before_action like filters for inertia_share

lib/inertia_rails/action_filter.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+#
+# Based on AbstractController::Callbacks::ActionFilter
+# https://github.com/rails/rails/blob/v7.2.0/actionpack/lib/abstract_controller/callbacks.rb#L39
+module InertiaRails
+  class ActionFilter
+    def initialize(conditional_key, actions)
+      @conditional_key = conditional_key
+      @actions = Array(actions).map(&:to_s).to_set
+    end
+
+    def match?(controller)
+      missing_action = @actions.find { |action| !controller.available_action?(action) }
+      if missing_action
+        message = <<~MSG
+          The #{missing_action} action could not be found for the :inertia_share
+          callback on #{controller.class.name}, but it is listed in the controller's
+          #{@conditional_key.inspect} option.
+        MSG
+
+        raise AbstractController::ActionNotFound.new(message, controller, missing_action)
+      end
+
+      @actions.include?(controller.action_name)
+    end
+  end
+end

lib/inertia_rails/controller.rb

@@ -1,5 +1,6 @@
 require_relative "inertia_rails"
 require_relative "helper"
+require_relative "action_filter"
 
 module InertiaRails
   module Controller
@@ -14,10 +15,19 @@ module Controller
     end
 
     module ClassMethods
-      def inertia_share(attrs = {}, &block)
-        @inertia_share ||= []
-        @inertia_share << attrs.freeze unless attrs.empty?
-        @inertia_share << block if block
+      def inertia_share(hash = nil, **props, &block)
+        options = extract_inertia_share_options(props)
+        return push_to_inertia_share(**(hash || props), &block) if options.empty?
+
+        push_to_inertia_share do
+          next unless options[:if].all? { |filter| instance_exec(&filter) } if options[:if]
+          next unless options[:unless].none? { |filter| instance_exec(&filter)  } if options[:unless]
+
+          next hash unless block
+
+          res = instance_exec(&block)
+          hash ? hash.merge(res) : res
+        end
       end
 
       def inertia_config(**attrs)
@@ -55,6 +65,53 @@ def _inertia_shared_data
           end.freeze
         end
       end
+
+      private
+
+      def push_to_inertia_share(**attrs, &block)
+        @inertia_share ||= []
+        @inertia_share << attrs.freeze unless attrs.empty?
+        @inertia_share << block if block
+      end
+
+      def extract_inertia_share_options(props)
+        options = props.slice(:if, :unless, :only, :except)
+
+        return options if options.empty?
+
+        if props.except(:if, :unless, :only, :except).any?
+          raise ArgumentError, "You must not mix shared data and [:if, :unless, :only, :except] options, pass data as a hash or a block."
+        end
+
+        transform_inertia_share_option(options, :only, :if)
+        transform_inertia_share_option(options, :except, :unless)
+
+        options.transform_values! do |filters|
+          Array(filters).map!(&method(:filter_to_proc))
+        end
+
+        options
+      end
+
+      def transform_inertia_share_option(options, from, to)
+        if (from_value = options.delete(from))
+          filter = InertiaRails::ActionFilter.new(from, from_value)
+          options[to] = Array(options[to]).unshift(filter)
+        end
+      end
+
+      def filter_to_proc(filter)
+        case filter
+        when Symbol
+          -> { send(filter) }
+        when Proc
+          filter
+        when InertiaRails::ActionFilter
+          -> { filter.match?(self) }
+        else
+          raise ArgumentError, "You must pass a symbol or a proc as a filter."
+        end
+      end
     end
 
     def default_render

spec/dummy/app/controllers/inertia_conditional_sharing_controller.rb

@@ -7,6 +7,32 @@ class InertiaConditionalSharingController < ApplicationController
     {conditionally_shared_show_prop: 1} if action_name == "show"
   end
 
+  inertia_share only: :edit do
+    {edit_only_only_block_prop: 1}
+  end
+
+  inertia_share except: [:show, :index] do
+    {edit_only_except_block_prop: 1}
+  end
+
+  inertia_share if: -> { is_edit? } do
+    {edit_only_if_proc_prop: 1}
+  end
+
+  inertia_share unless: -> { !is_edit? } do
+    {edit_only_unless_proc_prop: 1}
+  end
+
+  inertia_share({edit_only_only_prop: 1}, only: :edit)
+
+  inertia_share({edit_only_if_prop: 1}, if: [:is_edit?, -> { true }])
+
+  inertia_share({edit_only_unless_prop: 1}, unless: :not_edit?)
+
+  inertia_share({edit_only_only_if_prop: 1}, only: :edit, if: -> { true })
+
+  inertia_share({edit_only_except_if_prop: 1}, except: [:index, :show], if: -> { true })
+
   def index
     render inertia: 'EmptyTestComponent', props: {
       index_only_prop: 1,
@@ -25,9 +51,23 @@ def show_with_a_problem
     }
   end
 
+  def edit
+    render inertia: 'EmptyTestComponent', props: {
+      edit_only_prop: 1,
+    }
+  end
+
   protected
 
   def conditionally_share_a_prop
     self.class.inertia_share incorrectly_conditionally_shared_prop: 1
   end
+
+  def not_edit?
+    !is_edit?
+  end
+
+  def is_edit?
+    action_name == "edit"
+  end
 end

spec/dummy/config/routes.rb

@@ -52,5 +52,6 @@
 
   get 'conditional_share_index' => 'inertia_conditional_sharing#index'
   get 'conditional_share_show' => 'inertia_conditional_sharing#show'
+  get 'conditional_share_edit' => 'inertia_conditional_sharing#edit'
   get 'conditional_share_show_with_a_problem' => 'inertia_conditional_sharing#show_with_a_problem'
 end

spec/inertia/action_filter_spec.rb

@@ -0,0 +1,55 @@
+# spec/lib/inertia_rails/action_filter_spec.rb
+
+require 'rails_helper'
+
+RSpec.describe InertiaRails::ActionFilter do
+  let(:controller) do
+    instance_double(
+      'ActionController::Base',
+      action_name: 'current_action',
+      class: instance_double('Class', name: 'TestController')
+    ).tap do |stub|
+      allow(stub).to receive(:available_action?).and_return(true)
+      allow(stub).to receive(:available_action?).with('nonexistent').and_return(false)
+    end
+  end
+
+  describe '#match?' do
+    context 'when action exists' do
+      it 'returns true if action matches' do
+        filter = described_class.new(:only, 'current_action')
+        expect(filter.match?(controller)).to be true
+      end
+
+      it 'returns false if action does not match' do
+        filter = described_class.new(:only, 'other_action')
+        expect(filter.match?(controller)).to be false
+      end
+
+      it 'handles multiple actions' do
+        filter = described_class.new(:only, %w[current_action other actions])
+        expect(filter.match?(controller)).to be true
+      end
+
+      it 'handles symbol actions' do
+        filter = described_class.new(:only, :current_action)
+        expect(filter.match?(controller)).to be true
+      end
+    end
+
+    context 'when action does not exist' do
+      it 'raises ActionNotFound with appropriate message' do
+        filter = described_class.new(:only, :nonexistent)
+        expected_message = <<~MSG
+          The nonexistent action could not be found for the :inertia_share
+          callback on TestController, but it is listed in the controller's
+          :only option.
+        MSG
+
+        expect {
+          filter.match?(controller)
+        }.to raise_error(AbstractController::ActionNotFound, expected_message)
+      end
+    end
+  end
+end

spec/inertia/conditional_sharing_spec.rb

@@ -2,18 +2,43 @@
 # but it can be done by referencing the action name in an inertia_share block.
 RSpec.describe "conditionally shared data in a controller", type: :request do
   context "when there is data inside inertia_share only applicable to a single action" do
-    it "does not leak the data between requests" do
-      get conditional_share_show_path, headers: {'X-Inertia' => true}
-      expect(JSON.parse(response.body)['props'].deep_symbolize_keys).to eq({
-        normal_shared_prop: 1,
+    let(:edit_only_props) do
+      {
+        edit_only_only_block_prop: 1,
+        edit_only_except_block_prop: 1,
+        edit_only_if_proc_prop: 1,
+        edit_only_unless_proc_prop: 1,
+        edit_only_only_prop: 1,
+        edit_only_if_prop: 1,
+        edit_only_unless_prop: 1,
+        edit_only_only_if_prop: 1,
+        edit_only_except_if_prop: 1,
+        edit_only_prop: 1,
+      }
+    end
+
+    let(:show_only_props) do
+      {
         show_only_prop: 1,
         conditionally_shared_show_prop: 1,
-      })
+      }
+    end
+
+    let(:index_only_props) do
+      {
+        index_only_prop: 1,
+      }
+    end
+
+    it "does not leak the data between requests" do
+      get conditional_share_show_path, headers: {'X-Inertia' => true}
+      expect(JSON.parse(response.body)['props'].deep_symbolize_keys).to eq(show_only_props.merge(normal_shared_prop: 1))
 
       get conditional_share_index_path, headers: {'X-Inertia' => true}
-      expect(JSON.parse(response.body)['props'].deep_symbolize_keys).not_to include({
-        conditionally_shared_show_prop: 1,
-      })
+      expect(JSON.parse(response.body)['props'].deep_symbolize_keys).to eq(index_only_props.merge(normal_shared_prop: 1))
+
+      get conditional_share_edit_path, headers: { 'X-Inertia' => true }
+      expect(JSON.parse(response.body)['props'].deep_symbolize_keys).to eq(edit_only_props.merge(normal_shared_prop: 1))
     end
   end