Fastify crashes when reply code is not recognized

[chiku]

🐛 Bug Report

Fastify crashes when reply code is not recognized.

To Reproduce

Steps to reproduce the behavior:

Run fastify server that returns an exotic response code.

const fastify = require('fastify')({ logger: true });

fastify.get('/', async (request, reply) => {
  reply.code(525); // exotic response code
  return { hello: 'world' };
});

const start = async () => {
  try {
    await fastify.listen(3000);
    fastify.log.info(`server listening on ${fastify.server.address().port}`);
  } catch (err) {
    fastify.log.error(err);
    process.exit(1);
  }
};

start();

Make a request to the server

curl http://localhost:3000

The application crashes.

The HTTP response code is 500 and the response body is as follows.

{"statusCode":500,"code":"FST_ERR_BAD_STATUS_CODE","error":"Internal Server Error","message":"FST_ERR_BAD_STATUS_CODE: Called reply with malformed status code"}

Expected behavior

The application should not crash

Your Environment

• node version: v10.19.0
• fastify version: 2.13.0
• os: Mac

[chiku]

This is the application stack-trace

FastifyError [FST_ERR_BAD_STATUS_CODE]: FST_ERR_BAD_STATUS_CODE: Called reply with malformed status code
    at _Reply.Reply.code (node_modules/fastify/lib/reply.js:202:11)
    at Object.fastify.get (index.js:4:9)
    at preHandlerCallback (node_modules/fastify/lib/handleRequest.js:111:30)
    at preValidationCallback (node_modules/fastify/lib/handleRequest.js:100:5)
    at handler (node_modules/fastify/lib/handleRequest.js:69:5)
    at handleRequest (node_modules/fastify/lib/handleRequest.js:18:5)
    at onRunMiddlewares (node_modules/fastify/lib/middleware.js:22:5)
    at middlewareCallback (node_modules/fastify/lib/route.js:381:5)
    at Object.routeHandler [as handler] (node_modules/fastify/lib/route.js:359:7)
    at Router.lookup (node_modules/find-my-way/index.js:349:14)

[chiku]

I have figured that code fails if it is not defined in node_modules/statuses/codes.json

[Eomm]

Good catch!

To reproduce we need to use this endpoint:

fastify.get('/', (request, reply) => {
  reply.code(525).send({ hello: 'world' })
})

with async handler the server doesn't crash.

In the earlier version 2.12, the code was simply set as the user wanted:

curl ...
HTTP/1.1 525 unknown

Moving this issue to the main repo as regression

I think we should:

• throw if it is not a number
• throw an error every time only in v3

cc @mcollina
PR that introduce this check: #2082

[mcollina]

The bug that #2082 tried to fix is reply.code(undefined). I think an alternative implementation of https://github.com/fastify/fastify/pull/2082/files#diff-d2fdf63c1d7f1d9f68270b6dfa8c930cR201 can be provided to pass the given unit test that does not crash the above code. I do not think we should have a different behavior between v2 and v3, this is just a regression.

@leorossi would you be able to do a follow-up PR?

[leorossi]

Yes assign it to me please