module ActionDispatch # When called, this middleware renders an error page. By default if an HTML # response is expected it will render static error pages from the `/public` # directory. For example when this middleware receives a 500 response it will # render the template found in `/public/500.html`. # If an internationalized locale is set, this middleware will attempt to render # the template in `/public/500..html`. If an internationalized template # is not found it will fall back on `/public/500.html`. # # When a request with a content type other than HTML is made, this middleware # will attempt to convert error information into the appropriate response type. class PublicExceptions attr_accessor :public_path def initialize(public_path) @public_path = public_path end def call(env) request = ActionDispatch::Request.new(env) status = request.path_info[1..-1].to_i content_type = request.formats.first body = { :status => status, :error => Rack::Utils::HTTP_STATUS_CODES.fetch(status, Rack::Utils::HTTP_STATUS_CODES[500]) } render(status, content_type, body) end private def render(status, content_type, body) format = "to_#{content_type.to_sym}" if content_type if format && body.respond_to?(format) render_format(status, content_type, body.public_send(format)) else render_html(status) end end def render_format(status, content_type, body) [status, {'Content-Type' => "#{content_type}; charset=#{ActionDispatch::Response.default_charset}", 'Content-Length' => body.bytesize.to_s}, [body]] end def render_html(status) path = "#{public_path}/#{status}.#{I18n.locale}.html" path = "#{public_path}/#{status}.html" unless (found = File.exist?(path)) if found || File.exist?(path) render_format(status, 'text/html', File.read(path)) else [404, { "X-Cascade" => "pass" }, []] end end end end