1 files changed, 45 insertions, 0 deletions
diff --git a/actionpack/lib/action_dispatch/middleware/public_exceptions.rb b/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
new file mode 100644
index 0000000000..6c8944e067
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
@@ -0,0 +1,45 @@
+module ActionDispatch
+  class PublicExceptions
+    attr_accessor :public_path
+
+    def initialize(public_path)
+      @public_path = public_path
+    end
+
+    def call(env)
+      status       = env["PATH_INFO"][1..-1]
+      request      = ActionDispatch::Request.new(env)
+      content_type = request.formats.first
+      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
+
+    private
+
+    def render(status, content_type, body)
+      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
+        render_html(status)
+      end
+    end
+
+    def render_format(status, content_type, body)
+      [status, {'Content-Type' => "#{content_type}; charset=#{ActionDispatch::Response.default_charset}",
+                'Content-Length' => body.bytesize.to_s}, [body]]
+    end
+
+    def render_html(status)
+      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))
+      else
+        [404, { "X-Cascade" => "pass" }, []]
+      end
+    end
+  end
+end