Net-cat

How to start

Server:

[USAGE]: go run ./cmd/server/ *port*
$ go run ./cmd/server/ 8989
Listening on the port :8989
$ go run ./cmd/server/ 2525
Listening on the port :2525
$ go run ./cmd/server/ 2525 localhost
[USAGE]: ./TCPChat $port
$

Client:

$ go run ./cmd/client *host* *port*
for example
$ go run ./cmd/client localhost 8989

Objectives

This project consists on recreating the NetCat in a Server-Client Architecture that can run in a server mode on a specified port listening for incoming connections, and it can be used in client mode, trying to connect to a specified port and transmitting information to the server.

• NetCat, nc system command, is a command-line utility that reads and writes data across network connections using TCP or UDP. It is used for anything involving TCP, UDP, or UNIX-domain sockets, it is able to open TCP connections, send UDP packages, listen on arbitrary TCP and UDP ports and many more.

• To see more information about NetCat inspect the manual man nc.

This project must work in a similar way that the original NetCat works, in other words, you must create a group chat. The project must have the following features :

• TCP connection between server and multiple clients (relation of 1 to many).
• A name requirement to the client.
• Control connections quantity.
• Clients must be able to send messages to the chat.
• Do not broadcast EMPTY messages from a client.
• Messages sent, must be identified by the time that was sent and the user name of who sent the message, example : [2020-01-20 15:48:41][client.name]:[client.message]
• If a Client joins the chat, all the previous messages sent to the chat must be uploaded to the new Client.
• If a Client connects to the server, the rest of the Clients must be informed by the server that the Client joined the group.
• If a Client exits the chat, the rest of the Clients must be informed by the server that the Client left.
• All Clients must receive the messages sent by other Clients.
• If a Client leaves the chat, the rest of the Clients must not disconnect.
• If there is no port specified, then set as default the port 8989. Otherwise, program must respond with usage message: [USAGE]: ./TCPChat $port

Instructions

• Project must be written in Go
• Start TCP server, listen and accept connections
• Project must have Go-routines
• Project must have channels or Mutexes
• Maximum 10 connections
• The code must respect the good practices
• It is recommended to have test files for unit testing both the server connection and the client.

Allowed Packages

• io
• log
• os
• fmt
• net
• sync
• time
• bufio
• errors
• strings
• reflect

This project will help learn about :

• Manipulation of structures.
• Net-Cat
• TCP/UDP
  • TCP/UDP connection
  • TCP/UDP socket
• Go concurrency
  • Channels
  • Goroutines
• Mutexes
• IP and ports