I'm new to rails and I have this small problem about helpers and controllers. Is it possible to include my custom helper to a controller?
Let's say I have this helper class.
Module UsersHelper
def my_helper
...
end
end
Then I have this controller.
class UsersController < ApplicationController
end
Can I use the my_helper in my controller?
Yes - There are several ways, not least including (mixing-in) the helper into the controller, or using the loophole explained here
But... if it's hard to do, or results in ugly code, it may not be the right way to do it. Can the method that's in the helper not be moved into the controller, and then delegated back to the helper using "helper_method"?
Yes. you can do by using include, but I don't recommend you doing this. Because Rails constructs under MVC architecture, you can learn more about MVC before include UserHelper in your controllers.
MVC Reference:
http://guides.rubyonrails.org/getting_started.html#the-mvc-architecture
Model–view–controller
Related
Is there a proper place for helper methods for models in Rails? There are helper methods for controllers and views, but I'm not sure where the best place to put model helper methods. Aside from adding a method to ActiveRecord::Base, which I'd prefer not to.
UPDATE: It seems Concerns make a lot of sense. Here's an example of what I want. Certain models can never be deleted, so I add a callback that always throws an exception:
before_destroy :nope
def nope
raise 'Deleting not allowed'
end
With concerns, I could do something like this?
class MyModel < ActiveRecord::Base
include Undeletable
end
module Undeletable
extend ActiveSupport::Concern
included do
before_destroy :nope
end
def nope
raise 'Deleting not allowed'
end
end
Is this the Rails way of doing this?
If you want to use a helper_method my_helper_method inside a model, you can write
ApplicationController.helpers.my_helper_method
If you need a bit more flexibility, for example if you also need to override some methods, you can do this:
class HelperProxy < ActionView::Base
include ApplicationController.master_helper_module
def current_user
#let helpers act like we're a guest
nil
end
def self.instance
#instance ||= new
end
end
and then use with
HelperProxy.instance.my_helper_method
If you have strong nerves, you can also try to include the ApplicationController.master_helper_module directly into your model.
via : makandracards's post.
For your reference: http://railscasts.com/episodes/132-helpers-outside-views
If what you are asking is where to put code that is shared across multiple models in rails 4.2, then the standard answer has to be to use Concerns: How to use concerns in Rails 4
However, there are some good arguments (e.g. this) to just using standard rails module includes, and extends as marek-lipka suggests.
I would strongly recommend NOT using ApplicationController helper methods in a model, as you'll be importing a lot unnecessary baggage along with it. Doing so is usually a bad smell in my opinion, as it means you are not separating the MVC elements, and there is too much interdependency in your app.
If you need to modify a model object by adding a method that is just used within a view, then have a look at decorators. For example https://github.com/drapergem/draper
i am using refinery cms at the moment. I created an engine and with it some helpers in app/helpers/admin/.
now i would like to use those helpers in my frontend view (ie. app/views/myapp/index) as well. but i can not...undefined methode error.
what do i have to do short of copying the whole thing to app/helpers/?
the helper looks like this
module Admin
module myHelper
def somefunc
end
end
end
so is it possible to use somefunc outside of the Admin module?
The "Rails way" to include a helper from a non-standard path in a view is to use the .helper method within your controller.
class MyController < ApplicationController
helper Admin::MyHelper
...
end
http://apidock.com/rails/AbstractController/Helpers/ClassMethods/helper
In your application_helper.rb:
module ApplicationHelper
include Admin::MyHelper
end
This will import those helper methods into the ApplicationHelper, thus making them available in your views. You could do this in any of your helpers really.
You might try to use the full object reference like Admin::myHelper::somefunc to call somefunc from outside the Admin module.
I have a couple of controllers with associated helper modules. I got some helper methods that should behave similarly across different modules, meaning:
module UserHelper
..
def destroy(user)
link_to t(:destroy_user), user ...
end
end
module PhotosHelper
..
def destroy(photo)
link_to t(:destroy_photo), photo ...
end
end
I didn't know (realize) that all of these helper modules are included by default, (which is ok, I guess,) and it doesn't matter what view you're calling the helper method from.
What is the best way to separate the rest of the helpers from my current controller/view so that, when controller_name == 'photos', only Photos and Application helpers are used?
The concept of Helpers is not really clear to me. Why not just have a single ApplicationController if all helpers are already mixed in? Is it just for "logical separation"?
I mean, of course, there's a number of workarounds. But is it just me, or it really feels like there's no reason to include all of the helpers globally?
If you called clear_helpers at ApplicationController class, they won't share among different helper classes
clear_helpers()
Clears up all existing helpers in this class, only keeping the helper with the same name as this class.
ref: http://api.rubyonrails.org/classes/AbstractController/Helpers/ClassMethods.html#method-i-clear_helpers
You could put the common methods on the ApplicationHelper and pass the resource as a parameter.
So then use the specific helper resource for specific methods only.
Methods (helpers) that you can share anyway, goes to ApplicationHelper file.
I have defined my helper function in Helper:
module CarsHelper
def my_helper
...
end
end
But I can neither used it(my_helper) in my CarsController nor in Car model, is it so that the custom helper can only be used in View?
Helpers are normally for views. But you can include them in your controllers as well. Just add
helper :cars
to your controller. (docs)
Models are out of scope for helpers. Use class or instance methods in there instead.
The new way to use view helpers in controllers is to use:
helpers.[helpername]
See this for more.
I have an easy question:
Where to put the helper methods that is called many times by a controller ?
My wish is to keep clear my controller ( user_controller) and I have an helper methods that is called many times (check_permits)
is it possible to put this method inside user_helper ?
If yes ==> how to recall it inside user_controller ? If I simply recall check_permits it doesen't recognize it.
If no ==>, where to put the helper methods ?
You are using confusing terminology. In rails, controllers do not have helpers. Helpers are defined as being for the views. It's possible to call helper methods from a controller by using the "helpers" method (see http://api.rubyonrails.org/classes/ActionController/Helpers/ClassMethods.html), but I don't think that's what you're looking for (and generally that's not a good idea anyway).
What you probably want is to either (1) put the method directly in your users_controller.rb as a protected method:
class UsersController < ApplicationController
...
protected
def check_permits
...
end
end
Or (2) put it in the application_controller.rb if you call it from multiple controllers.
Or (3) put it in a library file as a module and include it in whatever controllers need it. For example, you might create lib/check_permits.rb:
module CheckPermits
protected
def check_permits
...
end
end
And then in users_controller.rb:
class UsersController < ApplicationController
include CheckPermits
...
end
You can put global helper methods in the application_helper.rb file, but if it's only to be used by one controller each controller can have it's own helper file. Look in app/helper (or app/controller/helper).