"""HTTP MCP客户端 - 实现JSON-RPC 2.0协议""" import httpx from typing import Dict, Any, List, Optional from app.logger import get_logger import time logger = get_logger(__name__) class MCPError(Exception): """MCP错误""" pass class HTTPMCPClient: """HTTP模式MCP客户端（类似Cursor/Claude Code实现）""" def __init__( self, url: str, headers: Optional[Dict[str, str]] = None, env: Optional[Dict[str, str]] = None, timeout: float = 60.0, http_client: Optional[httpx.AsyncClient] = None ): """ 初始化HTTP MCP客户端 Args: url: MCP服务器URL headers: HTTP请求头 env: 环境变量（用于API Key等） timeout: 超时时间（秒） http_client: 可选的共享HTTP客户端（用于连接池复用） """ self.url = url.rstrip('/') self.headers = headers or {} self.env = env or {} self.timeout = timeout # 设置MCP必需的Accept头 # MCP服务器要求客户端必须接受 application/json 和 text/event-stream if 'Accept' not in self.headers: self.headers['Accept'] = 'application/json, text/event-stream' # 设置Content-Type if 'Content-Type' not in self.headers: self.headers['Content-Type'] = 'application/json' # 如果env中有API Key，添加到headers if 'API_KEY' in self.env: self.headers['Authorization'] = f'Bearer {self.env["API_KEY"]}' # 使用共享客户端或创建新客户端 self._owns_client = http_client is None if http_client: self.client = http_client else: self.client = httpx.AsyncClient( timeout=httpx.Timeout(timeout), headers=self.headers ) self._request_id = 0 def _next_request_id(self) -> int: """获取下一个请求ID""" self._request_id += 1 return self._request_id async def _call_jsonrpc( self, method: str, params: Optional[Dict[str, Any]] = None ) -> Dict[str, Any]: """ 调用JSON-RPC 2.0方法 Args: method: 方法名 params: 参数 Returns: 响应结果 Raises: MCPError: 调用失败时抛出 """ request_id = self._next_request_id() payload = { "jsonrpc": "2.0", "id": request_id, "method": method, "params": params or {} } try: logger.debug(f"MCP请求: {method} -> {self.url}") response = await self.client.post( self.url, json=payload, headers=self.headers # 显式传递headers（对于共享客户端很重要） ) response.raise_for_status() # 获取响应内容 response_text = response.text content_type = response.headers.get('content-type', '') # 如果是空响应 if not response_text or response_text.strip() == '': raise MCPError("服务器返回空响应") # 处理SSE格式响应 if 'text/event-stream' in content_type or response_text.startswith('event:'): logger.debug("检测到SSE格式响应，开始解析") data = self._parse_sse_response(response_text) else: # 标准JSON响应 try: data = response.json() except ValueError as e: logger.error(f"JSON解析失败，响应内容: {response_text[:500]}") raise MCPError(f"无法解析JSON响应: {str(e)}") # 检查JSON-RPC错误 if "error" in data: error = data["error"] error_msg = error.get("message", "Unknown error") error_code = error.get("code", -1) logger.error(f"MCP错误 [{error_code}]: {error_msg}") raise MCPError(f"[{error_code}] {error_msg}") if "result" not in data: raise MCPError("响应中缺少result字段") return data["result"] except httpx.HTTPStatusError as e: logger.error(f"HTTP错误 {e.response.status_code}: {e.response.text}") raise MCPError(f"HTTP错误 {e.response.status_code}: {e.response.text}") except httpx.RequestError as e: logger.error(f"请求错误: {str(e)}") raise MCPError(f"请求错误: {str(e)}") except MCPError: raise except Exception as e: logger.error(f"未知错误: {str(e)}") raise MCPError(f"未知错误: {str(e)}") def _parse_sse_response(self, sse_text: str) -> Dict[str, Any]: """ 解析SSE格式的响应 SSE格式示例: event: message data: {"result": {...}} Args: sse_text: SSE格式的文本 Returns: 解析后的JSON数据 """ import json lines = sse_text.strip().split('\n') data_lines = [] for line in lines: line = line.strip() if line.startswith('data:'): # 提取data后面的内容 data_content = line[5:].strip() data_lines.append(data_content) if not data_lines: raise MCPError("SSE响应中没有找到data字段") # 合并所有data行（某些SSE可能分多行） full_data = ''.join(data_lines) try: return json.loads(full_data) except json.JSONDecodeError as e: logger.error(f"解析SSE data失败: {full_data[:200]}") raise MCPError(f"SSE data不是有效的JSON: {str(e)}") async def list_tools(self) -> List[Dict[str, Any]]: """ 列举可用工具 Returns: 工具列表 """ try: result = await self._call_jsonrpc("tools/list") tools = result.get("tools", []) logger.info(f"获取到 {len(tools)} 个工具") return tools except Exception as e: logger.error(f"获取工具列表失败: {e}") raise async def call_tool( self, tool_name: str, arguments: Dict[str, Any] ) -> Any: """ 调用工具 Args: tool_name: 工具名称 arguments: 工具参数 Returns: 工具执行结果 """ try: logger.info(f"调用工具: {tool_name}") logger.debug(f"参数: {arguments}") result = await self._call_jsonrpc( "tools/call", { "name": tool_name, "arguments": arguments } ) # MCP返回的result通常包含content数组 if isinstance(result, dict) and "content" in result: content = result["content"] if isinstance(content, list) and len(content) > 0: # 提取第一个content项的text first_content = content[0] if isinstance(first_content, dict) and "text" in first_content: return first_content["text"] return first_content return content return result except Exception as e: logger.error(f"调用工具失败: {tool_name}, 错误: {e}") raise async def list_resources(self) -> List[Dict[str, Any]]: """ 列举可用资源 Returns: 资源列表 """ try: result = await self._call_jsonrpc("resources/list") resources = result.get("resources", []) logger.info(f"获取到 {len(resources)} 个资源") return resources except Exception as e: logger.error(f"获取资源列表失败: {e}") raise async def read_resource(self, uri: str) -> Any: """ 读取资源 Args: uri: 资源URI Returns: 资源内容 """ try: result = await self._call_jsonrpc( "resources/read", {"uri": uri} ) return result except Exception as e: logger.error(f"读取资源失败: {uri}, 错误: {e}") raise async def test_connection(self) -> Dict[str, Any]: """ 测试连接 Returns: 测试结果 """ start_time = time.time() try: # 尝试列举工具来测试连接 tools = await self.list_tools() end_time = time.time() response_time = round((end_time - start_time) * 1000, 2) return { "success": True, "message": "连接测试成功", "response_time_ms": response_time, "tools_count": len(tools), "tools": tools } except MCPError as e: end_time = time.time() response_time = round((end_time - start_time) * 1000, 2) return { "success": False, "message": "连接测试失败", "response_time_ms": response_time, "error": str(e), "error_type": "MCPError", "suggestions": [ "请检查服务器URL是否正确", "请确认API Key是否有效", "请检查网络连接" ] } except Exception as e: end_time = time.time() response_time = round((end_time - start_time) * 1000, 2) return { "success": False, "message": "连接测试失败", "response_time_ms": response_time, "error": str(e), "error_type": type(e).__name__, "suggestions": [ "请检查服务器是否在线", "请确认配置是否正确" ] } async def close(self): """关闭客户端（仅在拥有客户端所有权时关闭）""" if self._owns_client and self.client: await self.client.aclose()