[hunchentoot-devel] suggested imporvement: setting content-type with keywords

[Edi Weitz]

I'm taking this back to the mailing list.  I think there's no need to
discuss this in private.

FWIW, I agree with Hans and don't think this is a very useful patch.
You argue that with the patch you won't have to memorize mime types,
but then you'll have to memorize file suffixes instead.  And even if
you don't need to learn them (as many of those suffixes have become
second nature to us), they are a pretty arbitrary classification from
the olden days of operating systems.  Finally, how many different mime
types will you use in a typical web application?  Is it such a big
deal?

Thanks,
Edi.



On Wed, Apr 7, 2010 at 12:05 AM, Hans Hübner <hans.huebner at gmail.com> wrote:
> Ala'a,
>
> hereby I forward your reply to Edi.  I think the basic concern is that
> MIME types are standardized, whereas keywords are not, and that it is
> not clear what keywords are supported and how keywords would be added.
>  I agree with you that abstraction is good, but it is good only if it
> does not break easily, because, say, no new MIME types can be added,
> or there is ambiguity between MIME types and keywords as in the case
> of XML.  Sometimes, something that first seemed simple and
> straightforward becomes cumbersome and ugly.  This is not to say that
> your patch is in that class, I'm just saying that there may be valid
> counterarguments against including such a simple thing in the base
> HTTP surrogate because it does not scale beyond the simple use cases
> provoided as example.
>
> That said, let's see if Edi has an opinion.
>
> -Hans
>
>
> ---------- Forwarded message ----------
> From: Ala'a (cmo-0) <amalawi at gmail.com>
> Date: Tue, Apr 6, 2010 at 19:16
> Subject: Re: [hunchentoot-devel] suggested imporvement: setting
> content-type with keywords
> To: Hans Hübner <hans.huebner at gmail.com>
>
>
> Hi Hans,
>
> I understand, thus the followings are the motives/notes/thoughts
> regarding the patch:
>
> - As a developer I do not want to be concerned/or memorize that
> sending pdf should be
>  using "application/pdf". The details of mime types should be hidden
> (a kind of abstraction)
>  in other words, moving from constructing the details of the response
> (as much as possible),
>  and concentrating on the task at hand which is developing the web
> content (js, ajax, html
>  and other content dynamic and/or static). In general there is no
> productivity boost, except
>  to avoid looking for the right mime type, Is it
> application/something? or text/something?
>  Maybe its time for googling mime types again ;)
>
> - There are some uses of keyword designators in the API (like in
> *lisp-errors-log-level* and
>  the use of :post :get and :both in define-esay-handler) which could
> be strings, so I
>  thought/assumed that my patch will not be a stranger within the current API.
>
> - Still the API is backward compatible, there is no need to force the
> users to use the new
>  designator. And the code uses the already built in database for mime types.
>
> - This patch can propagate the API abstraction upward and be used by
> other extension (maybe another patch) like:
> (defun set-content-spec (mime-type-designator &optional
> disposition-type filename) ...)
> where
> mime-type-designator: the same value as taken by (setf content-type*).
> filename: the name of sent content.
> disposition-type: is either :inline (open within the browser) or
> :attachment (open a save-as dialog).
> so I can say something like:
> (defun lpo-pdf ()
>  (let ((lpo (query-for-lpo ...))) ;lpo is short for: local purchase order
>     (set-content-spec :pdf :attachment (format nil "~A.pdf" (serial lpo)))
>     (generate-pdf-content)))
>
> sheesh, this is almost triple the size of the patch ;)
>
> Regards,
>
> Ala'a (cmo-0)
>
>