ruby on rails 3.2 - How can I specify prefix parameters when saving a nested ActiveResource? -

i have nested activeresource model (i.e. it's within model's namespace). trying call save raises:

activeresource::missingprefixparam: client_id prefix_option missing 

how supply needed prefix?

here's class:

class foo::bar < activeresource::base   self.site = "http://www.example.com"   self.prefix = "/clients/:client_id"   self.element_name = "policy"   self.collection_name = "policies" end 

here's save attempt:

bar = foo::bar.new :client_id => 123 bar.valid? # => true bar.client_id # => 123 bar.save # => activeresource::missingprefixparam... 

time , again i've looked elucidation on this, find same instruction:

when requested nested resource , don’t provide prefix_param activeresource::missingprefixparam raised.

i'm trying access our server's api endpoint @ http://www.example.com/clients/[client_id]/policies, i'm apparently failing supply client_id, app makes request http://www.example.com/clients//policies

the server log tells me: actioncontroller::routingerror (no route matches "/clients//policies/" {:method=>:post}).

it work if create method prefix_options, supplies hash containing needed client_id prefix_option, so:

def prefix_options   { :client_id => client_id } end