download.rb

require 'open-uri'
require 'json'

uid = ARGV[0]

puts "downloading #{uid}"

response = JSON.parse(URI.open("https://api.mujrozhlas.cz/serials/#{uid}/episodes").read)

response["data"].each do |episode|
  attributes =  episode["attributes"]
  serial = attributes["mirroredSerial"]
  total_parts = serial["totalParts"].to_s
  part = attributes["part"].to_s.rjust(total_parts.length, "0")

  name = "#{part}-#{total_parts} - #{attributes["title"]}.mp3"
  link = attributes["audioLinks"].first["url"]

  puts "downloading #{link} to #{name}"

  audio = URI.open(link)
  file = File.open(name, 'wb')
  IO.copy_stream(audio, file)
end

use.txt

$ ruby download.rb d51df021-bceb-36e0-a65c-38ec64b3f8a5                                                                                                                         
downloading d51df021-bceb-36e0-a65c-38ec64b3f8a5                                                                                                                                              
downloading https://croaod.cz/download/aaaaedff-e642-4752-942e-5c0c9c140687.mp3 to 01-14 - O Křesomyslu a Horymírovi.mp3                                                                       
downloading https://croaod.cz/download/5c2dcc4e-6331-4126-b24a-3f1028421cef.mp3 to 02-14 - Faustův dům.mp3                                                                                     
downloading https://croaod.cz/download/b20df09c-cb4e-4ddf-9471-fa09d7dab113.mp3 to 03-14 - O Bruncvíkovi.mp3                                                                                   
downloading https://croaod.cz/download/655438f9-5913-4bb9-9f46-817d0e0a827a.mp3 to 04-14 - O králi Ječmínkovi.mp3                                                                              
downloading https://croaod.cz/download/2c899b71-7f1f-4b6a-bb03-90586a2c242b.mp3 to 05-14 - Dívčí válka.mp3                                                                                     
downloading https://croaod.cz/download/f91b7c29-9adc-47d1-adfe-a0e6dbcf9511.mp3 to 06-14 - Blaničtí rytíři.mp3                                                                                 
downloading https://croaod.cz/download/66c69eb4-e4de-4e1e-835f-52f9a00ce2e7.mp3 to 07-14 - Ze starobylých proroctví.mp3                                                                        
downloading https://croaod.cz/download/75445f89-4525-46e8-b7b5-874ff0248bb9.mp3 to 08-14 - O Daliborovi z Kozojed.mp3                                                                          
downloading https://croaod.cz/download/f1c0efa4-2e92-4c09-9f55-5b3e1e87850f.mp3 to 09-14 - O králi Václavovi.mp3                                                                               
downloading https://croaod.cz/download/30afea5d-b893-4d98-9e34-41d198473f7c.mp3 to 10-14 - O staré Praze.mp3                                                                                   
downloading https://croaod.cz/download/8668d850-f1aa-42ad-adf3-9734d27dd03c.mp3 to 11-14 - Žito kouzelník.mp3                                                                                  
downloading https://croaod.cz/download/b6b473e2-1c04-4ce0-8545-0a6bf5b93fb2.mp3 to 12-14 - Staroměstský orloj.mp3                                                                              
downloading https://croaod.cz/download/fedd178c-1c70-4291-af12-a8455e1e4fd5.mp3 to 13-14 - Smutná místa.mp3                                                                                    
downloading https://croaod.cz/download/0cfb1825-830f-4724-96f2-d3a62aebe2ab.mp3 to 14-14 - Ze židovského města.mp3