rails Import csv file, but saving blank - ruby-on-rails

Question

My github address https://github.com/ParkHyunDo/ImportCsv
I am studying how to import an excel file using roo. The import works fine, but everything is blank.
Like this....
Here is my code
product.rb
class Product < ActiveRecord::Base
acts_as_xlsx
def self.import(file)
spreadsheet = open_spreadsheet(file)
header = spreadsheet.row(1)
(2..spreadsheet.last_row).each do |i|
row = Hash[[header, spreadsheet.row(i)].transpose]
product = find_by_id(row["id"]) || new
product.attributes = row.to_hash.slice(accepts_nested_attributes_for)
product.save!
end
end
def self.open_spreadsheet(file)
case File.extname(file.original_filename)
# You're using a tab seperated file, so specify seperator as a tab with \t
when ".csv" then Roo::CSV.new(file.path, csv_options: {col_sep: "\t"})
when ".xls" then Roo::Excel.new(file.path)
when ".xlsx" then Roo::Excelx.new(file.path)
else raise "Unknown file type: #{file.original_filename}"
end
end
end
products_controller.rb
def import
Product.import(params[:file])
redirect_to root_url, notice: "Products imported."
end
Please help me!

Answer 1

This line seems strange:
product.attributes = row.to_hash.slice(accepts_nested_attributes_for)
The class method accepts_nested_attributes_for has a completely different purpose than listing the attribute names of Product. But you could use attribute_names. Try this:
product.attributes = row.to_hash.stringify_keys.slice(*attribute_names)
Note that stringify_keys might be unnecessary, depending on how exactly the hash returned by row.to_hash looks. Also note that slice takes a list of attribute names, not an array. The asterisk * allows us to use the elements of an array as individual arguments to a function.