http: avoid retaining unneeded memory

[lpinca]

Prevents the events listeners of the sockets obtained with the HTTP upgrade mechanism from retaining unneeded objects like state.

Reduces memory usage by ~20%.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

Affected core subsystem(s)

[lpinca]

I'm not sure if this is ok but there are 2 listeners for the drain event and both seem to be useless for upgrade requests.
The first checks if _httpMessage is set and this is never true for upgrade requests.
The second checks if the socket is _paused but unless I'm missing something this flag is never set for upgrade requests.

[bnoordhuis]

.removeAllListeners() also removes any user-installed 'drain' event listeners so no, probably not a good idea.

[lpinca]

Yeah I get that but can a user add a listener for the drain event before this is called?

[bnoordhuis]

Yes, server.on('connection', c => c.on('drain', ondrain)).

[jasnell]

/cc @nodejs/http

[cjihrig]

LGTM pending CI

[lpinca]

Refs: #11868

[bnoordhuis]

.removeAllListeners() also removes any user-installed 'drain' event listeners so no, probably not a good idea.

[lpinca]

@bnoordhuis updated, PTAL.
This listener is no longer removed as I can't find a clean way to selectively remove it without exporting the function.

[bnoordhuis]

@lpinca You could move it to lib/internal/http.js.

[lpinca]

Done, thanks.

[bnoordhuis]

I'd add a comma, saves one line in the diff next time someone adds a property.

[jasnell]

CI: https://ci.nodejs.org/job/node-test-pull-request/6968/

[jasnell]

@lpinca ... this is not landing cleanly for some reason (even tho it shows zero conflicts...) can you please squash the commits, rebase, and I'll try again.

[lpinca]

@jasnell done.

[jasnell]

Landed in e0a9ad1

[MylesBorins]

This will need to be manually backported to v7.x

[MylesBorins]

Looks like this change is breaking spdy. Example breakage from spdy tests.

 6) SPDY Server spdy/3 plain mode should not crash on .writeHead() after socket close:
Uncaught TypeError: Cannot read property 'emit' of null
at Socket.socketOnError (_http_server.js:450:19)
at Stream.onStreamError (lib/spdy/handle.js:110:18)
at node_modules/spdy-transport/lib/spdy-transport/connection.js:749:12
at Array.forEach (native)
at Connection.destroyStreams (node_modules/spdy-transport/lib/spdy-transport/connection.js:745:33)
at Socket.onclose (node_modules/spdy-transport/lib/spdy-transport/connection.js:185:10)
at TCP._handle.close [as _onclose] (net.js:534:12)

[ronkorving]

@indutny Any chance this could be solved on the spdy side of things?

[bnoordhuis]

Removing the backport-to-v7.x label and adding dont-land-on labels until this is resolved.

[lpinca]

Not sure if the following is the proper way to fix the issue but it seems to work:

diff --git a/lib/spdy/server.js b/lib/spdy/server.js
index 777f682..d5321c2 100644
--- a/lib/spdy/server.js+++ b/lib/spdy/server.js@@ -189,6 +189,8 @@ proto._onStream = function _onStream (stream) {
socket = new net.Socket(socketOptions)
}
+ socket.server = this;+
handle.assignSocket(socket)
// For v0.8

Will send a PR.

[lpinca]

That patch seems to not work on Node.js 0.10 and 0.12.

The problem is that node-spdycalls the connectionListener on a new socket for which the server property is null.