Add comprehensive logging to debug Redis transport issues

- Add detailed logging to Redis transport lifecycle
- Log session validation and message flow
- Track MCP server request handling
- Add diagnostics for streamable HTTP transport connections

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/handlers/common.ts

@@ -0,0 +1,57 @@
+import { NextFunction, Request, Response } from "express";
+import { withContext } from "../context.js";
+import { readMcpInstallation } from "../services/auth.js";
+
+import { JSONRPCError, JSONRPCNotification, JSONRPCRequest, JSONRPCResponse } from "@modelcontextprotocol/sdk/types.js";
+
+export function logMcpMessage(
+  message: JSONRPCError | JSONRPCNotification | JSONRPCRequest | JSONRPCResponse,
+  sessionId: string,
+) {
+  // check if message has a method field
+  if ("method" in message) {
+    if (message.method === "tools/call") {
+      console.info(
+        `[session ${sessionId}] Processing ${message.method}, for tool ${message.params?.name}`,
+      );
+    } else {
+      console.info(
+        `[session ${sessionId}] Processing ${message.method} method`,
+      );
+  }
+  } else if ("error" in message) {
+    console.warn(
+      `[session ${sessionId}] Received error message: ${message.error.message}, ${message.error.code}`,
+    )
+  }
+}
+
+
+export async function authContext(
+  req: Request,
+  res: Response,
+  next: NextFunction,
+) {
+  const authInfo = req.auth
+
+  if (!authInfo) {
+    res.set("WWW-Authenticate", 'Bearer error="invalid_token"');
+    res.status(401).json({ error: "Invalid access token" });
+    return;
+  }
+
+  const token = authInfo.token;
+
+  // Load UpstreamInstallation based on the access token
+  const mcpInstallation = await readMcpInstallation(token);
+  if (!mcpInstallation) {
+    res.set("WWW-Authenticate", 'Bearer error="invalid_token"');
+    res.status(401).json({ error: "Invalid access token" });
+    return;
+  }
+
+  // Wrap the rest of the request handling in the context
+  withContext({ mcpAccessToken: token, fakeUpstreamInstallation: mcpInstallation.fakeUpstreamInstallation }, () =>
+    next(),
+  );
+}