修复循环推理bug

backend/app/main_graph/nodes/web_search.py

@@ -0,0 +1,115 @@
+"""
+联网搜索节点 - 执行搜索并将结果保存到状态
+"""
+
+from typing import Dict, Any, Optional
+from datetime import datetime
+
+from app.main_graph.state import MainGraphState, ErrorRecord, ErrorSeverity
+from app.logger import info
+
+
+async def web_search_node(state: MainGraphState, config: Optional[Dict[str, Any]] = None) -> MainGraphState:
+    """
+    联网搜索节点：执行搜索并将结果保存到状态
+    """
+    state.current_phase = "web_searching"
+
+    # 发送开始事件
+    if config:
+        try:
+            from langchain_core.callbacks.manager import adispatch_custom_event
+            callbacks = config.get("callbacks")
+            if callbacks:
+                await adispatch_custom_event(
+                    "react_reasoning",
+                    {
+                        "step": state.reasoning_step,
+                        "action": "web_search_start",
+                        "confidence": 1.0,
+                        "reasoning": "开始执行联网搜索..."
+                    },
+                    callbacks=callbacks
+                )
+        except Exception as e:
+            info(f"[web_search_node] 无法发送开始事件: {e}")
+
+    # 获取搜索查询
+    reasoning_result = state.debug_info.get("reasoning_result")
+    search_query = reasoning_result.metadata.get("search_query", state.user_query) if reasoning_result else state.user_query
+
+    try:
+        from app.core import web_search
+
+        print(f"[WebSearch] 搜索: {search_query}")
+        search_result = web_search(search_query, max_results=5)
+
+        # 保存搜索结果到状态
+        if not hasattr(state, "web_search_results"):
+            state.web_search_results = []
+        state.web_search_results.append(search_result)
+
+        # 将搜索结果添加到 rag_context，供 LLM 使用
+        if state.rag_context:
+            state.rag_context = f"{state.rag_context}\n\n---\n\n## 🌐 联网搜索结果:\n{search_result}"
+        else:
+            state.rag_context = f"## 🌐 联网搜索结果:\n{search_result}"
+
+        state.success = True
+        print(f"[WebSearch] 搜索完成")
+
+        # 发送完成事件
+        if config:
+            try:
+                from langchain_core.callbacks.manager import adispatch_custom_event
+                callbacks = config.get("callbacks")
+                if callbacks:
+                    await adispatch_custom_event(
+                        "react_reasoning",
+                        {
+                            "step": state.reasoning_step,
+                            "action": "web_search_complete",
+                            "confidence": 1.0,
+                            "reasoning": f"联网搜索完成，找到 {len(search_result) if isinstance(search_result, list) else 1} 条结果"
+                        },
+                        callbacks=callbacks
+                    )
+            except Exception as e:
+                info(f"[web_search_node] 无法发送完成事件: {e}")
+
+    except Exception as e:
+        error_record = ErrorRecord(
+            error_type="WebSearchError",
+            error_message=str(e),
+            severity=ErrorSeverity.WARNING,
+            source="web_search_node",
+            timestamp=datetime.now().isoformat(),
+            retry_count=0,
+            max_retries=2,
+            context={"search_query": search_query}
+        )
+        state.errors.append(error_record)
+        state.current_error = error_record
+        state.current_phase = "error_handling"
+        state.success = False
+
+        # 发送错误事件
+        if config:
+            try:
+                from langchain_core.callbacks.manager import adispatch_custom_event
+                callbacks = config.get("callbacks")
+                if callbacks:
+                    await adispatch_custom_event(
+                        "react_reasoning",
+                        {
+                            "step": state.reasoning_step,
+                            "action": "web_search_error",
+                            "confidence": 1.0,
+                            "reasoning": f"联网搜索失败: {str(e)}"
+                        },
+                        callbacks=callbacks
+                    )
+            except Exception as e:
+                info(f"[web_search_node] 无法发送错误事件: {e}")
+
+    return state