Support custom form builders (#291)

Author: joeldrapper

lib/phlex/rails.rb

@@ -7,12 +7,6 @@ module Rails
 		class HelpersCalledBeforeRenderError < StandardError; end
 
 		autoload :Buffered, "phlex/rails/buffered"
-		autoload :Decorator, "phlex/rails/decorator"
-
-		autoload :FormBuilder, "phlex/rails/form_builder"
-		autoload :LabelBuilder, "phlex/rails/label_builder"
-		autoload :CheckboxBuilder, "phlex/rails/checkbox_builder"
-		autoload :RadioButtonBuilder, "phlex/rails/radio_button_builder"
 
 		autoload :CSV, "phlex/rails/csv"
 
@@ -26,6 +20,8 @@ class HelpersCalledBeforeRenderError < StandardError; end
 		autoload :Layout, "phlex/rails/layout"
 		autoload :Partial, "phlex/rails/partial"
 		autoload :Streaming, "phlex/rails/streaming"
+
+		autoload :Builder, "phlex/rails/builder"
 	end
 
 	CSV.prepend(Phlex::Rails::CSV)

lib/phlex/rails/builder.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class Phlex::Rails::Builder < BasicObject
+	def initialize(object, component:)
+		@object = object
+		@component = component
+	end
+
+	define_method :send, ::Kernel.instance_method(:send)
+
+	def respond_to_missing?(method_name, include_private = false)
+		@object.respond_to?(method_name, include_private)
+	end
+
+	def method_missing(*, **, &block)
+		output = if block
+			@object.public_send(*, **) do |builder|
+				yield ::Phlex::Rails::Builder.new(builder, component: @component)
+			end
+		else
+			@object.public_send(*, **)
+		end
+
+		case output
+		when ::ActiveSupport::SafeBuffer
+			@component.raw(output)
+		else
+			output
+		end
+	end
+end

lib/phlex/rails/checkbox_builder.rb

@@ -33,14 +33,14 @@ def #{method_name}(*args, **kwargs, &block)
 		RUBY
 	end
 
-	def register_builder_yielding_helper(method_name, builder)
+	def register_builder_yielding_helper(method_name)
 		class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
 			# frozen_string_literal: true
 
 			def #{method_name}(*args, **kwargs)
 				output = if block_given?
 					view_context.#{method_name}(*args, **kwargs) { |builder|
-					yield #{builder.name}.new(builder, component: self)
+					yield Phlex::Rails::Builder.new(builder, component: self)
 					}
 				else
 					view_context.#{method_name}(*args, **kwargs)

lib/phlex/rails/decorator.rb

@@ -4,5 +4,5 @@ module Phlex::Rails::Helpers::CollectionCheckBoxes
 	extend Phlex::Rails::HelperMacros
 
 	# [Rails Docs](https://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#method-i-collection_check_boxes)
-	register_builder_yielding_helper def collection_check_boxes(...) = nil, Phlex::Rails::CheckboxBuilder
+	register_builder_yielding_helper def collection_check_boxes(...) = nil
 end

lib/phlex/rails/form_builder.rb

@@ -4,5 +4,5 @@ module Phlex::Rails::Helpers::CollectionRadioButtons
 	extend Phlex::Rails::HelperMacros
 
 	# [Rails Docs](https://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#method-i-collection_radio_buttons)
-	register_builder_yielding_helper def collection_radio_buttons(...) = nil, Phlex::Rails::RadioButtonBuilder
+	register_builder_yielding_helper def collection_radio_buttons(...) = nil
 end

lib/phlex/rails/helper_macros.rb

@@ -4,5 +4,5 @@ module Phlex::Rails::Helpers::Fields
 	extend Phlex::Rails::HelperMacros
 
 	# [Rails Docs](https://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-fields)
-	register_builder_yielding_helper def fields(...) = nil, Phlex::Rails::FormBuilder
+	register_builder_yielding_helper def fields(...) = nil
 end

lib/phlex/rails/helpers/collection_check_boxes.rb

@@ -4,5 +4,5 @@ module Phlex::Rails::Helpers::FieldsFor
 	extend Phlex::Rails::HelperMacros
 
 	# [Rails Docs](https://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-fields_for)
-	register_builder_yielding_helper def fields_for(...) = nil, Phlex::Rails::FormBuilder
+	register_builder_yielding_helper def fields_for(...) = nil
 end

lib/phlex/rails/helpers/collection_radio_buttons.rb

@@ -4,5 +4,5 @@ module Phlex::Rails::Helpers::FormFor
 	extend Phlex::Rails::HelperMacros
 
 	# [Rails Docs](https://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_for)
-	register_builder_yielding_helper def form_for(...) = nil, Phlex::Rails::FormBuilder
+	register_builder_yielding_helper def form_for(...) = nil
 end

lib/phlex/rails/helpers/fields.rb

@@ -4,5 +4,5 @@ module Phlex::Rails::Helpers::FormWith
 	extend Phlex::Rails::HelperMacros
 
 	# [Rails Docs](https://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_with)
-	register_builder_yielding_helper def form_with(...) = nil, Phlex::Rails::FormBuilder
+	register_builder_yielding_helper def form_with(...) = nil
 end

lib/phlex/rails/helpers/fields_for.rb

@@ -4,5 +4,5 @@ module Phlex::Rails::Helpers::Label
 	extend Phlex::Rails::HelperMacros
 
 	# [Rails Docs](https://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-label)
-	register_builder_yielding_helper def label(...) = nil, Phlex::Rails::LabelBuilder
+	register_builder_yielding_helper def label(...) = nil
 end

lib/phlex/rails/helpers/form_for.rb

@@ -42,3 +42,36 @@
 		</form>
 	HTML
 end
+
+class CustomFormBuilder < ActionView::Helpers::FormBuilder
+	def fancy_input(attribute, options = {})
+		@template.content_tag(:div, class: "fancy-input") do
+			"Fancy input for #{attribute}"
+		end
+	end
+end
+
+test "form_with with custom builder" do
+	component = Class.new(Phlex::HTML) do
+		include Phlex::Rails::Helpers::FormWith
+
+		define_method :view_template do
+			form_with(url: "/", builder: CustomFormBuilder) do |form|
+				form.fancy_input :bar
+				nil # important, otherwise the return value is output
+			end
+		end
+	end
+
+	controller.define_singleton_method(:form_authenticity_token) { |_| "(example form authenticity token)" }
+
+	output = render(component)
+
+	assert_equivalent_html output, <<~HTML
+		<form action="/" accept-charset="UTF-8" method="post">
+			<input name="utf8" type="hidden" value="✓" autocomplete="off">
+			<input type="hidden" name="authenticity_token" value="(example form authenticity token)" autocomplete="off">
+			<div class="fancy-input">Fancy input for bar</div>
+		</form>
+	HTML
+end