WebSocket¶
HTML5およびWebSocket¶
The WebSocket protocol was standardized in 2011 with the original goal of allowing browsers to create stable and bidirectional connections with a server. Before that, browsers used to only support HTTPRequests, which is not well-suited for bidirectional communication.
プロトコルは非常にシンプルで、メッセージベースであり、ブラウザにプッシュ通知を送信するための非常に強力なツールであり、チャット、ターンベースのゲームなどを実装するために使用されています。遅延のため、VoIPやテンポの速いゲームなどのリアルタイムアプリケーションには適していません(これらのユースケースについては、WebRTC を参照してください)。
そのシンプルさ、幅広い互換性、および生のTCP接続より使いやすいため、WebSocketは、ネットワークサーバーと通信するための手段として、ブラウザ以外のネイティブアプリケーションですぐに広がり始めました。
Godotは、ネイティブエクスポートとHTML5エクスポートの両方でWebSocketをサポートしています。
GodotでWebソケットを使う¶
WebSocketは、3つのメインクラス WebSocketClient、WebSocketServer および WebSocketPeer を介してGodotに実装されます。WebSocket実装は、High Level Multiplayerと互換性があります。詳細については、high-level multiplayer のセクションを参照してください。
警告
When exporting to Android, make sure to enable the INTERNET
permission in the Android export preset before exporting the project or
using one-click deploy. Otherwise, network communication of any kind will be
blocked by Android.
最小限のクライアントの例¶
この例では、リモートサーバーへのWebSocket接続を作成する方法と、データを送受信する方法を示します。
extends Node
# The URL we will connect to
export var websocket_url = "wss://libwebsockets.org"
# Our WebSocketClient instance
var _client = WebSocketClient.new()
func _ready():
# Connect base signals to get notified of connection open, close, and errors.
_client.connect("connection_closed", self, "_closed")
_client.connect("connection_error", self, "_closed")
_client.connect("connection_established", self, "_connected")
# This signal is emitted when not using the Multiplayer API every time
# a full packet is received.
# Alternatively, you could check get_peer(1).get_available_packets() in a loop.
_client.connect("data_received", self, "_on_data")
# Initiate connection to the given URL.
var err = _client.connect_to_url(websocket_url, ["lws-mirror-protocol"])
if err != OK:
print("Unable to connect")
set_process(false)
func _closed(was_clean = false):
# was_clean will tell you if the disconnection was correctly notified
# by the remote peer before closing the socket.
print("Closed, clean: ", was_clean)
set_process(false)
func _connected(proto = ""):
# This is called on connection, "proto" will be the selected WebSocket
# sub-protocol (which is optional)
print("Connected with protocol: ", proto)
# You MUST always use get_peer(1).put_packet to send data to server,
# and not put_packet directly when not using the MultiplayerAPI.
_client.get_peer(1).put_packet("Test packet".to_utf8())
func _on_data():
# Print the received packet, you MUST always use get_peer(1).get_packet
# to receive data from server, and not get_packet directly when not
# using the MultiplayerAPI.
print("Got data from server: ", _client.get_peer(1).get_packet().get_string_from_utf8())
func _process(delta):
# Call this in _process or _physics_process. Data transfer, and signals
# emission will only happen when calling this function.
_client.poll()
これは次のように出力されます:
Connected with protocol:
Got data from server: Test packet
最小限のサーバーの例¶
This example will show you how to create a WebSocket server that listens for remote connections, and how to send and receive data.
extends Node
# The port we will listen to
const PORT = 9080
# Our WebSocketServer instance
var _server = WebSocketServer.new()
func _ready():
# Connect base signals to get notified of new client connections,
# disconnections, and disconnect requests.
_server.connect("client_connected", self, "_connected")
_server.connect("client_disconnected", self, "_disconnected")
_server.connect("client_close_request", self, "_close_request")
# This signal is emitted when not using the Multiplayer API every time a
# full packet is received.
# Alternatively, you could check get_peer(PEER_ID).get_available_packets()
# in a loop for each connected peer.
_server.connect("data_received", self, "_on_data")
# Start listening on the given port.
var err = _server.listen(PORT)
if err != OK:
print("Unable to start server")
set_process(false)
func _connected(id, proto):
# This is called when a new peer connects, "id" will be the assigned peer id,
# "proto" will be the selected WebSocket sub-protocol (which is optional)
print("Client %d connected with protocol: %s" % [id, proto])
func _close_request(id, code, reason):
# This is called when a client notifies that it wishes to close the connection,
# providing a reason string and close code.
print("Client %d disconnecting with code: %d, reason: %s" % [id, code, reason])
func _disconnected(id, was_clean = false):
# This is called when a client disconnects, "id" will be the one of the
# disconnecting client, "was_clean" will tell you if the disconnection
# was correctly notified by the remote peer before closing the socket.
print("Client %d disconnected, clean: %s" % [id, str(was_clean)])
func _on_data(id):
# Print the received packet, you MUST always use get_peer(id).get_packet to receive data,
# and not get_packet directly when not using the MultiplayerAPI.
var pkt = _server.get_peer(id).get_packet()
print("Got data from client %d: %s ... echoing" % [id, pkt.get_string_from_utf8()])
_server.get_peer(id).put_packet(pkt)
func _process(delta):
# Call this in _process or _physics_process.
# Data transfer, and signals emission will only happen when calling this function.
_server.poll()
これは(クライアントが接続したときに)次のようなものを出力します:
Client 1348090059 connected with protocol: selected-protocol
Got data from client 1348090059: Test packet ... echoing
高度なチャットデモ¶
オプションとして、マルチプレイヤーの中レベルの抽象化とハイレベルマルチプレイヤーデモを使用するより高度なチャットデモは、networking/websocket_chat と networking/websocket_multiplayer 内の `godot demo projects <https://github.com/godotengine/godot-demo-projects> `_ にあります。