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Class: ActionView::StreamingTemplateRenderer

Do not use. This class is for internal use only.
Relationships & Source Files
Namespace Children
Classes:
Body
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, TemplateRenderer, AbstractRenderer
Instance Chain:
self, TemplateRenderer, AbstractRenderer
Inherits: ActionView::TemplateRenderer
Defined in: actionview/lib/action_view/renderer/streaming_template_renderer.rb

Overview

TODO

  • Support streaming from child templates, partials and so on.

  • Rack::Cache needs to support streaming bodies

Constant Summary

AbstractRenderer - Inherited

NO_DETAILS

Class Method Summary

AbstractRenderer - Inherited

.new

Instance Attribute Summary

AbstractRenderer - Inherited

#formats

Instance Method Summary

TemplateRenderer - Inherited

#render,
#determine_template

Determine the template to be rendered using the given options.
#find_layout

This is the method which actually finds the layout using details in the lookup context object.
#render_template

Renders the given template.
#render_with_layout, #resolve_layout

AbstractRenderer - Inherited

#any_templates?, #render, #template_exists?, #build_rendered_collection, #build_rendered_template, #extract_details, #prepend_formats

Constructor Details

This class inherits a constructor from ActionView::AbstractRenderer

Instance Method Details

#delayed_render(buffer, template, layout, view, locals) (private)

[ GitHub ] 

  


# File 'actionview/lib/action_view/renderer/streaming_template_renderer.rb', line 57



def delayed_render(buffer, template, layout, view, locals)
  # Wrap the given buffer in the StreamingBuffer and pass it to the
  # underlying template handler. Now, every time something is concatenated
  # to the buffer, it is not appended to an array, but streamed straight
  # to the client.
  output  = ActionView::StreamingBuffer.new(buffer)
  yielder = lambda { |*name| view._layout_for(*name) }

  ActiveSupport::Notifications.instrument(
    "render_template.action_view",
    identifier: template.identifier,
    layout: layout && layout.virtual_path,
    locals: locals
  ) do
    outer_config = I18n.config
    fiber = Fiber.new do
      I18n.config = outer_config
      if layout
        layout.render(view, locals, output, &yielder)
      else
        # If you don't have a layout, just render the thing
        # and concatenate the final result. This is the same
        # as a layout with just <%= yield %>
        output.safe_concat view._layout_for
      end
    end

    # Set the view flow to support streaming. It will be aware
    # when to stop rendering the layout because it needs to search
    # something in the template and vice-versa.
    view.view_flow = StreamingFlow.new(view, fiber)

    # Yo! Start the fiber!
    fiber.resume

    # If the fiber is still alive, it means we need something
    # from the template, so start rendering it. If not, it means
    # the layout exited without requiring anything from the template.
    if fiber.alive?
      content = template.render(view, locals, &yielder)

      # Once rendering the template is done, sets its content in the :layout key.
      view.view_flow.set(:layout, content)

      # In case the layout continues yielding, we need to resume
      # the fiber until all yields are handled.
      fiber.resume while fiber.alive?
    end
  end
end


  








  

    #render_template(view, template, layout_name = nil, locals = {})  
  



  

    

For streaming, instead of rendering a given a template, we return a StreamingTemplateRenderer::Body object that responds to each. This object is initialized with a block that knows how to render the template.


  



  [ GitHub ]


  

  


# File 'actionview/lib/action_view/renderer/streaming_template_renderer.rb', line 45



def render_template(view, template, layout_name = nil, locals = {}) # :nodoc:
  return [super.body] unless layout_name && template.supports_streaming?

  locals ||= {}
  layout   = find_layout(layout_name, locals.keys, [formats.first])

  Body.new do |buffer|
    delayed_render(buffer, template, layout, view, locals)
  end
end