having a default condition in model

rubyonrails-talk
1

Is there a way to specify at the model level that you want all calls to find(), find_by_xxxx(), etc, to include a certain :conditions clause?

for instance, if normally you wanted to only select articles where "is_published = 1" (which you could of course override in admin mode or something)

because with this flag, when you are selecting articles from different views and/or controllers, it requires them to have knowledge of the underlying articles model and even the DB table. Doesn't seem very DRY.

And in fact we wanted to add another default flag, "is_active = 0" (because deleted articles are really just flagged, not deleted). So now having to go through the whole app....

thanks Sam

2

Find with scope, then alias' the find methods. There is an example of
this in acts_as_versioned by Rick Olson

Zach Inglis → Blog — http://www.zachinglis.com → Company — http://www.lt3media.com → Portfolio — http://portfolio.zachinglis.com

3

Sam,

You're asking two different questions actually :

   > Is there a way to specify at the model level that you want all calls to    > find(), find_by_xxxx(), etc, to include a certain :conditions clause?

The plugin ScopedAccess   http://agilewebdevelopment.com/plugins/scoped_access does just that. You may look at the code to see how it works.

   > for instance, if normally you wanted to only select articles    > where "is_published = 1"

That's a different case, and much easier to satisfy thanks to Rails associations.

Ex:   class User << AR       has_many :articles       has_many :published_articles , :conditions => "is_published = 1" ,                    :class_name => 'Article', :foreign_key => 'article_id'   end

Alain Ravet

4

Thanks for the quick response!

Sam,

You're asking two different questions actually :

   > Is there a way to specify at the model level that you want all

calls to

   > find(), find_by_xxxx(), etc, to include a certain :conditions

clause?

The plugin ScopedAccess   http://agilewebdevelopment.com/plugins/scoped_access does just that. You may look at the code to see how it works.

ok that looks cool - but according to a comment at the bottom of that page "This has been incorporated into Rails" - is that true? The homepage for it gives a 404 and there seems to be some red flags about it in other posts... hmm. Another scary plugin? http://www.mail-archive.com/rubyonrails-core@googlegroups.com/msg01489.html

[another topic: Is there anything in Rails equivalent to CPAN or PEAR where you can reasonably be sure the code is stable and high-quality? I've already gone down the road with a few plugins that were broken or deprecated or at least early beta]

   > for instance, if normally you wanted to only select articles    > where "is_published = 1"

That's a different case, and much easier to satisfy thanks to Rails associations.

Ex:   class User << AR       has_many :articles       has_many :published_articles , :conditions => "is_published

= 1" ,

                   :class_name => 'Article', :foreign_key

=> 'article_id'

  end

ok I was aware of this option but how would I over-ride it if the current user was an admin for instance? Do I have to create a separate association for every combination of flags then, and call different methods based on the role of the current_user? (say I have is_published, is_deleted, is_public_domain - that's 9 potential associations, yux)

Thanks Sam