Re: [libmicrohttpd] Change reason phrase

[Evgeny Grin]

From the new RFC 9112.
https://www.rfc-editor.org/rfc/rfc9112.html#section-4
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The simplest way is use special header, like
Unauthorized-Reason: Account frozen



--
Evgeny

On 06.12.2022 8:52, Christian Grothoff wrote:

A client SHOULD ignore the reason-phrase content because it is not a reliable channel for information (it might be translated for a given locale, overwritten by intermediaries, or discarded when the message is forwarded via other versions of HTTP). So unless you are communicating only within a closed network, you cannot be sure that "reason-phrase" will be delivered. HTTP is quite flexible, so you could deliver the same message via special header or within the body (context) or your reply. This is very simple, supported by HTTP, reliable and could be easily implemented with current MHD API.

Well, the RFC says that the client SHOULD ignore it. Yes, the server MAY change it, but to rely on it doesn't create a robust protocol: For example, by my reading, HTTP (reverse) proxies between client and server MAY change the message...

On 12/6/22 05:24, Tiaan via libmicrohttpd wrote:

So yes, having the 'wrong' message technically doesn't break the standard, but using the message to convey significant information does.

Thank you, importantly you've answered my question that it is not possible.

May I complete the record then and respectfully disagree with your
assessment of the merit. I quote from RFC7231:

6.1 <https://www.rfc-editor.org/rfc/rfc7231#section-6.1>.  Overview of
Status Codes

    The status codes listed below are defined in this specification,
    Section 4 of [RFC7232]
<https://www.rfc-editor.org/rfc/rfc7232#section-4>, Section 4 of
[RFC7233] <https://www.rfc-editor.org/rfc/rfc7233#section-4>, and
Section 3 of
    [RFC7235] <https://www.rfc-editor.org/rfc/rfc7235#section-3>.  The
reason phrases listed here are only recommendations
    -- they can be replaced by local equivalents without affecting the
    protocol.


and from 7230:

The reason-phrase element exists for the sole purpose of providing a
    textual description associated with the numeric status code, mostly
    out of deference to earlier Internet application protocols that were
    more frequently used with interactive text clients.  A client SHOULD
    ignore the reason-phrase content.

      reason-phrase  = *( HTAB / SP / VCHAR / obs-text )


Regards

Only by changing the source code and recompiling MHD. But you should not
do this, this is a very bad idea. You should stick to the standard
messages of the HTTP protocol. If you need to convey additional
information, do it in the body or in a header; try to use HTTP status
codes narrowly to what the HTTP standard says they are for.

On 12/5/22 10:26, Tiaan via libmicrohttpd wrote:

Hi, is it possible to change the reason phrase of responses e.g. instead

of

HTTP/1.1 401 Unauthorized rather HTTP/1.1 401 Account frozen?

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