Give a custom file name to each file being zipped - ruby-on-rails

Question

I am downloading multiple files from S3 and zipping them. How do I give a custom name to each file being zipped?
def download_all_files
folder_path = "#{Rails.root}/public/downloads/"
zipfile_name = "#{Rails.root}/public/archive.zip"
FileUtils.remove_dir(folder_path) if Dir.exist?(folder_path)
FileUtils.remove_entry(zipfile_name) if File.exist?(zipfile_name)
Dir.mkdir("#{Rails.root}/public/downloads")
#model_object.each do |attachment|
open(folder_path + "#{attachment.avatar.file.filename}", 'wb') do |file|
file << open("#{attachment.avatar.url}").read
end
end
input_filenames = Dir.entries(folder_path).select {|f| !File.directory? f}
Zip::File.open(zipfile_name, Zip::File::CREATE) do |zipfile|
input_filenames.each do |attachment|
zipfile.add(attachment,File.join(folder_path,attachment))
end
end
send_file(File.join("#{Rails.root}/public/", 'archive.zip'), :type => 'application/zip', :filename => "#{Time.now.to_date}.zip")
end

Answer 1

Looks like you have 2 ways you can accomplish this. To the end user, both of these should yield the same result, just depends how you want them on your server.
1. Change it while zipping the files together
This will leave the files as they are currently named on your system and only change them in the output archive.zip
Looking at this gem it looks like
Zip::File.open(zipfile_name, Zip::File::CREATE) do |zipfile|
input_filenames.each do |filename|
# Two arguments:
# - The name of the file as it will appear in the archive
# - The original file, including the path to find it
zipfile.add(filename, folder + '/' + filename)
end
zipfile.get_output_stream("myFile") { |os| os.write "myFile contains just this" }
end
So, in your code just change the first occurrence of 'attachment' on
zipfile.add(attachment, File.join(folder_path, attachment))
to whatever you want the name to be.
2. Change it while writing the file to your server
Since you are writing the file just a few lines above there
open(folder_path + "#{attachment.avatar.file.filename}", 'wb') do |file|
you could change the file name on this line as well. This would change the filename on your server and in the archive.zip