add GET to examples servers

Author: ihrpr

src/client/streamableHttp.ts

@@ -131,7 +131,6 @@ export class StreamableHTTPClientTransport implements Transport {
           `Failed to open SSE stream: ${response.statusText}`,
         );
       }
-
       // Successful connection, handle the SSE stream as a standalone listener
       this._handleSseStream(response.body);
     } catch (error) {

src/examples/client/simpleStreamableHttp.ts

@@ -25,7 +25,7 @@ async function main(): Promise<void> {
   const transport = new StreamableHTTPClientTransport(
     new URL('http://localhost:3000/mcp')
   );
-  const supportsStandaloneSse = false;
+  let supportsStandaloneSse = false;
 
   // Connect the client using the transport and initialize the server
   await client.connect(transport);
@@ -34,7 +34,7 @@ async function main(): Promise<void> {
   console.log('Opening SSE stream to receive server notifications...');
   try {
     await transport.openSseStream();
-    const supportsStandaloneSse = false;
+    supportsStandaloneSse = true;
     console.log('SSE stream established successfully. Waiting for notifications...');
   }
   catch (error) {

src/examples/server/jsonResponseStreamableHttp.ts

@@ -138,6 +138,13 @@ app.post('/mcp', async (req: Request, res: Response) => {
   }
 });
 
+// Handle GET requests for SSE streams according to spec
+app.get('/mcp', async (req: Request, res: Response) => {
+  // Since this is a very simple example, we don't support GET requests for this server
+  // The spec requires returning 405 Method Not Allowed in this case
+  res.status(405).set('Allow', 'POST').send('Method Not Allowed');
+});
+
 // Helper function to detect initialize requests
 function isInitializeRequest(body: unknown): boolean {
   if (Array.isArray(body)) {

src/examples/server/simpleStreamableHttp.ts

@@ -174,6 +174,19 @@ app.post('/mcp', async (req: Request, res: Response) => {
   }
 });
 
+// Handle GET requests for SSE streams (now using built-in support from StreamableHTTP)
+app.get('/mcp', async (req: Request, res: Response) => {
+  const sessionId = req.headers['mcp-session-id'] as string | undefined;
+  if (!sessionId || !transports[sessionId]) {
+    res.status(400).send('Invalid or missing session ID');
+    return;
+  }
+
+  console.log(`Establishing SSE stream for session ${sessionId}`);
+  const transport = transports[sessionId];
+  await transport.handleRequest(req, res);
+});
+
 // Helper function to detect initialize requests
 function isInitializeRequest(body: unknown): boolean {
   if (Array.isArray(body)) {