Question

I’m starting to use Paper Trail gem, I have this Product model:

• name:string qty:integer color:string

and inside my product.rb I have this:

• has_paper_trail

So everything works fine, I mave 2 updates to a single product only modifying the qty.
In my rails console I did the following:

Product.last.versions.map(&:object)

And got this

[“—\nname: p1\nqty: 20\ncolor: c1\ncreated_at: 2012-03-14 03:02:22.186453000 Z\nupdated_at: 2012-03-14 03:02:22.186453000 Z\nid: 3\n”, “—\nname: p1\nqty: 40\ncolor: c1\ncreated_at: 2012-03-14 03:02:22.186453000 Z\nupdated_at: 2012-03-14 03:07:53.291624000 Z\nid: 3\n”]

and when I do this:

puts Product.last.versions.map(&:object)

I got this:

---
name: p1
qty: 20
color: c1
created_at: 2012-03-14 03:02:22.186453000 Z
updated_at: 2012-03-14 03:02:22.186453000 Z
id: 3
---
name: p1
qty: 40
color: c1
created_at: 2012-03-14 03:02:22.186453000 Z
updated_at: 2012-03-14 03:07:53.291624000 Z
id: 3

I was wondering how to obtain the qty of each change. I though of regex but I’m not sure how.

I want to show this in my view

• Product:

  • Name: c1 Qty: 980

  • Changes:

  • (date1) : 20 | (date2) : 40 | …….. | (dateN) : N

Any suggestions?

thanks in advance

Answer 1

Its serialized into YAML. There is one way to do it. I’m using the object as product_versions you got from the versions map.

product_versions.map{ |product_version| YAML::load(product_version)}.map{|item| [item["updated_at"],item["qty"]]}

This will give you

[[2012-03-14 03:02:22 UTC, 20], [2012-03-14 03:07:53 UTC, 40]]