CSV file encoding in Rails with S3 and Heroku - ruby-on-rails

Question

My rails app uploads CSV files to S3, then subsequently pulls them down into a tempfile to send each row's data to a Sidekiq worker. I'm using Carrierwave and fog to handle the uploading.
This all worked beautifully until recently switching to Heroku, and now, when trying to create my tempfile I get the following error:
Error type Encoding::UndefinedConversionError
Error message "\xA2" from ASCII-8BIT to UTF-8
I've tried setting the encoding when creating the tempfile as well as working with the CSV file and continue to get the same error. I cannot reproduce this error on my local machine, which has made this entire process that much more fun :)
Currently, my Sidekiq worker calls the following method:
def upload_csv(filename, file_path)
file = Tempfile.new(filename, Rails.root.join('tmp'), encoding: "ISO8859-1:utf-8").tap do |f|
open(file_path).rewind
f.write(open(file_path).read)
f.close
end
CSV.foreach(file, headers: true, encoding: "ISO8859-1:utf-8")do |row|
#do stuff to rows
end
end
I understand the very basics of encoding, but I'm super stuck on this. Any insight would be appreciated.
Thanks!

Answer 1

Not sure if this will help anyone else, but I found a solution that works for me:
def upload_csv(filename, file_path)
file = Tempfile.new(filename, Rails.root.join('tmp')).tap do |f|
open(file_path).rewind
f.write(open(file_path).read.force_encoding('utf-8'))
f.close
end
CSV.foreach(file, headers: true)do |row|
#do stuff to rows
end
end
Even though I could confirm that the file was UTF-8 encoded before it was uploaded, open(#file_path).read.encoding returning an ASCII-8BIT encoding. It was getting confused on how to write the file and convert it from ASCII-8BIT to UTF-8.