TCP echo server for Node.js

README.md

TCP echo server for Node.js

Usage

1. Make sure you have a modern-ish version of Node.js installed.
2. Type npx https://gist.github.com/kfox/1280c2f0ee8324067dba15300e0f2fd3
3. Connect to it from a client, e.g. netcat or similar: nc localhost 9000

echo.mjs

#!/usr/bin/env node

import net from 'node:net'

const port = process.argv[2] || 9000

const server = net.createServer((connection) => {
  const { address, port } = connection.address()
  const socket = `${address}:${port}`

  console.log(`${socket} - client connected`)

  connection.on('data', (data) => {
    console.log(`${socket} - client sent: %s`, String(data).trim())
    connection.write(data)
  })

  connection.on('end', () => {
    console.log(`${socket} - client disconnected`)
  })
})

server.listen({ port }, () => {
  const { address, port } = server.address()
  console.log('listening on %s:%d', address, port)
})

package.json

{
  "name": "tcp-echo-server",
  "version": "1.0.0",
  "bin": "./echo.mjs"
}

Doesn't work from npx for me 😢

✗ npx https://gist.github.com/kfox/1280c2f0ee8324067dba15300e0f2fd3
Need to install the following packages:
  tcp-echo-server@1.0.0
Ok to proceed? (y) y
/var/folders/zm/m0hqdgz50n3f3h5ccv2lb49r0000gn/T/npx69462768599.sh: line 2: tcp-echo-server: command not found

Also, npx -v === 8.13.2

Doesn't work from npx for me 😢

✗ npx https://gist.github.com/kfox/1280c2f0ee8324067dba15300e0f2fd3
Need to install the following packages:
  tcp-echo-server@1.0.0
Ok to proceed? (y) y
/var/folders/zm/m0hqdgz50n3f3h5ccv2lb49r0000gn/T/npx69462768599.sh: line 2: tcp-echo-server: command not found

Also, npx -v === 8.13.2

You need a newer version of node, which should also update npx. I'm not sure what the minimum version numbers for each binary are, but if you are running on a more recent version it should work. I have the following versions installed:

⮑  node -v
v20.6.1
⮑  npx -v
10.1.0
⮑  npx https://gist.github.com/kfox/1280c2f0ee8324067dba15300e0f2fd3
listening on :::9000

Amazing, it works now! Super cool idea, by the way