[whatwg] element "img" with HTTP POST method

[Nils Dagsson Moskopp]

Martin Janecke <whatwg.org at kaor.in> schrieb am Thu, 9 Dec 2010 19:59:02
+0100:

> What is your opinion on enabling the HTTP POST method for the img
> element? The motivation behind this is that there are services which
> generate images automatically based on parameters given -- nowadays
> provided as query string in a GET request -- for inclusion in web
> pages. I've listed examples below. However, these query strings can
> get really long and it seems to me that the HTTP POST method would be
> more appropriate than the GET method for such services. Not only
> because it would better match the intended use of these methods (see
> http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9),

I do not agree. Maybe I do not grasp something here, but I was of
the impression that POST creates content while GET requests resources,
also explicitly resources that are created by “data-producing
process[es]”.

Also, quote RFC 2616, Section 9, Subsection 5:

> the posted entity is subordinate to that URI in the same way that a
> file is subordinate to a directory containing it, a news article is
> subordinate to a newsgroup to which it is posted, or a record is
> subordinate to a database. 

I don't see this with image generation at all.

Back to your mail:

> but also
> for practical reasons: URLs in GET requests are (inconsistently)
> limited in length by browsers and server software, which limits these
> services (inconsistently). And long URLs bloat server logs.

These are implementation issues. What makes you believe that the
relatively complex task of adding a new attribute would be implemented
before the relatively simple task of extending the URL length?

Also, filtering out GET variables from logs is a simple task.

> This could be implemented with an optional attribute, e.g.
> "post-data". The client would request the source using the POST
> method if the attribute is present and send the attribute's value as
> the request's message body.

New clients. What would old clients do?
What if the given URL contained GET variables?

> […]
>
> === Example/Use Cases ===
> 
> (1) MimeTeX and MathTeX are used to display mathematical formulae in
> web pages. This is often used in science forums. Info:
> 
> […]

Why not use inline MathML? It is semantically accurate and stylable.

> […]
>
> <img
> src="http://qrcode.kaywa.com/img.php?s=8&d=Ah%2C%20distinctly%20I%20remember%20it%20was%20in%20the%20bleak%20December%2C%0D%0AAnd%20each%20separate%20dying%20ember%20wrought%20its%20ghost%20upon%20the%20floor."
> alt="qrcode">
> 
> Possible future use:
> 
> <img src="http://qrcode.kaywa.com/img.php"
> post-data="s=8&d=Ah%2C%20distinctly%20I%20remember%20it%20was%20in%20the%20bleak%20December%2C%0D%0AAnd%20each%20separate%20dying%20ember%20wrought%20its%20ghost%20upon%20the%20floor."
> alt="qrcode">

This seems to be largely an aesthetical (but non-backwards-compatible!)
change. Also, at least to me it does not seem to be “more” readable.


Cheers,
-- 
Nils Dagsson Moskopp // erlehmann
<http://dieweltistgarnichtso.net>
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