ReMe/reme/components/client/mcp_client.py
jinliyl b9caae1e50
feat(service): support explicit wildcard network binds (#547)
* feat(service): bind network services to all interfaces

* fix(service): keep network listeners local by default

* fix(service): make remote access explicit
2026-09-15 14:26:33 +08:00

112 lines
3.8 KiB
Python

"""MCP client for ReMe services."""
from collections.abc import AsyncGenerator
from typing import TYPE_CHECKING, Any
from .base_client import BaseClient
from ..component_registry import R
if TYPE_CHECKING:
from fastmcp.client.client import CallToolResult
_VALID_TRANSPORTS = {"sse", "stdio", "streamable-http"}
@R.register("mcp")
class MCPClient(BaseClient):
"""MCP client that communicates with ReMe MCP service via fastmcp.Client.
Usage:
# SSE (default)
client = MCPClient(host="localhost", port=8000)
async with client:
async for text in client(action="my_tool", query="hello"):
print(text)
# Streamable HTTP
client = MCPClient(transport="streamable-http", host="localhost", port=8000)
# Stdio
client = MCPClient(transport="stdio", command="python", args=["server.py"])
# Custom transport object
from fastmcp.client import SSETransport
client = MCPClient(transport=SSETransport(url="http://host:port/sse"))
"""
def __init__(
self,
transport: str | Any = "sse",
host: str | None = None,
port: int | None = None,
timeout: float = 30.0,
**kwargs,
):
super().__init__(**kwargs)
if isinstance(transport, str) and transport not in _VALID_TRANSPORTS:
raise ValueError(f"Unknown transport: {transport!r}, expected one of {sorted(_VALID_TRANSPORTS)}")
if isinstance(transport, str) and transport != "stdio":
self.host, self.port = self._resolve_service_address(host, port)
self.transport = transport
self.timeout = timeout
def _build_transport(self):
if not isinstance(self.transport, str):
return self.transport
from fastmcp.client import SSETransport, StdioTransport, StreamableHttpTransport
transport_map = {
"sse": SSETransport,
"stdio": StdioTransport,
"streamable-http": StreamableHttpTransport,
}
cls = transport_map[self.transport]
if self.transport == "stdio":
command = self.kwargs.get("command", "")
args = self.kwargs.get("args", [])
return cls(command=command, args=args)
path = "/sse" if self.transport == "sse" else "/mcp"
url = f"http://{self.host}:{self.port}{path}"
return cls(url=url)
# pylint: disable=unnecessary-dunder-call
async def _start(self) -> None:
if self.client is None:
from fastmcp import Client
self.client = Client(self._build_transport(), timeout=self.timeout)
await self.client.__aenter__()
# pylint: disable=invalid-overridden-method
async def _execute(self, action: str, payload: dict) -> AsyncGenerator[str, None]:
if self.client is None:
raise RuntimeError("Client not initialized. Call _start() first.")
result: "CallToolResult" = await self.client.call_tool(action, payload)
yield self._extract_text(result)
async def list_actions(self) -> list[dict]:
"""Return raw MCP Tool dumps; each dict gets an `action` key (the tool name)."""
if self.client is None:
raise RuntimeError("Client not initialized. Call _start() first.")
tools = await self.client.list_tools()
return [tool.model_dump() for tool in tools]
# pylint: disable=unnecessary-dunder-call
async def _close(self) -> None:
if self.client is not None:
await self.client.__aexit__(None, None, None)
self.client = None
@staticmethod
def _extract_text(result: "CallToolResult") -> str:
for block in result.content:
if hasattr(block, "text"):
return block.text
return str(result.content)