main.py•3.73 kB
# 2025/6/25
# zhangzhong
# https://modelcontextprotocol.io/quickstart/server
from typing import Any
import httpx
# from mcp.server.fastmcp import FastMCP
from fastmcp import FastMCP
# The FastMCP class uses Python type hints and docstrings to automatically generate tool definitions, making it easy to create and maintain MCP tools.
# Initialize FastMCP server
mcp = FastMCP(name="weather")
# Constants
NWS_API_BASE = "https://api.weather.gov" # 这是一个独立的API服务
# 那我们这个server其实也只是转调别人的API而已
USER_AGENT = "weather-app/1.0"
async def make_nws_request(url: str) -> dict[str, Any] | None:
"""Make a request to the NWS API with proper error handling."""
headers = {
"User-Agent": USER_AGENT,
"Accept": "application/geo+json",
}
async with httpx.AsyncClient() as client:
try:
response = await client.get(url, headers=headers, timeout=30.0)
response.raise_for_status()
return response.json()
except Exception as e:
return None
def format_alert(feature: dict) -> str:
"""Format an alert feature into a readable string."""
props = feature["properties"]
return f"""
Event: {props.get('event', 'Unknown')}
Area: {props.get('areaDesc', 'Unknown')}
Severity: {props.get('severity', 'Unknown')}
Description: {props.get('description', 'No description available')}
Instructions: {props.get('instruction', 'No specific instructions provided')}
"""
# https://modelcontextprotocol.io/quickstart/server#implementing-tool-execution
# The tool execution handler is responsible for actually executing the logic of each tool.
@mcp.tool()
async def get_alerts(state: str) -> str:
"""Get weather alerts for a US state.
Args:
state: Two-letter US state code (e.g. CA, NY)
"""
url: str = f"{NWS_API_BASE}/alerts/active/area/{state}"
data: dict[str, Any] | None = await make_nws_request(url=url)
if not data or "features" not in data:
return "Unable to fetch alerts or not alerts found."
if not data["features"]:
return "No active alerts for this state."
alerts: list[str] = [format_alert(feature) for feature in data["features"]]
return "\n---\n".join(alerts)
# 好像mcp的tool都是返回一个string
@mcp.tool()
async def get_forecast(latitude: float, longitude: float) -> str:
"""Get weather forecast for a location.
Args:
latitude: Latitude of the location
longitude: Longitude of the location
"""
# First get the forecast grid endpoint
points_url = f"{NWS_API_BASE}/points/{latitude},{longitude}"
points_data = await make_nws_request(points_url)
if not points_data:
return "Unable to fetch forecast data for this location."
# Get the forecast URL from the points response
forecast_url = points_data["properties"]["forecast"]
forecast_data = await make_nws_request(forecast_url)
if not forecast_data:
return "Unable to fetch detailed forecast."
# Format the periods into a readable forecast
periods = forecast_data["properties"]["periods"]
forecasts = []
for period in periods[:5]: # Only show next 5 periods
forecast = f"""
{period['name']}:
Temperature: {period['temperature']}°{period['temperatureUnit']}
Wind: {period['windSpeed']} {period['windDirection']}
Forecast: {period['detailedForecast']}
"""
forecasts.append(forecast)
return "\n---\n".join(forecasts)
if __name__ == "__main__":
# Initialize and run the server
# [06/25/25 21:05:39] INFO Starting MCP server 'weather' with transport 'sse' on http://0.0.0.0:8000/sse/
mcp.run(transport="sse", host="0.0.0.0", port=8000)