websocket server file - #21
Conversation
📝 WalkthroughWalkthroughA new Changes
Sequence DiagramsequenceDiagram
participant Server as Server Process
participant NextApp as Next.js App
participant HTTPServer as HTTP Server
participant WSServer as WebSocket Server
participant Client as HTTP/WebSocket Client
Server->>NextApp: next({dev, hostname, port})
Server->>NextApp: app.prepare()
NextApp-->>Server: Ready
Server->>HTTPServer: createServer(requestHandler)
Server->>WSServer: initWebSocketServer(httpServer)
WSServer-->>HTTPServer: Attached to server
Server->>HTTPServer: listen(port)
HTTPServer-->>Server: Listening
Client->>HTTPServer: HTTP Request
HTTPServer->>HTTPServer: parseUrl()
HTTPServer->>NextApp: handle(req, res, parsedUrl)
NextApp-->>HTTPServer: Response
HTTPServer-->>Client: Response
Note over HTTPServer: Error during request
HTTPServer->>HTTPServer: Log error
HTTPServer-->>Client: 500 Internal Server Error
Estimated code review effort🎯 2 (Simple) | ⏱️ ~12 minutes Possibly related PRs
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🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 inconclusive)
✅ Passed checks (4 passed)
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Actionable comments posted: 3
🧹 Nitpick comments (1)
server.js (1)
1-41: Consider adding graceful shutdown handlers.There are no
SIGTERM/SIGINThandlers to close the HTTP server and WebSocket connections cleanly. In containerized/orchestrated environments this can lead to dropped in-flight requests and abrupt WS closures (clients see 1006 instead of a clean close). A small handler that callsserver.close()and iterateswss.clientsto close them with code 1001 ("Going Away") improves resilience.🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@server.js` around lines 1 - 41, Add graceful shutdown handlers that close the HTTP server and WebSocket clients: modify the initWebSocketServer invocation (or export a reference) so you can obtain the WebSocket server instance (e.g., return wss from initWebSocketServer), then install SIGINT/SIGTERM listeners after server.listen that call server.close(callback) and iterate wss.clients to call client.close(1001, "Server Shutdown"); also set a fallback forced process.exit after a short timeout if close callbacks hang and ensure errors during shutdown are logged. Use the existing symbols server, initWebSocketServer, server.close, and wss.clients / client.close to locate where to hook this logic.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@server.js`:
- Around line 8-11: The PORT environment variable is left as a string so `port`
can be a string or number; coerce it to a number where `port` is defined so
`next({ dev, hostname, port })` and any `server.listen(port)` calls always
receive a number. Replace the current assignment for `port` with a numeric
conversion (e.g., parseInt/Number) with the same fallback (3000) and guard
against NaN by defaulting to 3000 so `port` is always a valid number used by
`next()` and server listen calls.
- Line 14: app.prepare() is missing a .catch handler so startup rejections are
unhandled; update the promise chain that starts with app.prepare().then(() => {
... }) to append a .catch handler that logs the error (using your existing
logger or console.error) with context and then calls process.exit(1) to ensure
the process exits with a non-zero code when prepare fails; target the
app.prepare() promise chain in server.js and add the .catch(...) logic there.
- Around line 34-41: Remove the unused (err) parameter from the server.listen
callback and instead add an 'error' event handler on the server that handles
listen failures (e.g., EADDRINUSE) — implement server.on('error', (err) => { ...
}) to log the error and exit/handle gracefully, and keep the existing
console.log inside the server.listen callback (now with no args); reference the
server.listen callback and server.on('error') when making the change.
---
Nitpick comments:
In `@server.js`:
- Around line 1-41: Add graceful shutdown handlers that close the HTTP server
and WebSocket clients: modify the initWebSocketServer invocation (or export a
reference) so you can obtain the WebSocket server instance (e.g., return wss
from initWebSocketServer), then install SIGINT/SIGTERM listeners after
server.listen that call server.close(callback) and iterate wss.clients to call
client.close(1001, "Server Shutdown"); also set a fallback forced process.exit
after a short timeout if close callbacks hang and ensure errors during shutdown
are logged. Use the existing symbols server, initWebSocketServer, server.close,
and wss.clients / client.close to locate where to hook this logic.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
| const port = process.env.PORT || 3000; | ||
|
|
||
| // Initialize Next.js in development or production mode | ||
| const app = next({ dev, hostname, port }); |
There was a problem hiding this comment.
Coerce PORT to a number.
process.env.PORT is a string when defined, so port becomes a string in that case and a number otherwise. Next.js's next({ port }) option is typed as number, and passing it to server.listen works but the inconsistency can cause subtle bugs (e.g., string concatenation, equality checks). Normalize at the source.
🔧 Proposed fix
-const port = process.env.PORT || 3000;
+const port = parseInt(process.env.PORT, 10) || 3000;📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| const port = process.env.PORT || 3000; | |
| // Initialize Next.js in development or production mode | |
| const app = next({ dev, hostname, port }); | |
| const port = parseInt(process.env.PORT, 10) || 3000; | |
| // Initialize Next.js in development or production mode | |
| const app = next({ dev, hostname, port }); |
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@server.js` around lines 8 - 11, The PORT environment variable is left as a
string so `port` can be a string or number; coerce it to a number where `port`
is defined so `next({ dev, hostname, port })` and any `server.listen(port)`
calls always receive a number. Replace the current assignment for `port` with a
numeric conversion (e.g., parseInt/Number) with the same fallback (3000) and
guard against NaN by defaulting to 3000 so `port` is always a valid number used
by `next()` and server listen calls.
| const app = next({ dev, hostname, port }); | ||
| const handle = app.getRequestHandler(); | ||
|
|
||
| app.prepare().then(() => { |
There was a problem hiding this comment.
Missing .catch() on app.prepare() — startup errors are silently swallowed.
If app.prepare() rejects (build manifest missing, port binding issues during prepare, etc.), the promise rejection goes unhandled and the process may continue without a working server, or exit with an opaque UnhandledPromiseRejection. Add a .catch that logs and exits with a non-zero code so process supervisors (PM2, systemd, Docker) can restart cleanly.
🔧 Proposed fix
-app.prepare().then(() => {
+app.prepare().then(() => {
// 1. Create the standard Node.js HTTP Server
...
-});
+}).catch((err) => {
+ console.error("Failed to start server:", err);
+ process.exit(1);
+});🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@server.js` at line 14, app.prepare() is missing a .catch handler so startup
rejections are unhandled; update the promise chain that starts with
app.prepare().then(() => { ... }) to append a .catch handler that logs the error
(using your existing logger or console.error) with context and then calls
process.exit(1) to ensure the process exits with a non-zero code when prepare
fails; target the app.prepare() promise chain in server.js and add the
.catch(...) logic there.
| server.listen(port, (err) => { | ||
| if (err) throw err; | ||
| console.log( | ||
| `> Neura Engine Started` + | ||
| `\n> Mode: ${dev ? "Development" : "Production"}` + | ||
| `\n> Local: http://${hostname}:${port}` | ||
| ); | ||
| }); |
There was a problem hiding this comment.
🧩 Analysis chain
🌐 Web query:
Does Node.js http.Server.listen callback receive an error argument?
💡 Result:
No, the Node.js http.Server.listen callback does not receive an error argument. The callback is invoked only on successful binding and has the signature => void. It is added as a listener for the 'listening' event. Errors during listen (e.g., EADDRINUSE) are handled via the 'error' event on the server or synchronous exceptions for invalid arguments (e.g., invalid port). Official Node.js documentation for net.Server.listen (which http.Server inherits) shows the callback as optional with no parameters, confirmed across multiple versions including v25.x, v20.x, v18.x. Source code analysis shows the callback is attached via server.once('listening', cb), and libuv's uv_listen emits no error to it. Stack Overflow discussions confirm the callback is never passed an error; use server.on('error') instead.
Citations:
- 1: https://nodejs.org/api/http.html
- 2: https://nodejs.org/docs/latest/api/http.html
- 3: https://docs.deno.com/api/node/net/~/Server.prototype.listen
- 4: https://nodejs.org/docs/v7.0.0/api/net.html
- 5: https://nodejs.org/docs/latest-v18.x/api/net.html
- 6: https://nodejs.org/docs/v20.14.0/api/net.html
- 7: https://www.nodejs.org
- 8: nodejs/node@fd6af98c2d
- 9: net: refactor Server.prototype.listen nodejs/node#4039
- 10: https://github.com/nodejs/node/blob/main/src/tcp_wrap.cc
- 11: https://github.com/nodejs/node/blob/main/doc/api/net.md
Add error handler for listen failures and remove unused error parameter.
The server.listen callback in Node.js does not receive an error argument — it is invoked only on successful binding as a one-time listener for the 'listening' event. The (err) parameter will always be undefined. Listen failures (e.g., EADDRINUSE) are emitted on the 'error' event, which currently has no handler and will crash the process.
🔧 Proposed fix
+ server.on("error", (err) => {
+ console.error("HTTP server error:", err);
+ process.exit(1);
+ });
+
- server.listen(port, (err) => {
- if (err) throw err;
- console.log(
+ server.listen(port, () => {
+ console.log(
`> Neura Engine Started` +
`\n> Mode: ${dev ? "Development" : "Production"}` +
`\n> Local: http://${hostname}:${port}`
);
});🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@server.js` around lines 34 - 41, Remove the unused (err) parameter from the
server.listen callback and instead add an 'error' event handler on the server
that handles listen failures (e.g., EADDRINUSE) — implement server.on('error',
(err) => { ... }) to log the error and exit/handle gracefully, and keep the
existing console.log inside the server.listen callback (now with no args);
reference the server.listen callback and server.on('error') when making the
change.
1 participant
Summary by CodeRabbit
Release Notes
New Features
Infrastructure & Reliability