Ruby Forum Ruby on Rails > Recycled objects

Hi,

I am developing a Rails app where I need to pass an object around
between views. I am doing this by sending each view the object_id, and
then doing

@theObject = ObjectSpace._id2ref(params[:objid])

There are two problems with this: One, it's not very elegant. Is there a
better
way? Two, I get an intermittent error, "RangeError : 0xfooba4 is
recycled object". I *suspect* this happens because my object is getting
garbage collected
between views. Since it is an instance member of my controller object
(I've also
experimented with making it a class member), I feel this ought not to
happen,
but there it is. Can anyone suggest a better method for persisting my
object
so all my views have access to it, and it doesn't get garbage collected?

Thanks,

Rolf Andreassen.

Use :locals when you render your views. like:

<%= render :partial => 'foo', :locals => {:bar => some_var} %>

Now in your partial, that variable is available as the local variable 
bar.

-Bill

Rolf Andreassen wrote:
> way? Two, I get an intermittent error, "RangeError : 0xfooba4 is
> Thanks,
>
> Rolf Andreassen.
>   

--
Sincerely,

William Pratt

On 12 Nov 2007, at 21:36, Rolf Andreassen wrote:

>
> Hi,
>
> I am developing a Rails app where I need to pass an object around
> between views. I am doing this by sending each view the object_id, and
> then doing
>
> @theObject = ObjectSpace._id2ref(params[:objid])
>

This is a really bad idea (and of course were you ever to have more
than one mongrel then the 2 requests could be server by completely
separate processes, which means that it would be completely impossible
for this to ever work).

> happen,
> but there it is.
A given instance of controller only lasts for one request. I suspect
you're running in dev mode, so classes are also reloaded after each
request.

> Can anyone suggest a better method for persisting my
> object
> so all my views have access to it, and it doesn't get garbage  
> collected?
>
Serialize it and store the data in the db, memcached or even the
session.

Fred

Hmm, ok, I took him to mean views as, well, views. If you indeed mean
between page requests, then yes, store them in the session or another
persistent area. However, if you really do mean between separate views
in during the same request, then :locals is what you want.

-Bill

Frederick Cheung wrote:
>>
>> better
> A given instance of controller only lasts for one request. I suspect  
> Serialize it and store the data in the db, memcached or even the  
>> Posted via http://www.ruby-forum.com/.
>>
>>     
>
>
> >
>   

--
Sincerely,

William Pratt

> A given instance of controller only lasts for one request. I suspect
> you're running in dev mode, so classes are also reloaded after each
> request.

I see. That explains it, yes.

> Serialize it and store the data in the db, memcached or even the
> session.

You really advise me to read from the database at every request? Seems a 
little inefficient. I can't use the session, since the object (a game 
state) includes some information that shouldn't be available to all 
users. Can you expand on memcaching?

Thanks for your replies so far. :)

Rolf Andreassen

Most web apps do database reads on every request. If it is semi-static
you can always use page or view caching if it turns out to be a
bottleneck. For a web server the load must be very high (wrt request/
second) before the db becomes the bottleneck, especially for a Rails
app.

Regarding sessions they (to me) seem to be what you want to use. There
is not a problem with different users. The point of a session is that
the web server creates a specific session for each user. So if you
write session[:user_name] = params[:name] in a controller it will
store different values for different web users. If the objects are
large they should not be stored in the sessions, there are multiple
articles around on this but I don't have any references handy.

If you need further tips, please specify more precisely what you want
to store between requests.

Regards

Erik Lindblad


On 13 Nov, 00:27, Rolf Andreassen <rails-mailing-l...@andreas-s.net>