Module: ActionView::Layouts

Included in:
Base
Defined in:
lib/action_view/render/layouts.rb

Overview

Action View Layouts

Instance Method Summary collapse

Instance Method Details

#_layout_for(*args, &block) ⇒ Object

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 yield :some_name, the block, by default, returns content_for(:some_name). If the user calls simply yield, the default block returns content_for(:layout).

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 content_for(:layout), this method returns the block that was passed in to render :layout, 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 render :layout, and the struct specified would be passed into the block as an argument. The result would be

<html>
  Hello David
</html>



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# File 'lib/action_view/render/layouts.rb', line 50

def _layout_for(*args, &block) #:nodoc:
  name = args.first

  if name.is_a?(Symbol)
    @_content_for[name].html_safe
  elsif block
    capture(*args, &block)
  else
    @_content_for[:layout].html_safe
  end
end

#_render_layout(layout, locals, &block) ⇒ Object

Contains the logic that actually renders the layout.



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# File 'lib/action_view/render/layouts.rb', line 79

def _render_layout(layout, locals, &block) #:nodoc:
  layout.render(self, locals){ |*name| _layout_for(*name, &block) }
end

#find_layout(layout) ⇒ Object

This is the method which actually finds the layout using details in the lookup context object. If no layout is found, it checks if at least a layout with the given name exists across all details before raising the error.



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# File 'lib/action_view/render/layouts.rb', line 65

def find_layout(layout)
  begin
    with_layout_format do
      layout =~ /^\// ?
        with_fallbacks { find_template(layout) } : find_template(layout)
    end
  rescue ActionView::MissingTemplate => e
    update_details(:formats => nil) do
      raise unless template_exists?(layout)
    end
  end
end