141 lines
5.1 KiB
C#
141 lines
5.1 KiB
C#
using System;
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using System.Threading.Tasks;
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using System.Net.WebSockets;
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using LeanCloud.Common;
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using LeanCloud.Realtime.Internal.Router;
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namespace LeanCloud.Realtime.Internal.WebSocket {
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/// <summary>
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/// WebSocket 客户端，只与通信协议相关
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/// </summary>
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internal class LCWebSocketClient {
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// .net standard 2.0 好像在拼合 Frame 时有 bug，所以将这个值调整大一些
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private const int RECV_BUFFER_SIZE = 1024 * 5;
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private const int CLOSE_TIMEOUT = 5000;
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internal Action<byte[]> OnMessage;
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internal Action OnDisconnect;
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internal Action OnReconnect;
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private ClientWebSocket ws;
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private readonly LCRTMRouter router;
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internal LCWebSocketClient() {
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router = new LCRTMRouter();
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}
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internal async Task Connect() {
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LCRTMServer rtmServer = await router.GetServer();
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try {
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LCLogger.Debug($"Primary Server");
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await Connect(rtmServer.Primary);
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} catch (Exception e) {
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LCLogger.Error(e.Message);
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LCLogger.Debug($"Secondary Server");
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await Connect(rtmServer.Secondary);
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}
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// 接收
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_ = StartReceive();
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}
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private async Task Connect(string server) {
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LCLogger.Debug($"Connecting WebSocket: {server}");
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Task timeoutTask = Task.Delay(5000);
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ws = new ClientWebSocket();
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ws.Options.AddSubProtocol("lc.protobuf2.3");
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Task connectTask = ws.ConnectAsync(new Uri(server), default);
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if (await Task.WhenAny(connectTask, timeoutTask) == connectTask) {
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LCLogger.Debug($"Connected WebSocket: {server}");
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} else {
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throw new TimeoutException("Connect timeout");
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}
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}
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internal async Task Close() {
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LCLogger.Debug("Closing WebSocket");
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OnMessage = null;
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OnDisconnect = null;
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OnReconnect = null;
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try {
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// 发送关闭帧可能会很久，所以增加超时
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// 主动挥手关闭，不会再收到 Close Frame
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Task closeTask = ws.CloseAsync(WebSocketCloseStatus.NormalClosure, "", default);
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Task delayTask = Task.Delay(CLOSE_TIMEOUT);
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await Task.WhenAny(closeTask, delayTask);
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} catch (Exception e) {
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LCLogger.Error(e.Message);
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} finally {
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ws.Abort();
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ws.Dispose();
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LCLogger.Debug("Closed WebSocket");
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}
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}
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internal async Task Send(byte[] data) {
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ArraySegment<byte> bytes = new ArraySegment<byte>(data);
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if (ws.State == WebSocketState.Open) {
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try {
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await ws.SendAsync(bytes, WebSocketMessageType.Binary, true, default);
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} catch (Exception e) {
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LCLogger.Error(e.Message);
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throw e;
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}
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} else {
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string message = $"Error Websocket state: {ws.State}";
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LCLogger.Error(message);
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throw new Exception(message);
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}
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}
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private async Task StartReceive() {
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byte[] buffer = new byte[RECV_BUFFER_SIZE];
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try {
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while (ws.State == WebSocketState.Open) {
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WebSocketReceiveResult result = await ws.ReceiveAsync(new ArraySegment<byte>(buffer), default);
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if (result.MessageType == WebSocketMessageType.Close) {
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// 由服务端发起关闭
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LCLogger.Debug($"Receive Closed: {result.CloseStatusDescription}");
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try {
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// 挥手关闭
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await ws.CloseAsync(WebSocketCloseStatus.NormalClosure, string.Empty, default);
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} catch (Exception ex) {
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LCLogger.Error(ex.Message);
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} finally {
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HandleClose();
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}
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} else if (result.MessageType == WebSocketMessageType.Binary) {
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// 拼合 WebSocket Message
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int length = result.Count;
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byte[] data = new byte[length];
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Array.Copy(buffer, data, length);
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OnMessage?.Invoke(data);
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} else {
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LCLogger.Error($"Error message type: {result.MessageType}");
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}
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}
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} catch (Exception e) {
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// 客户端网络异常
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LCLogger.Error(e.Message);
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LCLogger.Debug($"WebSocket State: {ws.State}");
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HandleClose();
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}
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}
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private void HandleClose() {
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try {
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ws.Abort();
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ws.Dispose();
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} catch (Exception e) {
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LCLogger.Error(e.Message);
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} finally {
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OnDisconnect?.Invoke();
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}
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}
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}
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}
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