maeqtt/main.go

package main

import (
	"bufio"
	"log"
	"net"
	"runtime/debug"

	"badat.dev/maeqtt/v2/mqtt/packets"
	"badat.dev/maeqtt/v2/session"
)

func main() {
	listen_addr := ":1883"
	listener, err := net.Listen("tcp", listen_addr)

	if err != nil {
		log.Fatal(err)
	}

	for {
		conn, err := listener.Accept()
		if err != nil {
			log.Println("Failed accepting connection ", err)
		}
		go handleConnection(conn)
	}
}

func handleConnection(con net.Conn) {
	defer handlePanic(con)

	reader := bufio.NewReader(con)

	packet, err := packets.ReadPacket(reader)
	if err != nil {
		log.Println("Error reading packet ", err)
		return
	}
	connect, isConn := (*packet).(packets.ConnectPacket)
	if !isConn {
		log.Println("Didn't recieve a connect packet")
		err := packets.DisconnectPacket{
			ReasonCode: packets.DisconnectReasonCodeProtocolError,
		}.Write(con)
		if err != nil {
			log.Println("Failed to disconnect after not recieving a connect packet", err)
		}
		return
	}

	conn := session.NewConnection(connect, con)
	sess := session.NewSession(&conn, connect)

	sess.HandlerLoop()
}

func handlePanic(con net.Conn) {
	if r := recover(); r != nil {
		log.Println("Recovering from panic:", r)
		log.Println("Stack Trace:")
		debug.PrintStack()

		err := packets.DisconnectPacket{
			ReasonCode: packets.DisconnectReasonCodeImplErorr,
		}.Write(con)
		if err != nil {
			log.Println("Failed to send a disconnect packet after recovering from panic", err)
		}
	}
}