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UDPServer¶

Helper class to implement a UDP server.

Description¶

A simple server that opens a UDP socket and returns connected PacketPeerUDP upon receiving new packets. See also PacketPeerUDP.connect_to_host.

After starting the server (listen), you will need to poll it at regular intervals (e.g. inside Node._process) for it to process new packets, delivering them to the appropriate PacketPeerUDP, and taking new connections.

Below a small example of how it can be used:

# server_node.gd
class_name ServerNode
extends Node

var server := UDPServer.new()
var peers = []

func _ready():
    server.listen(4242)

func _process(delta):
    server.poll() # Important!
    if server.is_connection_available():
        var peer: PacketPeerUDP = server.take_connection()
        var packet = peer.get_packet()
        print("Accepted peer: %s:%s" % [peer.get_packet_ip(), peer.get_packet_port()])
        print("Received data: %s" % [packet.get_string_from_utf8()])
        # Reply so it knows we received the message.
        peer.put_packet(packet)
        # Keep a reference so we can keep contacting the remote peer.
        peers.append(peer)

    for i in range(0, peers.size()):
        pass # Do something with the connected peers.

// ServerNode.cs
using Godot;
using System.Collections.Generic;

public partial class ServerNode : Node
{
    private UdpServer _server = new UdpServer();
    private List<PacketPeerUdp> _peers  = new List<PacketPeerUdp>();

    public override void _Ready()
    {
        _server.Listen(4242);
    }

    public override void _Process(double delta)
    {
        _server.Poll(); // Important!
        if (_server.IsConnectionAvailable())
        {
            PacketPeerUdp peer = _server.TakeConnection();
            byte[] packet = peer.GetPacket();
            GD.Print($"Accepted Peer: {peer.GetPacketIP()}:{peer.GetPacketPort()}");
            GD.Print($"Received Data: {packet.GetStringFromUtf8()}");
            // Reply so it knows we received the message.
            peer.PutPacket(packet);
            // Keep a reference so we can keep contacting the remote peer.
            _peers.Add(peer);
        }
        foreach (var peer in _peers)
        {
            // Do something with the peers.
        }
    }
}

# client_node.gd
class_name ClientNode
extends Node

var udp := PacketPeerUDP.new()
var connected = false

func _ready():
    udp.connect_to_host("127.0.0.1", 4242)

func _process(delta):
    if !connected:
        # Try to contact server
        udp.put_packet("The answer is... 42!".to_utf8_buffer())
    if udp.get_available_packet_count() > 0:
        print("Connected: %s" % udp.get_packet().get_string_from_utf8())
        connected = true

// ClientNode.cs
using Godot;

public partial class ClientNode : Node
{
    private PacketPeerUdp _udp = new PacketPeerUdp();
    private bool _connected = false;

    public override void _Ready()
    {
        _udp.ConnectToHost("127.0.0.1", 4242);
    }

    public override void _Process(double delta)
    {
        if (!_connected)
        {
            // Try to contact server
            _udp.PutPacket("The Answer Is..42!".ToUtf8Buffer());
        }
        if (_udp.GetAvailablePacketCount() > 0)
        {
            GD.Print($"Connected: {_udp.GetPacket().GetStringFromUtf8()}");
            _connected = true;
        }
    }
}

Properties¶

int

max_pending_connections

16

Methods¶

int	get_local_port ( ) const
bool	is_connection_available ( ) const
bool	is_listening ( ) const
Error	listen ( int port, String bind_address="*" )
Error	poll ( )
void	stop ( )
PacketPeerUDP	take_connection ( )

Property Descriptions¶

int max_pending_connections = 16

void set_max_pending_connections ( int value )
int get_max_pending_connections ( )

Define the maximum number of pending connections, during poll, any new pending connection exceeding that value will be automatically dropped. Setting this value to 0 effectively prevents any new pending connection to be accepted (e.g. when all your players have connected).

Method Descriptions¶

int get_local_port ( ) const

Returns the local port this server is listening to.

bool is_connection_available ( ) const

Returns true if a packet with a new address/port combination was received on the socket.

bool is_listening ( ) const

Returns true if the socket is open and listening on a port.

Error listen ( int port, String bind_address="*" )

Starts the server by opening a UDP socket listening on the given port. You can optionally specify a bind_address to only listen for packets sent to that address. See also PacketPeerUDP.bind.

Error poll ( )

Call this method at regular intervals (e.g. inside Node._process) to process new packets. And packet from known address/port pair will be delivered to the appropriate PacketPeerUDP, any packet received from an unknown address/port pair will be added as a pending connection (see is_connection_available, take_connection). The maximum number of pending connection is defined via max_pending_connections.

void stop ( )

Stops the server, closing the UDP socket if open. Will close all connected PacketPeerUDP accepted via take_connection (remote peers will not be notified).

PacketPeerUDP take_connection ( )

Returns the first pending connection (connected to the appropriate address/port). Will return null if no new connection is available. See also is_connection_available, PacketPeerUDP.connect_to_host.