Using mounted method within params

[Nix41]

When constructing a namespace, where options are passed through the configuration hash
In order to declare the params using the entity set in the configuration, as per the documentation:

params do
  requires :all, using: mounted { configuration[:entity] }.documentation
end
post do
  resource = configuration[:model].create!(
  present resource, with: mounted { configuration[:entity] }
end

Results in:

NoMethodError:
  undefined method `mounted' for #<Grape::Validations::ParamsScope:0x00007f1a325c2df0 @element=nil, @element_renamed=nil, @parent=nil, @api=#<Class:0x00007f1a325cc508>, @optional=false, @type=Hash, @group=nil, @dependent_on=nil, @declared_params=[], @index=nil>

The mounted method, does seem to be accessible via the @api variable within Grape::Validations::ParamsScope
Maybe I am missing something?

In any case, thanks in advance for taking a look

Here the full backtrace or the Error:

# ./app/api/admin_dashboard/resources/templates/crud.rb:21:in `block (2 levels) in <class:Crud>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/validations/params_scope.rb:70:in `instance_eval'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/validations/params_scope.rb:70:in `initialize'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/dsl/validations.rb:39:in `new'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/dsl/validations.rb:39:in `params'
# ./app/api/admin_dashboard/resources/templates/crud.rb:20:in `block in <class:Crud>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:118:in `instance_eval'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:118:in `block in evaluate_as_instance_with_configuration'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/util/lazy_block.rb:11:in `evaluate_from'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:125:in `evaluate_as_instance_with_configuration'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:107:in `block in nest'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:107:in `each'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:107:in `nest'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/dsl/routing.rb:175:in `block in namespace'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/dsl/settings.rb:160:in `within_namespace'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/dsl/routing.rb:172:in `namespace'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:160:in `replay_step_on'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:151:in `block in add_setup'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:150:in `each'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:150:in `add_setup'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:55:in `block (2 levels) in override_all_methods!'
# ./app/api/admin_dashboard/resources/templates/crud.rb:10:in `<class:Crud>'
# ./app/api/admin_dashboard/resources/templates/crud.rb:6:in `<module:Templates>'
# ./app/api/admin_dashboard/resources/templates/crud.rb:5:in `<module:Resources>'
# ./app/api/admin_dashboard/resources/templates/crud.rb:4:in `<module:AdminDashboard>'
# ./app/api/admin_dashboard/resources/templates/crud.rb:3:in `<top (required)>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/zeitwerk-2.6.8/lib/zeitwerk/kernel.rb:30:in `require'
# /usr/share/rvm/gems/ruby-3.1.3/gems/zeitwerk-2.6.8/lib/zeitwerk/kernel.rb:30:in `require'
# ./app/api/admin_dashboard/resources/admins.rb:7:in `block in <class:Admins>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:118:in `instance_eval'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:118:in `block in evaluate_as_instance_with_configuration'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/util/lazy_block.rb:11:in `evaluate_from'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:125:in `evaluate_as_instance_with_configuration'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:107:in `block in nest'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:107:in `each'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api/instance.rb:107:in `nest'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/dsl/routing.rb:175:in `block in namespace'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/dsl/settings.rb:160:in `within_namespace'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/dsl/routing.rb:172:in `namespace'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:160:in `replay_step_on'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:151:in `block in add_setup'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:150:in `each'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:150:in `add_setup'
# /usr/share/rvm/gems/ruby-3.1.3/gems/grape-1.7.0/lib/grape/api.rb:55:in `block (2 levels) in override_all_methods!'
# ./app/api/admin_dashboard/resources/admins.rb:6:in `<class:Admins>'
# ./app/api/admin_dashboard/resources/admins.rb:5:in `<module:Resources>'
# ./app/api/admin_dashboard/resources/admins.rb:4:in `<module:AdminDashboard>'
# ./app/api/admin_dashboard/resources/admins.rb:3:in `<top (required)>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/zeitwerk-2.6.8/lib/zeitwerk/kernel.rb:30:in `require'
# /usr/share/rvm/gems/ruby-3.1.3/gems/zeitwerk-2.6.8/lib/zeitwerk/kernel.rb:30:in `require'
# ./app/api/admin_dashboard/base.rb:19:in `<class:Base>'
# ./app/api/admin_dashboard/base.rb:4:in `<module:AdminDashboard>'
# ./app/api/admin_dashboard/base.rb:3:in `<top (required)>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/zeitwerk-2.6.8/lib/zeitwerk/kernel.rb:30:in `require'
# /usr/share/rvm/gems/ruby-3.1.3/gems/zeitwerk-2.6.8/lib/zeitwerk/kernel.rb:30:in `require'
# ./app/api/api.rb:59:in `<class:Api>'
# ./app/api/api.rb:5:in `<module:Api>'
# ./app/api/api.rb:4:in `<top (required)>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/zeitwerk-2.6.8/lib/zeitwerk/kernel.rb:30:in `require'
# /usr/share/rvm/gems/ruby-3.1.3/gems/zeitwerk-2.6.8/lib/zeitwerk/kernel.rb:30:in `require'
# ./config/routes.rb:812:in `block in <top (required)>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/actionpack-7.0.4.3/lib/action_dispatch/routing/route_set.rb:428:in `instance_exec'
# /usr/share/rvm/gems/ruby-3.1.3/gems/actionpack-7.0.4.3/lib/action_dispatch/routing/route_set.rb:428:in `eval_block'
# /usr/share/rvm/gems/ruby-3.1.3/gems/actionpack-7.0.4.3/lib/action_dispatch/routing/route_set.rb:410:in `draw'
# ./config/routes.rb:7:in `<top (required)>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/application/routes_reloader.rb:50:in `load'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/application/routes_reloader.rb:50:in `block in load_paths'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/application/routes_reloader.rb:50:in `each'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/application/routes_reloader.rb:50:in `load_paths'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/application/routes_reloader.rb:24:in `reload!'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/application.rb:149:in `reload_routes!'
# /usr/share/rvm/gems/ruby-3.1.3/gems/devise-4.9.2/lib/devise/rails.rb:17:in `block in <class:Engine>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/activesupport-7.0.4.3/lib/active_support/lazy_load_hooks.rb:92:in `block in execute_hook'
# /usr/share/rvm/gems/ruby-3.1.3/gems/activesupport-7.0.4.3/lib/active_support/lazy_load_hooks.rb:85:in `with_execution_control'
# /usr/share/rvm/gems/ruby-3.1.3/gems/activesupport-7.0.4.3/lib/active_support/lazy_load_hooks.rb:90:in `execute_hook'
# /usr/share/rvm/gems/ruby-3.1.3/gems/activesupport-7.0.4.3/lib/active_support/lazy_load_hooks.rb:76:in `block in run_load_hooks'
# /usr/share/rvm/gems/ruby-3.1.3/gems/activesupport-7.0.4.3/lib/active_support/lazy_load_hooks.rb:75:in `each'
# /usr/share/rvm/gems/ruby-3.1.3/gems/activesupport-7.0.4.3/lib/active_support/lazy_load_hooks.rb:75:in `run_load_hooks'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/application/finisher.rb:73:in `block in <module:Finisher>'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/initializable.rb:32:in `instance_exec'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/initializable.rb:32:in `run'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/initializable.rb:61:in `block in run_initializers'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/initializable.rb:60:in `run_initializers'
# /usr/share/rvm/gems/ruby-3.1.3/gems/railties-7.0.4.3/lib/rails/application.rb:372:in `initialize!'
# ./config/environment.rb:5:in `<top (required)>'
# ./spec/rails_helper.rb:6:in `require'
# ./spec/rails_helper.rb:6:in `<top (required)>'

Here the rest of the relevant code

# frozen_string_literal: true

module AdminDashboard
  module Resources
    class Admins < Base
      resource :admins do
        mount Resources::Templates::Crud, with: { index: Admin.all, entity: Entities::Admin }
      end
    end
  end
end

# frozen_string_literal: true

module AdminDashboard
  module Resources
    module Templates
      class Crud < Base
        include Grape::Kaminari

        namespace do
          params do
            use :pagination, per_page: 10, max_per_page: 30
          end
          get do
            list = configuration[:index]

            present paginate(list), with: mounted { configuration[:entity] }
          end

          params do
            requires :all, using: mounted { configuration[:entity] }.documentation
          end
          post do
            resource = configuration[:model].create!(permitted_params)

            present resource, with: mounted { configuration[:entity] }
          end
        end
      end
    end
  end
end

[dblock]

I don't think you're missing anything. Try adding it to ParamScope?

[Nix41]

Hi @dblock , thanks for answering, as far as I can see, the code is as the documentation specifies, specifically: https://github.com/ruby-grape/grape#mount-configuration , I should be able to do this without modifying the gem, right?
This is why I thought this might be a bug, and not a new feature

[dblock]

Ah I see. Yes, that would be a bug. Care to add a (failing) test?

[myxoh]

Hi - this is my bad as clearly I got overly eager on the docs.

We can fix it in one of two ways:

First just update the docs. The behaviour described on those docs is achievable without the mounted { } block (that block is really only needed for top-level configuration that is evaluated at the class level - while the params block is only really evaluated after the endpoint is mounted (and therefore doesn't need to be lazy loaded)

Alternatively: Define the mounted block in ParamsScope - I don't really think there's much value in doing it this way - but we certainly can define a dummy mounted block for consistency.

Added this PR: #2339

[dblock]

Closed via #2339