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Re: URI Templates - optional variables?

From: Roy T. Fielding <fielding@gbiv.com>
Date: Tue, 16 Oct 2007 13:18:37 -0700
Message-Id: <9BCE3D4D-0DEF-4E1A-AF79-0967BF98D4F0@gbiv.com>
Cc: "'Stefan Eissing'" <stefan.eissing@greenbytes.de>, "'Mark Nottingham'" <mnot@mnot.net>, "'URI'" <uri@w3.org>, "'Joe Gregorio'" <joe@bitworking.org>
To: Mike Schinkel <mikeschinkel@gmail.com>

On Oct 16, 2007, at 12:48 PM, Mike Schinkel wrote:
> Roy T. Fielding wrote:
>
>> Easy to read by whom?  I went through the readable bits with
>> HTTP and it turned out to be a big mistake.  Nobody reads
>> HTTP in real practice, yet the overhead of parsing HTTP
>> messages is huge.
>>
>> I think of URI templates as a generalization of
>> server-provided info on how to construct the URI for a
>> resource space, in the same way that server-side image maps
>> defined a constructor for map points.
>> I think the main use case is going to be within the Link (or
>> was it Link-Template?) header fields, which means they will
>> be protocol bits and reducing the length of those bits will
>> be important.
>
> That's a sadly limited vision, especially from you Roy, for a  
> technology
> that can address why so many people violate the RESTian principle of
> "Hypermedia being the engine of application state."

Do you even know what that means?  When you do, you will realize
that URI templates are for describing the relationship of resource
mapping to data storage mechanisms -- they are the opposite end of
the spectrum from hypertext, and any use of them as a replacement
for hypertext would violate REST and reintroduce client coupling
to server implementation in fairly obvious ways.  Thus, I have
no use for them outside the server-internal contexts of
CMS/Service configuration and the server-provided form of link
automation, both of which are contexts of use by and for real
programmers who can read documentation and/or follow a link
that explains a given template.

The users you are talking about don't use text editors to
configure their sites, and don't read HTML script to figure
out how to interact with services.  The pretty view of them
that you are thinking of can be auto-generated on the fly by
whatever software they happen to be using at the moment, just
as Day's software provides graphical depictions of folder
hierarchy and workflow that are far easier for an end-user
to understand than our internal representations of the same.

What we are talking about here is the PROTOCOL format exchange,
not the GUI presentation, because that's what we standardize.

....Roy
Received on Tuesday, 16 October 2007 20:18:50 GMT

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