Rails module scope - ruby-on-rails

Given the following controller structure:
# application_controller.rb
class ApplicationController < ActiveController::Base; end
# pages_controller.rb
class PagesController < ApplicationController; end
# admin/application_controller.rb
module Admin
class ApplicationController < ::ApplicationController; end
end
# admin/pages_controller.rb
module Admin
class PagesController < ApplicationController; end
end
One would expect Admin::PagesController to inherit from Admin::ApplicationController and it does. But I have noticed that sometimes it inherits from ::ApplicationController.
So I decided not to risk it and changed declaration of all controllers in /admin to specifically target Admin::ApplicationController
# admin/pages_controller.rb
module Admin
class PagesController < Admin::ApplicationController; end
end
Okay that works, but from what I know it was correct in the first place. Why Rails inherits from a wrong controller sometimes?
Admin::PagesController sometimes inherits from ApplicationController instead of Admin::ApplicationController despite both being in the same module Admin

The problem here is rails' development mode code loading: in general code is loaded when you try to do something with a constant (eg subclass from it) and that constant doesn't exist. This results in const_missing being called and rails uses it this to try to load the class (for a detailed description see the guide).
If neither ApplicationController nor Admin::ApplicationController exist then when you access your admin pages controller ruby will hit that const_missing and try to load admin/application_controller.rb
However if ApplicationController is already loaded then ruby won't fire const_missing since it perfectly legal for a class in the admin module to inherit from something at the toplevel.
The solution as you say is to make explicit what you are inheriting from. Personally in my own apps I use Admin::BaseController as the base class.

Another option is to use require_dependency to point Rails to the correct file:
# admin/application_controller.rb
require_dependency 'admin/application_controller'
module Admin
class PagesController < ApplicationController
end
end

Related

uninitialized constant Admin::AdminController

Getting an "uninitialized constant" error. I am trying to make a "AdminCotroller"(subcontroller) to the ApplicationController to control one area of the website (the "admin" area).
The routing seems to be correctly set up. I attach 2 things (both from: app/controller/admin/ folder) which produce the error:
1) the "parent" controller
class Admin::AdminController < ApplicationController
layout "admin/layout"
end
2) the "child" controller
class Admin::ProductsController < Admin::AdminController
PS: I wanted to make a separate layout and this was the only solution I could think off.
PPS: Folder Structure
Check the above file structure, that's what I have used.
And controllers as below:
class Admin::BaseController < ApplicationController
layout 'admin'
...
end
class Admin::AdminUsersController < Admin::BaseController
...
end
I don't know what I messed up those days. I haven't tried a given answer but instead I found a workable solution for naming I would like to share:
module Admin
class UsersController < BaseController
...
end
end
this way you achieve a namespace in a folder "admin" too.

Rails Controller Namespace Inheritance Missing Layout

Using a namespaced controller and the app's Application layout isn't being loaded.
# controllers/application_controller.rb
class ApplicationController < ActionController::Base
protect_from_forgery with: :exception
end
# controllers/servers/base_controller.rb
module Servers
class BaseController < ApplicationController
def initialize
# I noticed params are not accessible here either...
# Only in the child controller.
end
end
end
# controllers/servers/test_controller.rb
module Servers
class TestController < BaseController
def index
end
end
end
A pretty basic setup here. Anytime I route to /servers/:id it loads the page with the parameter, but the application layout does not load. I have a series of a couple controllers I'd like to all inherit from this BaseController to initialize a few things. I also noticed that besides the layout issue, the BaseController doesn't have access to url parameters. The TestController does though... Can anyone explain these two issues I'm seeing?
Rails 5.1.4
ruby 2.4.1p111
Figured out my issue. Don't use an initialize method in your class. Rails doesn't like that. Use before_action instead.

Calling a method from another controller

If I've got a method in a different controller to the one I'm writing in, and I want to call that method, is it possible, or should I consider moving that method to a helper?
You could technically create an instance of the other controller and call methods on that, but it is tedious, error prone and highly not recommended.
If that function is common to both controllers, you should probably have it in ApplicationController or another superclass controller of your creation.
class ApplicationController < ActionController::Base
def common_to_all_controllers
# some code
end
end
class SuperController < ApplicationController
def common_to_some_controllers
# some other code
end
end
class MyController < SuperController
# has access to common_to_all_controllers and common_to_some_controllers
end
class MyOtherController < ApplicationController
# has access to common_to_all_controllers only
end
Yet another way to do it as jimworm suggested, is to use a module for the common functionality.
# lib/common_stuff.rb
module CommonStuff
def common_thing
# code
end
end
# app/controllers/my_controller.rb
require 'common_stuff'
class MyController < ApplicationController
include CommonStuff
# has access to common_thing
end
Try and progressively move you methods to your models, if they don't apply to a model then a helper and if it still needs to be accessed elsewhere put in the ApplicationController
If you requirement has to Do with some DB operations, then you can write a common function (class method) inside that Model. Functions defined inside model are accessible across to all the controllers. But this solution does to apply to all cases.
I don't know any details of your problem, but maybe paths could be solution in your case (especially if its RESTful action).
http://guides.rubyonrails.org/routing.html#path-and-url-helpers

how do you put before filters in modular controllers?

I have several controllers that are in a module:
class SoapTest::DashboardController < ApplicationController
class SoapTest::TestCasesController < ApplicationController
etc.
I want to be able to check if a user has certain permissions for a module, and since I don't have a "parent" controller where the above ones inherit, i thought to put the check in a before filter in applications. But I can't seem to get the module name:
in application controller, i have:
before_filter :check_company_features
def check_company_features
puts controller_name
end
but controller_name just returns "dashboard". I need to get the "SoapTest" clause
Be attention, what you currently call modules actually are namespaces.
The reason why controller_name returns only the class name (and not the fully qualified name) is because Rails explicitly strips the namespaces. You can get them by calling the Ruby #name method on the controller class.
class SoapTest::DashboardController < ApplicationController
before_filter :check_company_features
def check_company_features
puts controller_name
# => "dashboard_controller"
puts self.class.name
# => "SoapTest::DashboardController"
end
end
There are several String inflection methods you can call on the #name to get the formatted version.
However, I strongly encourage you to use a namespaced main controller.
Instead of using
class SoapTest::DashboardController < ApplicationController
you can extend a SoapTest::ApplicationController
class SoapTest::ApplicationController < ApplicationController
before_filter :check_company_features
def check_company_features
# ...
end
end
class SoapTest::DashboardController < SoapTest::ApplicationController
end

Is there any partial kind of thing for controllers in Ruby on Rails

I have a controller having more than 1000 lines of code.
Right not I am doing Code review for this controller.
I arrange my methods according to the module.
Now I realise that my controller is not easy to maintain and so I want to something like following
class UsersController < ApplicationController
#Code to require files here
#before filter code will goes here
#############Here i want to call that partial like things. following is just pseudo #########
history module
account module
calendar module
shipment module
payment module
####################################################################
end #end of class
this help me so much to maintained the code as when i change history module i am sure that my account module is unchanged.I know CVS but i prefer 50 copies of each module instead 200 copies of my users_controller.rb itself.
P.S. :- I would like Affirmative answer.please don't answer like, you should use different controller for different module.....bla...bla...bla... as it's not possible for me to do so.
EDIT:- My Versions Are
rails -v
Rails 2.3.4
ruby -v
ruby 1.8.6 (2008-08-11 patchlevel 287) [i386-linux]
This should work for you:
app/controllers/some_controller.rb
class SomeController < ApplicationController
include MyCustomMethods
end
lib/my_custom_methods.rb
module MyCustomMethods
def custom
render :text => "Rendered from a method included from a module!"
end
end
config/routes.rb
# For rails 3:
match '/cool' => "some#custom"
# For rails 2:
map.cool 'cool', :controller => "some", :action => "custom"
Fire up your app and hit http://localhost:3000/cool, and you'll get your custom method included from a module.
Assuming from you pseudocode that you are referring to Ruby modules, and not something else, just put all your requires/modules in a separate module and include that or have your UsersController inherit from a base class if you are reusing those files. In the first case you can think of a module as a mix-in and it is designed for exactly the modularity you want.
module AllMyStuff
include History
include Account
...
end
class UsersController < ApplicationController
include AllMyStuff
def new
end
...
end
or you can inherit from a base controller,in this case its probably a reasonable solution.
def BaseController < ActionController
include history
include account
end
def UsersController < BaseController
# modules available to this controller by inheritance
def new
end
...
end
I tried the following method and I have it running, maybe it suits for you:
app/user_controller.rb
require 'index.rb'
class UsersController < ApplicationController
# some other code
end
app/index.rb
class UsersController < ApplicationController
def index
#users = User.all
end
end
MY ENV: rails 3 beta4

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