Add automatic response time header?

[bompus]

I'd like to see maybe another hook that gets executed after User Handler or after Reply, just prior to sending off the headers, which would allow me to setHeader X-Response-Time or whatever I'd like.

Perhaps this is already possible, but the only way I could see is to hijack res.writeHead, etc to inject my header. It'd be much easier if there were simply a hook where I could add this.

If this is already possible and I am ignorant, please let me know!

[delvedor]

Hi, thank you for trying Fastify!
We are currently working on a 'onResponse' hook that will run just after the user handler (in other word, after the reply.send call).

[bompus]

That would work perfectly. I'll wait for that to arrive, and thank you!

[jsumners]

Actually, unless I followed the flow incorrectly, onResponse isn't going to work. This new hook is run via the standard library's onResFinshed event. That means the headers have already been finalized.

What we really need is a postHandler hook that has the signature postHandler(fastifyRequest, fastifyReply, next).

[delvedor]

@jsumners onResponse will run once the response has finished, checkout the lifecycle.

What you need is the onSend or postHandler hook, @lucamaraschi is working on it :)

[lolo32]

I just impemented onHeaders from express, that I derived in two packages: fastify-onheader and fastify-response-time.
I'm waiting for pull request to be accepted.

[jsumners]

This should be more generic than just for headers.

[delvedor]

@jsumners the onSend hook will provide support for this and more :)

[jsumners]

@delvedor right. I was responding to @lolo32.

[delvedor]

Closing this, if you have more questions feel free to reopen :)