This guide will show you how to:
- configure and use Refinery::Pages::MenuPresenter
- use a decorator to add custom functionality to Refinery::Page class
- use a decorator to allow attributes in Refinery::Admin::PagesController
- override Refinery's view
Let's start with requirements. I tried to bring them together in the following steps:
- We need to add an additional navigation menu in the footer section of each page right above Refinery's copyright notice.
- Admin should be able to specify which pages appear in the footer menu, so we also need to add a checkbox under "Advanced options" in the page edit form.
- Data about whether page shows up in the footer should be persisted to the database.
Alright, it's time to dive deep into the code.
Adding a show_in_footer column to the refinery_pages database table
The requirement was to persist the data to the database, so we will start by creating a migration that a will add show_in_footer column to the refinery_pages database table. Open up terminal and type:
rails generate migration add_show_in_footer_to_refinery_pages
This will generate an empty migration. Open it and add the following code:
class AddShowInFooterToRefineryPages < ActiveRecord::Migration def change add_column :refinery_pages, :show_in_footer, :boolean, default: false end end
Run the migration:
Decorating the Refinery::Page model
We want to decorate the Refinery::Page class. Create a file app/decorators/models/refinery/page_decorator.rb with this content:
Refinery::Page.class_eval do def self.footer_menu_pages where show_in_footer: true end end
We added footer_menu_pages class method to abstract away ActiveRecord query method.
Allow show_in_footer attribute in Refinery::Admin::PagesController
Before overriding Refinery's form view, we want to decorate the Refinery::Admin::PagesController class. Create a file app/decorators/controllers/refinery/admin/pages_controller_decorator.rb with this content:
Refinery::Admin::PagesController.prepend( Module.new do def permitted_page_params super << :show_in_footer end end )
We added show_in_footer to the permitted attributes list so that it doesn't raise a mass-assignment error each time someone tries to save the page.
Overriding the form view
As I previously mentioned, let's make it so that a "Show in footer" checkbox appears right after Admin expands the "Advanced options" when editing a page. To do this, we have to override the file _form_extra_fields_for_more_options.html.erb partial. Type this in the terminal:
Now open the _form_extra_fields_for_more_options.html.erb partial and add the following code right after the commented line :
Creating and configuring the Presenter
Now let's focus on the presenter itself. Once instantiated, it is also possible to configure its CSS/HTML using this instance. We will use a Rails helper to instantiate a new instance of Refinery::Pages::MenuPresenter and also configure it there. We're taking this approach because we don't want to pollute the view with configuration code.
Open the ApplicationHelper and add this code:
def footer_menu menu_items = Refinery::Menu.new(Refinery::Page.footer_menu_pages) Refinery::Pages::MenuPresenter.new(menu_items, self).tap do |presenter| presenter.dom_id = "footer_menu" presenter.css = "footer_menu" presenter.menu_tag = :div end end
We create an instance of Refinery::Menu by passing a collection of footer pages (Refinery::Page.footer_menu_pages) to it. We need it because it will be the data that will be "presented" by Refinery::Pages::MenuPresenter. We assign this instance to a variable called presenter in order to configure this presenter. I want my footer menu to be wrapped inside of a div tag instead of the default nav tag and I also want it to have a CSS class and an ID of footer_menu instead of the default menu one:
Now that we have configured the menu presenter we need to return it because we'll have to call .to_html on it in the view later on.
Rendering the Menu in the View
Requirement was for the footer menu to appear just above Refinery's copyright notice. To do that we will simply override Refinery's footer view:
rake refinery:override view=refinery/_footer.html
Next, add this code in the footer partial, above the existing code:
<%= footer_menu.to_html %>
Taking a look at it
Now it's time to take a look at how everything is working. Edit a couple of pages and for some of them check the "Show in footer" checkbox located under "Advanced options". Now go to the root url of your site and take a look at the bottom; you should see links for the pages for which you checked the "Show in footer" checkbox. Also here's how the generated HTML should look: