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RE: URI Template experience

From: Eran Hammer-Lahav <eran@hueniverse.com>
Date: Tue, 26 May 2009 10:30:23 -0700
To: Joe Gregorio <joe@bitworking.org>, "Roy T. Fielding" <fielding@gbiv.com>
CC: URI <uri@w3.org>
Message-ID: <90C41DD21FB7C64BB94121FBBC2E72343780C6119E@P3PW5EX1MB01.EX1.SECURESERVER.NET>
For the protocols I'm involved in (XRD, LRDD, WebFinger, OpenID, host-meta, etc.) we have been talking about a very simple template syntax:

* Use {variable} for variable substitution with a predefined vocabulary (based on the relation type in our case).
* Prefix variable names with % to indicate the value should be percent-encoded for all non-unreserved characters (with unreserved characters left unencoded).

This allows us to use very simple parsers that do not have to understand the structure of the URI to determine how the variables should or should not be encoded. Our use case is basically transforming one URI (context) into another URI (target), creating templates for Link relations. For this use case there is no need for any other template functionality.

I am a fan of Roy's previous proposal on this list, but would like to see the % operator (or another character) used to indicate when a parameter value should be encoded or not (assuming no other operator present with other instructions).

In terms of timing, I hope to get the XRD specification finished over the next 2 months and it would be extremely helpful to decide on this use case so that the XRD template syntax does not conflict with this proposed standard but represents a small subset of it (leaving the door open for using this proposal once it is published).

EHL

-----Original Message-----
> From: uri-request@w3.org [mailto:uri-request@w3.org] On Behalf Of Joe
> Gregorio
> Sent: Friday, May 22, 2009 7:24 AM
> To: Roy T. Fielding
> Cc: URI
> Subject: Re: URI Template experience
> 
> On Mon, May 18, 2009 at 5:38 PM, Roy T. Fielding <fielding@gbiv.com>
> wrote:
> > Hi Joe,
> >
> > Your question implies that the features in the current draft are
> > somehow dependent on the extent to which the current draft has
> > been implemented in the wild.  I think that is backwards, since
> > the draft received many comments and did not change as a result.
> > For example,
> >
> > http://www.w3.org/mid/07109D44-233D-42F3-ACB0-56B4A6562903@gbiv.com
> >
> > So, the answer to your question is that implementors are patiently
> > waiting (perhaps too patiently) for the draft to be updated.
> > Would it help if I issued a draft with the alternative syntax?
> 
> I asked the question because there are a bunch of implementations and
> if
> there was a great attraction to the current syntax beyond {foo} then I
> wanted
> to know that. From what I can tell from the ensuing conversation there
> is a need
> for more complex capabilities beyond {foo}, but no one is in love with
> the current
> syntax. That's good news to me because I prefer your proposed system.
> 
> I can update the current draft to your proposal, or you can generate
> a draft yourself if you think that will go faster.
> 
>    Thanks,
>    -joe
> 
> >
> > ....Roy
> >
> 
> 
> 
> --
> Joe Gregorio        http://bitworking.org
Received on Tuesday, 26 May 2009 17:31:24 GMT

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