Light http over tcp server as an example of net package in Go

server.go

package main

import ("fmt"; "io"; "net"; "strings"; "sync/atomic")

var clientsCount int64 = 0

func main() {
	server, _ := net.Listen("tcp", "127.0.0.1:28563")
	defer server.Close()

	for {
		connection, err := server.Accept()
		if (err == nil) { go processClient(connection) }
	}
}

func processClient(socket net.Conn) {
	atomic.AddInt64(&clientsCount, 1); defer atomic.AddInt64(&clientsCount, -1)
	fmt.Printf("%d concurrent clients are connected\n", atomic.LoadInt64(&clientsCount))

	toProcess, buffer := "", make([]byte, 2048)
	defer socket.Close()

	for {
		count, err := socket.Read(buffer)

		if err == io.EOF || count == 0 {
			break // client closed the connection
		}

		request := toLF(string(buffer[:count]))
		queries := strings.Split(toProcess + request, "\n\n")
		toProcess, queries = queries[len(queries)-1], queries[:len(queries)-1]

		for _, query := range queries {
			// Return an HTTP-answer with the 8th char of the original request
			socket.Write([]byte("HTTP/1.1 200 OK\nServer: super fast mexmat server\nContent-Type: text/html\nContent-Length: 1\n\n"))

			if len(query) > 7 {
				socket.Write([]byte{ query[7] })
			}
		}
	}
}

func toLF(s string) string { return strings.Replace(s, "\r\n", "\n", -1) }