Rails使用多态模型创建多态网址

Question

I have the basic setup:

class Document < ActiveRecord::Base
  belongs_to :documentable, polymorphic: true
end

class Contact < ActiveRecord::Base
  has_many :documents, as: :documentable
end

class Case < ActiveRecord::Base
  has_many :documents, as: :documentable
end

Now in _index.html.erb of my documents view, I want to do the following:

<%= link_to "New Document", polymorphic_path([:new, @documentable, Document.new]) %>

where @documentable will either be an instance of Contact or Case.

I expect the above to generate a url like new_contact_document_path, but instead it just tries to produce a url like new_documents_path.

What might I be doing wrong?

Answer 1

Try

<%= link_to "New Document", new_polymorphic_path([@documentable, Document]) %>

Note two differences here from your posted code:

1. Use the "prefixed" polymorphic_path helper instead of embedding the new action inside the passed array
2. Use Document instead of Document.new , which seems to be the preferred approach

See the ActionDispatch docs for more details.