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Re: cunked transfert-Encoding without content length

From: Daniel Stenberg via curl-library <>
Date: Fri, 20 Dec 2019 13:25:01 +0100 (CET)

On Fri, 20 Dec 2019, GENESTIER Denis via curl-library wrote:

> Since the curl version 7.58, the chunked Transfer-Encoding response that
> contains a negative content length are considered as invalid.

*All* responses that contain Content-Length and Transfer-Encoding are invalid.
Or in the words of RFC 7230 section 3.3.2:

    A sender MUST NOT send a Content-Length header field in any message
    that contains a Transfer-Encoding header field.

> These kinds of message seem correct to me (cf
> and
> I may considering this as a regression from curl.

I don't understand what you refer to. What part in that wikipedia article
would indicate that this is a legitimate HTTP response?

I'm pretty sure a lot of other HTTP clients will also similarly go nuts on
such a response.

> Actually I have to specify the option CURLOPT_IGNORE_CONTENT_LENGTH, to
> maintain the curl integration in my code to communicate with our legacy
> server. Is there any ways to adapt this behavior in the file http.c, to not
> take in account a negative content length in case of chunked response?

Historically, we once supported negative content-lengths (without chunking)
because some servers in the early 2000s would do that when serving larger than
32 bit contents.

We removed that work-around as you say before 7.58.0 was released. Worked on
in this PR:

Landed in this exact commit:
(in January 2018).

To me, it sounds like CURLOPT_IGNORE_CONTENT_LENGTH is the perfect rememdy for
this case. It is a HTTP violation to send both headers, but you can make curl
put up a blind eye for that if you're willing to take the consequences - with
a special option.

Or am I missing something?

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Received on 2019-12-20