Express example (`@arcp/express`)

Run an ARCP runtime side-by-side with normal Express HTTP routes on a single port. @arcp/express provides:

createArcpExpressApp({ allowedHosts }) — an Express instance with x-powered-by disabled and a Host-header DNS-rebind guard on the HTTP side.
attachArcpToExpress(httpServer, { path, allowedHosts, onTransport }) — registers the WS upgrade handler on the underlying http.Server with the same Host check.

The Express request pipeline never sees the ARCP traffic; the upgrade event fires on the raw http.Server before Express's router runs.

Run

In one terminal:

pnpm tsx examples/express/server.ts

In a second terminal:

pnpm tsx examples/express/client.ts

The client makes GET /health first, then opens a WebSocket to /arcp, submits an echo job, and prints the result. Stop the server with Ctrl+C.

One Node HTTP server, two protocols on one port (HTTP + ARCP WS).
DNS-rebinding protection via allowedHosts on both the HTTP routes and the WebSocket upgrade.
The same ARCPServer/agent-registration code as every other example — the middleware is purely a mount point.