Class: ActiveRecord::Associations::CollectionProxy
- Inherits:
-
Object
- Object
- ActiveRecord::Associations::CollectionProxy
- Defined in:
- lib/active_record/associations/collection_proxy.rb
Overview
Association proxies in Active Record are middlemen between the object that holds the association, known as the @owner
, and the actual associated object, known as the @target
. The kind of association any proxy is about is available in @reflection
. That’s an instance of the class ActiveRecord::Reflection::AssociationReflection.
For example, given
class Blog < ActiveRecord::Base
has_many :posts
end
blog = Blog.first
the association proxy in blog.posts
has the object in blog
as @owner
, the collection of its posts as @target
, and the @reflection
object represents a :has_many
macro.
This class has most of the basic instance methods removed, and delegates unknown methods to @target
via method_missing
. As a corner case, it even removes the class
method and that’s why you get
blog.posts.class # => Array
though the object behind blog.posts
is not an Array, but an ActiveRecord::Associations::HasManyAssociation.
The @target
object is not loaded until needed. For example,
blog.posts.count
is computed directly through SQL and does not trigger by itself the instantiation of the actual post records.
Instance Method Summary collapse
- #<<(*records) ⇒ Object (also: #push)
-
#===(other) ⇒ Object
Forwards
===
explicitly to the target because the instance method removal above doesn’t catch it. - #clear ⇒ Object
-
#initialize(association) ⇒ CollectionProxy
constructor
A new instance of CollectionProxy.
- #method_missing(method, *args, &block) ⇒ Object
- #proxy_association ⇒ Object
- #reload ⇒ Object
- #respond_to?(name, include_private = false) ⇒ Boolean
- #scoped ⇒ Object
- #to_ary ⇒ Object (also: #to_a)
Constructor Details
#initialize(association) ⇒ CollectionProxy
Returns a new instance of CollectionProxy.
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# File 'lib/active_record/associations/collection_proxy.rb', line 53 def initialize(association) @association = association Array.wrap(association.[:extend]).each { |ext| proxy_extend(ext) } end |
Dynamic Method Handling
This class handles dynamic methods through the method_missing method
#method_missing(method, *args, &block) ⇒ Object
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# File 'lib/active_record/associations/collection_proxy.rb', line 77 def method_missing(method, *args, &block) match = DynamicFinderMatch.match(method) if match && match.instantiator? send(:find_or_instantiator_by_attributes, match, match.attribute_names, *args) do |record| proxy_association.send :set_owner_attributes, record proxy_association.send :add_to_target, record yield(record) if block_given? end.tap do |record| proxy_association.send :set_inverse_instance, record end elsif target.respond_to?(method) || (!proxy_association.klass.respond_to?(method) && Class.respond_to?(method)) if load_target if target.respond_to?(method) target.send(method, *args, &block) else begin super rescue NoMethodError => e raise e, e..sub(/ for #<.*$/, " via proxy for #{target}") end end end else scoped.readonly(nil).send(method, *args, &block) end end |
Instance Method Details
#<<(*records) ⇒ Object Also known as: push
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# File 'lib/active_record/associations/collection_proxy.rb', line 117 def <<(*records) proxy_association.concat(records) && self end |
#===(other) ⇒ Object
Forwards ===
explicitly to the target because the instance method removal above doesn’t catch it. Loads the target if needed.
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# File 'lib/active_record/associations/collection_proxy.rb', line 108 def ===(other) other === load_target end |
#clear ⇒ Object
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# File 'lib/active_record/associations/collection_proxy.rb', line 122 def clear delete_all self end |
#proxy_association ⇒ Object
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# File 'lib/active_record/associations/collection_proxy.rb', line 60 def proxy_association @association end |
#reload ⇒ Object
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# File 'lib/active_record/associations/collection_proxy.rb', line 127 def reload proxy_association.reload self end |
#respond_to?(name, include_private = false) ⇒ Boolean
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# File 'lib/active_record/associations/collection_proxy.rb', line 71 def respond_to?(name, include_private = false) super || (load_target && target.respond_to?(name, include_private)) || proxy_association.klass.respond_to?(name, include_private) end |
#scoped ⇒ Object
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# File 'lib/active_record/associations/collection_proxy.rb', line 64 def scoped association = @association association.scoped.extending do define_method(:proxy_association) { association } end end |
#to_ary ⇒ Object Also known as: to_a
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# File 'lib/active_record/associations/collection_proxy.rb', line 112 def to_ary load_target.dup end |