Add option to pass path params for nested resource fetching

Author: SValkanov

README.md

@@ -265,7 +265,7 @@ for feature specs:
 
 ### Passing options to Select2
 
-It is possible to pass and define configuration options to Select2 
+It is possible to pass and define configuration options to Select2
 via `data-attributes` using nested (subkey) options.
 
 Attributes need to be added to the `input_html` option in the form input.
@@ -285,6 +285,65 @@ has stopped typing before sending the request:
    ...
 ```
 
+### Path options for nested resources
+
+Example for the following setup:
+
+```ruby
+# Models
+class OptionType < ActiveRecord::Base; end
+
+class OptionValue < ActiveRecord::Base
+  belongs_to :option_type
+end
+
+class Product < ActiveRecord::Base
+  belongs_to :option_type
+  has_many :variants
+end
+
+class Variant < ActiveRecord::Base
+  belongs_to :product
+  belongs_to :option_value
+end
+
+# ActiveAdmin
+ActiveAdmin.register(OptionType)
+
+ActiveAdmin.register(Product)
+
+ActiveAdmin.register(OptionValue) do
+  belongs_to :option_type
+  searchable_select_options(scope: lambda do |params|
+                                     OptionValue.where(
+                                       option_type_id: params[:option_type_id]
+                                     )
+                                   end,
+                            text_attribute: :value)
+end
+```
+
+It is possible to pass path parameters for correctly generating URLs for nested resources fetching via `path_params`
+
+```ruby
+ActiveAdmin.register(Variant) do
+  belongs_to :product
+
+  form do |f|
+    ...
+    f.input(:option_value,
+            as: :searchable_select,
+            path_params: {
+              option_type_id: f.object.product.option_type_id
+            },
+            ajax: { resource: OptionValue })
+    ...
+  end
+end
+```
+
+This will generate the path for fetching as `all_options_admin_option_type_option_values(option_type_id: f.object.product.option_type_id)` (e.g. `/admin/option_types/2/option_values/all_options`)
+
 
 ## Development
 

lib/activeadmin/searchable_select/select_input_extension.rb

@@ -45,7 +45,7 @@ def collection_from_options
 
       def ajax_url
         return unless options[:ajax]
-        [ajax_resource.route_collection_path,
+        [ajax_resource.route_collection_path(path_params),
          '/',
          option_collection.collection_action_name,
          '?',
@@ -124,6 +124,10 @@ def ajax_params
         ajax_options.fetch(:params, {})
       end
 
+      def path_params
+        options[:path_params]
+      end
+
       def ajax_options
         options[:ajax] == true ? {} : options[:ajax]
       end

spec/features/end_to_end_spec.rb

@@ -94,6 +94,92 @@
     end
   end
 
+  context 'class with nested belongs_to association' do
+    before(:each) do
+      ActiveAdminHelpers.setup do
+        ActiveAdmin.register(OptionType)
+
+        ActiveAdmin.register(Product)
+
+        ActiveAdmin.register(OptionValue) do
+          belongs_to :option_type
+          searchable_select_options(scope: lambda do |params|
+                                             OptionValue.where(
+                                               option_type_id: params[:option_type_id]
+                                             )
+                                           end,
+                                    text_attribute: :value)
+        end
+
+        ActiveAdmin.register(Variant) do
+          belongs_to :product
+
+          form do |f|
+            input :price
+            input(:option_value,
+                  as: :searchable_select,
+                  path_params: { option_type_id: f.object.product.option_type_id },
+                  ajax: {
+                    resource: OptionValue
+                  })
+          end
+        end
+
+        ActiveAdmin.setup {}
+      end
+    end
+
+    describe 'new page with searchable select filter' do
+      it 'loads filter input options' do
+        option_type = OptionType.create(name: 'Color')
+        ot = OptionType.create(name: 'Size')
+        OptionValue.create(value: 'Black', option_type: option_type)
+        OptionValue.create(value: 'Orange', option_type: option_type)
+        OptionValue.create(value: 'M', option_type: ot)
+        product = Product.create(name: 'Cap', option_type: option_type)
+
+        visit "/admin/products/#{product.id}/variants/new"
+
+        expand_select_box
+        wait_for_ajax
+
+        expect(select_box_items).to eq(%w(Black Orange))
+      end
+
+      it 'allows filtering options by term' do
+        option_type = OptionType.create(name: 'Color')
+        ot = OptionType.create(name: 'Size')
+        OptionValue.create(value: 'Black', option_type: option_type)
+        OptionValue.create(value: 'Orange', option_type: option_type)
+        OptionValue.create(value: 'M', option_type: ot)
+        product = Product.create(name: 'Cap', option_type: option_type)
+
+        visit "/admin/products/#{product.id}/variants/new"
+
+        expand_select_box
+        enter_search_term('O')
+        wait_for_ajax
+
+        expect(select_box_items).to eq(%w(Orange))
+      end
+
+      it 'loads more items when scrolling down' do
+        option_type = OptionType.create(name: 'Color')
+        15.times { |i| OptionValue.create(value: "Black #{i}", option_type: option_type) }
+        product = Product.create(name: 'Cap', option_type: option_type)
+
+        visit "/admin/products/#{product.id}/variants/new"
+
+        expand_select_box
+        wait_for_ajax
+        scroll_select_box_list
+        wait_for_ajax
+
+        expect(select_box_items.size).to eq(15)
+      end
+    end
+  end
+
   def expand_select_box
     find('.select2-container').click
   end

spec/internal/db/schema.rb

@@ -31,6 +31,26 @@
     t.integer :color_id
   end
 
+  create_table(:option_types, force: true) do |t|
+    t.string :name
+  end
+
+  create_table(:option_values, force: true) do |t|
+    t.string :value
+    t.belongs_to :option_type
+  end
+
+  create_table(:products, force: true) do |t|
+    t.string :name
+    t.belongs_to :option_type
+  end
+
+  create_table(:variants, force: true) do |t|
+    t.integer :price
+    t.belongs_to :product
+    t.belongs_to :option_value
+  end
+
   create_table(:users, force: true) do |t|
     t.string :name
   end

spec/support/active_admin_helpers.rb

@@ -2,7 +2,7 @@ module ActiveAdminHelpers
   module_function
 
   def setup
-    ActiveAdmin.application = nil
+    ActiveAdmin.unload!
     yield
     Rails.application.reload_routes!
   end

spec/support/models.rb

@@ -27,6 +27,22 @@ class TagName < ActiveRecord::Base
   end
 end
 
+class OptionType < ActiveRecord::Base; end
+
+class OptionValue < ActiveRecord::Base
+  belongs_to :option_type
+end
+
+class Product < ActiveRecord::Base
+  belongs_to :option_type
+  has_many :variants
+end
+
+class Variant < ActiveRecord::Base
+  belongs_to :product
+  belongs_to :option_value
+end
+
 RSpec.configure do |config|
   config.after do
     DatabaseCleaner.strategy = :truncation