convert-serialization/bin/convert-serialization

#!/usr/bin/env ruby
# frozen_string_literal: true
# sharable_constant_value: literal

begin
  require 'optparse'

  input_format = nil
  output_format = nil
  input_file = nil
  output_file = nil
  OptionParser.new do |opts|
    opts.banner = 'Usage: convert-serialization [options] input_file output_file'

    opts.on('-s', '--inf INPUT_FORMAT', 'Specifies the input format (msgpack / json / yaml / toml).') do |format|
      input_format = format
    end

    opts.on('-d', '--outf OUTPUT_FORMAT', 'Specifies the output format (msgpack / json / yaml / toml).') do |format|
      output_format = format
    end

    opts.on('-i', '--in INPUT_FILE', 'Specifies the input file.') do |file|
      input_file = file
    end

    opts.on('-o', '--out OUTPUT_FILE', 'Specifies the output file.') do |file|
      output_file = file
    end
  end.parse!

  raise ArgumentError, 'Input format missing.' unless input_format
  raise ArgumentError, 'Output format missing.' unless output_format
  raise ArgumentError, 'Input file is missing.' unless input_file
  raise ArgumentError, 'Output file is missing.' unless output_file

  input_format.strip!
  input_format.downcase!
  output_format.strip!
  output_format.downcase!
  input_file.strip!
  input_file.downcase!
  output_file.strip!
  output_file.downcase!

  in_handler = case input_format
               when 'msgpack'
                 lambda do |filename|
                   require 'msgpack'
                   file = File.new filename, 'rb'
                   result = MessagePack.unpack file
                   file.close

                   result
                 end
               when 'json'
                 lambda do |filename|
                   require 'psych'
                   Psych.load_file filename
                 end
               when 'yaml'
                 lambda do |filename|
                   require 'psych'
                   Psych.load_file filename
                 end
               when 'toml'
                 lambda do |filename|
                   require 'toml-rb'
                   TomlRB.load_file filename
                 end
               else
                 raise ArgumentError, 'Unknown input format.'
               end

  out_handler = case output_format
                when 'msgpack'
                  lambda do |object, filename|
                    require 'msgpack'

                    file = File.new filename, 'wb'
                    MessagePack.pack object, file
                    file.close
                  end
                when 'json'
                  lambda do |object, filename|
                    require 'json'

                    file = File.new filename, 'w'
                    JSON.dump object, file
                    file.close
                  end
                when 'yaml'
                  lambda do |object, filename|
                    require 'psych'

                    file = File.new filename, 'w'
                    Psych.dump object, file
                    file.close
                  end
                when 'toml'
                  lambda do |object, filename|
                    raise 'The primary toml block must consist of key-value pairs.' unless object.is_a? Hash

                    require 'toml-rb'
                    file = File.new filename, 'w'
                    file.write TomlRB.dump(object)
                    file.close
                  end
                else
                  raise ArgumentError, 'Unknown output format.'
                end

  input_object = in_handler.call(input_file)
  out_handler.call(input_object, output_file)

  warn 'Conversion successful!'
rescue StandardError => e
  warn 'Conversion failed!'
  warn "Error: #{e.message}"
end