maeqtt/session/connection.go

package session

import (
	"bufio"
	"errors"
	"io"
	"log"
	"time"

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

type Connection struct {
	MaxPacketSize   *uint32
	RecvMax         uint16
	TopicAliasMax   uint16
	WantsRespInf    bool
	WantsProblemInf bool
	Will            packets.Will

	KeepAliveInterval time.Duration
	keepAliveTicker   time.Ticker

	PacketChannel          chan packets.ClientPacket
	ClientDisconnectedChan chan bool

	rw io.ReadWriteCloser
}

func (c *Connection) resetKeepAlive() {
	if c.KeepAliveInterval != 0 {
		panic("TODO")
		// TODO IMPLEMENT THIS
		//s.keepAliveTicker.Reset(s.KeepAliveInterval)
	}
}

func (c *Connection) readPacket() (*packets.ClientPacket, error) {
	return packets.ReadPacket(bufio.NewReader(c.rw))
}

func (c *Connection) sendPacket(p packets.ServerPacket) error {
	c.resetKeepAlive()
	return p.Write(c.rw)
}

func (c *Connection) close() error {
	close(c.PacketChannel)
	return c.rw.Close()
}

func (c *Connection) PacketReadLoop() {
	for {
		pack, err := c.readPacket()
		if err != nil {
			c.ClientDisconnectedChan <- true
			c.close()
		} else {
			c.PacketChannel <- *pack
		}
	}
}

var FirstPackNotConnect error = errors.New("Failed to connect, first packet is not connect")

func NewConnection(rw io.ReadWriteCloser) (ConnectionRequest, error) {
	connReq := ConnectionRequest{}

	conn := Connection{}
	connReq.Connection = &conn

	conn.rw = rw
	packet, err := conn.readPacket()
	conPack, isConn := (*packet).(packets.ConnectPacket)
	if !isConn {
		log.Println("Didn't receive a connect packet")
		err := packets.DisconnectPacket{
			ReasonCode: packets.DisconnectReasonCodeProtocolError,
		}.Write(rw)
		if err != nil {
			log.Println("Failed to disconnect after not receiving a connect packet", err)
		}
		return connReq, FirstPackNotConnect
	}
	connReq.ConnectPakcet = conPack

	if conPack.Properties.ReceiveMaximum.Value != nil {
		conn.RecvMax = *conPack.Properties.ReceiveMaximum.Value
	} else {
		conn.RecvMax = 65535
	}
	conn.MaxPacketSize = conPack.Properties.MaximumPacketSize.Value

	if conPack.Properties.TopicAliasMaximum.Value != nil {
		conn.TopicAliasMax = *conPack.Properties.TopicAliasMaximum.Value
	} else {
		conn.TopicAliasMax = 0
	}

	if conPack.Properties.RequestProblemInformation.Value != nil {
		conn.WantsRespInf = *conPack.Properties.RequestProblemInformation.Value != 0
	} else {
		conn.WantsRespInf = false
	}

	conn.KeepAliveInterval = time.Duration(conPack.KeepAliveInterval) * time.Second

	conn.PacketChannel = make(chan packets.ClientPacket, 1)

	return connReq, err
}