RESTful Web services and DAL

[Paul Harrison]

On 14.03.2007, at 11:16, Norman Gray wrote:

>
>> REST has no use for a parameter-based GET since the latter is an
>> operation or method performed upon some object, and conflates actions
>> with resources.
>
> I think there is a role for URLs with parameters in a REST-style  
> interface (others disagree, I know).  However it's rare, because it  
> encourages this false analogy with procedure calls, and because of  
> the problems which Guy describes in his earlier message.  At the  
> same time, I don't believe that this is the core issue, and that  
> arguing about whether SIAP cutout URLs are RESTful or not is  
> possibly a bit of a blind alley.

I too think that there is definitely a role for URLs with parameters  
in a REST-style interface - in the S*AP services, there is no strong  
natural ordering of parameters, and some of them are optional, so  
mapping them to a strict path style just does not work, as you cannot  
reliably associate them with a level in the path hierarchy

unless you start do to things like...

http://server.com/siap/ra=30/dec=20/

but even then

http://server.com/siap/dec=20/ra=30/

obviously (to a human reader) points at the same "resource" even  
though they are different uris - which is not usefully RESTful  
behaviour.

It seems to me that trying to be blindly 100% compliant with any  
methodology nearly always produces worse results than being a little  
flexible - in fact the skill of a good programmer is knowing when to  
break the rules.

Paul Harrison
ESO Garching
www.eso.org