Rails clone copy or duplicate

Question

I have a nested form and once I save, I want to be able to click a link on the show page to copy or clone that form and open a new one. From there I should be able to make edits (like a new id) and save as a new record. I have seen some examples like this deep_cloneable gem, but I have no idea how to implement it. I think this should be simple, but I just don't understand where to put things in the controller and in the show view.

Answer 1

I found these answers a little hard to follow. One answer shows this:

@post = Post.new(@existing_post.attributes)

which will not work as it will also pass the id, and timestamp values. I used .dup to fix that and I show that in my answer.

Here's how I achieved creating a new item from an existing item.

The model is for a Product, the controller Products_Controller.rb. We're going to add a new action to the controller called copy and we're going to link to it from the show view on an existing Product and render a filled out new view ready to be edited and saved.

First we create a route for the copy action in routes.rb

# Routes.rb
resources :Products do
  member do
    get 'copy'
  end
end

Then a copy action in Products_controller.rb

 # ProductController.rb
 def copy
   @source = Product.find(params[:id])
   @product = @source.dup
   render 'new'
 end

Now we need to add a Link to the show view to call our copy action.

# show.html.erb
<%= link_to "copy", copy_product_path(params[:id]) %>

Rails 4-6 Update:

The strong parameter scaffold makes it even shorter:

# ProductController.rb
# GET /products/1/copy
def copy
  @product = @product.dup
  render :new
end

And in the erb template:

# show.html.erb
<%= link_to "copy", copy_product_path(@product) %>