Weather MCP Server

#!/usr/bin/env node import { Server } from "@modelcontextprotocol/sdk/server/index.js"; import { CallToolRequestSchema, ListToolsRequestSchema, Tool, } from "@modelcontextprotocol/sdk/types.js"; import { WeatherService } from "./weather-service.js"; import * as http from "http"; // ==================== Type Definitions ==================== interface JSONRPCRequest { jsonrpc: string; id: string | number; method: string; params?: any; } interface JSONRPCResponse { jsonrpc: string; id: string | number | null; result?: any; error?: { code: number; message: string; data?: any; }; } interface MCPCapabilities { tools: {}; } interface ServerInfo { name: string; version: string; } // ==================== Constants ==================== const PROTOCOL_VERSION = "2025-03-26"; const SERVER_NAME = "weather-mcp-http"; const SERVER_VERSION = "1.0.0"; const JSON_RPC_ERRORS = { PARSE_ERROR: -32700, INVALID_REQUEST: -32600, METHOD_NOT_FOUND: -32601, INVALID_PARAMS: -32602, INTERNAL_ERROR: -32603, } as const; // ==================== Main Server Class ==================== class WeatherHTTPServer { private server: Server; private weatherService: WeatherService; private httpServer!: http.Server; private port: number; constructor(port: number = 8080) { this.port = port; this.server = this.createMCPServer(); this.weatherService = new WeatherService(); this.setupMCPHandlers(); this.createHTTPServer(); } // ==================== MCP Server Setup ==================== private createMCPServer(): Server { return new Server( { name: SERVER_NAME, version: SERVER_VERSION, }, { capabilities: { tools: {}, }, } ); } private setupMCPHandlers(): void { this.setupToolsListHandler(); this.setupToolsCallHandler(); } private setupToolsListHandler(): void { this.server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: this.getAvailableTools(), }; }); } private setupToolsCallHandler(): void { this.server.setRequestHandler(CallToolRequestSchema, async (request) => { const { name, arguments: args } = request.params; return await this.executeWeatherTool(name, args); }); } // ==================== Tool Definitions ==================== private getAvailableTools(): Tool[] { return [ { name: "get_current_weather", description: "Get current weather information for a specified location", inputSchema: { type: "object", properties: { location: { type: "string", description: "Location name (e.g., Hong Kong, Tokyo, London)", }, }, required: ["location"], }, }, { name: "get_weather_forecast", description: "Get weather forecast for a specified location", inputSchema: { type: "object", properties: { location: { type: "string", description: "Location name", }, days: { type: "number", description: "Forecast days (1-7 days, default 3 days)", minimum: 1, maximum: 7, }, }, required: ["location"], }, }, { name: "get_weather_alerts", description: "Get weather alert information", inputSchema: { type: "object", properties: { location: { type: "string", description: "Location name (optional, if not provided will get all alerts)", }, }, }, }, { name: "search_locations", description: "Search supported locations", inputSchema: { type: "object", properties: { query: { type: "string", description: "Search keyword", }, }, required: ["query"], }, }, { name: "get_weather_stats", description: "Get weather statistics information", inputSchema: { type: "object", properties: {}, }, }, ] as Tool[]; } // ==================== Tool Execution ==================== private async executeWeatherTool(toolName: string, args: any): Promise<any> { try { switch (toolName) { case "get_current_weather": return await this.handleCurrentWeather(args); case "get_weather_forecast": return await this.handleWeatherForecast(args); case "get_weather_alerts": return await this.handleWeatherAlerts(args); case "search_locations": return await this.handleSearchLocations(args); case "get_weather_stats": return await this.handleWeatherStats(); default: throw new Error(`Unknown tool: ${toolName}`); } } catch (error) { return { content: [ { type: "text", text: `Error: ${ error instanceof Error ? error.message : String(error) }`, }, ], isError: true, }; } } private async handleCurrentWeather(args: { location: string }) { const { location } = args; const weather = await this.weatherService.getCurrentWeather(location); return { content: [ { type: "text", text: JSON.stringify(weather, null, 2), }, ], }; } private async handleWeatherForecast(args: { location: string; days?: number; }) { const { location, days = 3 } = args; const forecast = await this.weatherService.getWeatherForecast( location, days ); return { content: [ { type: "text", text: JSON.stringify(forecast, null, 2), }, ], }; } private async handleWeatherAlerts(args: { location?: string }) { const { location } = args; const alerts = await this.weatherService.getWeatherAlerts(location); return { content: [ { type: "text", text: JSON.stringify(alerts, null, 2), }, ], }; } private async handleSearchLocations(args: { query: string }) { const { query } = args; const locations = await this.weatherService.searchLocations(query); return { content: [ { type: "text", text: JSON.stringify(locations, null, 2), }, ], }; } private async handleWeatherStats() { const stats = await this.weatherService.getWeatherStats(); return { content: [ { type: "text", text: JSON.stringify(stats, null, 2), }, ], }; } // ==================== MCP Request Handling ==================== private async handleMCPRequest( mcpRequest: JSONRPCRequest ): Promise<JSONRPCResponse> { try { switch (mcpRequest.method) { case "initialize": return this.handleInitialize(mcpRequest); case "tools/list": return this.handleToolsList(mcpRequest); case "tools/call": return await this.handleToolsCall(mcpRequest); default: return this.createErrorResponse( mcpRequest.id, JSON_RPC_ERRORS.METHOD_NOT_FOUND, "Unsupported method" ); } } catch (error) { return this.createErrorResponse( mcpRequest.id, JSON_RPC_ERRORS.INTERNAL_ERROR, "Internal error", error instanceof Error ? error.message : String(error) ); } } private handleInitialize(mcpRequest: JSONRPCRequest): JSONRPCResponse { return { jsonrpc: "2.0", id: mcpRequest.id, result: { protocolVersion: PROTOCOL_VERSION, capabilities: { tools: {}, } as MCPCapabilities, serverInfo: { name: SERVER_NAME, version: SERVER_VERSION, } as ServerInfo, }, }; } private handleToolsList(mcpRequest: JSONRPCRequest): JSONRPCResponse { return { jsonrpc: "2.0", id: mcpRequest.id, result: { tools: this.getAvailableTools(), }, }; } private async handleToolsCall( mcpRequest: JSONRPCRequest ): Promise<JSONRPCResponse> { const { name, arguments: args } = mcpRequest.params; const result = await this.executeWeatherTool(name, args); return { jsonrpc: "2.0", id: mcpRequest.id, result: result, }; } private createErrorResponse( id: string | number | null, code: number, message: string, data?: any ): JSONRPCResponse { return { jsonrpc: "2.0", id: id, error: { code, message, ...(data && { data }), }, }; } // ==================== HTTP Server Setup ==================== private createHTTPServer(): void { this.httpServer = http.createServer(async (req, res) => { this.setCORSHeaders(res); if (req.method === "OPTIONS") { res.writeHead(200); res.end(); return; } try { await this.handleHTTPRequest(req, res); } catch (error) { console.error("HTTP Server Error:", error); this.sendErrorResponse(res, 500, { error: "Server Error", message: error instanceof Error ? error.message : String(error), }); } }); } private setCORSHeaders(res: http.ServerResponse): void { res.setHeader("Access-Control-Allow-Origin", "*"); res.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS"); res.setHeader( "Access-Control-Allow-Headers", "Content-Type, Authorization" ); } private async handleHTTPRequest( req: http.IncomingMessage, res: http.ServerResponse ): Promise<void> { // MCP Endpoint Handling if (this.isMCPEndpoint(req)) { await this.handleMCPEndpoint(req, res); return; } // Documentation Page if (req.url === "/" && req.method === "GET") { this.sendDocumentationPage(res); return; } // 404 Error this.sendErrorResponse(res, 404, { error: "Endpoint Not Found" }); } private isMCPEndpoint(req: http.IncomingMessage): boolean { return (req.url === "/" || req.url === "/mcp") && req.method === "POST"; } private async handleMCPEndpoint( req: http.IncomingMessage, res: http.ServerResponse ): Promise<void> { let body = ""; req.on("data", (chunk) => { body += chunk.toString(); }); req.on("end", async () => { try { const mcpRequest = JSON.parse(body) as JSONRPCRequest; const response = await this.handleMCPRequest(mcpRequest); res.writeHead(200, { "Content-Type": "application/json" }); res.end(JSON.stringify(response)); } catch (error) { console.error("MCP Request Processing Error:", error); const errorResponse = this.createErrorResponse( null, JSON_RPC_ERRORS.PARSE_ERROR, "Parse Error", error instanceof Error ? error.message : String(error) ); res.writeHead(400, { "Content-Type": "application/json" }); res.end(JSON.stringify(errorResponse)); } }); } private sendErrorResponse( res: http.ServerResponse, statusCode: number, errorData: any ): void { res.writeHead(statusCode, { "Content-Type": "application/json" }); res.end(JSON.stringify(errorData)); } // ==================== Documentation Page ==================== private sendDocumentationPage(res: http.ServerResponse): void { res.writeHead(200, { "Content-Type": "text/html; charset=utf-8" }); res.end(this.generateDocumentationHTML()); } private generateDocumentationHTML(): string { return ` <!DOCTYPE html> <html> <head> <title>Simple Weather MCP Server</title> <meta charset="utf-8"> <style> body { font-family: Arial, sans-serif; margin: 40px; line-height: 1.6; } h1 { color: #333; } h2 { color: #666; border-bottom: 2px solid #eee; padding-bottom: 10px; } .endpoint { background: #f5f5f5; padding: 15px; margin: 10px 0; border-radius: 5px; } .method { background: #007acc; color: white; padding: 3px 8px; border-radius: 3px; font-size: 12px; } pre { background: #333; color: #fff; padding: 10px; border-radius: 3px; overflow-x: auto; } .example { background: #e8f4f8; padding: 10px; border-left: 4px solid #007acc; margin: 10px 0; } .tools-list { background: #f9f9f9; padding: 15px; border-radius: 5px; } .tool-item { margin: 10px 0; padding: 10px; background: white; border-radius: 3px; } </style> </head> <body> <h1>🌤️ Simple Weather MCP Server</h1> <p>Server running on port <strong>${this.port}</strong></p> <h2>MCP Endpoints</h2> <div class="endpoint"> <h3><span class="method">POST</span> / or /mcp</h3> <p>Handle MCP requests (supports two endpoints)</p> <p><strong>Content-Type:</strong> application/json</p> <div class="example"> <h4>Example 1: Initialize</h4> <pre> curl -X POST http://localhost:${this.port}/ \\ -H "Content-Type: application/json" \\ -d '{ "jsonrpc": "2.0", "id": 1, "method": "initialize", "params": { "protocolVersion": "2025-03-26", "capabilities": {}, "clientInfo": {"name": "test-client", "version": "1.0.0"} } }' </pre> </div> <div class="example"> <h4>Example 2: List Tools</h4> <pre> curl -X POST http://localhost:${this.port}/ \\ -H "Content-Type: application/json" \\ -d '{ "jsonrpc": "2.0", "id": 2, "method": "tools/list" }' </pre> </div> <div class="example"> <h4>Example 3: Get Weather</h4> <pre> curl -X POST http://localhost:${this.port}/ \\ -H "Content-Type: application/json" \\ -d '{ "jsonrpc": "2.0", "id": 3, "method": "tools/call", "params": { "name": "get_current_weather", "arguments": { "location": "Hong Kong" } } }' </pre> </div> <div class="example"> <h4>Example 4: Standard MCP Configuration</h4> <pre> { "mcpServers": { "weather": { "transport": "http", "url": "http://localhost:${this.port}", "reconnect": { "enabled": true, "maxAttempts": 5, "delayMs": 2000 }, "automaticSSEFallback": false } } } </pre> </div> </div> <h2>Available Tools</h2> <div class="tools-list"> <div class="tool-item"> <strong>get_current_weather</strong> - Get current weather for specified location <br><em>Parameters: location (required)</em> </div> <div class="tool-item"> <strong>get_weather_forecast</strong> - Get weather forecast for specified location <br><em>Parameters: location (required), days (1-7, default 3)</em> </div> <div class="tool-item"> <strong>get_weather_alerts</strong> - Get weather alert information <br><em>Parameters: location (optional)</em> </div> <div class="tool-item"> <strong>search_locations</strong> - Search supported locations <br><em>Parameters: query (required)</em> </div> <div class="tool-item"> <strong>get_weather_stats</strong> - Get weather statistics <br><em>Parameters: none</em> </div> </div> <h2>Supported Locations</h2> <p>Hong Kong, Tokyo, London, New York</p> <h2>Protocol Flow</h2> <ol> <li><strong>Initialize:</strong> Client sends <code>initialize</code> method</li> <li><strong>Get Tools:</strong> Client sends <code>tools/list</code> method</li> <li><strong>Call Tools:</strong> Client sends <code>tools/call</code> method</li> </ol> </body> </html> `; } // ==================== Server Lifecycle ==================== async start(): Promise<void> { return new Promise<void>((resolve) => { this.httpServer.listen(this.port, () => { console.log( `🌤️ Simple Weather MCP Server started at http://localhost:${this.port}` ); console.log(`📖 API Documentation: http://localhost:${this.port}`); console.log( `🔗 MCP Endpoint: http://localhost:${this.port}/ (root path)` ); console.log( `🔗 MCP Endpoint: http://localhost:${this.port}/mcp (alternative path)` ); resolve(); }); }); } async stop(): Promise<void> { return new Promise<void>((resolve) => { this.httpServer.close(() => { console.log("Simple HTTP server stopped"); resolve(); }); }); } } // ==================== Program Entry Point ==================== async function main() { const port = parseInt(process.argv[2]) || 8080; const server = new WeatherHTTPServer(port); // Graceful shutdown handling process.on("SIGINT", async () => { console.log("\nShutting down server..."); await server.stop(); process.exit(0); }); process.on("SIGTERM", async () => { console.log("\nShutting down server..."); await server.stop(); process.exit(0); }); try { await server.start(); } catch (error) { console.error("Simple HTTP server failed to start:", error); process.exit(1); } } // Start the server main();