Question

There is one http://localhost:3000/me/posts/new?type=note

I want to create a model by the params typein my controller and I have a model named Post::Note.

so how to create it by params[:type] string ?

Answer 1

Try this:

note_klass = params[:type].camelize.constantize
note = note_klass.new

RE: question edit

If your Note class is not global, you can use this:

const_name = params[:type].camelize
note_klass = Post.const_get(const_name)