144 lines
2.5 KiB
Go
144 lines
2.5 KiB
Go
package server
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import (
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"encoding/binary"
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"fmt"
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"io"
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"log"
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"net"
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"strconv"
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)
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const (
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MsgKeyPress uint16 = 1
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MsgGameState uint16 = 2
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MSGServerStatus uint16 = 3
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MSGOnConnect uint16 = 4
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MSGOnPlayerConnect uint16 = 5
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)
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var num_clients int = 0
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var clients = make(map[string]client)
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type client struct {
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x uint
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y uint
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client_id string
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conn net.Conn
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}
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func Start() {
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listener, err := net.Listen("tcp", ":9000")
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if err != nil {
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log.Fatal(err)
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}
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fmt.Println("Server listening on port 9000")
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for {
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conn, err := listener.Accept()
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if err != nil {
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fmt.Println("Accept error:", err)
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continue
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}
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// client connects
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num_clients += 1
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client_id := strconv.Itoa(num_clients)
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fmt.Println(client_id)
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go SendPacket(MSGOnConnect, []byte(client_id))
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go SendPacket(MSGOnPlayerConnect, []byte(client_id))
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addClient(conn, client_id)
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go handle(conn)
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}
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}
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func addClient(conn net.Conn, id string) {
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var new_client client = client{
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client_id: id,
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conn: conn,
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}
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clients[id] = new_client
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}
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func SendPacket(msgID uint16, payload []byte) error {
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// Length matches Lua: 2 (msgID) + payload size
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length := uint32(2 + len(payload))
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buf := make([]byte, 4+2+len(payload))
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binary.BigEndian.PutUint32(buf[0:4], length)
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binary.BigEndian.PutUint16(buf[4:6], msgID)
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copy(buf[6:], payload)
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for _, client := range clients {
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n, err := client.conn.Write(buf)
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if err != nil {
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return err
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}
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if n != len(buf) {
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return fmt.Errorf("short write: expected %d bytes, got %d", len(buf), n)
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}
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}
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return nil
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}
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func handle(conn net.Conn) {
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defer conn.Close()
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for {
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// Read packet length
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var length uint32
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err := binary.Read(conn, binary.BigEndian, &length)
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if err != nil {
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if err != io.EOF {
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fmt.Println("Read length error:", err)
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}
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fmt.Println("Client disconnected")
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num_clients -= 1
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return
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}
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// Prevent invalid packets
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if length < 2 {
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fmt.Println("Invalid packet length:", length)
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return
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}
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// Read message ID
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var msgID uint16
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err = binary.Read(conn, binary.BigEndian, &msgID)
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if err != nil {
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fmt.Println("Read message ID error:", err)
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return
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}
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// Read payload
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payload := make([]byte, length-2)
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_, err = io.ReadFull(conn, payload)
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if err != nil {
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fmt.Println("Read payload error:", err)
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return
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}
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switch msgID {
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case MsgKeyPress:
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msg := string(payload)
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fmt.Println(msg)
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// Send something back to the client
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go SendPacket(MsgGameState, []byte(msg))
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default:
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fmt.Println("Unknown message:", msgID)
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}
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}
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}
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