byte size of the response

[HassanIyan]

is there any way i can get and record the size of the response returned from a route?

[metcoder95]

Not at the moment. Though can be an interesting addition 🤔

As a workaround, you can measure the byte length of your request on the onSend hook and attach it to the reply object, to later use it within the onResponse hook.

[Eomm]

Do you mean like this?

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

fastify.get(
  '/',
  {
    onResponse: function hook(request, reply, done) {
      console.log(reply.raw.getHeader('Content-Length'));
      done();
    },
  },
  async (request, reply) => {
    return 'a'.repeat(42);
  }
);

fastify.inject('/').then((response) => {});

[metcoder95]

Ah, yes, pretty much. I was having in mind calculating the byte length with Buffer but totally missed we already do that for the Content-Length header. Thanks for the heads up 🙇