我读到ruby中的模块(在本例中是ActiveSupport::Concern)在初始化的类的所有实例之间共享。因此,如果这是真的,这意味着任何实例变量都将在内存中的所有实例之间共享。
module SetPassword
extend ActiveSupport::Concern
attr_reader :password
def password=(new_password)
@password = new_password
self.crypted_password = password_digest(new_password, salt)
end
end
class User
include SetPassword
end
u = User.new; u.password = 'abcdef'
u2 = User.new; u2.password = '123456'
上面的代码使用起来安全吗?或者第二个用户会覆盖第一个用户?
发布于 2019-02-27 13:32:13
Module#include
正在暗中调用Module#append_features
。这意味着,没有任何东西是共享的,这可能很容易检查(ActiveSupport::Concern
与您要检查的代码无关)。
module SetPassword
attr_reader :password
def password=(new_password)
@password = new_password
puts <<~EOS
Setting password to: #{@password} (id: #{@password.__id__}).
Object: #{self.class.name} (#{self.__id__}).
Method: #{__callee__} on #{self.method(__callee__).__id__}.
EOS
end
end
class User
include SetPassword
end
u1 = User.new; u1.password = 'abcdef'
u2 = User.new; u2.password = '123456'
▶ u1 = User.new; u1.password = 'abcdef'
#⇒ Setting password to: abcdef (id: 46968741459360).
# Object: User (46968741459420).
# Method: password= on 46968741459040.
▶ u2 = User.new; u2.password = '123456'
#⇒ Setting password to: 123456 (id: 46968734231740).
# Object: User (46968734232020).
# Method: password= on 46968734230640.
https://stackoverflow.com/questions/54897865
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