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

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Sep 11, 2018, 04:29 UTC
Message-ID: <20180911042919.GE20518@aiede.svl.corp.google.com>
In-Reply-To: <xmqqo9d4r7j2.fsf@gitster-ct.c.googlers.com>

Junio C Hamano wrote:

> Jonathan Nieder <jrnieder@gmail.com> writes:

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>> 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).

[...]

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>> 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/.

[...]

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>> 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