https://github.com/mwlang/binance/blob/master/spec/support/vcr.cr

response_body_output.txt

response # => #<HTTP::Client::Response:0x10fcb6b40
 @body=nil,
 @body_io=
  #<HTTP::FixedLengthContent:0x10fcb23f0
   @closed=false,
   @continue_sent=false,
   @decoder=nil,
   @encoder=nil,
   @encoding=IO::EncodingOptions(@invalid=:skip, @name="UTF-8"),
   @expects_continue=false,
   @io=
    #<OpenSSL::SSL::Socket::Client:0x10fcd8f00
     @bio=
      OpenSSL::BIO(
       @bio=Pointer(LibCrypto::Bio)@0x7fba07704bf0,
       @boxed_io=Pointer(Void)@0x10fcb1c00,
       @io=#<TCPSocket:fd -1>),
     @buffer_size=8192,
     @closed=true,
     @decoder=nil,
     @encoder=nil,
     @encoding=nil,
     @flush_on_newline=false,
     @in_buffer=Pointer(UInt8)@0x10fcdc000,
     @in_buffer_rem=
      Bytes[123,
       34,
       115,
       101,
       114,
       118,
       101,
       114,
       84,
       105,
       109,
       101,
       34,
       58,
       49,
       54,
       48,
       55,
       54,
       48,
       55,
       49,
       51,
       49,
       48,
       48,
       48,
       125],
     @out_buffer=Pointer(UInt8)@0x10fcd9000,
     @out_count=0,
     @read_buffering=true,
     @ssl=Pointer(Void)@0x7fba0980a200,
     @sync=false,
     @sync_close=true>,
   @read_remaining=28,
   @sync_close=false>,
 @cookies=nil,
 @headers=
  HTTP::Headers{"Access-Control-Allow-Methods" => "GET, HEAD, OPTIONS",
   "Access-Control-Allow-Origin" => "*",
   "Cache-Control" => "no-cache, no-store, must-revalidate",
   "Connection" => "close",
   "Content-Length" => "28",
   "Content-Security-Policy" => "default-src 'self'",
   "Content-Type" => "application/json;charset=UTF-8",
   "Date" => "Thu, 10 Dec 2020 13:32:11 GMT",
   "Expires" => "0",
   "Pragma" => "no-cache",
   "Server" => "nginx",
   "Strict-Transport-Security" => "max-age=31536000; includeSubdomains",
   "Via" => "1.1 ea6d44855948fa16c9e8fb87911af869.cloudfront.net (CloudFront)",
   "X-Amz-Cf-Id" => "3o7ihnh6gRJBVCygCsIZwEIpodbe_YehS6Z53IvblXnoQXyaHXJdxw==",
   "X-Amz-Cf-Pop" => "ATL56-C4",
   "X-Cache" => "Miss from cloudfront",
   "X-Content-Security-Policy" => "default-src 'self'",
   "X-Content-Type-Options" => "nosniff",
   "X-Frame-Options" => "SAMEORIGIN",
   "X-WebKit-CSP" => "default-src 'self'",
   "X-Xss-Protection" => "1; mode=block",
   "x-mbx-used-weight" => "1",
   "x-mbx-used-weight-1m" => "1",
   "x-mbx-uuid" => "3985d2ac-acad-496d-962a-ccb1b9d968e0"},
 @status=OK,
 @status_message="OK",
 @version="HTTP/1.1">
********************************************************************************
(response.as(HTTP::Client::Response)).body # => ""
********************************************************************************

vcr.rb

def record_cassette(service, name : String)
  WebMock.callbacks.add do
    after_live_request do |request, response|
      uri = "#{request.scheme}://#{request.headers["Host"]}#{request.resource.split("?")[0]}"
      data = {
        request: {
          method:       request.method,
          uri:          uri,
          body:         request.body.to_s,
          query_params: request.query_params.to_s,
          headers:      request.headers,
          timestamp:    Time.utc.to_unix_ms,
        },
        response: {
          status: response.status_code,
          body:   response.body,
        },
      }
      pp! response
      puts "*" * 80
      pp! response.as(HTTP::Client::Response).body
      puts "*" * 80
      File.open(cassette_filepath(service, name), "w") { |f| YAML.dump(data, f) }
    end
  end
  WebMock.allow_net_connect = true
end