first commit

lib/telnetserver.js

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+'use strict'
+
+const net = require('net')
+
+let server = null
+let sockets = []
+
+// cleans the input of carriage return, newline
+const cleanInput = data => data.toString().replace(/(\r\n|\n|\r)/gm, '')
+
+// executed when data is received from a socket
+const receiveData = (socket, data) => {
+  const cleanData = cleanInput(data)
+  if (cleanData === "@quit") {
+    socket.end('Goodbye!\n')
+  } else {
+    for (let i = 0; i < sockets.length; i++) {
+      if (sockets[i] !== socket) {
+        sockets[i].write(data)
+      }
+    }
+  }
+}
+
+// executed when a socket ends
+const closeSocket = socket => {
+   const i = sockets.indexOf(socket)
+   if (i != -1) sockets.splice(i, 1)
+}
+
+// callback method executed when a new TCP socket is opened
+const newSocket = socket => {
+   sockets.push(socket)
+   socket.write('Welcome to the Telnet server!\n')
+   socket.on('data', data => receiveData(socket, data))
+   socket.on('end', () => closeSocket(socket))
+}
+
+// create a new server
+module.exports = (port) => { 
+  if (server === null) server = net.createServer(newSocket).listen(port)
+  return server
+}