actionview/lib/action_view/helpers/rendering_helper.rb
# frozen_string_literal: true
module ActionView
module Helpers # :nodoc:
# = Action View \Rendering \Helpers
#
# Implements methods that allow rendering from a view context.
# In order to use this module, all you need is to implement
# view_renderer that returns an ActionView::Renderer object.
module RenderingHelper
# Returns the result of a render that's dictated by the options hash. The primary options are:
#
# * <tt>:partial</tt> - See ActionView::PartialRenderer.
# * <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>:plain</tt> - Renders the text passed in out. Setting the content
# type as <tt>text/plain</tt>.
# * <tt>:html</tt> - Renders the HTML safe string passed in out, otherwise
# performs HTML escape on the string first. Setting the content type as
# <tt>text/html</tt>.
# * <tt>:body</tt> - Renders the text passed in, and inherits the content
# type of <tt>text/plain</tt> from ActionDispatch::Response object.
#
# If no <tt>options</tt> hash is passed or if <tt>:update</tt> is specified, then:
#
# If an object responding to +render_in+ is passed, +render_in+ is called on the object,
# passing in the current view context.
#
# Otherwise, a partial is rendered using the second parameter as the locals hash.
def render(options = {}, locals = {}, &block)
case options
when Hash
in_rendering_context(options) do |renderer|
if block_given?
view_renderer.render_partial(self, options.merge(partial: options[:layout]), &block)
else
view_renderer.render(self, options)
end
end
else
if options.respond_to?(:render_in)
options.render_in(self, &block)
else
view_renderer.render_partial(self, partial: options, locals: locals, &block)
end
end
end
# Overrides _layout_for in the context object so it supports the case a block is
# passed to a partial. Returns the contents that are yielded to a layout, given a
# name or a block.
#
# You can think of a layout as a method that is called with a block. If the user calls
# <tt>yield :some_name</tt>, the block, by default, returns <tt>content_for(:some_name)</tt>.
# If the user calls simply +yield+, the default block returns <tt>content_for(:layout)</tt>.
#
# The user can override this default by passing a block to the layout:
#
# # The template
# <%= render layout: "my_layout" do %>
# Content
# <% end %>
#
# # The layout
# <html>
# <%= yield %>
# </html>
#
# In this case, instead of the default block, which would return <tt>content_for(:layout)</tt>,
# this method returns the block that was passed in to <tt>render :layout</tt>, and the response
# would be
#
# <html>
# Content
# </html>
#
# Finally, the block can take block arguments, which can be passed in by +yield+:
#
# # The template
# <%= render layout: "my_layout" do |customer| %>
# Hello <%= customer.name %>
# <% end %>
#
# # The layout
# <html>
# <%= yield Struct.new(:name).new("David") %>
# </html>
#
# In this case, the layout would receive the block passed into <tt>render :layout</tt>,
# and the struct specified would be passed into the block as an argument. The result
# would be
#
# <html>
# Hello David
# </html>
#
def _layout_for(*args, &block)
name = args.first
if block && !name.is_a?(Symbol)
capture(*args, &block)
else
super
end
end
end
end
end