This is just pseudo-code to give you a general idea:
# client code
class MyClient
def get(params)
RestClient.get '/some/api', params
end
end
# resource code
allow_filter :name do |scope, val|
scope.merge!(name: val)
end
def resolve(scope)
MyClient.new.get(scope)
end
# controller code
# our "scope" is just a hash this time
render_jsonapi({})