Sinatra + Mongoid update embedded document

Question

I'm having issues updating both a document and its embedded document on one go with Sinatra 1.4.4 and Mongoid 3.1.5. As it stands, the embedded document is not modified, but just takes the nested attributes and adds them to the parent level.

Assumptions:

Given a form such as:

<form action="/persons/edit/52cad9f0d2a57d2ded000070 method="post">
  <input name="name" value="Some Guy" />
  <input name="address[street]" value="Evergreen Street" />
  <button type="submit">Save</button>
</form>

A model like:

class Person
  include Mongoid::Document
  include Addressable
  accepts_nested_attributes_for :address

  field :name, type: String
end

class Addressable
  extend ActiveSupport::Concern
  included do
    embeds_one :address, class_name: 'Address', cascade_callbacks: true
  end
end

class Address
  include Mongoid::Document

  field :street, type: String

  before_save :strip_whitespace

  def remove_whitespace
    attributes.each do |attr_name, value|
      next unless value.is_a? String
      send("#{attr_name}=", value.strip.gsub(/\s(\s+)/, ' '))
    end
  end
end

A document such as:

{
  name: "Default Name",
  address: {
    _id: ObjectId("52fc501f266d9841d000007c"),
    street: "Default Street"
  },
}

And finally, a route like so:

post '/persons/edit/:id' do |id|
  p = Persons.find(id)
  p.update_attributes params
end

Results

I expect the document to end up as:

{
  name: "Some Guy", //this is okay
  address: {
    _id: ObjectId("52fc501f266d9841d000007c"),
    street: "Evergreen Street"
  }
}

But instead end up with:

{
  name: "Some Guy", //this is okay
  address: {
    _id: ObjectId("52fc501f266d9841d000007c"),
    street: "Default Street" //not changed
  },
  street: "Evergreen Street" //WTF?
}

I know I'm doing something wrong, but for the life of me, I can't see what. I find weird that if I change the name attribute on my forms from using brackets to dots, such as address.street, the update works, but Sinatra doesn't recognize the parameter as a Hash, but rather just a key within the whole params.

Any ideas on how to fix this? Am I missing something?

Thanks for helping me out!

Answer 1

I guess, the problem that you didn't specify embedded_in relation in Address document. I suggest you use common practice for polymorphic behavior - http://mongoid.org/en/mongoid/docs/relations.html#common (Polymorphism)