Adding a Helper Method with a Gem

Adding a helper method with a gem

Create a module somewhere for your helper methods:

module MyHelper
  def mymethod
  end
end

Mix it into ActionView::Base (such as in init.rb or lib/your_lib_file.rb)

ActionView::Base.send :include, MyHelper

Add method to a gem's helpers

What's the point of altering the gem with additional methods? If it's a view helper, simply create an appropriate file in the app/helpers directory of your app and add your custom helper there.

The custom helper will be available to all views.

How to include my helpers into my gem and load them into rails app

Last time I did it with rails 2.
I've placed helper module in lib directory with following line added in init.rb which is placed in root directory of a gem/plugin:

ActionController::Base.helper TestHelper

It makes TestHelper module methods available for template. Here is how above helper method works: helper method

Creating a Gem that adds a rails form helper

After searching, I found a different gem that adds a FormBuilder method. I used their repo as a guide to structure my own. For others with this questions, you can view my repo and their repo here respectively:

https://github.com/dyeje/rails_json_field

https://github.com/Brantron/john_hancock

How to override controller helper method loaded from a gem

This solved my issue. Simple:

# /rails/app/helpers/controllers/page_title_helper.rb

module Controllers
  module PageTitleHelper
    include OsmUiHelper

    alias old_page_title page_title

    # rubocop:disable Style/OptionHash
    def page_title(options = {})
      company_id = settings ? settings.company_id : 0
      if Feature.on?('omnibar_enabled', company_id)
        # New logic here
      else
        # Use the old page_title in the gem
        old_page_title(options)
      end
    end
    # rubocop:enable Style/OptionHash
  end
end

How do I extract Rails view helpers into a gem?

In my opinion, a full Engine is overkill for this task. You could instead just create a Railtie which includes your helpers into ActionView::Base when it initializes.

# lib/my_gem/view_helpers.rb
module MyGem
  module ViewHelpers
    def pre(text)
      content_tag :pre, text
    end

    def another_helper
      # super secret stuff
    end
  end
end

# lib/my_gem/railtie.rb
require 'my_gem/view_helpers'
module MyGem
  class Railtie < Rails::Railtie
    initializer "my_gem.view_helpers" do
      ActiveSupport.on_load(:action_view) { include MyGem::ViewHelpers }
    end
  end
end

# lib/my_gem.rb
require 'my_gem/railtie' if defined?(Rails)

How do I make functions in a gem available to Sinatra views?

You’re mainly just missing the call to Sinatra.register (in cool_gem/sinatra.rb):

require 'sinatra/base'
require 'cool_gem/helper_functions'

module CoolGem
  # you could just put this directly in the CoolGem module if you wanted,
  # rather than have a Sinatra sub-module
  module Sinatra

    def self.registered(app)
      #no need to create another module here
      app.helpers CoolGem::HelperFunctions
    end

  end
end

# this is what you're missing:
Sinatra.register CoolGem::Sinatra

Now any classic style Sinatra app that requires cool_gem will have the helpers available. If you use the modular style you’ll also need to call register CoolGem::Sinatra inside the Sinatra::Base subclass.

In this case, if you are just providing some helper methods, an easier way might be to just use the helpers method (again in cool_gem/sinatra.rb):

require 'sinatra/base'
require 'cool_gem/helper_functions'

Sinatra.helpers CoolGem::HelperFunctions

Now the methods will be available in classic style apps, and modular style apps will need to call helpers CoolGem::HelperFunctions. This is a bit simpler, but if you are adding methods to the DSL context you will need to use registered as above.

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