refactor(module11): restructure MCP client implementation and migrate to chapter 11

m11_mcp_advanced/mcp_client.py

@@ -0,0 +1,92 @@
+import uuid
+from contextlib import AsyncExitStack
+from typing import Optional,Literal
+
+from .transports.base import MCPTransport
+from .transports.http import HttpMCPTransport
+from .transports.stdio import StdioMCPTransport
+
+
+class MCPClient:
+
+    # 编辑器 _impl 必须满足MCPTransport协议
+    _impl:MCPTransport
+
+    def __init__(
+            self,
+            transport:Literal["stdio","http"]="stdio",
+            command:str=None,
+            args:list[str]=None,
+            env:dict=None,
+            url:str=None
+    ):
+        """
+        MCP 客户端 - 支持 stdio 与 HTTP 两种传输方式
+
+        :param transport: 传输模式 "stdio" / "http"
+        :param command: stdio 模式的命令 （如npx）
+        :param args: stdio 模式的参数
+        :param env: stdio 模式的环境变量
+        :param url: http模式的端点 URL
+        """
+
+        if transport=="stdio":
+            if command is None:
+                raise ValueError("stdio 传输模式需要参数 'command'")
+            self._impl = StdioMCPTransport(command=command,args=args or [],env=env)
+        elif transport=="http":
+            if url is None:
+                raise ValueError("http 传输模式需要参数 'command'")
+            self._impl = HttpMCPTransport(url=url)
+        else:
+            raise ValueError(f"不支持的传输模式: {transport}")
+
+
+
+    async def connect(self):
+        """ 建立MCP连接(stdio或HTTP) """
+        await self._impl.connect()
+
+
+    async def list_tools(self):
+        """查询工具列表，为LLM建立上下文用"""
+        return await self._impl.list_tools()
+
+    async def call_tool(self,name:str,args:dict):
+        """调用工具（工程化：加上防御性处理）"""
+        return await self._impl.call_tool(name,args)
+
+
+    async def cleanup(self):
+        """关闭MCP服务、会话和transport"""
+        return await self._impl.cleanup()
+
+
+    async def _http_request(self,method:str,params:dict=None):
+        """ 发送 HTTP JSON-RPC 请求 """
+        payload = {
+            "jsonrpc":"2.0",
+            "id":str(uuid.uuid4()),
+            "method":method,
+        }
+        if params:
+            payload["params"] = params
+
+        headers = {
+            "Content-Type": "application/json",
+            "Accept": "application/json, text/event-stream"
+        }
+        if self.session_id:
+            headers["Mcp-Session-Id"] = self.session_id
+
+        response = await self.http_client.post(
+            self.url,
+            json=payload,
+            headers=headers
+        )
+
+        if "Mcp-Session-Id" in response.headers:
+            self.session_id = response.headers["Mcp-Session-Id"]
+
+        response.raise_for_status()
+        return response.json()