class method
self.method_missing
Ruby on Rails 2.3.18
Since v2.2.3 Last seen in v3.1.12 PrivateSignature
self.method_missing(method_id, *arguments, &block)
Enables dynamic finders like find_by_user_name(user_name) and find_by_user_name_and_password(user_name, password) that are turned into find(:first, :conditions => ["user_name = ?", user_name]) and find(:first, :conditions => ["user_name = ? AND password = ?", user_name, password]) respectively. Also works for find(:all) by using find_all_by_amount(50) that is turned into find(:all, :conditions => ["amount = ?", 50]).
It’s even possible to use all the additional parameters to find. For example, the full interface for find_all_by_amount is actually find_all_by_amount(amount, options).
Also enables dynamic scopes like scoped_by_user_name(user_name) and scoped_by_user_name_and_password(user_name, password) that are turned into scoped(:conditions => [“user_name = ?”, user_name]) and scoped(:conditions => [“user_name = ? AND password = ?”, user_name, password]) respectively.
Each dynamic finder, scope or initializer/creator is also defined in the class after it is first invoked, so that future attempts to use it do not run through method_missing.
Parameters
-
method_idreq -
argumentsrest -
blockblock
Source
# File activerecord/lib/active_record/base.rb, line 1873
def method_missing(method_id, *arguments, &block)
if match = DynamicFinderMatch.match(method_id)
attribute_names = match.attribute_names
super unless all_attributes_exists?(attribute_names)
if match.finder?
finder = match.finder
bang = match.bang?
# def self.find_by_login_and_activated(*args)
# options = args.extract_options!
# attributes = construct_attributes_from_arguments(
# [:login,:activated],
# args
# )
# finder_options = { :conditions => attributes }
# validate_find_options(options)
# set_readonly_option!(options)
#
# if options[:conditions]
# with_scope(:find => finder_options) do
# find(:first, options)
# end
# else
# find(:first, options.merge(finder_options))
# end
# end
self.class_eval <<-EOS, __FILE__, __LINE__ + 1
def self.#{method_id}(*args)
options = if args.length > #{attribute_names.size}
args.extract_options!
else
{}
end
attributes = construct_attributes_from_arguments(
[:#{attribute_names.join(',:')}],
args
)
finder_options = { :conditions => attributes }
validate_find_options(options)
set_readonly_option!(options)
#{'result = ' if bang}if options[:conditions]
with_scope(:find => finder_options) do
find(:#{finder}, options)
end
else
find(:#{finder}, options.merge(finder_options))
end
#{'result || raise(RecordNotFound, "Couldn\'t find #{name} with #{attributes.to_a.collect {|pair| "#{pair.first} = #{pair.second}"}.join(\', \')}")' if bang}
end
EOS
send(method_id, *arguments)
elsif match.instantiator?
instantiator = match.instantiator
# def self.find_or_create_by_user_id(*args)
# guard_protected_attributes = false
#
# if args[0].is_a?(Hash)
# guard_protected_attributes = true
# attributes = args[0].with_indifferent_access
# find_attributes = attributes.slice(*[:user_id])
# else
# find_attributes = attributes = construct_attributes_from_arguments([:user_id], args)
# end
#
# options = { :conditions => find_attributes }
# set_readonly_option!(options)
#
# record = find(:first, options)
#
# if record.nil?
# record = self.new { |r| r.send(:attributes=, attributes, guard_protected_attributes) }
# yield(record) if block_given?
# record.save
# record
# else
# record
# end
# end
self.class_eval <<-EOS, __FILE__, __LINE__ + 1
def self.#{method_id}(*args)
attributes = [:#{attribute_names.join(',:')}]
protected_attributes_for_create, unprotected_attributes_for_create = {}, {}
args.each_with_index do |arg, i|
if arg.is_a?(Hash)
protected_attributes_for_create = args[i].with_indifferent_access
else
unprotected_attributes_for_create[attributes[i]] = args[i]
end
end
find_attributes = (protected_attributes_for_create.merge(unprotected_attributes_for_create)).slice(*attributes)
options = { :conditions => find_attributes }
set_readonly_option!(options)
record = find(:first, options)
if record.nil?
record = self.new do |r|
r.send(:attributes=, protected_attributes_for_create, true) unless protected_attributes_for_create.empty?
r.send(:attributes=, unprotected_attributes_for_create, false) unless unprotected_attributes_for_create.empty?
end
#{'yield(record) if block_given?'}
#{'record.save' if instantiator == :create}
record
else
record
end
end
EOS
send(method_id, *arguments, &block)
end
elsif match = DynamicScopeMatch.match(method_id)
attribute_names = match.attribute_names
super unless all_attributes_exists?(attribute_names)
if match.scope?
self.class_eval <<-EOS, __FILE__, __LINE__ + 1
def self.#{method_id}(*args) # def self.scoped_by_user_name_and_password(*args)
options = args.extract_options! # options = args.extract_options!
attributes = construct_attributes_from_arguments( # attributes = construct_attributes_from_arguments(
[:#{attribute_names.join(',:')}], args # [:user_name, :password], args
) # )
#
scoped(:conditions => attributes) # scoped(:conditions => attributes)
end # end
EOS
send(method_id, *arguments)
end
else
super
end
end
Defined in activerecord/lib/active_record/base.rb line 1873
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Defined in ActiveRecord::Base