Keep-Alive ignored for HTTP(S) HEAD requests

[Limess]

Version: v.4.8.0, v7.9.0
Platform: OSX 10.10.5 (Darwin MC-S103314.local 14.5.0 Darwin Kernel Version 14.5.0: Sun Sep 25 22:07:15 PDT 2016; root:xnu-2782.50.9~1/RELEASE_X86_64 x86_64)
Subsystem: http / net

http(s) HEAD requests don't obey Keep-Alive, even when Connection: Keep-Alive is set.
The same http(s) GET request obeys Keep-Alive.

I believe I've followed this down to:

1. node/deps/http_parser/http_parser.c

   Line 2105 in db1087c

   parser->flags & F_SKIPBODY) { /* response to a HEAD request */

   which is called from

2. node/deps/http_parser/http_parser.c

   Line 2132 in db1087c

   return !http_message_needs_eof(parser);

   this propagates back to

3. node/lib/_http_common.js

   Line 61 in a4b9c58

   function parserOnHeadersComplete(versionMajor, versionMinor, headers, method,

   with shouldKeepAlive set to false, regardless of a Connection: Keep-Alive header.

I've been unable to find anything in any linked RFC from the above code block to support this being per-specification, if it is I'd appreciate someone highlighting it to me.

[Trott]

@nodejs/http

[dougwilson]

I don't know the history here, but I have seen similar behavior in other clients as well, with some documentating that the reason to close after a HEAD request is to interop with misbehaving servers that may send a body in the response.

[bnoordhuis]

@dougwilson is spot on. The current behavior was implemented in 2011 in commit e576d4e.

I'll close this out because I don't think we want to change it. It would probably do more bad than good.