godot/doc/classes/MultiplayerAPIExtension.xml

<?xml version="1.0" encoding="UTF-8" ?>
<class name="MultiplayerAPIExtension" inherits="MultiplayerAPI" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
	<brief_description>
		Base class used for extending the [MultiplayerAPI].
	</brief_description>
	<description>
		This class can be used to augment or replace the default [MultiplayerAPI] implementation via script or extensions.
		The following example augment the default implementation ([SceneMultiplayer]) by logging every RPC being made, and every object being configured for replication.
		[codeblocks]
		[gdscript]
		extends MultiplayerAPIExtension
		class_name LogMultiplayer

		# We want to augment the default SceneMultiplayer.
		var base_multiplayer = SceneMultiplayer.new()

		func _init():
		    # Just passthourgh base signals (copied to var to avoid cyclic reference)
		    var cts = connected_to_server
		    var cf = connection_failed
		    var pc = peer_connected
		    var pd = peer_disconnected
		    base_multiplayer.connected_to_server.connect(func(): cts.emit())
		    base_multiplayer.connection_failed.connect(func(): cf.emit())
		    base_multiplayer.peer_connected.connect(func(id): pc.emit(id))
		    base_multiplayer.peer_disconnected.connect(func(id): pd.emit(id))

		# Log RPC being made and forward it to the default multiplayer.
		func _rpc(peer: int, object: Object, method: StringName, args: Array) -&gt; int: # Error
		    print("Got RPC for %d: %s::%s(%s)" % [peer, object, method, args])
		    return base_multiplayer.rpc(peer, object, method, args)

		# Log configuration add. E.g. root path (nullptr, NodePath), replication (Node, Spawner|Synchronizer), custom.
		func _object_configuration_add(object, config: Variant) -&gt; int: # Error
		    if config is MultiplayerSynchronizer:
		        print("Adding synchronization configuration for %s. Synchronizer: %s" % [object, config])
		    elif config is MultiplayerSpawner:
		        print("Adding node %s to the spawn list. Spawner: %s" % [object, config])
		    return base_multiplayer.object_configuration_add(object, config)

		# Log configuration remove. E.g. root path (nullptr, NodePath), replication (Node, Spawner|Synchronizer), custom.
		func _object_configuration_remove(object, config: Variant) -&gt; int: # Error
		    if config is MultiplayerSynchronizer:
		        print("Removing synchronization configuration for %s. Synchronizer: %s" % [object, config])
		    elif config is MultiplayerSpawner:
		        print("Removing node %s from the spawn list. Spawner: %s" % [object, config])
		    return base_multiplayer.object_configuration_remove(object, config)

		# These can be optional, but in our case we want to augment SceneMultiplayer, so forward everything.
		func _set_multiplayer_peer(p_peer: MultiplayerPeer):
		    base_multiplayer.multiplayer_peer = p_peer

		func _get_multiplayer_peer() -&gt; MultiplayerPeer:
		    return base_multiplayer.multiplayer_peer

		func _get_unique_id() -&gt; int:
		    return base_multiplayer.get_unique_id()

		func _get_peer_ids() -&gt; PackedInt32Array:
		    return base_multiplayer.get_peers()
		[/gdscript]
		[/codeblocks]
		Then in your main scene or in an autoload call [method SceneTree.set_multiplayer] to start using your custom [MultiplayerAPI]:
		[codeblocks]
		[gdscript]
		# autoload.gd
		func _enter_tree():
		    # Sets our custom multiplayer as the main one in SceneTree.
		get_tree().set_multiplayer(LogMultiplayer.new())
		[/gdscript]
		[/codeblocks]
		Native extensions can alternatively use the [method MultiplayerAPI.set_default_interface] method during initialization to configure themselves as the default implementation.
	</description>
	<tutorials>
	</tutorials>
	<methods>
		<method name="_get_multiplayer_peer" qualifiers="virtual">
			<return type="MultiplayerPeer" />
			<description>
				Called when the [member MultiplayerAPI.multiplayer_peer] is retrieved.
			</description>
		</method>
		<method name="_get_peer_ids" qualifiers="virtual const">
			<return type="PackedInt32Array" />
			<description>
				Callback for [method MultiplayerAPI.get_peers].
			</description>
		</method>
		<method name="_get_remote_sender_id" qualifiers="virtual const">
			<return type="int" />
			<description>
				Callback for [method MultiplayerAPI.get_remote_sender_id].
			</description>
		</method>
		<method name="_get_unique_id" qualifiers="virtual const">
			<return type="int" />
			<description>
				Callback for [method MultiplayerAPI.get_unique_id].
			</description>
		</method>
		<method name="_object_configuration_add" qualifiers="virtual">
			<return type="int" />
			<param index="0" name="object" type="Object" />
			<param index="1" name="configuration" type="Variant" />
			<description>
				Callback for [method MultiplayerAPI.object_configuration_add].
			</description>
		</method>
		<method name="_object_configuration_remove" qualifiers="virtual">
			<return type="int" />
			<param index="0" name="object" type="Object" />
			<param index="1" name="configuration" type="Variant" />
			<description>
				Callback for [method MultiplayerAPI.object_configuration_remove].
			</description>
		</method>
		<method name="_poll" qualifiers="virtual">
			<return type="int" />
			<description>
				Callback for [method MultiplayerAPI.poll].
			</description>
		</method>
		<method name="_rpc" qualifiers="virtual">
			<return type="int" />
			<param index="0" name="peer" type="int" />
			<param index="1" name="object" type="Object" />
			<param index="2" name="method" type="StringName" />
			<param index="3" name="args" type="Array" />
			<description>
				Callback for [method MultiplayerAPI.rpc].
			</description>
		</method>
		<method name="_set_multiplayer_peer" qualifiers="virtual">
			<return type="void" />
			<param index="0" name="multiplayer_peer" type="MultiplayerPeer" />
			<description>
				Called when the [member MultiplayerAPI.multiplayer_peer] is set.
			</description>
		</method>
	</methods>
</class>