Re: Why env.object_id is different in each middleware?

[Tim Carey-Smith <g@spork.in>]

On 10/12/2009, at 12:15 PM, Iñaki Baz Castillo wrote:

> El Miércoles, 9 de Diciembre de 2009, Iñaki Baz Castillo escribió:
>> Since env is a hash I cannot understand why its object_id changes.  
>> Any
>> explanation for it?
>> This explains that when I change env[XXX] into my final appplication
>> MyApp.handle_request the change doesn't exist after calling
>> resp = @app.call(env)
>> in the first middleware.
>
> If I add a env["LALA"] in the first middleware then it's visible for  
> following
> middlewares.
> However if I add env["LOLO"] in the second middleware this is not  
> visible for
> first middleware after calling "@app.call(env)".
>
> Is it the expected behavior?
>
> Thanks.

Hi there,

I've hit this before. This is because you are using Rack::URLMap (via  
Builder#map).
The inner app is called with a new env hash.

> diff --git a/lib/rack/urlmap.rb b/lib/rack/urlmap.rb
> index b699d35..3374535 100644
> --- a/lib/rack/urlmap.rb
> +++ b/lib/rack/urlmap.rb
> @@ -45,7 +45,7 @@ module Rack
>          next unless rest.empty? || rest[0] == ?/
>
>          return app.call(
> -          env.merge(
> +          env.merge!(
>              'SCRIPT_NAME' => (script_name + location),
>              'PATH_INFO'   => rest))
>        }

Is this patch useful?
Is it useful to assume that a request will only have a single env hash?
Will it make Rack::Cascade and friends behave incorrectly?

Should URLMap revert the change in an ensure to allow subsequent  
requests to function?

Hope this explains the behaviour,
Tim