Array of nested attributes given as a hash parameter

Question

I get an xml file which I have to parse. From it I take data for 2 models. Product and Attachment. An attachment is an image for product. This is how the code goes, I will follow it by an explanation:

def add_to_db_from_file
    transaction do
        save!
        xml = Nokogiri::XML(File.open(self.file.current_path))
        xml.xpath("//item").each do |item|
            product_hash = %w[campaign_name widget_name title description short_message price category
                                                    subcategory url product_id aff_code].each_with_object({}) do |n, h|
                                                        h[n.intern] = n != 'price' ? item.at(n).text : item.at(n).text.to_i
                                            end
            attachments_array = item.css('image_urls').map do |url| 
                                                        url.text.split(' ')
                                                    end.flatten
            @product = self.products.create!(product_hash)
            attachments_array.each do |p|
                @product.attachments.create!(remote_picture_url: p)
            end
        end
    end
end

I open an xml file and I parse it creating a hash with the proucts params(product_hash). At the same time a product can have one or more Attachments given by the tag image_urls . I parse after that tag for each product and make an array with the urls of the images a product has. I create the product and for each image I create an attachment.

However I want to create the attachments with the help of nested attributes so I added this in my product model:

accepts_nested_attributes_for :attachments

And this in my permited params in product controller(along the other attributes):

params.require(:product).permit( attachments_attributes: [:id, :product_id, :picture, :remote_picture_url])

I have tried making a hash out of attachments_array and merging it with the product_hash thus it should create the attachments along with the product using the nested attributes:

attachments_array = item.css('image_urls').map do |url| 
                     {remote_picture_url: url.text.split(' ') }
                   end.flatten
@product = self.products.create!(product_hash.merge!({attachments_attributes: attachments_array}))

However this clearly is not a solution as I get:

NoMethodError: undefined method `gsub' for #<Array:0x007f3b6d832138>

My question is how can I send an array of nested attributes along with the main object to be created?

bigsolom · Accepted Answer · 2015-09-18 11:24:11Z

1

You can build product attachments then save the product

product = Product.new(product_hash)
attachements_array.each do |url|
  product.attachements.build(remote_picture_url: url)
end
product.save

If you want to include all your items in a hash, then your product hash will be

product_hash = {product_attr1: product_attr1_val, product_attr2: product_attr2_val, attachementes_attributes: [{attach_attr1: attach_attr1_val}, {attach_attr1: attach_attr1_val}] }
Product.create(product_hash)

More on that: http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html

answered Sep 18, 2015 at 11:24

bigsolom

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1 Comment

Lucian Tarna Over a year ago

So I wasn't wrong, and I managed to figure out once you stated that my attachments_array had an array as an attribute in the hash. I will let this question here since it could be useful . Even more so when you gave a clear answer to what you should send.

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