Introduce `render :body` for render raw content

This is an option for sending a raw content back to browser. Note that
this rendering option will unset the default content type and does not
include "Content-Type" header back in the response.

You should only use this option if you are expecting the "Content-Type"
header to not be set. More information on "Content-Type" header can be
found on RFC 2616, section 7.2.1.

Please see #12374 for more detail.

10 files changed, 219 insertions, 11 deletions

diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 35b0a419d3..dcccc99d5b 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,3 +1,15 @@
+*   Introduce `render :body` as an option for sending a raw content back to
+    browser. Note that this rendering option will unset the default content type
+    and does not include "Content-Type" header back in the response.
+
+    You should only use this option if you are expecting the "Content-Type"
+    header to not be set. More information on "Content-Type" header can be found
+    on RFC 2616, section 7.2.1.
+
+    Please see #12374 for more detail.
+
+    *Prem Sichanugrist*
+
 *   Set stream status to 500 (or 400 on BadRequest) when an error is thrown
     before commiting.
 
diff --git a/actionpack/lib/abstract_controller/rendering.rb b/actionpack/lib/abstract_controller/rendering.rb
index f24b03ad16..349bbf4ee7 100644
--- a/actionpack/lib/abstract_controller/rendering.rb
+++ b/actionpack/lib/abstract_controller/rendering.rb
@@ -23,7 +23,7 @@ module AbstractController
     def render(*args, &block)
       options = _normalize_render(*args, &block)
       self.response_body = render_to_body(options)
-      _process_format(rendered_format) if rendered_format
+      _process_format(rendered_format, options) if rendered_format
       self.response_body
     end
 
@@ -98,7 +98,7 @@ module AbstractController
 
     # Process the rendered format.
     # :api: private
-    def _process_format(format)
+    def _process_format(format, options = {})
     end
 
     # Normalize args and options.
diff --git a/actionpack/lib/action_controller/metal/rendering.rb b/actionpack/lib/action_controller/metal/rendering.rb
index 5c48b4ab98..c9ae1ab388 100644
--- a/actionpack/lib/action_controller/metal/rendering.rb
+++ b/actionpack/lib/action_controller/metal/rendering.rb
@@ -27,14 +27,19 @@ module ActionController
     end
 
     def render_to_body(options = {})
-      super || options[:text].presence || ' '
+      super || options[:body].presence || options[:text].presence || ' '
     end
 
     private
 
-    def _process_format(format)
+    def _process_format(format, options = {})
       super
       self.content_type ||= format.to_s
+
+      if options[:body].present?
+        self.content_type = "none"
+        self.headers.delete "Content-Type"
+      end
     end
 
     # Normalize arguments by catching blocks and setting them on :update.
@@ -46,12 +51,16 @@ module ActionController
 
     # Normalize both text and status options.
     def _normalize_options(options) #:nodoc:
+      if options.key?(:body) && options[:body].respond_to?(:to_text)
+        options[:body] = options[:body].to_text
+      end
+
       if options.key?(:text) && options[:text].respond_to?(:to_text)
         options[:text] = options[:text].to_text
       end
 
-      if options.delete(:nothing) || (options.key?(:text) && options[:text].nil?)
-        options[:text] = " "
+      if options.delete(:nothing) || (options.key?(:body) && options[:body].nil?) || (options.key?(:text) && options[:text].nil?)
+        options[:body] = " "
       end
 
       if options[:status]
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 2c6bcf7b7b..15a177aaff 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -288,7 +288,7 @@ module ActionDispatch # :nodoc:
     end
 
     def assign_default_content_type_and_charset!(headers)
-      return if headers[CONTENT_TYPE].present?
+      return if headers[CONTENT_TYPE].present? || @content_type == "none"
 
       @content_type ||= Mime::HTML
       @charset      ||= self.class.default_charset unless @charset == false
diff --git a/actionpack/test/controller/new_base/render_body_test.rb b/actionpack/test/controller/new_base/render_body_test.rb
new file mode 100644
index 0000000000..a7e4f87bd9
--- /dev/null
+++ b/actionpack/test/controller/new_base/render_body_test.rb
@@ -0,0 +1,175 @@
+require 'abstract_unit'
+
+module RenderBody
+  class MinimalController < ActionController::Metal
+    include AbstractController::Rendering
+    include ActionController::Rendering
+
+    def index
+      render body: "Hello World!"
+    end
+  end
+
+  class SimpleController < ActionController::Base
+    self.view_paths = [ActionView::FixtureResolver.new]
+
+    def index
+      render body: "hello david"
+    end
+  end
+
+  class WithLayoutController < ::ApplicationController
+    self.view_paths = [ActionView::FixtureResolver.new(
+      "layouts/application.erb" => "<%= yield %>, I'm here!",
+      "layouts/greetings.erb"   => "<%= yield %>, I wish thee well.",
+      "layouts/ivar.erb"        => "<%= yield %>, <%= @ivar %>"
+    )]
+
+    def index
+      render body: "hello david"
+    end
+
+    def custom_code
+      render body: "hello world", status: 404
+    end
+
+    def with_custom_code_as_string
+      render body: "hello world", status: "404 Not Found"
+    end
+
+    def with_nil
+      render body: nil
+    end
+
+    def with_nil_and_status
+      render body: nil, status: 403
+    end
+
+    def with_false
+      render body: false
+    end
+
+    def with_layout_true
+      render body: "hello world", layout: true
+    end
+
+    def with_layout_false
+      render body: "hello world", layout: false
+    end
+
+    def with_layout_nil
+      render body: "hello world", layout: nil
+    end
+
+    def with_custom_layout
+      render body: "hello world", layout: "greetings"
+    end
+
+    def with_ivar_in_layout
+      @ivar = "hello world"
+      render body: "hello world", layout: "ivar"
+    end
+  end
+
+  class RenderBodyTest < Rack::TestCase
+    test "rendering body from a minimal controller" do
+      get "/render_body/minimal/index"
+      assert_body "Hello World!"
+      assert_status 200
+    end
+
+    test "rendering body from an action with default options renders the body with the layout" do
+      with_routing do |set|
+        set.draw { get ':controller', action: 'index' }
+
+        get "/render_body/simple"
+        assert_body "hello david"
+        assert_status 200
+      end
+    end
+
+    test "rendering body from an action with default options renders the body without the layout" do
+      with_routing do |set|
+        set.draw { get ':controller', action: 'index' }
+
+        get "/render_body/with_layout"
+
+        assert_body "hello david"
+        assert_status 200
+      end
+    end
+
+    test "rendering body, while also providing a custom status code" do
+      get "/render_body/with_layout/custom_code"
+
+      assert_body "hello world"
+      assert_status 404
+    end
+
+    test "rendering body with nil returns an empty body padded for Safari" do
+      get "/render_body/with_layout/with_nil"
+
+      assert_body " "
+      assert_status 200
+    end
+
+    test "Rendering body with nil and custom status code returns an empty body padded for Safari and the status" do
+      get "/render_body/with_layout/with_nil_and_status"
+
+      assert_body " "
+      assert_status 403
+    end
+
+    test "rendering body with false returns the string 'false'" do
+      get "/render_body/with_layout/with_false"
+
+      assert_body "false"
+      assert_status 200
+    end
+
+    test "rendering body with layout: true" do
+      get "/render_body/with_layout/with_layout_true"
+
+      assert_body "hello world, I'm here!"
+      assert_status 200
+    end
+
+    test "rendering body with layout: 'greetings'" do
+      get "/render_body/with_layout/with_custom_layout"
+
+      assert_body "hello world, I wish thee well."
+      assert_status 200
+    end
+
+    test "rendering body with layout: false" do
+      get "/render_body/with_layout/with_layout_false"
+
+      assert_body "hello world"
+      assert_status 200
+    end
+
+    test "rendering body with layout: nil" do
+      get "/render_body/with_layout/with_layout_nil"
+
+      assert_body "hello world"
+      assert_status 200
+    end
+
+    test "rendering from minimal controller returns response with no content type" do
+      get "/render_body/minimal/index"
+
+      assert_header_no_content_type
+    end
+
+    test "rendering from normal controller returns response with no content type" do
+      get "/render_body/simple/index"
+
+      assert_header_no_content_type
+    end
+
+    def assert_header_no_content_type
+      assert_not response.headers.has_key?("Content-Type"),
+        %(Expect response not to have Content-Type header, got "#{response.headers["Content-Type"]}")
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/response_test.rb b/actionpack/test/dispatch/response_test.rb
index 959a3bc5cd..26b77dfaf7 100644
--- a/actionpack/test/dispatch/response_test.rb
+++ b/actionpack/test/dispatch/response_test.rb
@@ -235,6 +235,14 @@ class ResponseTest < ActiveSupport::TestCase
       assert_equal @response.body, body.each.to_a.join
     end
   end
+
+  test "does not add default content-type if Content-Type is none" do
+    resp = ActionDispatch::Response.new.tap { |response|
+      response.content_type = 'none'
+    }
+
+    assert_not resp.headers.has_key?('Content-Type')
+  end
 end
 
 class ResponseIntegrationTest < ActionDispatch::IntegrationTest
diff --git a/actionview/lib/action_view/helpers/rendering_helper.rb b/actionview/lib/action_view/helpers/rendering_helper.rb
index 458086de96..77d63b7f86 100644
--- a/actionview/lib/action_view/helpers/rendering_helper.rb
+++ b/actionview/lib/action_view/helpers/rendering_helper.rb
@@ -12,6 +12,8 @@ module ActionView
       # * <tt>:file</tt> - Renders an explicit template file (this used to be the old default), add :locals to pass in those.
       # * <tt>:inline</tt> - Renders an inline template similar to how it's done in the controller.
       # * <tt>:text</tt> - Renders the text passed in out.
+      # * <tt>:body</tt> - Renders the text passed in, and does not set content
+      # type in the response.
       #
       # If no options hash is passed or :update specified, the default is to render a partial and use the second parameter
       # as the locals hash.
diff --git a/actionview/lib/action_view/layouts.rb b/actionview/lib/action_view/layouts.rb
index ffa67649da..b67b749af5 100644
--- a/actionview/lib/action_view/layouts.rb
+++ b/actionview/lib/action_view/layouts.rb
@@ -420,7 +420,7 @@ module ActionView
     end
 
     def _include_layout?(options)
-      (options.keys & [:text, :inline, :partial]).empty? || options.key?(:layout)
+      (options.keys & [:body, :text, :inline, :partial]).empty? || options.key?(:layout)
     end
   end
 end
diff --git a/actionview/lib/action_view/renderer/template_renderer.rb b/actionview/lib/action_view/renderer/template_renderer.rb
index 668831dff3..8f24f8dab0 100644
--- a/actionview/lib/action_view/renderer/template_renderer.rb
+++ b/actionview/lib/action_view/renderer/template_renderer.rb
@@ -21,7 +21,9 @@ module ActionView
     def determine_template(options) #:nodoc:
       keys = options.fetch(:locals, {}).keys
 
-      if options.key?(:text)
+      if options.key?(:body)
+        Template::Text.new(options[:body])
+      elsif options.key?(:text)
         Template::Text.new(options[:text], formats.first)
       elsif options.key?(:file)
         with_fallbacks { find_template(options[:file], nil, false, keys, @details) }
@@ -35,7 +37,7 @@ module ActionView
           find_template(options[:template], options[:prefixes], false, keys, @details)
         end
       else
-        raise ArgumentError, "You invoked render but did not give any of :partial, :template, :inline, :file or :text option."
+        raise ArgumentError, "You invoked render but did not give any of :partial, :template, :inline, :file, :text or :body option."
       end
     end
 
diff --git a/actionview/lib/action_view/rendering.rb b/actionview/lib/action_view/rendering.rb
index 7c17220d14..017302d40f 100644
--- a/actionview/lib/action_view/rendering.rb
+++ b/actionview/lib/action_view/rendering.rb
@@ -100,7 +100,7 @@ module ActionView
       end
 
       # Assign the rendered format to lookup context.
-      def _process_format(format) #:nodoc:
+      def _process_format(format, options = {}) #:nodoc:
         super
         lookup_context.formats = [format.to_sym]
         lookup_context.rendered_format = lookup_context.formats.first