Implement fallback address support in client (Closes #537)

4 files changed, 75 insertions, 32 deletions

diff --git a/client/game.gd b/client/game.gd
index 13eedcda..d57099ed 100644
--- a/client/game.gd
+++ b/client/game.gd
@@ -78,10 +78,9 @@ var spectating_mode: SpectatingMode = SpectatingMode.CENTER
 
 func _ready():
 	mp.packet.connect(handle_packet)
-	mp.connection_closed.connect(func(reason: String):
-		get_parent().replace_menu("res://gui/menus/error.tscn", [reason, menu.data])
-	)
-	mp.connect_to_url(menu.data)
+	mp.connection_closed.connect(func(reason: String): show_error(reason))
+	mp.connect_to_urls(menu.data)
+	
 	text_message.connect(func(m):
 		text_message_history.push_back(m)
 		while text_message_history.size() > 64:
@@ -391,7 +390,7 @@ func handle_packet(p):
 			get_parent().replace_menu("res://gui/menus/game.tscn", p.uri[0])
 		"disconnect":
 			var m := MessageParser.new(p.reason, self)
-			get_parent().replace_menu("res://gui/menus/error.tscn", [m.result, menu.data])
+			show_error(m.result)
 		"replay_start":
 			is_replay = true
 		"replay_stop":
@@ -404,6 +403,9 @@ func handle_packet(p):
 			pass # Only implemented in test client
 		_: push_warning("Unrecognized packet type: %s" % p.type)
 
+func show_error(message: String):
+	get_parent().replace_menu("res://gui/menus/error.tscn", [message, menu.data])
+
 func system_message(s: String):
 	var message = TextMessage.new()
 	message.text = s
@@ -509,7 +511,6 @@ func spectate_center():
 		$Center.position = Vector3(map_center.x, 0.,map_center.y)
 		$FollowCamera.camera_distance_target = (extents[1] - extents[0]).length() / 2
 
-
 func spectate_free():
 	var direction := Input.get_vector("left", "right", "forwards", "backwards")
 	direction = direction.rotated(-follow_camera.angle_target)
diff --git a/client/gui/menus/main/play.gd b/client/gui/menus/main/play.gd
index 4633ee1a..bb2ecf3c 100644
--- a/client/gui/menus/main/play.gd
+++ b/client/gui/menus/main/play.gd
@@ -81,12 +81,11 @@ func update_server_list(lists: Array[Array]):
 			var server_item: ServerListItem = server_list_item.instantiate()
 			server_list.add_child(server_item)
 			
-			var address: Array[String] = []
-			address.append_array(i.address)
+			var urls: Array[String] = []
+			urls.append_array(i.address)
 			
-			# TODO: Implement fallback address correctly
-			server_item.setup(i.name, roundi(i.players_online), i.version, address)
-			server_item.button.pressed.connect(connect_to.bind(i.address[0]))
+			server_item.setup(i.name, roundi(i.players_online), i.version, urls)
+			server_item.button.pressed.connect(connect_to.bind(urls))
 			# Focus the same server with the same index as the previously focused one
 			if idx == prev_selected_idx:
 				server_item.button.grab_focus()
@@ -119,8 +118,9 @@ func _on_connect_pressed():
 			url = url + ":27032"
 		connect_uri.text = url
 	Profile.write("last_server_url", url)
-	connect_to(url)
+	connect_to([url])
 
+# TODO unused code
 func _on_quick_connect_pressed():
 	if OS.has_feature("web"):
 		connect_to(JavaScriptBridge.eval("""
@@ -129,11 +129,10 @@ func _on_quick_connect_pressed():
 			: `ws://${window.location.hostname}:27032/`
 		"""))
 	else:
-		connect_to("wss://hurrycurry.metamuffin.org/")
+		connect_to(["wss://hurrycurry.metamuffin.org/"])
 
-func connect_to(url: String):
-	print("Connecting to %s" % url)
-	get_parent().replace_menu("res://gui/menus/game.tscn", url)
+func connect_to(urls: Array[String]):
+	get_parent().replace_menu("res://gui/menus/game.tscn", urls)
 
 func _on_server_control_pressed():
 	match Server.state:
@@ -148,10 +147,10 @@ func _on_editor_control_pressed():
 		Service.State.FAILED: Editor.start()
 
 func _on_server_connect_pressed():
-	connect_to("ws://%s:%d" % [ServerService.connect_address(), Settings.read("server.bind_port")])
+	connect_to(["ws://%s:%d" % [ServerService.connect_address(), Settings.read("server.bind_port")]])
 
 func _on_editor_connect_pressed():
-	connect_to("ws://[::1]:27035/")
+	connect_to(["ws://[::1]:27035/"])
 
 func _process(_delta):
 	server_control.disabled = false
diff --git a/client/multiplayer.gd b/client/multiplayer.gd
index 5ce5bb93..d5d31322 100644
--- a/client/multiplayer.gd
+++ b/client/multiplayer.gd
@@ -23,25 +23,66 @@ static var VERSION_MAJOR: int = 12
 static var VERSION_MINOR: int = 0
 
 var connected := false
-var socket := WebSocketPeer.new()
+var socket: WebSocketPeer
+var keep_alive := Timer.new()
 
 func _ready():
-	print("Multiplayer connect")
-	socket.inbound_buffer_size = 1024 * 1024 * 4
-	
-	var keep_alive := Timer.new()
 	add_child(keep_alive)
 	keep_alive.wait_time = 1.
 	keep_alive.timeout.connect(send_keep_alive)
-	keep_alive.start()
 
-func connect_to_url(url):
-	socket.connect_to_url(url)
+func connect_to_urls(urls: Array[String]):
+	if urls.is_empty():
+		connection_closed.emit("No connection address available.")
+		return
+	
+	var error_info: Dictionary[String, int] = {}
+	
+	# Create a WebSocketPeer for each url
+	var peers: Array[WebSocketPeer] = []
+	for url: String in urls:
+		var ws := WebSocketPeer.new()
+		ws.inbound_buffer_size = 1024 * 1024 * 4
+		var err := ws.connect_to_url(url)
+		if err == OK: peers.append(ws)
+		else: error_info[url] = err
+	
+	# Now keep polling until one of them is succesful, or we run out of peers.
+	# Peers are removed from the peers array when they fail to connect.
+	var open_peer_found := false
+	while not peers.is_empty() and not open_peer_found:
+		await get_tree().physics_frame
+		for peer: WebSocketPeer in peers:
+			peer.poll()
+			var state := peer.get_ready_state()
+			match state:
+				WebSocketPeer.STATE_CLOSED:
+					print("URL %s failed" % peer.get_requested_url())
+					error_info[peer.get_requested_url()] = peer.get_close_code()
+					peers.erase(peer)
+				WebSocketPeer.STATE_OPEN:
+					# We found a connection that works. Close all others.
+					print("URL %s connected!" % peer.get_requested_url())
+					socket = peer
+					var other_peers := peers.filter(func (p): return p != peer)
+					for p: WebSocketPeer in other_peers:
+						p.close()
+					open_peer_found = true
+					break
+				_: pass
+	
+	if not open_peer_found:
+		var err_msg: String = tr("c.error.could_not_connect")
+		for url: String in error_info.keys():
+			err_msg += "\nURL %s failed with code %d" % [url, error_info[url]]
+		connection_closed.emit(err_msg)
+		return
+	
 	connected = true
+	keep_alive.start()
 
 func _notification(what):
-	if what == NOTIFICATION_PREDELETE:
-		print("Multiplayer disconnect");
+	if what == NOTIFICATION_PREDELETE and socket != null:
 		socket.close()
 		connected = false
 
@@ -52,10 +93,8 @@ func _process(_delta):
 		while socket.get_available_packet_count():
 			handle_packet(socket.get_packet())
 		if state == WebSocketPeer.STATE_CLOSED:
-			var code = socket.get_close_code()
-			var reason = socket.get_close_reason() if code == socket.STATE_CLOSED else tr("c.error.websocket.unavailable")
-			connection_closed.emit(tr("c.error.websocket").format([code, reason, code != -1]))
-			self.queue_free()
+			connection_closed.emit("c.error.connection_closed")
+			connected = false
 
 func fix_packet_types(val):
 	match typeof(val):
diff --git a/client/project.godot b/client/project.godot
index f1827fb9..efc2abc6 100644
--- a/client/project.godot
+++ b/client/project.godot
@@ -284,6 +284,10 @@ toggle_first_person={
 
 pointing/android/enable_pan_and_scale_gestures=true
 
+[network]
+
+limits/tcp/connect_timeout_seconds=10
+
 [physics]
 
 3d/physics_engine="Dummy"