node-tcp-netcat-error

main.js

import TCP from "net"
import Promise from "Bluebird"

const log = console.log



/* TODO

WHY IS THIS HAPPENING?

Observe, a socket-object error on server with client:

  TERMINAL 1
  netcat localhost 9000
  Hello.
  Goodbye.

  TERMINAL 2
  ==> A Connection connected
  ==> The Server is disconnecting a connection
  { [Error: read ECONNRESET] code: 'ECONNRESET', errno: 'ECONNRESET', syscall: 'read' }

Now observe, no socket-object error on server with client:

  TERMINAL 1
  telnet localhost 9000
  Trying ::1...
  Connected to localhost.
  Escape character is '^]'.
  Hello.
  Goodbye.
  Connection closed by foreign host.

  TERMINAL 2
  ==> A Connection connected
  ==> The Server is disconnecting a connection
  ==> A Connection disconnected
*/





const server = TCP.createServer((conn) => {

  conn.setEncoding('utf8')

  log("==> A Connection connected")

  conn.write("Hello.\n", async function () {
    await Promise.delay(3000)
    if (!conn.destroyed) {
      log("==> The Server is disconnecting a connection")
      conn.end("Goodbye.\n")
    }
  })

  conn.on("error", log)

  conn.on("end", () => {
    log("==> A Connection disconnected")
  })

  conn.on("data", (message) => {
    log("==> A Connection says:\n%s", message)
  })
})



const port = 9000

server.listen(port, () => {
  log(`==> The Server is listening on port ${port}`)
})