server.listen(8080);