feat: migrate HTTP servers to use Express.js (#179)

* feat: migrate HTTP servers to use Express.js

- Replace raw Node.js HTTP servers with Express.js framework
- Add comprehensive Express server utility with CORS, health checks, and error handling
- Refactor SSE and Streamable services to use Express routes
- Improve server logging with endpoint information
- Add proper TypeScript types for Express middleware
- Maintain full backward compatibility with existing MCP protocol
- Fix parameter validation examples and documentation

Resolves #178

* refactor: optimize Express migration - reduce code duplication

- Remove unused httpServer.ts file (149 lines removed)
- Consolidate CORS, middleware and endpoints setup into single function
- Simplify Express server utility by combining duplicate code
- Remove redundant exports and clean up utils/index.ts
- Maintain all functionality while reducing overall code size

* refactor: simplify Express implementation following mcp-echarts pattern

* refactor: simplify Express-based MCP services following official SDK patterns

- Streamline SSE service
- Streamline Streamable service
- Follow official TypeScript SDK examples for minimal implementations
- Add cors dependency for proper browser support

* refactor: remove unused InMemoryEventStore and getBody utility functions

* Update package.json

---------

Co-authored-by: hustcc <i@hust.cc>

Author: Susuperli

package.json

@@ -1,7 +1,7 @@
 {
   "name": "@antv/mcp-server-chart",
   "description": "A Model Context Protocol server for generating charts using AntV. This is a TypeScript-based MCP server that provides chart generation capabilities. It allows you to create various types of charts through MCP tools.",
-  "version": "0.8.3",
+  "version": "0.9.0-beta.0",
   "main": "build/index.js",
   "types": "build/index.d.ts",
   "exports": {
@@ -30,8 +30,17 @@
     "registry": "https://registry.npmjs.org/",
     "access": "public"
   },
-  "files": ["build"],
-  "keywords": ["antv", "mcp", "data-visualization", "chart", "graph", "map"],
+  "files": [
+    "build"
+  ],
+  "keywords": [
+    "antv",
+    "mcp",
+    "data-visualization",
+    "chart",
+    "graph",
+    "map"
+  ],
   "repository": {
     "type": "git",
     "url": "https://github.com/antvis/mcp-server-chart"
@@ -44,12 +53,16 @@
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.11.4",
     "axios": "^1.11.0",
+    "cors": "^2.8.5",
+    "express": "^5.1.0",
     "zod": "^3.25.16",
     "zod-to-json-schema": "^3.24.5"
   },
   "devDependencies": {
     "@biomejs/biome": "1.9.4",
     "@modelcontextprotocol/inspector": "^0.14.2",
+    "@types/cors": "^2.8.19",
+    "@types/express": "^5.0.3",
     "@types/node": "^22.15.21",
     "husky": "^9.1.7",
     "lint-staged": "^15.5.2",

src/services/sse.ts

@@ -1,107 +1,43 @@
-import type { IncomingMessage, ServerResponse } from "node:http";
 import type { Server } from "@modelcontextprotocol/sdk/server/index.js";
 import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
-import { type RequestHandlers, createBaseHttpServer } from "../utils";
+import express from "express";
 
 export const startSSEMcpServer = async (
   server: Server,
   endpoint = "/sse",
   port = 1122,
 ): Promise<void> => {
-  const activeTransports: Record<string, SSEServerTransport> = {};
-
-  // Define the request handler for SSE-specific logic
-  const handleRequest: RequestHandlers["handleRequest"] = async (
-    req: IncomingMessage,
-    res: ServerResponse,
-  ) => {
-    if (!req.url) {
-      res.writeHead(400).end("No URL");
-      return;
-    }
-
-    const reqUrl = new URL(req.url, "http://localhost");
-
-    // Handle GET requests to the SSE endpoint
-    if (req.method === "GET" && reqUrl.pathname === endpoint) {
-      const transport = new SSEServerTransport("/messages", res);
-
-      activeTransports[transport.sessionId] = transport;
-
-      let closed = false;
-
-      res.on("close", async () => {
-        closed = true;
-
-        try {
-          await server.close();
-        } catch (error) {
-          console.error("Error closing server:", error);
-        }
-
-        delete activeTransports[transport.sessionId];
-      });
-
-      try {
-        await server.connect(transport);
-
-        await transport.send({
-          jsonrpc: "2.0",
-          method: "sse/connection",
-          params: { message: "SSE Connection established" },
-        });
-      } catch (error) {
-        if (!closed) {
-          console.error("Error connecting to server:", error);
-
-          res.writeHead(500).end("Error connecting to server");
-        }
-      }
-
-      return;
+  const app = express();
+  app.use(express.json());
+  
+  const transports: Record<string, SSEServerTransport> = {};
+
+  app.get(endpoint, async (req, res) => {
+    try {
+      const transport = new SSEServerTransport('/messages', res);
+      transports[transport.sessionId] = transport;
+      transport.onclose = () => delete transports[transport.sessionId];
+      await server.connect(transport);
+    } catch (error) {
+      if (!res.headersSent) res.status(500).send('Error establishing SSE stream');
     }
+  });
 
-    // Handle POST requests to the messages endpoint
-    if (req.method === "POST" && req.url?.startsWith("/messages")) {
-      const sessionId = new URL(
-        req.url,
-        "https://example.com",
-      ).searchParams.get("sessionId");
-
-      if (!sessionId) {
-        res.writeHead(400).end("No sessionId");
-        return;
-      }
-
-      const activeTransport: SSEServerTransport | undefined =
-        activeTransports[sessionId];
-
-      if (!activeTransport) {
-        res.writeHead(400).end("No active transport");
-        return;
-      }
-
-      await activeTransport.handlePostMessage(req, res);
-      return;
-    }
-
-    // If we reach here, no handler matched
-    res.writeHead(404).end("Not found");
-  };
-
-  // Custom cleanup for SSE server
-  const cleanup = () => {
-    // Close all active transports
-    for (const transport of Object.values(activeTransports)) {
-      transport.close();
+  app.post('/messages', async (req, res) => {
+    const sessionId = req.query.sessionId as string;
+    if (!sessionId) return res.status(400).send('Missing sessionId parameter');
+    
+    const transport = transports[sessionId];
+    if (!transport) return res.status(404).send('Session not found');
+    
+    try {
+      await transport.handlePostMessage(req, res, req.body);
+    } catch (error) {
+      if (!res.headersSent) res.status(500).send('Error handling request');
     }
-    server.close();
-  };
+  });
 
-  // Create the HTTP server using our factory
-  createBaseHttpServer(port, endpoint, {
-    handleRequest,
-    cleanup,
-    serverType: "SSE Server",
+  app.listen(port, () => {
+    console.log(`SSE Server listening on http://localhost:${port}${endpoint}`);
   });
 };