Is AR find(:all) a 100% named_scope?

Rails
1

hi there,
I have a method in a model that concatenates named_scopes at later
points in
the method if certain conditions given. The concatenations go ok when
all
that concatenation is done with named_scopes, but it blows when
ActiveRecord.all is used in it

see it in the gist: is_find_all_a_named_scope?.rb · GitHub

I could of course write that in some other way, but the question would
be:
could AR.all be turned into a NamedScope and not an Array?

any ideas? in the mean time I will refactor my code and make my specs
happy
:slight_smile:

cheers,
joaquin

2 
gs = if privates
            self.privates # with named_scopes everything runs fine
          else
            self.all # here we won't get a NamedScope, instead it'll
be an Array
          end

Try:

   gs = if privates
          self.privates
        else
          self
        end

在 2009/11/9 下午 7:35 時， Joaquin Rivera P. 寫到：

any ideas? in the mean time I will refactor my code and make my
specs happy :slight_smile:

cheers,
joaquin

HeChian H.
[email protected]

3

On 09 Nov 2009, at 12:35, Joaquin Rivera P. wrote:

any ideas? in the mean time I will refactor my code and make my
specs happy :slight_smile:

Well, the implementation of AR.all is not a named_scope as you
obviously found out:

   # This is an alias for find(:all).  You can pass in all the

same arguments to this method as you can
# to find(:all)
def all(*args)
find(:all, *args)
end

A quick google search revealed this blog post:
http://www.neeraj.name/blog/articles/871-fixing-activerecord-base-all-and-making-it-friendlier-to-named_scope

It outlines both the problem and provides a solution. I do agree that
since AR is clearly pushing chained scopes as a way to build queries,
a named scope implementation would be better. But named scopes have
quite a bit of work ahead, since arguments don’t get overridden if a
subsequent scope defines them differently etc. Example: if you
make :active => true the default scope and then make a named_scope
of :inactive, defined as :active => false, you’ll get a contradictory
query.

On the other hand, Rails is open source and well thought out and
tested contributions do make it into the core, so it’s only a matter
of someone stepping up to get it sorted. Other ORM options have
already tackled these problems more elegantly afaik, like Datamapper
and Arel.

Best regards

Peter De Berdt

4

hi all,
thanks for you reply,

2009/11/9 Peter De Berdt [email protected]

I could of course write that in some other way, but the question would be:
arguments to this method as you can
# to find(:all)
def all(*args)
find(:all, *args)
end

A quick google search revealed this blog post:
http://www.neeraj.name/blog/articles/871-fixing-activerecord-base-all-and-making-it-friendlier-to-named_scope

Peter yep, nice post, only for the moment I don’t feel like patching
AR::Base, and I get lots of warnings when running my specs:

/home/joahking/dev/rails/tucamon/app/models/group.rb:44: warning:
multiple
values for a block parameter (0 for 1)
from
/home/joahking/dev/rails/tucamon/vendor/rails/activerecord/lib/active_record/named_scope.rb:92

line 44: named_scope :all, lambda { |args| args ||= {} }

I’ll go with HeChian H. idea, it ended like this:
gs = if PrivacyLevels.include? privacy
self.send privacy
else
self # AR itself
end

if name
  gs.named_like name
else
  gs.all # and all again
end

I know it’s not a very general solution, but it keeps all them specs
green
:slight_smile:

I have to move on given my deadlines, but if I stumble again I’ll give a
second thought

thanks for your responses,
joaquin

It outlines both the problem and provides a solution. I do agree that
since

problems more elegantly afaik, like Datamapper and Arel.

Best regards

Peter De Berdt

–

5

On Nov 9, 11:35 am, Joaquin Rivera P. [email protected] wrote:

ActiveRecord.all is used in it

see it in the gist:is_find_all_a_named_scope?.rb · GitHub

I could of course write that in some other way, but the question would be:
could AR.all be turned into a NamedScope and not an Array?

It could be interesting to do this. For now instead of doing self.all
you could try self.all.scoped({})

Fred