Re: [PATCH] http-backend: treat empty CONTENT_LENGTH as zero

From: Jonathan Nieder <jrnieder@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Max Kirillov" <max@max630.net>,
	git@vger.kernel.org, "Jeff King" <peff@peff.net>,
	"Jelmer Vernooĳ" <jelmer@jelmer.uk>,
	"Florian Manschwetus" <manschwetus@cs-software-gmbh.de>
Subject: Re: [PATCH] http-backend: treat empty CONTENT_LENGTH as zero
Date: Mon, 10 Sep 2018 21:29:19 -0700	[thread overview]
Message-ID: <20180911042919.GE20518@aiede.svl.corp.google.com> (raw)
In-Reply-To: <xmqqo9d4r7j2.fsf@gitster-ct.c.googlers.com>

Junio C Hamano wrote:
> Jonathan Nieder <jrnieder@gmail.com> writes:

>> RFC 3875 (the CGI specification) explains:
>>
>>    The CONTENT_LENGTH variable contains the size of the message-body
>>    attached to the request, if any, in decimal number of octets.  If no
>>    data is attached, then NULL (or unset).
[...]
>> But that specification was written before HTTP/1.1 and chunked
>> encoding.
>
> RFC 3875 is from October 2004, while RFC 2616 (HTTP/1.1) is from
> June 1999; I presume that 3875 only writes down what has already
> been an established practice and that is where the date discrepancy
> comes from.

Yes, CGI 1.1 is from 1995.  More details are at
https://www.w3.org/CGI/.

[...]
>> Fortunately, there's a way out.  Use the HTTP_TRANSFER_ENCODING
>> environment variable to distinguish the two cases.
>
> Cute.
>
> I'm anxious to learn how well this works in practice. Or is this a
> trick you know somebody else's system already uses (in which case,
> that's wonderful)?

Alas, I came up with it today so I don't know yet how well it will
work in practice.

I can poke around a little tomorrow in Apache to sanity-check the
approach.  Results from anyone able to test using various HTTP servers
(lighttpd, etc) would also be very welcome.

Thanks,
Jonathan