@tus/server: handle request cancellation gracefully (#774)

This PR fixes 2 regressions:

- Handle gracefully the request cancellation by aborting the context,
which will allow the locks to be released immediately and available to
be acquired by subsequent requests. Currently, this has been broken
since the context was never cancelled when the request was aborted

- Force closing the connection when the request was aborted, to prevent
the client from needing to send the whole body before realising that the
upload was cancelled (potentially from another request acquiring the
lock)

---------

Co-authored-by: Merlijn Vos <[email protected]>

Author: fenos

.changeset/modern-birds-appear.md

@@ -0,0 +1,5 @@
+---
+"@tus/server": patch
+---
+
+Handle request cancellation gracefully on Node.js runtime

packages/server/src/server.ts

@@ -134,6 +134,17 @@ export class Server extends EventEmitter {
     const context = this.createContext()
     const headers = new Headers()
 
+    // Special case on the Node.js runtime,
+    // We handle gracefully request errors such as disconnects or timeouts.
+    // This is important to avoid memory leaks and ensure that the server can
+    // handle subsequent requests without issues.
+    if ('node' in req && req.node) {
+      const nodeReq = (req.node as {req: http.IncomingMessage}).req
+      nodeReq.once('error', () => {
+        context.abort()
+      })
+    }
+
     const onError = async (error: {
       status_code?: number
       body?: string
@@ -212,7 +223,16 @@ export class Server extends EventEmitter {
     // Invoke the handler for the method requested
     const handler = this.handlers[req.method as keyof Handlers]
     if (handler) {
-      return handler.send(req, context, headers).catch(onError)
+      const resp = await handler.send(req, context, headers).catch(onError)
+
+      if (context.signal.aborted) {
+        // If the request was aborted, we should not send any response body.
+        // The server should just close the connection.
+        resp.headers.set('Connection', 'close')
+        return resp
+      }
+
+      return resp
     }
 
     return this.write(context, headers, 404, 'Not found\n')
@@ -253,7 +273,7 @@ export class Server extends EventEmitter {
     return new Response(body, {status, headers})
   }
 
-  // biome-ignore lint/suspicious/noExplicitAny: <explanation>
+  // biome-ignore lint/suspicious/noExplicitAny: it's fine
   listen(...args: any[]): http.Server {
     return http.createServer(this.handle.bind(this)).listen(...args)
   }