Refactor http transport into separate file.

Author: tillahoffmann

src/http-transport.ts

@@ -0,0 +1,53 @@
+import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
+import express from "express";
+import { Request, Response } from "express";
+import { server } from './server.js';
+
+export async function runHttpServer(port: number): Promise<void> {
+  // We return a new promise that never resolves to keep the server alive.
+  return new Promise((resolve, reject) => {
+    // Start a server based on the official @modelcontextprotocol/sdk documentation.
+    const app = express();
+    app.use(express.json());
+
+    app.post('/', async (req: Request, res: Response) => {
+      // In stateless mode, create a new instance of transport and server for each request
+      // to ensure complete isolation. A single instance would cause request ID collisions
+      // when multiple clients connect concurrently.
+
+      try {
+        const transport: StreamableHTTPServerTransport = new StreamableHTTPServerTransport({
+          sessionIdGenerator: undefined,
+        });
+        res.on('close', () => {
+          transport.close();
+          server.close();
+        });
+        await server.connect(transport);
+        await transport.handleRequest(req, res, req.body);
+      } catch (error) {
+        console.error('Error handling MCP request:', error);
+        if (!res.headersSent) {
+          res.status(500).json({
+            jsonrpc: '2.0',
+            error: {
+              code: -32603,
+              message: 'Internal server error',
+            },
+            id: null,
+          });
+        }
+      }
+    });
+
+    // Start the server
+    const httpServerInstance = app.listen(port, () => {
+      console.log(`MCP Stateless Streamable HTTP Server listening on port ${port}`);
+    });
+
+    httpServerInstance.on('error', (err) => {
+      console.error(`HTTP Server failed to start or encountered an error: ${err.message}`);
+      reject(err);
+    });
+  });
+}

src/index.ts

@@ -1,9 +1,7 @@
 #!/usr/bin/env node
 
 import { FilteredStdioServerTransport } from './custom-stdio.js';
-import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
-import express from "express";
-import { Request, Response } from "express";
+import { runHttpServer } from './http-transport.js';
 import { server } from './server.js';
 import { configManager } from './config-manager.js';
 import { join, dirname } from 'path';
@@ -140,55 +138,6 @@ async function runServer() {
   }
 }
 
-async function runHttpServer(port: number) {
-  // We return a new promise that never resolves to keep the server alive.
-  return new Promise((resolve, reject) => {
-    // Start a server based on the official @modelcontextprotocol/sdk documentation.
-    const app = express();
-    app.use(express.json());
-
-    app.post('/', async (req: Request, res: Response) => {
-      // In stateless mode, create a new instance of transport and server for each request
-      // to ensure complete isolation. A single instance would cause request ID collisions
-      // when multiple clients connect concurrently.
-
-      try {
-        const transport: StreamableHTTPServerTransport = new StreamableHTTPServerTransport({
-          sessionIdGenerator: undefined,
-        });
-        res.on('close', () => {
-          transport.close();
-          server.close();
-        });
-        await server.connect(transport);
-        await transport.handleRequest(req, res, req.body);
-      } catch (error) {
-        console.error('Error handling MCP request:', error);
-        if (!res.headersSent) {
-          res.status(500).json({
-            jsonrpc: '2.0',
-            error: {
-              code: -32603,
-              message: 'Internal server error',
-            },
-            id: null,
-          });
-        }
-      }
-    });
-
-    // Start the server
-    const httpServerInstance = app.listen(port, () => {
-      console.log(`MCP Stateless Streamable HTTP Server listening on port ${port}`);
-    });
-
-    httpServerInstance.on('error', (err) => {
-      console.error(`HTTP Server failed to start or encountered an error: ${err.message}`);
-      reject(err);
-    });
-  });
-}
-
 async function runStdioServer() {
   console.error("Connecting server through stdio transport ...");
   const transport = new FilteredStdioServerTransport();