Rails - Dec 2005 - restful interfaces and preserving PATH_INFO in custom dispatch/route

i''m working on a restful interface to existing models in an app. 
ideally i''d
like to preserve the existing dispatch mechanism and support a parrallel one
that looks like

   http://0.0.0.0/rest/mime/model/id

to do this i''d like to setup a rest controller which dispatches based
on the
http request method and path into.  for example, a get sent to

   http://0.0.0.0/rest/xml/student/42

returns xml for student(s) with id 42.  a post of xml to

   http://0.0.0.0/rest/xml/student/42

updates the record via a xml doc.  of course i''ll never use these and
will
prefer

   http://0.0.0.0/rest/yaml/student/42

;-)

because i want to preserve the default rails dispatching mechanism and isolate
all rest code into a single controller, thereby enabling the site to be rest
enables for various formats with the addition of a single controller and no
other code modification.  the tricky bit is

   - how to configure rails such that the path_info (/student/42) is preserved
   - how to reuse as much of the existing route/dispaching code as possible to
     handle parsing this path_info

any hints appreciated.

-a
-- 
==============================================================================|
ara [dot] t [dot] howard [at] noaa [dot] gov
| all happiness comes from the desire for others to be happy.  all misery
| comes from the desire for oneself to be happy.
| -- bodhicaryavatara
===============================================================================

On 4-dec-2005, at 20:42, Ara.T.Howard wrote:
>
> i''m working on a restful interface to existing models in an app.
> ideally i''d
> like to preserve the existing dispatch mechanism and support a  
> parrallel one
> that looks like
>
>   http://0.0.0.0/rest/mime/model/id
>
> to do this i''d like to setup a rest controller which dispatches  
> based on the
> http request method and path into.  for example, a get sent to
>
>   http://0.0.0.0/rest/xml/student/42
>
> returns xml for student(s) with id 42.  a post of xml to
>
>   http://0.0.0.0/rest/xml/student/42
>
> updates the record via a xml doc.  of course i''ll never use these
> and will
> prefer
>
>   http://0.0.0.0/rest/yaml/student/42
>
> ;-)
>
> because i want to preserve the default rails dispatching mechanism  
> and isolate
> all rest code into a single controller, thereby enabling the site  
> to be rest
> enables for various formats with the addition of a single  
> controller and no
> other code modification.  the tricky bit is
>
>   - how to configure rails such that the path_info (/student/42) is  
> preserved
>   - how to reuse as much of the existing route/dispaching code as  
> possible to
>     handle parsing this path_info
>
> any hints appreciated.
map.connect ''rest/:format/:model/:action/:id

on the controller side

def index
     request.post? ? update_student : return_student
end

I think it should parse the params for you if they are YAML or XML  
but I''m not sure.
Why would you want path-info here?


--
Julian ''Julik'' Tarkhanov
me at julik.nl

On Sun, 4 Dec 2005, Julian ''Julik'' Tarkhanov wrote:
>> 
>> any hints appreciated.
>
> map.connect ''rest/:format/:model/:action/:id
                                       ^
                                       ^
                                       ^

this is inferred from the REQUEST_METHOD.


the idea is that a url like

   http://127.0.0.1/rest/student/42

is used for all of PUT (create), GET (read), POST (edit), and DELETE (delete).
> on the controller side
>
> def index
>    request.post? ? update_student : return_student
> end
but a post can be either an insert or an update...
> I think it should parse the params for you if they are YAML or XML but
I''m
> not sure.  Why would you want path-info here?
   http://127.0.0.1/rest/xml/student/42
                     ^    ^    ^^^^^^^
                     ^    ^    ^^^^^^^
                     ^    ^    ^^^^^^^

             controller action  path_info

but now i think i understand what you are getting at... maybe a

   map.connect ''rest/:format/:model/:id''

for a specific record

and

   map.connect ''rest/:format/:model/''

for all tuples.

but i''m new to routes and don''t quite get the exact approach.

thanks for the idea.

-a
-- 
==============================================================================|
ara [dot] t [dot] howard [at] noaa [dot] gov
| all happiness comes from the desire for others to be happy.  all misery
| comes from the desire for oneself to be happy.
| -- bodhicaryavatara
===============================================================================