StoreBackEnd/pkg/network/ClientMulticast.go

package network

import (
	"StoreBackEnd/pkg/protocol/repository"
	"StoreBackEnd/pkg/protocol/rules/writers"
	"StoreBackEnd/pkg/utils"
	"fmt"
	"net"
	"time"
)

// CreateClientMulticast Méthode de construction d'un instance de la stuct ClientMulticast
func CreateClientMulticast(netInterface string, address string, domain string, port int, second time.Duration, repository *repository.ProtocolRepository) ClientMulticast {
	return ClientMulticast{
		netInter:   netInterface,
		address:    address,
		domain:     domain,
		port:       port,
		second:     second,
		repository: repository,
	}
}

// ClientMulticast Cette structure représente une communication en multicast.
// TODO : Prévoir une fermeture de la connection (con.Close())
type ClientMulticast struct {
	// netInter Interface réseaux multicast
	netInter string
	// address Adresse de multicast
	address string
	// address Domain de du StoreBackEnd
	domain string
	// port Port de connexion en unicast
	port int
	// second Temps en seconde entre chaque ping
	second time.Duration
	// repository de protocol permettant de
	repository *repository.ProtocolRepository
}

// Run Cette méthode démarre une commmunication multicast
func (client ClientMulticast) Run() {
	// Resolve multicast addr
	rAddr, failedRA := client.ResolveAddr()
	if failedRA {
		return
	}

	// Resolve interface addr
	lAddr, failedRIA := ResolveInterfaceAddr(client.netInter)
	if failedRIA {
		println("Error : No IPv4 found in interface")
		return
	}

	// Init UDP server flux
	con, failedDU := client.DialUdp(lAddr, rAddr)
	if failedDU {
		return
	}

	writerResult := client.repository.ExecuteWriter(writers.HelloRulePrefix, client.domain, fmt.Sprintf("%d", client.port))
	if writerResult == nil {
		println("[ClientMulticast] Hello rule isn't correct")
		return
	}

	for {
		_, _ = con.Write([]byte(writerResult.Cmd))
		time.Sleep(time.Second * client.second)
	}
}

// ResolveAddr Permet de résoude l'addresse multicast
func (client ClientMulticast) ResolveAddr() (*net.UDPAddr, bool) {
	addr, err := net.ResolveUDPAddr("udp", client.address)
	if err != nil {
		println(err.Error())
		return nil, true
	}
	return addr, false
}

// ResolveInterfaceAddr Resolves the network interface address.
func ResolveInterfaceAddr(inter string) (*net.UDPAddr, bool) {
	ip, err := utils.RetrieveIPv4FromInterface(inter)
	if err != nil {
		println("Error : " + err.Error())
		return nil, true
	}
	println("Selected IP : " + ip.String())
	return &net.UDPAddr{IP: ip}, false
}

// DialUdp Ouvre une connection UDP
func (client ClientMulticast) DialUdp(lAddr *net.UDPAddr, rAddr *net.UDPAddr) (*net.UDPConn, bool) {
	con, errDial := net.DialUDP("udp", lAddr, rAddr)
	if errDial != nil {
		println(errDial.Error())
		return nil, true
	}
	return con, false
}