Add an ExceptionWrapper that wraps an exception and provide convenien…

…ce helpers.

actionpack/lib/action_controller/log_subscriber.rb

@@ -20,7 +20,7 @@ def process_action(event)
 
       status = payload[:status]
       if status.nil? && payload[:exception].present?
-        status = Rack::Utils.status_code(ActionDispatch::ShowExceptions.rescue_responses[payload[:exception].first]) rescue nil
+        status = Rack::Utils.status_code(ActionDispatch::ExceptionWrapper.new({}, payload[:exception]).status_code)
       end
       message = "Completed #{status} #{Rack::Utils::HTTP_STATUS_CODES[status]} in %.0fms" % event.duration
       message << " (#{additions.join(" | ")})" unless additions.blank?

actionpack/lib/action_dispatch.rb

@@ -51,6 +51,7 @@ module ActionDispatch
     autoload :BestStandardsSupport
     autoload :Callbacks
     autoload :Cookies
+    autoload :ExceptionWrapper
     autoload :Flash
     autoload :Head
     autoload :ParamsParser

actionpack/lib/action_dispatch/middleware/exception_wrapper.rb

@@ -0,0 +1,77 @@
+require 'active_support/core_ext/exception'
+
+module ActionDispatch
+  class ExceptionWrapper
+    cattr_accessor :rescue_responses
+    @@rescue_responses = Hash.new(:internal_server_error)
+    @@rescue_responses.merge!(
+      'ActionController::RoutingError'             => :not_found,
+      'AbstractController::ActionNotFound'         => :not_found,
+      'ActionController::MethodNotAllowed'         => :method_not_allowed,
+      'ActionController::NotImplemented'           => :not_implemented,
+      'ActionController::InvalidAuthenticityToken' => :unprocessable_entity
+    )
+
+    cattr_accessor :rescue_templates
+    @@rescue_templates = Hash.new('diagnostics')
+    @@rescue_templates.merge!(
+      'ActionView::MissingTemplate'         => 'missing_template',
+      'ActionController::RoutingError'      => 'routing_error',
+      'AbstractController::ActionNotFound'  => 'unknown_action',
+      'ActionView::Template::Error'         => 'template_error'
+    )
+
+    attr_reader :env, :exception
+
+    def initialize(env, exception)
+      @env = env
+      @exception = original_exception(exception)
+    end
+
+    def rescue_template
+      @@rescue_templates[@exception.class.name]
+    end
+
+    def status_code
+      Rack::Utils.status_code(@@rescue_responses[@exception.class.name])
+    end
+
+    def application_trace
+      clean_backtrace(:silent)
+    end
+
+    def framework_trace
+      clean_backtrace(:noise)
+    end
+
+    def full_trace
+      clean_backtrace(:all)
+    end
+
+    private
+
+    def original_exception(exception)
+      if registered_original_exception?(exception)
+        exception.original_exception
+      else
+        exception
+      end
+    end
+
+    def registered_original_exception?(exception)
+      exception.respond_to?(:original_exception) && @@rescue_responses.has_key?(exception.original_exception.class.name)
+    end
+
+    def clean_backtrace(*args)
+      if backtrace_cleaner
+        backtrace_cleaner.clean(@exception.backtrace, *args)
+      else
+        @exception.backtrace
+      end
+    end
+
+    def backtrace_cleaner
+      @backtrace_cleaner ||= @env['action_dispatch.backtrace_cleaner']
+    end
+  end
+end

actionpack/lib/action_dispatch/middleware/show_exceptions.rb

@@ -1,7 +1,6 @@
-require 'active_support/core_ext/exception'
 require 'action_controller/metal/exceptions'
-require 'active_support/notifications'
 require 'action_dispatch/http/request'
+require 'action_dispatch/middleware/exception_wrapper'
 require 'active_support/deprecation'
 
 module ActionDispatch
@@ -10,25 +9,6 @@ module ActionDispatch
   class ShowExceptions
     RESCUES_TEMPLATE_PATH = File.join(File.dirname(__FILE__), 'templates')
 
-    cattr_accessor :rescue_responses
-    @@rescue_responses = Hash.new(:internal_server_error)
-    @@rescue_responses.merge!(
-      'ActionController::RoutingError'             => :not_found,
-      'AbstractController::ActionNotFound'         => :not_found,
-      'ActionController::MethodNotAllowed'         => :method_not_allowed,
-      'ActionController::NotImplemented'           => :not_implemented,
-      'ActionController::InvalidAuthenticityToken' => :unprocessable_entity
-    )
-
-    cattr_accessor :rescue_templates
-    @@rescue_templates = Hash.new('diagnostics')
-    @@rescue_templates.merge!(
-      'ActionView::MissingTemplate'         => 'missing_template',
-      'ActionController::RoutingError'      => 'routing_error',
-      'AbstractController::ActionNotFound'  => 'unknown_action',
-      'ActionView::Template::Error'         => 'template_error'
-    )
-
     FAILSAFE_RESPONSE = [500, {'Content-Type' => 'text/html'},
       ["<html><body><h1>500 Internal Server Error</h1>" <<
        "If you are the administrator of this website, then please read this web " <<
@@ -59,13 +39,13 @@ def call(env)
 
     private
       def render_exception(env, exception)
-        log_error(env, exception)
-        exception = original_exception(exception)
+        wrapper = ExceptionWrapper.new(env, exception)
+        log_error(env, wrapper)
 
         if env['action_dispatch.show_detailed_exceptions'] == true
-          rescue_action_diagnostics(env, exception)
+          rescue_action_diagnostics(wrapper)
         else
-          rescue_action_error_page(exception)
+          rescue_action_error_page(wrapper)
         end
       rescue Exception => failsafe_error
         $stderr.puts "Error during failsafe response: #{failsafe_error}\n  #{failsafe_error.backtrace * "\n  "}"
@@ -74,17 +54,17 @@ def render_exception(env, exception)
 
       # Render detailed diagnostics for unhandled exceptions rescued from
       # a controller action.
-      def rescue_action_diagnostics(env, exception)
+      def rescue_action_diagnostics(wrapper)
         template = ActionView::Base.new([RESCUES_TEMPLATE_PATH],
-          :request => Request.new(env),
-          :exception => exception,
-          :application_trace => application_trace(env, exception),
-          :framework_trace => framework_trace(env, exception),
-          :full_trace => full_trace(env, exception)
+          :request => Request.new(wrapper.env),
+          :exception => wrapper.exception,
+          :application_trace => wrapper.application_trace,
+          :framework_trace => wrapper.framework_trace,
+          :full_trace => wrapper.full_trace
         )
-        file = "rescues/#{@@rescue_templates[exception.class.name]}"
+        file = "rescues/#{wrapper.rescue_template}"
         body = template.render(:template => file, :layout => 'rescues/layout')
-        render(status_code(exception), body)
+        render(wrapper.status_code, body)
       end
 
       # Attempts to render a static error page based on the
@@ -94,8 +74,8 @@ def rescue_action_diagnostics(env, exception)
       # it will first attempt to render the file at <tt>public/500.da.html</tt>
       # then attempt to render <tt>public/500.html</tt>. If none of them exist,
       # the body of the response will be left empty.
-      def rescue_action_error_page(exception)
-        status = status_code(exception)
+      def rescue_action_error_page(wrapper)
+        status = wrapper.status_code
         locale_path = "#{public_path}/#{status}.#{I18n.locale}.html" if I18n.locale
         path = "#{public_path}/#{status}.html"
 
@@ -108,10 +88,6 @@ def rescue_action_error_page(exception)
         end
       end
 
-      def status_code(exception)
-        Rack::Utils.status_code(@@rescue_responses[exception.class.name])
-      end
-
       def render(status, body)
         [status, {'Content-Type' => "text/html; charset=#{Response.default_charset}", 'Content-Length' => body.bytesize.to_s}, [body]]
       end
@@ -120,53 +96,26 @@ def public_path
         defined?(Rails.public_path) ? Rails.public_path : 'public_path'
       end
 
-      def log_error(env, exception)
-        return unless logger(env)
+      def log_error(env, wrapper)
+        logger = logger(env)
+        return unless logger
+
+        exception = wrapper.exception
 
         ActiveSupport::Deprecation.silence do
           message = "\n#{exception.class} (#{exception.message}):\n"
           message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
-          message << "  " << application_trace(env, exception).join("\n  ")
-          logger(env).fatal("#{message}\n\n")
+          message << "  " << wrapper.application_trace.join("\n  ")
+          logger.fatal("#{message}\n\n")
         end
       end
 
-      def application_trace(env, exception)
-        clean_backtrace(env, exception, :silent)
-      end
-
-      def framework_trace(env, exception)
-        clean_backtrace(env, exception, :noise)
-      end
-
-      def full_trace(env, exception)
-        clean_backtrace(env, exception, :all)
-      end
-
-      def clean_backtrace(env, exception, *args)
-        env['action_dispatch.backtrace_cleaner'] ?
-          env['action_dispatch.backtrace_cleaner'].clean(exception.backtrace, *args) :
-          exception.backtrace
-      end
-
       def logger(env)
         env['action_dispatch.logger'] || stderr_logger
       end
 
       def stderr_logger
-        Logger.new($stderr)
-      end
-
-    def original_exception(exception)
-      if registered_original_exception?(exception)
-        exception.original_exception
-      else
-        exception
+        @stderr_logger ||= Logger.new($stderr)
       end
-    end
-
-    def registered_original_exception?(exception)
-      exception.respond_to?(:original_exception) && @@rescue_responses.has_key?(exception.original_exception.class.name)
-    end
   end
 end

actionpack/lib/action_dispatch/railtie.rb

@@ -22,8 +22,8 @@ class Railtie < Rails::Railtie
       ActionDispatch::Http::URL.tld_length = app.config.action_dispatch.tld_length
       ActionDispatch::Request.ignore_accept_header = app.config.action_dispatch.ignore_accept_header
 
-      ActionDispatch::ShowExceptions.rescue_responses.merge!(config.action_dispatch.rescue_responses)
-      ActionDispatch::ShowExceptions.rescue_templates.merge!(config.action_dispatch.rescue_templates)
+      ActionDispatch::ExceptionWrapper.rescue_responses.merge!(config.action_dispatch.rescue_responses)
+      ActionDispatch::ExceptionWrapper.rescue_templates.merge!(config.action_dispatch.rescue_templates)
 
       config.action_dispatch.always_write_cookie = Rails.env.development? if config.action_dispatch.always_write_cookie.nil?
       ActionDispatch::Cookies::CookieJar.always_write_cookie = config.action_dispatch.always_write_cookie