Godot Server Architecture

# dtls_secure_server.gd
# Encrypting ENet traffic using DTLS and certificates
extends Node

# EXPERT NOTE: DTLS provides encryption over UDP, 
# preventing man-in-the-middle attacks on sensitive data.

func secure_server(crypto_key: CryptoKey, cert: X509Certificate):
	var peer := ENetMultiplayerPeer.new()
	peer.create_server(7000)
	
	# Setting up the TLS/DTLS options for the host
	var server_options := TLSOptions.server(crypto_key, cert)
	peer.host.dtls_server_setup(server_options)
	
	multiplayer.multiplayer_peer = peer

# enet_optimized_host.gd
# Configuring high-performance UDP hosts for Godot servers
extends Node

# EXPERT NOTE: ENet is the preferred protocol for action games. 
# Defining precise bandwidth and client limits is vital for stability.

func setup_enet_server(port: int, max_clients: int):
	var peer := ENetMultiplayerPeer.new()
	# Port, Max Clients, Channels (0 for default), In/Out Bandwidth (0 for unlimited)
	var err := peer.create_server(port, max_clients, 0, 0, 0)
	
	if err == OK:
		multiplayer.multiplayer_peer = peer
		print("Server listening on port ", port)
	else:
		push_error("ENet Server Setup Failed: ", err)

# headless_init_manager.gd
# Detecting and initializing dedicated server environments
extends Node

# EXPERT NOTE: DisplayServer.get_name() returns "headless" 
# only if the binary was launched with the --headless argument.

func _ready():
	if DisplayServer.get_name() == "headless" or OS.has_feature("dedicated_server"):
		print_rich("[color=green]DEDICATED SERVER DETECTED[/color]")
		_start_server_logic()

func _start_server_logic():
	# Configure server-specific singletons or physics speeds
	Engine.max_fps = 60 # Servers don't need high FPS, but need stability

# skills/server-architecture/scripts/headless_manager.gd
extends Node

## Headless Server Manager Expert Pattern
## Manages headless state, arguments, and optimizations for dedicated servers.

class_name HeadlessManager

signal server_ready
signal server_shutdown

func _ready() -> void:
	# 1. Detect Headless Mode
	if DisplayServer.get_name() == "headless":
		print("[HeadlessManager] Running in Headless Mode")
		_configure_headless()
	else:
		print("[HeadlessManager] Running in Graphical Mode")
	
	# 2. Parse Arguments
	_parse_cmdline_args()

func _configure_headless() -> void:
	# Disable visual-only processing if necessary
	# Note: Godot 4 headless automatically disables rendering, but we can save more
	
	# Limit physics if not needed, or lock FPS
	Engine.max_fps = 60 # Server tick rate
	
	# Lower audio bus volume or disable
	AudioServer.set_bus_mute(0, true)

func _parse_cmdline_args() -> void:
	var args = OS.get_cmdline_user_args()
	for arg in args:
		if arg.begins_with("--port="):
			var port = arg.split("=")[1].to_int()
			print("[HeadlessManager] Override Port: ", port)
			# NetworkManager.start_server(port)

func _notification(what: int) -> void:
	if what == NOTIFICATION_WM_CLOSE_REQUEST:
		print("[HeadlessManager] Shutdown Requested")
		server_shutdown.emit()
		# Perform cleanup
		# Save state
		get_tree().quit()

## EXPERT USAGE:
## Add as AutoLoad. Call using standard --headless -- --port=7777

# isolated_multiplayer_api.gd
# Running Client and Server instances in a single Godot run
extends Node

# EXPERT NOTE: Use for Local Hosting where the same instance 
# needs to act as both authoritative server and local client.

func split_branches():
	var server_api = MultiplayerAPI.create_default_interface()
	# Isolate the /root/Server branch to its own MultiplayerAPI root
	get_tree().set_multiplayer(server_api, ^"/root/Server")
	
	print("Network branches isolated: Client and Server now run independently.")

# manual_network_poll.gd
# Running networking on a separate thread via manual polling
extends Node

# EXPERT NOTE: Disabling SceneTree.multiplayer_poll allows 
# you to control exactly when network packets are processed.

func _ready():
	# Stop the engine from automatically polling networking
	get_tree().multiplayer_poll = false

func _physics_process(_delta):
	# Manual pumping of the network stack, usually inside a Mutex lock
	if multiplayer.has_multiplayer_peer():
		multiplayer.poll()

# peer_kick_manager.gd
# Gracefully terminating peer connections
extends Node

# EXPERT NOTE: Disconnecting peers forcefully (disconnect_peer) 
# is cleaner than just erasing them from a list.

func remove_player(peer_id: int, reason: String):
	# Notify the peer first if possible
	_on_kicked.rpc_id(peer_id, reason)
	
	# Drop connection
	multiplayer.disconnect_peer(peer_id)
	print("Kicked peer ", peer_id, " for: ", reason)

@rpc("authority", "call_remote", "reliable")
func _on_kicked(reason: String):
	print("Disconnected by server: ", reason)

# physics_server_direct.gd
# Bypassing SceneTree overhead for high-density simulations
extends Node3D

# EXPERT NOTE: For MMO-scale logic, Nodes are too expensive. 
# Create bodies directly on the PhysicsServer3D and manage RIDs.

var server_bodies: Array[RID] = []

func spawn_server_body(xform: Transform3D) -> RID:
	var body_rid := PhysicsServer3D.body_create()
	PhysicsServer3D.body_set_mode(body_rid, PhysicsServer3D.BODY_MODE_KINEMATIC)
	# Link to the 3D world's physics space
	PhysicsServer3D.body_set_space(body_rid, get_world_3d().space)
	PhysicsServer3D.body_set_state(body_rid, PhysicsServer3D.BODY_STATE_TRANSFORM, xform)
	
	server_bodies.append(body_rid)
	return body_rid

func _exit_tree():
	for rid in server_bodies:
		PhysicsServer3D.free_rid(rid)

# skills/server-architecture/code/rid_performance_server.gd
extends Node

## Server Architecture Expert Pattern
## Implements High-Performance RID Management (Scene Tree Bypass).

var _instance_rids: Array[RID] = []
var _mesh_rid: RID
var _material_rid: RID

func _enter_tree() -> void:
    # 1. Resource ID (RID) Mastery
    # Expert logic: Manually manage drawing without MeshInstance3D nodes.
    _mesh_rid = RenderingServer.mesh_create()
    # Assume a pre-loaded mesh resource for brevity
    # RenderingServer.mesh_add_surface_from_arrays(_mesh_rid, RenderingServer.PRIMITIVE_TRIANGLES, arrays)
    
    _material_rid = RenderingServer.material_create()

func spawn_instances(count: int, area_size: float) -> void:
    # 2. Direct RenderingServer Calls
    # This bypasses the overhead of 10,000 Node3D objects.
    for i in range(count):
        var instance = RenderingServer.instance_create()
        RenderingServer.instance_set_base(instance, _mesh_rid)
        RenderingServer.instance_set_scenario(instance, get_world_3d().scenario)
        
        var xform = Transform3D(Basis(), Vector3(
            randf_range(-area_size, area_size),
            0,
            randf_range(-area_size, area_size)
        ))
        RenderingServer.instance_set_transform(instance, xform)
        _instance_rids.append(instance)

func query_physics_direct(origin: Vector3, direction: Vector3) -> Dictionary:
    # 3. Direct PhysicsServer Queries
    # Professional pattern: Query the server directly instead of using RayCast3D node.
    var space_state = PhysicsServer3D.space_get_direct_state(get_world_3d().space)
    var query = PhysicsRayQueryParameters3D.create(origin, origin + direction * 100.0)
    
    return space_state.intersect_ray(query)

func _exit_tree() -> void:
    # CRITICAL: Manual cleanup of RIDs is mandatory to prevent memory leaks.
    for rid in _instance_rids:
        RenderingServer.free_rid(rid)
    RenderingServer.free_rid(_mesh_rid)
    RenderingServer.free_rid(_material_rid)

## EXPERT NOTE:
## Use 'WorkerThreadPool Batching': For 1 million+ calculations, split 
## the loop across cores: 'WorkerThreadPool.add_native_group_task(self, "_proc", count)'.
## For 'Headless Simulation', run Godot with '--headless' to disable 
## the OS window and Vulkan/OpenGL context for pure low-latency servers.
## NEVER instantiate Nodes for pure data or invisible calculation; 
## use RIDs or plain Objects to save 90% memory overhead.

# safe_packet_decoder.gd
# Preventing RCE vulnerabilities in network serialization
extends Node

# EXPERT NOTE: NEVER pass true to get_var/set_var on untrusted data. 
# Object decoding allows a client to trigger arbitrary code.

func process_untrusted_packet(packet_peer: PacketPeerUDP):
	if packet_peer.get_available_packet_count() > 0:
		# EXPERT: Passing 'false' forbids Object decoding, preventing RCE.
		var data: Variant = packet_peer.get_var(false)
		_handle_data(data)

func _handle_data(data: Variant): pass

# server_authority_validator.gd
# Validating client requests at the entry point
extends Node

# EXPERT NOTE: RPC authority checks are the first line of defense. 
# Use get_remote_sender_id() to identify and validate peers.

@rpc("any_peer", "call_local", "reliable")
func commit_transaction(item_id: String, amount: int):
	if not multiplayer.is_server(): return
	
	var peer_id = multiplayer.get_remote_sender_id()
	if _can_afford(peer_id, amount):
		_apply_transaction(peer_id, item_id, amount)
	else:
		_notify_error.rpc_id(peer_id, "Insufficient funds")

@rpc("authority", "call_remote", "reliable")
func _notify_error(msg: String): pass

func _can_afford(id, amt): return true
func _apply_transaction(id, item, amt): pass

class_name ServerHealthExporter
extends Node

## Exports server telemetry and performance metrics for external monitoring (Prometheus/Grafana).
## Runs automatically in headless/dedicated server mode.

@export var export_interval: float = 10.0 # Seconds

func _ready() -> void:
	# Only run on dedicated/headless servers to save client resources
	if DisplayServer.get_name() != "headless":
		queue_free()
		return
	
	var timer = Timer.new()
	timer.wait_time = export_interval
	timer.autostart = true
	timer.timeout.connect(_export_metrics)
	add_child(timer)

func _export_metrics() -> void:
	var metrics = {
		"timestamp": Time.get_unix_time_from_system(),
		"performance": {
			"fps": Performance.get_monitor(Performance.TIME_FPS),
			"process": Performance.get_monitor(Performance.TIME_PROCESS),
			"physics_process": Performance.get_monitor(Performance.TIME_PHYSICS_PROCESS),
			"static_memory": Performance.get_monitor(Performance.MEMORY_STATIC),
			"objects": Performance.get_monitor(Performance.OBJECT_COUNT),
			"nodes": Performance.get_monitor(Performance.OBJECT_NODE_COUNT),
			"orphan_nodes": Performance.get_monitor(Performance.OBJECT_ORPHAN_NODE_COUNT)
		},
		"network": {
			"peers": multiplayer.get_peers().size(),
			"bandwidth_in": _get_enet_bandwidth_in(),
			"bandwidth_out": _get_enet_bandwidth_out()
		}
	}
	
	# Print to standard output in JSON format for scraping tools like Filebeat or Promtail
	print("METRICS_DUMP:" + JSON.stringify(metrics))

func _get_enet_bandwidth_in() -> float:
	var peer = multiplayer.multiplayer_peer
	if peer is ENetMultiplayerPeer:
		# Note: ENet doesn't expose raw bandwidth easily in high-level API, 
		# but you can track it via custom packet counting.
		return 0.0 
	return 0.0

func _get_enet_bandwidth_out() -> float:
	return 0.0

class_name ServerMatchmakerClient
extends Node

## Client-side logic for connecting to a central Load Balancer/Matchmaker.
## Uses HTTP to receive a dedicated server IP/Port handoff.

@export var matchmaker_url: String = "https://api.game.com/v1/match"
@export var auth_token: String = ""

signal match_found(ip: String, port: int)
signal match_failed(reason: String)

var _http: HTTPRequest

func _ready() -> void:
	_http = HTTPRequest.new()
	add_child(_http)
	_http.request_completed.connect(_on_request_completed)

## Requests a server assignment from the Load Balancer.
func request_match(region: String = "us-east") -> void:
	var headers = ["Content-Type: application/json"]
	if not auth_token.is_empty():
		headers.append("Authorization: Bearer " + auth_token)
	
	var body = JSON.stringify({"region": region})
	_http.request(matchmaker_url, headers, HTTPClient.METHOD_POST, body)

func _on_request_completed(result: int, response_code: int, _headers: PackedStringArray, body: PackedByteArray) -> void:
	if result != HTTPRequest.RESULT_SUCCESS or response_code != 200:
		match_failed.emit("HTTP Error: %d" % response_code)
		return
	
	var json = JSON.new()
	var err = json.parse(body.get_string_from_utf8())
	if err != OK:
		match_failed.emit("JSON Parse Error")
		return
		
	var data = json.get_data()
	if data.has("ip") and data.has("port"):
		match_found.emit(data.ip, int(data.port))
	else:
		match_failed.emit("Malformed matchmaker response")

# websocket_server_compat.gd
# WebSocket implementation for HTML5/Web browser servers
extends Node

# EXPERT NOTE: ENet is UDP-only and unsupported in browsers. 
# WebSocketMultiplayerPeer is required for web compatibility.

func start_web_server(port: int):
	var peer := WebSocketMultiplayerPeer.new()
	var err = peer.create_server(port)
	if err == OK:
		multiplayer.multiplayer_peer = peer
		print("WebSocket Server active on port ", port)