module ActionController #:nodoc: # Actions that fail to perform as expected throw exceptions. These exceptions can either be rescued for the public view # (with a nice user-friendly explanation) or for the developers view (with tons of debugging information). The developers view # is already implemented by the Action Controller, but the public view should be tailored to your specific application. So too # could the decision on whether something is a public or a developer request. # # You can tailor the rescuing behavior and appearance by overwriting the following two stub methods. module Rescue def self.included(base) #:nodoc: base.extend(ClassMethods) base.class_eval do alias_method_chain :perform_action, :rescue end end module ClassMethods #:nodoc: def process_with_exception(request, response, exception) new.process(request, response, :rescue_action, exception) end end protected # Exception handler called when the performance of an action raises an exception. def rescue_action(exception) log_error(exception) if logger erase_results if performed? if consider_all_requests_local || local_request? rescue_action_locally(exception) else rescue_action_in_public(exception) end end # Overwrite to implement custom logging of errors. By default logs as fatal. def log_error(exception) #:doc: ActiveSupport::Deprecation.silence do if ActionView::TemplateError === exception logger.fatal(exception.to_s) else logger.fatal( "\n\n#{exception.class} (#{exception.message}):\n " + clean_backtrace(exception).join("\n ") + "\n\n" ) end end end # Overwrite to implement public exception handling (for requests answering false to local_request?). def rescue_action_in_public(exception) #:doc: case exception when RoutingError, UnknownAction render_text(IO.read(File.join(RAILS_ROOT, 'public', '404.html')), "404 Not Found") else render_text(IO.read(File.join(RAILS_ROOT, 'public', '500.html')), "500 Internal Error") end end # Overwrite to expand the meaning of a local request in order to show local rescues on other occurrences than # the remote IP being 127.0.0.1. For example, this could include the IP of the developer machine when debugging # remotely. def local_request? #:doc: [request.remote_addr, request.remote_ip] == ["127.0.0.1"] * 2 end # Renders a detailed diagnostics screen on action exceptions. def rescue_action_locally(exception) add_variables_to_assigns @template.instance_variable_set("@exception", exception) @template.instance_variable_set("@rescues_path", File.dirname(rescues_path("stub"))) @template.send(:assign_variables_from_controller) @template.instance_variable_set("@contents", @template.render_file(template_path_for_local_rescue(exception), false)) response.content_type = Mime::HTML render_file(rescues_path("layout"), response_code_for_rescue(exception)) end private def perform_action_with_rescue #:nodoc: begin perform_action_without_rescue rescue Exception => exception # errors from action performed if defined?(Breakpoint) && params["BP-RETRY"] msg = exception.backtrace.first if md = /^(.+?):(\d+)(?::in `(.+)')?$/.match(msg) then origin_file, origin_line = md[1], md[2].to_i set_trace_func(lambda do |type, file, line, method, context, klass| if file == origin_file and line == origin_line then set_trace_func(nil) params["BP-RETRY"] = false callstack = caller callstack.slice!(0) if callstack.first["rescue.rb"] file, line, method = *callstack.first.match(/^(.+?):(\d+)(?::in `(.*?)')?/).captures message = "Exception at #{file}:#{line}#{" in `#{method}'" if method}." # `´ ( for ruby-mode) Breakpoint.handle_breakpoint(context, message, file, line) end end) retry end end rescue_action(exception) end end def rescues_path(template_name) File.dirname(__FILE__) + "/templates/rescues/#{template_name}.rhtml" end def template_path_for_local_rescue(exception) rescues_path( case exception when MissingTemplate then "missing_template" when RoutingError then "routing_error" when UnknownAction then "unknown_action" when ActionView::TemplateError then "template_error" else "diagnostics" end ) end def response_code_for_rescue(exception) case exception when UnknownAction, RoutingError "404 Page Not Found" else "500 Internal Error" end end def clean_backtrace(exception) exception.backtrace.collect { |line| Object.const_defined?(:RAILS_ROOT) ? line.gsub(RAILS_ROOT, "") : line } end end end