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Version: 3.2

Customizing the backend

This guide will teach you how to customize the Solidus admin panel.

Designing your feature​

When adding a feature to the backend UI, it's important that you spend some time designing the ideal UX for your store administrators. There are usually different ways to implement the same feature, and the best approach depends on how store admins use the backend.

In this guide, we'll implement a very simple rejection system that allows you to mark certain email addresses as rejected and require an admin to manually review and approve any orders placed with that email address.

To simplify the implementation, we'll assume the rejected email addresses are stored in an environment variable as a comma-separated string. Here are a couple of user stories we'll use as reference for the feature's requirement:

  • rejected orders are flagged automatically;
  • admins can manually approve rejected orders;
  • admins can list all rejected orders.

Without further ado, let's start writing some code!

Adding new columns​

The first step is to add the rejected column to the spree_orders table, which we'll use to determine whether an order has been rejected. This is quite simple to do with a migration:

$ rails g migration AddRejectedToSpreeOrders rejected:boolean

Edit the newly generated migration file so the new column can't be NULL and defaults to false.

<     add_column :spree_orders, :rejected, :boolean
---
>     add_column :spree_orders, :rejected, :boolean, null: false, default: false

Finally, update your database by running:

$ rails db:migrate

Hooking into order events​

The first step is to flag an order as rejected when the email address on the order has been rejected. You can do this by creating a class whose job is to analyze an order and determine whether it should be flagged as rejected:

app/models/amazing_store/order_analyzer.rb
# frozen_string_literal: true

module AmazingStore
  class OrderAnalyzer
    def analyze(order)
      order.update!(rejected: order_rejected?(order))
    end

    private

    def rejected_emails
      ENV.fetch('REJECTED_EMAILS', '').split(',')
    end

    def order_rejected?(order)
      order.email.in?(rejected_emails)
    end
  end
end

You will then need to subscribe to the order_finalized event, which is fired when an order is placed successfully, and call the analyzer:

config/initializers/spree_bus.rb
# frozen_string_literal: true

Rails.application.config.to_prepare do
  Spree::Bus.subscribe :order_finalized do |event|
    AmazingStore::OrderAnalyzer.new.analyze(event.payload[:order])
  end
end

At this point, we have a dead-simple order analyzer that determines whether each new order should be rejected or not. Now, we need to allow admins to manually review rejected orders and decide whether to reject them or remove them from the rejected.

Implementing new actions​

In order to allow admins to remove an order from the rejected, we'll add a button to the order detail page that will trigger a new controller action.

The first step is to add our custom action to Spree::Admin::OrdersController. We'll use an override (see the overrides section for how to set it up) to accomplish that:

app/overrides/amazing_store/spree/admin/orders_controller/add_remove_from_rejected_action.rb
# frozen_string_literal: true

module AmazingStore
  module Spree
    module Admin
      module OrdersController
        module AddRemoveFromRejectedAction
          def remove_from_rejected
            load_order

            @order.update!(rejected: false)

            redirect_to edit_admin_order_path(@order)
          end

          ::Spree::Admin::OrdersController.prepend self
        end
      end
    end
  end
end

Now that the controller action has been implemented, we can define a route for it:

config/routes.rb
# ...

Spree::Core::Engine.routes.draw do
  namespace :admin do
    resources :orders, only: [] do
      member do
        put :remove_from_rejected
      end
    end
  end
end

In the next section, we'll see how to hook our custom controller action to a new button in the backend.

Defacing admin views​

We are going to add a "Remove from rejected" to the order toolbar:

Deface example

We are going to use the popular Deface gem to apply a patch to the default view. In case you're not familiar with it, Deface is a gem that allows you to " virtually" patch third-party views, meaning you can edit them without having to completely replace them in your application.

info

Just like for the storefront, you can still copy-paste the backend views into your application if you want to override them. However, this approach is quite hard to maintain, since it would prevent you to get any Solidus upgrades to the backend for views that have been overridden. It becomes even more complex when you consider all the different overrides applied to the backend by Solidus extensions. Deface is a declarative, maintainable way of patching backend views while still benefitting from Solidus upgrades.

First of all, we need to install Deface by adding it to our Gemfile:

Gemfile
# ...
gem 'deface'

Once done, we need to identify which view we want to customize. By browsing through the backend's codebase, we can see the view in question is spree/admin/orders/edit.html.erb. If we inspect the view's source code, we can also see that we want our button to be included in the content for the :page_actions element, so that it's added to the toolbar actions when editing an order.

Equipped with this information, we can now write our Deface override:

app/overrides/spree/admin/orders/edit/add_remove_from_rejected.html.erb.deface
<!-- insert_before "erb[silent]:contains('if can?(:fire, @order)')" -->
<li>
  <% if @order.rejected? %>
    <%= button_to(
      t('spree.remove_from_rejected'),
      remove_from_rejected_admin_order_url(@order),
      method: :put,
      class: 'btn btn-primary btn-remove_order_from_rejected',
    ) %>
  <% end %>
</li>
danger

The path of overrides is extremely important: the directory where you put the override must match the path of the view you want to customize (minus the extension), and the override must have the .html.erb.deface extension for Deface to apply it correctly. If an override is not getting applied, the first thing you look at should be the path.

info

Deface provides a lot of selectors, actions and tools for debugging your overrides — taking the time to understand how to use them correctly will help you a lot when overriding different parts of the backend. You can look at the Deface documentation and even at Solidus extensions if you need some inspiration with a tricky override.

The last thing we need to do for our button to appear properly is add the spree.remove_from_rejected translation key to our application. We just need to add the key to the config/locales/en.yml file in our application, like this:

config/locales/en.yml
en:
  spree:
    remove_from_rejected: Remove from rejected
info

While it's also possible to hardcode the string in your views/controllers, using Rails' native internationalization features will allow you to write code that is easier to maintain and will make it easier to go global, should you ever need it.

info

You can override default Spree translations in the exact same way, if you want to change the default labels or messages in the backend.

Adding new search form fields​

The last point of our feature requires that users can list all the orders that are rejected. The most straightforward solution is adding a field to the orders' search form for our new :rejected attribute.

info

Search forms in Solidus use the ransack gem under the hood. Please, see its documentation for a complete description of everything that is supported.

The orders' search form is visible from the "Orders" menu item. We've already seen how to override views with Deface. This time we need to override the index template for orders:

app/overrides/spree/admin/orders/index/add_rejected_filter.html.erb.deface
<!-- insert_bottom "[data-hook=admin_orders_index_search] .field-block" -->
<div class="field">
  <%= label_tag :q_rejected_eq, t('spree.rejected') %>
  <%= f.select :rejected_eq, [[t('spree.say_yes'), true], [t('spree.say_no'), false]], include_blank: t('spree.all') %>
</div>

The new field is already visible. However, for security reasons, you're still required to explicitly include the new attribute to the list of allowed queryable columns:

config/initializers/spree.rb
# ...
Rails.application.config.to_prepare do
  Spree::Order.whitelisted_ransackable_attributes |= ['rejected']
end

After restarting the server, you can try it out and confirm it's working as expected!

Adding new menu items​

If you wanted to give maximum prominence to the problem with rejected orders, you could consider adding a new item to the main admin menu. You can do that by creating a new Spree::BackendConfiguration::MenuItem instance:

config/initializers/spree.rb
# ...
Spree::Backend::Config.configure do |config|
  # ...
  config.menu_items << config.class::MenuItem.new(
    [:rejected_orders],
    'ban',
    url: '/admin/orders?q[rejected_eq]=true',
    position: 0
  )
end

Our new :rejected_orders menu item points to the same URL generated when only the previously introduced filter is selected in the search form. We use ban as its Font Awesome icon and want its position to be the first one.

info

The position argument is always considered after the "Order" menu item, which will always be on the very top of the sidebar. Therefore, the :rejected_orders item will be second in our example.

Finally, we need to add the translation so its label is rendered:

config/locales/en.yml
# ...
en:
  spree:
    admin:
      tab:
        rejected_orders: Rejected orders

After restarting again your server, you can see how everything is in place.

There're other interesting options that you can give on the initialization of a menu item:

  • condition: can contain a Proc for when the menu item should be displayed. For instance, if we only wanted our example to be rendered when there's at least one rejected order, we could pass condition: -> { Spree::Order.where(rejected: true).any? }.
  • match_path: allows more flexibility to match the current URL and render the custom item as being active in the menu. For instance, we might want to have our example highlighted whenever the filter has been selected, regardless of other filters being applied: match_path: %r{[rejected_eq]=true}.
  • label: allows changing the key under {lang}.spree.admin.tab where the label translation can be found in the locale file.
  • partial: can be used in complex scenarios when you want a partial to be rendered as content within your menu item. For instance, partial: 'spree/admin/orders/rejected_orders'.

Customizing assets​

Solidus leverages the Rails asset pipeline to allow for customization and overriding of your backend assets. We recommend that you familiarize yourself with the Rails asset pipeline before going any further.

Some aspects of the style in the backend have been extracted into SCSS variables. You can look at them in the spree/backend/globals/_variables.scss file. If you want to redefine some of them, you can create a spree/backend/globals/_variables_override.scss file under your application stylesheets directory. For instance, if you wanted to make the header black:

app/assets/stylesheets/spree/backend/globals/_variables_override.scss
$color-header-bg: #000;

For more elaborated changes, take into account that, when you install Solidus, the two following manifest files are created:

  • vendor/assets/stylesheets/spree/backend/all.css, for your CSS assets.
  • vendor/assets/javascripts/spree/backend/all.js, for your Javascript assets.

If you glance at them, you'll see that they both include a spree/backend file, which is located in the Solidus' backend Rails engine, and, after that, they also require all the files recursively under their directories (the require_tree . directive). Any file you put under vendor/assets/{stylesheets,javascripts}/spree/backend directories will be loaded after Solidus' default assets, allowing you not only to customize but to override CSS and Javascript code.

danger

If you can, always go for adding instead of overriding default assets. There's no guarantee that a Solidus style won't change in the future and make your override useless or behave in unexpected ways.

Nonetheless, you might want to put the assets you control under app/assets, just like Sprockets recommends. For that, you need to add another directive to the generated manifest, as we'll demonstrate below.

danger

When dropping a file under app/assets, you must be careful. By default, the generated manifests under app/assets/{stylesheets,javascript}/application.{css,js} in a new Rails application contain directives to load any file below their hierarchy recursively. I.e., a style meant only to be used in the backend could interfere with your storefront. Make sure you update the generated manifests accordingly, including the removal of the require_tree . directive.

As a simple example, let's make the delete button a bit more prominent by uppercasing its label. We'll require another file from the Solidus CSS manifest at vendor/stylesheets/spree/backend/all.css

  *= require spree/backend
  *= require_self
  *= require_tree .
+ *= require spree/backend/custom
 */

We'll place it within the app/assets/stylesheets directory:

app/assets/stylesheets/spree/backend/custom.css
.btn-remove_order_from_rejected {
  text-transform: uppercase;
}

Pretty much the same when it comes to Javascript. In this case, we'd need to modify the vendor/assets/javascripts/spree/backend/all.js manifest.

 //= require rails-ujs
 //= require spree/backend
 //= require_tree .
+//= require spree/backend/custom

We could then put any new behavior in the expected file:

app/assets/javascripts/spree/backend/custom.js
// Javascript code

Taking it from here​

Congratulations! You have implemented your first custom feature for the Solidus backend.

Of course, we have just scratched the surface of what's possible: the backend provides a lot of UI components and capabilities you may leverage. We suggest spending some time in the backend's codebase to get accustomed with all the different tools at your disposal, and doing some planning/research before every custom feature.

By using a combination of custom controller actions, view overrides and automated tests, you'll be able to write custom admin features that are fully integrated with the Solidus experience, and yet are a joy to maintain and evolve over time.