upload testing.rb

def upload(filename, file_location)
  bucket = AWS::S3::Bucket.new(ENV["AWS_BUCKET_NAME"])
  key = "uploads/#{SecureRandom.uuid}/#{filename}"
  content_type = MIME::Types.type_for(filename).first.to_s
  presigned_post = bucket.presigned_post(key: key, content_type: content_type)
  url = presigned_post.url.to_s
  fields = presigned_post.fields
  `curl -i -v -X POST -F "AWSAccessKeyId=#{fields['AWSAccessKeyId']}" -F "key=#{fields['key']}" -F "policy=#{fields['policy']}" -F "signature=#{fields['signature']}" -F "Content-Type=#{content_type}" -F "file=@#{file_location + filename}" '#{url}'`
end

This version works!

def upl(filename, file_location)
  bucket = AWS::S3::Bucket.new(ENV["AWS_BUCKET_NAME"])
  key = "uploads/#{SecureRandom.uuid}/#{filename}"
  content_type = MIME::Types.type_for(filename).first.to_s
  presigned_post = bucket.presigned_post(key: key, content_type: content_type)
  url = presigned_post.url.to_s
  fields = presigned_post.fields
  `curl -i -v -X POST -F "AWSAccessKeyId=#{fields['AWSAccessKeyId']}" -F "key=#{fields['key']}" -F "policy=#{fields['policy']}" -F "signature=#{fields['signature']}" -F "Content-Type=#{content_type}" -F "file=@#{file_location + filename}" '#{url}'`
end