activeadmin · Fivell · Jun 1, 2026
diff --git a/features/index/non_ar_filters.feature b/features/index/non_ar_filters.feature
@@ -0,0 +1,113 @@
+@filters
+Feature: Filters on non-ActiveRecord resources
+
+  ActiveAdmin should let admins use the `filter` DSL on resources that
+  aren't ActiveRecord-backed (ActiveResource / API client wrappers,
+  ActiveModel objects, PORO query objects) — without monkey-patching.
+
+  The fixture model `ApiPost` mirrors the shape a real HTTP API client
+  would expose: `.fetch(page:, per_page:, filters...)` returns the page
+  of records plus a total_count reported by the upstream API, and the
+  controller adapts that response for ActiveAdmin's UI via
+  `Kaminari.paginate_array(records, total_count: ...)`.
+
+  Known limitation: the "Active Search" sidebar (filter chips with × to
+  clear) is tightly coupled to Ransack — it reads `Ransack::Condition`
+  objects (predicate / attributes / values / klass / reflect_on_all_
+  associations) that a plain `@search` object cannot supply. With the
+  nil guard in `Active#build_filters` the sidebar renders empty
+  ("No filters applied") instead of raising; the filter form, "Clear
+  Filters" link, pagination, and table are all unaffected. Users who
+  want chips for non-AR resources need to either provide a Ransack-
+  shaped search object themselves or set `config.current_filters =
+  false` to hide the sidebar entirely.
+
+  Background:
+    Given I am logged in
+    And a configuration of:
+    """
+      ActiveAdmin.register ApiPost do
+        actions :index
+
+        filter :title_cont, as: :string, label: "Title contains"
+        filter :status_eq,  as: :select, label: "Status",
+               collection: %w[active inactive]
+
+        index do
+          column :id
+          column :title
+          column :status
+        end
+
+        controller do
+          # Non-AR resources opt out of AA's AR DataAccess path by
+          # overriding `find_collection`. Pagination is server-side:
+          # the model returns the page plus total_count, the controller
+          # hands that to Kaminari.paginate_array so AA's pagination UI
+          # works (page links, "Showing X-Y of Z", etc.).
+          def find_collection(*)
+            q = params[:q] || {}
+            @search = ApiPost::Search.new(
+              title_cont: q[:title_cont],
+              status_eq: q[:status_eq]
+            )
+            page = (params[:page] || 1).to_i
+            per_page = 5
+
+            result = ApiPost.fetch(
+              page: page,
+              per_page: per_page,
+              title_cont: @search.title_cont,
+              status_eq: @search.status_eq
+            )
+
+            Kaminari.paginate_array(
+              result.records,
+              total_count: result.total_count,
+              limit:       result.limit,
+              offset:      result.offset
+            ).page(page).per(per_page)
+          end
+        end
+      end
+    """
+
+  Scenario: Server-side pagination across multiple pages
+    When I am on the index page for api_posts
+    Then I should see "Alpha"
+    And I should see "Epsilon"
+    And I should not see "Zeta"
+    And I should see "Showing 1-5 of 7"
+    And I should see pagination page 2 link
+    And I should see the following filters:
+      | Title contains | string |
+      | Status         | select |
+
+    When I follow "2"
+    Then I should see "Zeta"
+    And I should see "Eta"
+    And I should see "Showing 6-7 of 7"
+    And I should not see "Alpha"
+
+  Scenario: Filter narrows the result set to a single page (no pagination)
+    When I am on the index page for api_posts
+    Then I should see pagination page 2 link
+
+    When I select "inactive" from "Status"
+    And I press "Filter"
+    Then I should see "Beta"
+    And I should see "Epsilon"
+    And I should not see "Alpha"
+    And I should not see "Gamma"
+    And I should see "Showing all 2"
+    And I should not see pagination
+
+  Scenario: Filter narrows the result set to a single record
+    When I am on the index page for api_posts
+    And I fill in "Title contains" with "Bet"
+    And I press "Filter"
+    Then I should see "Beta"
+    And I should not see "Alpha"
+    And I should not see "Epsilon"
+    And I should see "Showing 1 of 1"
+    And I should not see pagination
diff --git a/lib/active_admin/filters/active.rb b/lib/active_admin/filters/active.rb
@@ -14,7 +14,8 @@ class Active
       # @see ActiveAdmin::ResourceController::DataAccess#apply_filtering
       def initialize(resource, search)
         @resource = resource
-        @filters = build_filters(search.conditions)
+        # Ransack::Search uses method_missing for #conditions, so gate on the class.
+        @filters = search.is_a?(::Ransack::Search) ? build_filters(search.conditions) : []
         @scopes = search.instance_variable_get(:@scope_args)
       end
 

diff --git a/lib/active_admin/filters/formtastic_addons.rb b/lib/active_admin/filters/formtastic_addons.rb
@@ -32,9 +32,12 @@ def column
       # The below are custom methods that Formtastic does not provide.
       #
 
-      # The resource class, unwrapped from Ransack
+      # The resource class, unwrapped from Ransack.
+      # Returns nil when @object is not a Ransack::Search-shaped object
+      # (e.g. ActiveResource/API-client wrappers, ActiveModel or PORO query
+      # objects), so the filter DSL can be used with non-AR resources.
       def klass
-        @object.object.klass
+        @object.object.klass if @object.respond_to?(:object) && @object.object.respond_to?(:klass)
       end
 
       def polymorphic_foreign_type?(method)
@@ -65,8 +68,12 @@ def has_predicate?
       end
 
       # Ransack supports exposing selected scopes on your model for advanced searches.
+      # Uses Ransack::Context.for_class (which returns nil for classes Ransack
+      # has no adapter for) so non-AR resources are handled without rescuing.
       def scope?
-        context = Ransack::Context.for klass
+        return false if klass.nil?
+
+        context = Ransack::Context.for_class(klass)
         context.respond_to?(:ransackable_scope?) && context.ransackable_scope?(method.to_s, klass)
       end
 

diff --git a/lib/active_admin/resource.rb b/lib/active_admin/resource.rb
@@ -116,6 +116,8 @@ def resource_table_name
     end
 
     def resource_column_names
+      return [] unless resource_class.respond_to?(:column_names)
+
       resource_class.column_names
     end
 

diff --git a/lib/active_admin/resource/attributes.rb b/lib/active_admin/resource/attributes.rb
@@ -5,6 +5,8 @@ class Resource
     module Attributes
 
       def default_attributes
+        return {} unless resource_class.respond_to?(:columns)
+
         resource_class.columns.each_with_object({}) do |c, attrs|
           unless reject_col?(c)
             name = c.name.to_sym

diff --git a/lib/active_admin/views/components/table_for.rb b/lib/active_admin/views/components/table_for.rb
@@ -160,7 +160,7 @@ def initialize(*args, &block)
         def sortable?
           if @options.has_key?(:sortable)
             !!@options[:sortable]
-          elsif @resource_class
+          elsif @resource_class.respond_to?(:column_names)
             @resource_class.column_names.include?(sort_column_name)
           else
             @title.present?

diff --git a/spec/support/rails_template.rb b/spec/support/rails_template.rb
@@ -49,6 +49,9 @@
 
 copy_file File.expand_path("templates/models/tagging.rb", __dir__), "app/models/tagging.rb"
 
+# Non-ActiveRecord PORO used in features/index/non_ar_filters.feature
+copy_file File.expand_path("templates/models/api_post.rb", __dir__), "app/models/api_post.rb"
+
 copy_file File.expand_path("templates/helpers/time_helper.rb", __dir__), "app/helpers/time_helper.rb"
 
 copy_file File.expand_path("templates/models/company.rb", __dir__), "app/models/company.rb"

diff --git a/spec/support/templates/models/api_post.rb b/spec/support/templates/models/api_post.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+# A non-ActiveRecord resource used in features to demonstrate that
+# ActiveAdmin's filter DSL renders for resources that bypass the AR
+# DataAccess path — HTTP-backed wrappers, SQL query objects, in-memory
+# aggregations, etc.
+#
+# Pagination is owned by the model — `.fetch` returns the requested page
+# plus total_count/limit/offset metadata, mirroring the shape an HTTP
+# API client would carry alongside the page payload (response headers,
+# meta blocks, cursors — wherever the upstream API surfaces the total).
+# The controller then adapts that response for AA's UI via
+# `Kaminari.paginate_array(records, total_count: ...)`.
+class ApiPost
+  extend ActiveModel::Naming
+
+  Record = Struct.new(:id, :title, :status, keyword_init: true)
+
+  # Lightweight `@search` wrapper. ActiveAdmin's filter form pre-fills
+  # input values via `@search.<filter_name>`, so this needs attribute
+  # readers for every declared filter — Struct gives us that with no
+  # OpenStruct dependency.
+  Search = Struct.new(:title_cont, :status_eq, keyword_init: true)
+
+  ALL_RECORDS = [
+    Record.new(id: 1, title: "Alpha", status: "active"),
+    Record.new(id: 2, title: "Beta", status: "inactive"),
+    Record.new(id: 3, title: "Gamma", status: "active"),
+    Record.new(id: 4, title: "Delta", status: "active"),
+    Record.new(id: 5, title: "Epsilon", status: "inactive"),
+    Record.new(id: 6, title: "Zeta", status: "active"),
+    Record.new(id: 7, title: "Eta", status: "active")
+  ].freeze
+
+  # Response shape mirrors what a real API client returns: the page of
+  # records plus the total_count reported by the upstream API — so the
+  # controller can hand AA's pagination UI an accurate total without
+  # loading every record.
+  Result = Struct.new(:records, :total_count, :limit, :offset, keyword_init: true)
+
+  def self.fetch(page: 1, per_page: 5, title_cont: nil, status_eq: nil)
+    page = [page.to_i, 1].max
+    per_page = per_page.to_i
+
+    records = ALL_RECORDS
+    records = records.select { |r| r.title.include?(title_cont) } if title_cont.present?
+    records = records.select { |r| r.status == status_eq } if status_eq.present?
+
+    offset = (page - 1) * per_page
+
+    Result.new(
+      records: records[offset, per_page] || [],
+      total_count: records.size,
+      limit: per_page,
+      offset: offset
+    )
+  end
+end
-Original file line number
+Diff line change
@@ Expand Up / @@ -116,6 +116,8 @@ def resource_table_name @@
         end
         def resource_column_names
+          return [] unless resource_class.respond_to?(:column_names)
           resource_class.column_names
         end
@@ Expand Down @@