[ruby] how to recursively process a zip file containing zip files in memory

recursive_zip_example.rb

#!/usr/bin/env ruby
# Note this doesn't deal with directories in zip files.
# That's documented elsewhere. The recursive processing of
# zip files in zip files was the tricky bit.

require 'zip'

def recursive_zip_reader(input)
  if input.is_a? String
    zip_file = Zip::File.open(input)
    recursive_zip_file_reader(zip_file)
  elsif input.is_a? Zip::File
    recursive_zip_file_reader(input)
  elsif input.is_a? Zip::Entry
    recursive_zip_entry_reader(input)
  elsif input.is_a? File
    recursive_zip_file_reader(Zip::File.open(input.path))
  else
    "unknown input type (#{input.class}): #{input}"
  end
end

def recursive_zip_file_reader(zip_file)
  file_names = []
  zip_file.entries.each do | zip_entry |
    # nobody wants macOS's bs finder metadata files
    next if zip_entry.name.start_with?("__MACOSX")
    file_names << recursive_zip_entry_reader(zip_entry)
  end
  file_names
end

def recursive_zip_entry_reader(zip_entry)
  name = zip_entry.name
  return name unless name.end_with?(".zip")

  entry_contents = zip_entry.get_input_stream.read
  nested_entry = Zip::File.open_buffer(entry_contents)
  {name => recursive_zip_reader(nested_entry)}
end


puts recursive_zip_reader("multizip.zip").inspect

# output should look like this 
# [
#   {
#     "subzip.zip": [
#       "pass.json",
#       "manifest.json",
#       "signature"
#     ]
#   }
# ]