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.
Related
I have some helpers that are defined on runtime that are specific for a single call, e.g. a single instance of a controller (the next call could have different helper methods). Is there a robust way to add a helper method to an instance of a controller and it's view only, without adding the helper to other instances and views of this controller?
To define a helper for ALL instances, you could use the .helper_method method, e.g.
class Article < ApplicationController
helper_method :my_helper
def my_helper
# do something
end
end
I digged around in the source code, and found the (fairly private looking) #_helpers method which returns a module that contains all helpers for this instance. I could now use some meta programming to define my methods on this module
def index
_helpers.define_singleton_method(:my_helper) do
# do something
end
end
But I don't like this approach because I'm using a clearly private intended method that could easily change in the future (see the leading _).
If I only needed the helper inside the controller instance only, I could just call #define_singleton_method on the instance directly, but this doesn't make it available to the view.
So I'm looking for an official "Rails way" to define a helper for a single instance of a controller and it's view, like Rails provides with it's class method .helper_method.
I'm not sure if there is an official Rails way of doing this.
You could create an anonymous module and extend from that. Since this solution uses pure Ruby, you'll have to extend both the controller and view.
before_action :set_helpers, only: :index
def index
# ...
end
private
def set_helpers
#helpers = Module.new do |mod|
define_method(:my_helper) do
# do something
end
end
extend(#helpers)
end
<% extend(#helpers) %>
In my Rails application I have this:
class ProjectsController < ApplicationController
include ApplicationHelper
def index
#payments = current_user.projects.custom_order
end
...
end
module ApplicationHelper
def custom_order
order("name ASC")
end
end
However, in my index view I get this error:
undefined method 'custom_order' for #<Class:0x007f8be606ff80>
How can this be done?
I would like to keep the custom_order method in a helper module because I am using it across various different controllers.
Thanks for any help.
I know what you mean, but the right way is use model scopes:
class Project < ActiveRecord::Base
#...
scope :custom_order, order('name ASC')
#...
end
Move it to application controller.and make it a helper method.
Or include application helper module in application controller. So you will be able to access all application helper methods in all controllers.
Normally View Helpers are meant for rendering html based outputs, There you couldn't expect your model based queries.
Once you write a helper method in Application helper, It can be called in Any views.
Change your query like this
#payments = current_user.projects.order("name")
Or otherwise In your model Make it with scope.
scope :custom_order, order('name ASC')
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
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 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).