FastMCPとOpen API Specification を使った天気予報Remote MCP Serverの実装

custom_httpx.py

import contextvars
from typing import Any
import httpx
from httpx import URL, Headers
from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
from starlette.requests import Request as StarletteRequest
from starlette.responses import Response as StarletteResponse

current_request_headers_var: contextvars.ContextVar[Headers | None] = contextvars.ContextVar("current_request_headers", default=None)


class ContextAwareAsyncClient(httpx.AsyncClient):
    async def request(self, method: str, url: URL | str, **kwargs: Any) -> httpx.Response:
        incoming_headers: Headers | None = current_request_headers_var.get()

        merged_headers: Headers = Headers(dict(self.headers))

        request_specific_headers_input = kwargs.pop("headers", None)
        request_specific_headers = Headers(request_specific_headers_input) if request_specific_headers_input else Headers()

        if incoming_headers:
            api_key = incoming_headers.get("X-API-Key")
            if api_key:
                merged_headers["X-API-Key"] = api_key

        for name, value in request_specific_headers.items():
            merged_headers[name] = value

        kwargs["headers"] = merged_headers
        return await super().request(method, url, **kwargs)



class RequestHeaderContextMiddleware(BaseHTTPMiddleware):
    async def dispatch(self, request: StarletteRequest, call_next: RequestResponseEndpoint) -> StarletteResponse:
        token = current_request_headers_var.set(Headers(headers=request.headers))
        try:
            response = await call_next(request)
        finally:
            current_request_headers_var.reset(token)
        return response

claude_desktop_config.json

{
  "mcpServers": {
    "WxTech1kmMeshPinpointWeatherForecast": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "https://wxtech.weathernews.com/api/beta/ss1wx/mcp/",
        "--header",
        "X-API-Key: [X_API_KEY]"
      ]
    },
    "WxTech5kmMeshGlobalWeatherForecast": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "https://wxtech.weathernews.com/api/beta/global/wx/mcp/",
        "--header",
        "X-API-Key: [X_API_KEY]"
      ]
    }
  }
}

mcp.json

{
 "servers": {
  "WxTech1kmMeshPinpointWeatherForecast": {
      "type": "http",
      "url": "https://wxtech.weathernews.com/api/beta/ss1wx/mcp/",
      "headers": {
        "X-API-Key": "[X_API_KEY]"
      }
    },
  "WxTech5kmMeshGlobalWeatherForecast": {
      "type": "http",
      "url": "https://wxtech.weathernews.com/api/beta/global/wx/mcp/",
      "headers": {
        "X-API-Key": "[X_API_KEY]"
      }
    }
 }
}