Is there a way to combine named scopes into a new named scope?
Solution 1
Well I'm still new to rails and I'm not sure exactly what you're going for here, but if you're just going for code reuse why not use a regular class method?
def self.ab(a, b)
a(a).b(b)
end
You could make that more flexible by taking *args instead of a and b, and then possibly make one or the other optional. If you're stuck on named_scope, can't you extend it to do much the same thing?
Let me know if I'm totally off base with what you're wanting to do.
Solution 2
At least since 3.2 there is a clever solution :
scope :optional, ->() {where(option: true)}
scope :accepted, ->() {where(accepted: true)}
scope :optional_and_accepted, ->() { self.optional.merge(self.accepted) }
Solution 3
Yes Reusing named_scope to define another named_scope
I copy it here for your convenience:
You can use proxy_options to recycle one named_scope into another:
class Thing
#...
named_scope :billable_by, lambda{|user| {:conditions => {:billable_id => user.id } } }
named_scope :billable_by_tom, lambda{ self.billable_by(User.find_by_name('Tom').id).proxy_options }
#...
end
This way it can be chained with other named_scopes.
I use this in my code and it works perfectly.
I hope it helps.
James A. Rosen
Updated on June 27, 2022Comments
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James A. Rosen almost 2 years
I have
class Foo < ActiveRecord::Base named_scope :a, lambda { |a| :conditions => { :a => a } } named_scope :b, lambda { |b| :conditions => { :b => b } } end
I'd like
class Foo < ActiveRecord::Base named_scope :ab, lambda { |a,b| :conditions => { :a => a, :b => b } } end
but I'd prefer to do it in a DRY fashion. I can get the same effect by using
Foo.a(something).b(something_else)
but it's not particularly lovely.
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aceofspades over 13 yearsCaveat is that proxy_options only returns the scope of the latest named scope, so this cannot be done against another derived named scope
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KARASZI István about 13 yearsWith this solution it won't behave the scope as a normal scope does. For e.g. it won't be in
Model.scopes
.