# See README for details.
module HTTPCaching

  # If the client provided an HTTP timestamp, return a 304 Not Modified if the
  # content has not been modified since +latest_content_timestamp+.
  def if_cached_before(latest_content_timestamp)
    if request.env['HTTP_IF_MODIFIED_SINCE'] && latest_content_timestamp <= Time.rfc2822(request.env['HTTP_IF_MODIFIED_SINCE'])
      render :text => '304 Not Modified', :status => 304
    else
      response.headers['Last-Modified'] = latest_content_timestamp.httpdate
      yield
    end
  end
  
  # Renders (using +options+) if the client's HTTP timestamp is older than
  # +latest_content_timestamp+.
  def render_if_cached_before(latest_content_timestamp, *options)
    if_cached_before latest_content_timestamp do
      render *options
    end
  end
  
end

module ActionController
  class Base
    include HTTPCaching
  end
end