feat: initial commit - EvoTraders project

量化交易多智能体系统，包含：
- 分析师、投资组合经理、风险经理等智能体
- 股票分析、投资组合管理、风险控制工具
- React 前端界面
- FastAPI 后端服务

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/services/websocket.js

@@ -0,0 +1,192 @@
+/**
+ * WebSocket Client for Read-Only Connection
+ * Handles connection, reconnection, and heartbeat
+ */
+
+import { WS_URL } from "../config/constants";
+
+export class ReadOnlyClient {
+  constructor(onEvent, { wsUrl = WS_URL, reconnectDelay = 3000, heartbeatInterval = 5000 } = {}) {
+    this.onEvent = onEvent;
+    this.wsUrl = wsUrl;
+    this.baseReconnectDelay = reconnectDelay;
+    this.reconnectDelay = reconnectDelay;
+    this.maxReconnectDelay = 30000;
+    this.heartbeatInterval = heartbeatInterval;
+    this.ws = null;
+    this.shouldReconnect = false;
+    this.reconnectTimer = null;
+    this.heartbeatTimer = null;
+    this.reconnectAttempts = 0;
+    this.lastPongTime = 0;
+  }
+
+  connect() {
+    this.shouldReconnect = true;
+    this.reconnectAttempts = 0;
+    this.reconnectDelay = this.baseReconnectDelay;
+    this._connect();
+  }
+
+  _connect() {
+    if (!this.shouldReconnect) {
+      return;
+    }
+
+    // Clear any existing connection
+    if (this.ws) {
+      this.ws.onopen = null;
+      this.ws.onmessage = null;
+      this.ws.onerror = null;
+      this.ws.onclose = null;
+      if (this.ws.readyState === WebSocket.OPEN || this.ws.readyState === WebSocket.CONNECTING) {
+        this.ws.close();
+      }
+      this.ws = null;
+    }
+
+    this.ws = new WebSocket(this.wsUrl);
+
+    this.ws.onopen = () => {
+      this.reconnectAttempts = 0;
+      this.reconnectDelay = this.baseReconnectDelay;
+      this.lastPongTime = Date.now();
+      this._safeEmit({ type: "system", content: "Connected to live server" });
+      console.log("WebSocket connected");
+      this._startHeartbeat();
+    };
+
+    this.ws.onmessage = (ev) => {
+      try {
+        const msg = JSON.parse(ev.data);
+
+        // Update pong time for any message (server is alive)
+        this.lastPongTime = Date.now();
+
+        if (msg.type === "pong") {
+          return;
+        }
+
+        console.log("[WebSocket] Message received:", msg.type || "unknown");
+        this._safeEmit(msg);
+      } catch (e) {
+        console.error("[WebSocket] Parse error:", e);
+      }
+    };
+
+    this.ws.onerror = (error) => {
+      console.error("WebSocket error:", error);
+    };
+
+    this.ws.onclose = (event) => {
+      const code = event.code || "Unknown";
+      console.log(`[WebSocket] Connection closed: Code=${code}, WasClean=${event.wasClean}`);
+
+      this._stopHeartbeat();
+      this.ws = null;
+
+      // Always attempt reconnect if shouldReconnect is true
+      if (this.shouldReconnect) {
+        this.reconnectAttempts++;
+        // Exponential backoff with cap
+        this.reconnectDelay = Math.min(
+          this.baseReconnectDelay * Math.pow(1.5, this.reconnectAttempts),
+          this.maxReconnectDelay
+        );
+
+        this._safeEmit({
+          type: "system",
+          content: "Try to connect to data server..."
+        });
+
+        if (this.reconnectTimer) {
+          clearTimeout(this.reconnectTimer);
+        }
+
+        this.reconnectTimer = setTimeout(() => {
+          console.log(`[WebSocket] Reconnect attempt ${this.reconnectAttempts}...`);
+          this._connect();
+        }, this.reconnectDelay);
+      }
+    };
+  }
+
+  _safeEmit(msg) {
+    try {
+      this.onEvent(msg);
+    } catch (e) {
+      console.error("[WebSocket] Error in event handler:", e);
+    }
+  }
+
+  _startHeartbeat() {
+    this._stopHeartbeat();
+    this.lastPongTime = Date.now();
+
+    this.heartbeatTimer = setInterval(() => {
+      this._sendPing();
+
+      // Check for stale connection (no response in 60s)
+      const timeSinceLastPong = Date.now() - this.lastPongTime;
+      if (timeSinceLastPong > 60000 && this.ws) {
+        console.warn("[WebSocket] Connection appears stale, forcing reconnect");
+        this.ws.close();
+      }
+    }, this.heartbeatInterval);
+  }
+
+  _sendPing() {
+    if (this.ws && this.ws.readyState === WebSocket.OPEN) {
+      try {
+        this.ws.send(JSON.stringify({ type: "ping" }));
+      } catch (e) {
+        console.error("Heartbeat send error:", e);
+      }
+    }
+  }
+
+  _stopHeartbeat() {
+    if (this.heartbeatTimer) {
+      clearInterval(this.heartbeatTimer);
+      this.heartbeatTimer = null;
+    }
+  }
+
+  send(message) {
+    if (this.ws && this.ws.readyState === WebSocket.OPEN) {
+      try {
+        const messageStr = typeof message === "string" ? message : JSON.stringify(message);
+        this.ws.send(messageStr);
+        return true;
+      } catch (e) {
+        console.error("Send error:", e);
+        return false;
+      }
+    } else {
+      console.warn("WebSocket is not connected, cannot send message");
+      return false;
+    }
+  }
+
+  disconnect() {
+    this.shouldReconnect = false;
+    this._stopHeartbeat();
+    if (this.reconnectTimer) {
+      clearTimeout(this.reconnectTimer);
+      this.reconnectTimer = null;
+    }
+    if (this.ws) {
+      this.ws.onopen = null;
+      this.ws.onmessage = null;
+      this.ws.onerror = null;
+      this.ws.onclose = null;
+      try {
+        this.ws.close();
+      } catch (e) {
+        console.error("Close error:", e);
+      }
+    }
+    this.ws = null;
+  }
+}
+