Adhere to the full Streams API

[mcollina]

Currently send does not implement the Streams API (even if it inherits from Stream), and in fact inside send(..).pipe(res), it does stream.pipe(res).

Specifically, we had to use an "hack" to make it work well on Fastify. See fastify/fastify-static#46, where we had to pipe it through a modified PassThrough.

I'm thinking of changing the API to something:

const { stream, headers, statusCode } = await send(req, path, options)

As well as:

send(req, path, options, (err,  { stream, headers, statusCode }) => {
  // ...
})

I would like to also remove the dependency on on-finished and some of the others modules that were needed in the 0.8/0.10 days.

I think this work should help as well with http2 compatibility as well. I'm happy to prototype this work in a forked module as well, just let me know.

cc @apapirovski

[dougwilson]

Yea, definitely would like to see. Node.js 0.8 will be dropped with the next major but 0.10 support won't be removed anytime soon, so if it's possible to still support 0.10 that would be super awesome.

[dougwilson]

FWIW I feel like the current API is pretty janky so totally open to an API that flows better, especially the output side. Many would like to see this write to a transform stream to do transformations, which sounds like you're ask too.

[dougwilson]

In addition for Node.js versions, everything in this org tries to support as many Node.js versions as possible -- it's part of our philosophy. We have the ideal support line (down to 0.10 currently) and the hard line of must go down to at least (4.0 currently). Really the minimum version is negotiable between those two, and if 0.10 isn't picked there should be some good reasons to why it's impossible to support lower (in the past we have used compat helps like on-finished to accomplish tasks like this, so perhaps it's just to make a new one).

[mcollina]

Yes, I need to apply a transform afterwards (compression).

I'll see what I can come up with, I'll target Node 4, and then we can see if we can stretch it to 0.10.

I'm in your same shoes for backward compat, as readable-stream@2 (pulled from Node 8) supports down to Node 0.8.

[bjohansebas]

@pillarjs/express-tc Is this something we still want?

[mcollina]

I would actually recommend to reconcile with https://github.com/fastify/send, which already has a variation of this implemented.

[bjohansebas]

I don't fully understand what you mean by reconciling it in this case. Could you elaborate, please?

[mcollina]

Basically take @fastify/send as the new base of this module and reconcile the two forks.

[bjohansebas]

That sounds good to me, although it was required for the TC to agree. I'll add it to the agenda.

edit: Okay, the label is not there. Once it is added, I will add it to the agenda.

[wesleytodd]

We are pretty sure this will need to be a part of the express v6 roadmap, and we have some STF funding which also partly covers this work. Timeline on this is likely to be later this year, just to make sure we are clear.

@mcollina If you were willing to, we would love to find a time to sync up with you on how to move forward here. So would you be willing to run us all through some of what your goals are here, what specific technical goals we should be aware of, and lastly what we will need to be aware of when reconciling these to test the ecosystem of modules that depend on this.