1 files changed, 14 insertions, 6 deletions
diff --git a/actionpack/lib/action_dispatch/middleware/public_exceptions.rb b/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
index 53bedaa40a..040cb215b7 100644
--- a/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
@@ -1,4 +1,14 @@
 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.<locale>.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
 
@@ -7,11 +17,10 @@ module ActionDispatch
     end
 
     def call(env)
-      exception    = env["action_dispatch.exception"]
       status       = env["PATH_INFO"][1..-1]
       request      = ActionDispatch::Request.new(env)
       content_type = request.formats.first
-      body         = { :status => status, :error => exception.message }
+      body         = { :status => status, :error => Rack::Utils::HTTP_STATUS_CODES.fetch(status.to_i, Rack::Utils::HTTP_STATUS_CODES[500]) }
 
       render(status, content_type, body)
     end
@@ -19,7 +28,7 @@ module ActionDispatch
     private
 
     def render(status, content_type, body)
-      format = content_type && "to_#{content_type.to_sym}"
+      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
@@ -33,9 +42,8 @@ module ActionDispatch
     end
 
     def render_html(status)
-      found = false
-      path = "#{public_path}/#{status}.#{I18n.locale}.html" if I18n.locale
-      path = "#{public_path}/#{status}.html" unless path && (found = File.exist?(path))
+      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))