Class instance creating with class name in variable Ruby

Question

I need to do something like that

class Foo
 define perform()
  puts 'hello'
 end
end

classname = 'Foo'

instance = create_instance(classname)
instance.perform();

Is something like that possible. If is the how?

Thanks a lot!

rjz · Accepted Answer · 2012-05-12 23:27:29Z

7

You could use const_get:

instance = Object.const_get(classname).new
instance.perform

answered May 12, 2012 at 23:27

rjz

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Comments

Grant Hutchins · Accepted Answer · 2012-05-12 23:29:26Z

4

klass = Object.const_get(classname)
instance = klass.new

But you might want to whitelist classname first if it's coming from user input. Otherwise you're potentially opening a security hole.

answered May 12, 2012 at 23:29

Grant Hutchins

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x1a4 · Accepted Answer · 2012-05-12 23:27:17Z

3

Yes, it's possible-

class Foo
  def perform
    puts 'hello'
  end
end

f = 'Foo'

klass = Object.const_get f

f.new.perform

answered May 12, 2012 at 23:27

x1a4

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