Rails - How to use a Helper Inside a Controller

Question

While I realize you are supposed to use a helper inside a view  I need a helper in my controller as I m building a JSON object to return  It goes a little like this  def xxxxx      comments   Array new      c comments each do  comment      comments  lt  lt          id   gt  comment id        content   gt  html format comment content          end     render  json   gt   comments end  How can I access my html format helper

User · Answer

One alternative missing from other answers is that you can go the other way around: define your method in your Controller, and then use helper_method to make it also available on views as, you know, a helper method.

For instance:


class ApplicationController < ActionController::Base

private

  def something_count
    # All other controllers that inherit from ApplicationController will be able to call `something_count`
  end
  # All views will be able to call `something_count` as well
  helper_method :something_count 

end

User · Answer

Note  This was written and accepted back in the Rails 2 days  nowadays grosser s answer is the way to go   Option 1  Probably the simplest way is to include your helper module in your controller   class MyController  lt  ApplicationController   include MyHelper    def xxxx      comments          Comment find each do  comment         comments  lt  lt    id   gt  comment id   html   gt  html format comment content       end   end end   Option 2  Or you can declare the helper method as a class function  and use it like so   MyHelper html format comment content    If you want to be able to use it as both an instance function and a class function  you can declare both versions in your helper   module MyHelper   def self html format str      process str    end    def html format str      MyHelper html format str    end end   Hope this helps

User · Answer

In Rails 5 use the helpers helper function in your controller   Example   def update           redirect to root url  notice   Updated   helpers pluralize count   record     end   Source  From a comment by  Markus on a different answer   I felt his answer deserved it s own answer since it s the cleanest and easier solution   Reference  https   github com rails rails pull 24866

User · Answer

class MyController  lt  ApplicationController       include your helper     include MyHelper       or Rails helper     include ActionView  Helpers  NumberHelper      def my action       price   number to currency 10000      end end   In Rails 5  simply use helpers  helpers number to currency 10000

User · Answer

In rails 6  simply add this to your controller  class UsersController  lt  ApplicationController   include UsersHelper        Your actions  end  Now the user helpers rb will be available in the controller

User · Answer

In Rails 5  you can simply use the function as demonstrated below with simple example   module ApplicationHelper     format datetime in the format  2018-12-01 12 12 PM   def datetime format datetime   nil      if datetime       datetime strftime   Y- m- d  H  M  p       else        NA      end   end end  class ExamplesController  lt  ApplicationController   def index     current datetime   helpers datetime format DateTime now     raise current datetime inspect   end end      OUTPUT   2018-12-10 01 01 AM

User · Answer

In general  if the helper is to be used in  just  controllers  I prefer to declare it as an instance method of class ApplicationController

User · Answer

You can use    helpers  lt helper gt  in Rails 5   or ActionController  Base helpers  lt helper gt   view context  lt helper gt   Rails 4  amp  3   WARNING  this instantiates a new view instance per call   template  lt helper gt   Rails 2   include helper in a singleton class and then singleton helper include the helper in the controller  WARNING  will make all helper methods into controller actions

User · Answer

My problem resolved with Option 1  Probably the simplest way is to include your helper module in your controller   class ApplicationController  lt  ActionController  Base   include ApplicationHelper

[ruby-on-rails] Rails - How to use a Helper Inside a Controller

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