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Dsysd Dev

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Let’s build our own protocol using tcp and net package in go, part 1

Building your own protocol using the TCP package in Go involves defining a set of rules for communication between a client and a server.

These rules determine how data is structured, how messages are framed, and how the client and server interact.

We are going to build our own custom protocol.

But before that we must know how to implement a custom net connection in golang where we have a server and clients connect to the server.

The clients sends messages to the server and we simply print those messages.

If you prefer the video format with indepth explanation

Explaining the code

func main() {
 // Create a TCP listener on localhost:3000
 l, err := net.Listen("tcp", "localhost:3000")
 if err != nil {
  log.Fatalln("couldn't listen to network")

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main Function: This is the entry point of the program. It does the following.

It attempts to create a TCP listener on localhost at port 3000 using the net.Listen function.

If an error occurs during this process, it logs an error message and exits the program using log.Fatalln .

 for {
  conn, err := l.Accept()
  if err != nil {
   log.Fatalln("err while accept", err)
  go handle(conn)
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Accepting Connections: Inside an infinite for loop, the code does the following...

It waits for incoming client connections using l.Accept() . When a client connection is accepted, it returns a new connection object (conn) and any potential errors.

If an error occurs during the acceptance of a connection, it logs an error message and continues listening for connections.

When a connection is successfully accepted, it spawns a new goroutine by calling the handle function with the conn as an argument.

This allows the server to handle multiple client connections concurrently.

func handle(conn net.Conn) {
 // We keep reading all the messages from the connection
 // until the connection is closed.
 fmt.Println("connected to: ", conn.RemoteAddr())
 for {
  var buffer [1024]byte // 1KB buffer to read data
  _, err := conn.Read(buffer[:])
  if err != nil {
   log.Printf("err while reading from conn: %v, exiting ...", err)
  fmt.Println("message read: ", string(buffer[:]))
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handle Function: This function is called for each client connection. It handles the communication with connected clients.

It prints a message indicating that a connection has been established, including the remote address of the client.

Inside a loop, it uses a 1KB buffer (buffer) to read data from the client connection using conn.Read().

If an error occurs while reading data from the client, it logs an error message and returns from the function, effectively closing the connection.

Otherwise, it prints the received message to the console.

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Top comments (1)

koteisaev profile image
Kote Isaev - #StandWithUkraine

Is there "anti-clap" function here?
I expected it will be example of some protocol built, with coverage some common mistakes in design of text of binary protocols, with making some protocol in process.
Headline was too "ambitious"