This middleware rescues any exception returned by the application and calls an exceptions app that will wrap it in a format for the end user.
The exceptions app should be passed as parameter on initialization of ShowExceptions. Everytime there is an exception, ShowExceptions will store the exception in env, rewrite the PATH_INFO to the exception status code and call the rack app.
If the application returns a “X-Cascade” pass response, this middleware will send an empty response as result with the correct status code. If any exception happens inside the exceptions app, this middleware catches the exceptions and returns a FAILSAFE_RESPONSE.
# File lib/action_dispatch/middleware/show_exceptions.rb, line 39 def initialize(app, exceptions_app = nil) if [true, false].include?(exceptions_app) ActiveSupport::Deprecation.warn "Passing consider_all_requests_local option to ActionDispatch::ShowExceptions middleware no longer works" exceptions_app = nil end if exceptions_app.nil? raise ArgumentError, "You need to pass an exceptions_app when initializing ActionDispatch::ShowExceptions. " "In case you want to render pages from a public path, you can use ActionDispatch::PublicExceptions.new('path/to/public')" end @app = app @exceptions_app = exceptions_app end
# File lib/action_dispatch/middleware/show_exceptions.rb, line 26 def rescue_responses ActiveSupport::Deprecation.warn "ActionDispatch::ShowExceptions.rescue_responses is deprecated. " "Please configure your exceptions using a railtie or in your application config instead." ExceptionWrapper.rescue_responses end
# File lib/action_dispatch/middleware/show_exceptions.rb, line 32 def rescue_templates ActiveSupport::Deprecation.warn "ActionDispatch::ShowExceptions.rescue_templates is deprecated. " "Please configure your exceptions using a railtie or in your application config instead." ExceptionWrapper.rescue_templates end
# File lib/action_dispatch/middleware/show_exceptions.rb, line 54 def call(env) begin response = @app.call(env) rescue Exception => exception raise exception if env['action_dispatch.show_exceptions'] == false end response || render_exception(env, exception) end
# File lib/action_dispatch/middleware/show_exceptions.rb, line 83 def pass_response(status) [status, {"Content-Type" => "text/html; charset=#{Response.default_charset}", "Content-Length" => "0"}, []] end
# File lib/action_dispatch/middleware/show_exceptions.rb, line 71 def render_exception(env, exception) wrapper = ExceptionWrapper.new(env, exception) status = wrapper.status_code env["action_dispatch.exception"] = wrapper.exception env["PATH_INFO"] = "/#{status}" response = @exceptions_app.call(env) response[1]['X-Cascade'] == 'pass' ? pass_response(status) : response rescue Exception => failsafe_error $stderr.puts "Error during failsafe response: #{failsafe_error}\n #{failsafe_error.backtrace * "\n "}" FAILSAFE_RESPONSE end
Define this method because some plugins were monkey patching it. Remove this after 3.2 is out with the other deprecations in this class.
# File lib/action_dispatch/middleware/show_exceptions.rb, line 68 def status_code(*) end