I have a simple class that I want to install as Rails Metal. I don’t
want to put it into a file in app/metal for reasons I don’t want to go
into. It looks like this, and handler is defined elsewhere.
class UrlFilter
ALLOW = [404]
DENY = [403]
def self.call(env)
handler.call(env[“PATH_INFO”]) ? ALLOW : DENY
end
end
I’ve tried installing it like this :
ActionController::Dispatcher.middleware.use UrlFilter
but on the first request it crashes with :
Sat Apr 03 00:29:43 +0800 2010: Read error: #<ArgumentError: wrong
number of arguments (0 for 1)>
/Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/middleware_stack.rb:31:in
call' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/middleware_stack.rb:31:inklass’
/Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/middleware_stack.rb:42:in
active?' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/middleware_stack.rb:112:inactive’
/Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:108:in
find_all' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/middleware_stack.rb:112:ineach’
/Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/middleware_stack.rb:112:in
find_all' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/middleware_stack.rb:112:inactive’
/Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/middleware_stack.rb:116:in
build' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:130:inbuild_middleware_stack’
/Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:113:in
call' /Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/reloader.rb:34:inrun’
/Library/Ruby/Gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:108:in
call' /Library/Ruby/Gems/1.8/gems/rails-2.3.5/lib/rails/rack/static.rb:31:incall’
/Library/Ruby/Gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:46:in call' /Library/Ruby/Gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:40:ineach’
/Library/Ruby/Gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:40:in call' /Library/Ruby/Gems/1.8/gems/rails-2.3.5/lib/rails/rack/log_tailer.rb:17:incall’
/Library/Ruby/Gems/1.8/gems/rack-1.0.1/lib/rack/content_length.rb:13:in
call' /Library/Ruby/Gems/1.8/gems/rack-1.0.1/lib/rack/chunked.rb:15:incall’
/Library/Ruby/Gems/1.8/gems/rack-1.0.1/lib/rack/handler/mongrel.rb:64:in
process' /Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:inprocess_client’
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in each' /Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:inprocess_client’
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in run' /Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:ininitialize’
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in new' /Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:inrun’
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in
initialize' /Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:innew’
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in run' /Library/Ruby/Gems/1.8/gems/rack-1.0.1/lib/rack/handler/mongrel.rb:34:inrun’
/Library/Ruby/Gems/1.8/gems/rails-2.3.5/lib/commands/server.rb:111
/Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in
gem_original_require' /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:inrequire’
script/server:3
The rails calling code looks like this :
def klass
if @klass.respond_to?(:call)
@klass.call
elsif @klass.is_a?(Class)
@klass
else
@klass.to_s.constantize
end
rescue NameError
@klass
end
def active?
return false unless klass
if @conditional.respond_to?(:call)
@conditional.call
else
@conditional
end
end
Notice when calling call no arguments are passed (twice!) ? Every metal
example I’ve seen defines the entry method as
def self.call(env)
yet this calling code doesn’t pass any.
Whats going on ? How do I define and install a metal class in code ?