Ruby中如何获取PUT请求返回的URL值？遇URL为null问题

我需要获取PUT请求返回的URL值，但当前PUT请求返回结果为：

{"result":{"attempts":1,"url":null}}

无法定位问题所在。

操作流程 #

• 先向/challenges发送POST请求启动挑战
• 在响应的actives_at字段指定的时间，向/challenges发送PUT请求，请求头携带X-Challenge-Id（挑战ID）

实现代码 #

loop do
  response = HTTParty.put("#{API_ENDPOINT}/challenges", headers: { 'X-Challenge-Id' => challenge_id })
  puts "Response: #{response}"

  if response['error']
    puts "Error: #{response['error']}"
  elsif response.key?('result')
    result = response['result']
    attempts = result['attempts']
    url = result['url']
    if attempts.zero?
      puts "Challenge failed. Attempts: #{attempts}"
    elsif url.nil?
      puts "Challenge succeeded but no URL available. Attempts: #{attempts}"
    else
      puts "Challenge succeeded. Attempts: #{attempts}"
      puts "URL with keyword: #{API_ENDPOINT}#{url}"
    end

    break
  end
end

当前程序输出“Challenge succeeded but no URL available. Attempts: 1”，始终无法获取有效的URL值。

内容的提问来源于stack exchange，提问作者Wanyu Jiang