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.append_features(base) #:nodoc: super base.extend(ClassMethods) base.class_eval do alias_method :perform_action_without_rescue, :perform_action alias_method :perform_action, :perform_action_with_rescue end end module ClassMethods 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) unless logger.nil? 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: 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 # Overwrite to implement public exception handling (for requests answering false to local_request?). def rescue_action_in_public(exception) #:doc: render_text "

Application error (Rails)

" end # Overwrite to expand the meaning of a local request in order to show local rescues on other occurances 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 == "127.0.0.1" end # Renders a detailed diagnostics screen on action exceptions. def rescue_action_locally(exception) @exception = exception @rescues_path = File.dirname(__FILE__) + "/templates/rescues/" add_variables_to_assigns @contents = @template.render_file(template_path_for_local_rescue(exception), false) @headers["Content-Type"] = "text/html" render_file(rescues_path("layout"), "500 Internal Error") end private def perform_action_with_rescue #:nodoc: begin perform_action_without_rescue rescue => exception if defined?(Breakpoint) and @params["BP-RETRY"] then 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}." 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 UnknownAction then "unknown_action" when ActionView::TemplateError then "template_error" else "diagnostics" end ) end def clean_backtrace(exception) exception.backtrace.collect { |line| Object.const_defined?(:RAILS_ROOT) ? line.gsub(RAILS_ROOT, "") : line } end end end