Mongomapper: copy a document into a new document

I have a mongomapper document with embedded documents, and want to make a copy of it.

In essence, what I am trying to do is something like this:

customer = Customer.find(params[:id])
new_custome开发者_StackOverflowr = Customer.new
new_customer = customer
new_customer.save

So I want to end up with two different mongomapper documents, but with identical content.

Any ideas how this should be done?

To accomplish this, you need to change the _id. Documents with the same _id are assumed to be the same document so saving a document with a different _id will create a new document.

customer = Customer.find(params[:id])
customer._id = BSON::ObjectId.new # Change _id to make a new record
  # NOTE: customer will now persist as a new document like the new_document 
  # described in the question.
customer.save # Save the new object

As an aside, I would be inclined to store the old _id somewhere in the new record so I could keep track of who derived from who, but it is not necessary.

You should simply be able to do this:

duplicate_doc = doc.clone
duplicate_doc.save

I don't think it is possible (or valid) to create copies of an existing document in mongodb/mongomapper because it seems to me that there would be a clash of the document/embedded documents and their ids of the original and copied documents.

So I solved my problem by copied the contents of the documents into new documents, rather than the documents themselves. Here is a sample:

inspection = Inspection.find(params[:inspection_id])  #old document
new_inspection = Inspection.create                    #new target document
items = inspection.items                              #get the embedded documents from inspection

items.each do |item|                                  #iterate through embedded documents
    new_item = Item.create                            #create a new embedded document in which
                                                      #  to copy the contents of the old embedded document
    new_item.area_comment = item.area_comment         #Copy contents of old doc into new doc
    new_item.area_name = item.area_name
    new_item.area_status = item.area_status
    new_item.clean = item.clean
    new_item.save                                     #Save new document, it now has the data of the original
    new_inspection.items << new_item                  #Embed the new document into its parent
  end

 new_inspection.save                                  #Save the new document, its data are a copy of the data in the original document

This actually worked very well in my scenario. But I am curious if people have a different solution.