Methods defined in helper
classes of a resource
are directly accessible only in corresponding views(of the same resource) and NOT in controller, so you would need to include the helper
module explicitly in the controller in order to access these helper methods.
module Api
module V1
class SessionsController < ApplicationController
include Api::V1::SessionsHelper ## Add this
## ...
end
end
end
You are getting the error because Api::V1::SessionsController
has no idea about the existence of sign_in
method.