Unknown Attribute error when uploading a CSV file - ruby-on-rails

Question

Here is what my CSV file that I am trying to upload looks like:
1,Order,”{‘customer_name’:’Jack’,’customer_address’:’Trade St.’,’status’:’unpaid’}”
2,Order,”{‘customer_name’:’Sam’,’customer_address’:’Gecko St.’,’status’:’unpaid’}”
1,Product,”{‘name’:’Laptop’,’price’:2100,’stock_levels’:29}"
1,Order,”{‘status’:’paid’,’ship_date’:’2017-01-18’,’shipping_provider’:’DHL’}”
2,Product,”{‘name’:’Microphones’,’price’:160,’stock_levels’:1500}"
1,Invoice,”{‘order_id’:7,’product_ids’:[1,5,3],’status’:’unpaid’,’total’:2500}"
1,Invoice,”{‘status’:’paid’}”
But I'm getting this error: ActiveModel::UnknownAttributeError in CustomersController#import
And these errors in my console:
app/models/customer.rb:4:in `block in import'
app/models/customer.rb:3:in `import'
app/controllers/customers_controller.rb:65:in `import'
Here is my customer.rb model:
class Customer < ApplicationRecord
def self.import(file)
CSV.foreach(file.path, headers: true) do |row|
Customer.create! row.to_hash
end
end
end
To be perfectly honest, part of the problem I'm having here stems from not totally understanding what row.to_hash is doing here. If this function does not iterate through a row, then we want to convert it to a hash. I feel like it may be causing other problems here that I may not be aware of though.
Here is the import function I have as well:
def import
Customer.import(params[:file])
redirect_to customer_path, notice: "Customer Added Successfully"
end

Answer 1

The error, ActiveModel::UnknownAttributeError happens when you pass an attribute that the model doesn't have to new or create, for instance:
User.create(not_a_real_attribute: 'some value')
# => ActiveModel::UnknownAttributeError: unknown attribute 'not_a_real_attribute' for User.
The reason you are getting this is because you are using a header-less CSV as if it had headers. In ruby, if a CSV has headers, it can convert the row to a hash using the header of a column as a key and the column of the current row as a value. So, by telling the CSV library you have headers (via headers: true in the foreach), it treats the first row as a header row and you end up with weird results:
enum = CSV.foreach("./customers.csv", headers: true)
enum.first.to_hash
# => {"1"=>"2", "Order"=>"Order", "”{‘customer_name’:’Jack’"=>"”{‘customer_name’:’Sam’", "’customer_address’:’Trade St.’"=>"’customer_address’:’Gecko St.’", "’status’:’unpaid’}”"=>"’status’:’unpaid’}”"}
Then you are passing that hash to Customer.create!.If you don't expect headers, you need to treat each row as an array:
enum = CSV.foreach("./customers.csv")
enum.first
# => ["1", "Order", "”{‘customer_name’:’Jack’", "’customer_address’:’Trade St.’", "’status’:’unpaid’}”"]
Or, if you want to use a hash, you can insert a better first row, corresponding to the attributes of your model:
"Maybe an ID?","Some kind of Class?","Customer Data?"
1,Order,”{‘customer_name’:’Jack’,’customer_address’:’Trade St.’,’status’:’unpaid’}”
# ... the rest of your file ...
enum = CSV.foreach("./customers.csv", headers: true)
enum.first.to_hash
# => {"Maybe an ID?"=>"1", "Some kind of Class?"=>"Order", "Customer Data?"=>"”{‘customer_name’:’Jack’", nil=>"’status’:’unpaid’}”"}
You'll also notice throughout these examples, those special quotes in your file weren't being handled properly, the results you get if you change those to normal quotes are:
# => {"Maybe an ID?"=>"1", "Some kind of Class?"=>"Order", "Customer Data?"=>"{'customer_name':'Jack','customer_address':'Trade St.','status':'unpaid'}"}
Also, if that last column is the customer data you want to create with, you'll need to pull that column out and parse it into a ruby hash on your own. Looks like maybe YAML?:
YAML.load enum.first.to_hash['Customer Data?']
# => {"customer_name"=>"Jack", "customer_address"=>"Trade St.", "status"=>"unpaid"}