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9918 :: Save audio stream to the file from httpstream

• demetera (orginal) [2023-02-20T21:30:17+01:00] view original

  Dear All,

  experimenting with http streams (write audio stream to the file) and can't figure out, what it wrong happening here:

  import std/[httpclient, streams]
  
  const radioURL = "http://radio-station.com/mp3.com"
  
  var buf : array[512, char]
  
  proc downloadStream() =
    var client = newHttpClient()
    let res = client.get(radioURL).bodyStream
    defer : res.close()
    let f = newFileStream("radiostr.mp3", fmWrite)
    defer : f.close()
    while true:
      discard res.readData(addr(buf), 512)
      f.writeData(buf.addr, 512)
      res.flush()
  
  downloadStream()
  
  Run

  Strategy is pretty simple here:

  • Open normal mp3 Http stream
  • Open File stream
  • Start endless loop to read data to buffer and write buffer to the file
  • Flush the buffer.

  I ended up with getting huge empty mp3 file. Even if I read few chars to array - array is empty.

  Thank you

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• sky_khan (orginal) [2023-02-20T22:18:21+01:00] view original

  I've just selected that radioURL and opened in new tab. It gives 404 error. So its not a surprise that bodyStream has no data.

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• demetera (orginal) [2023-02-20T22:21:55+01:00] view original

  I'm really sorry. I forgot to mention, it's fake URL - just for demonstration

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• sky_khan (orginal) [2023-02-20T22:32:49+01:00] view original

  Ok then, just an advice. Never ignore error codes or swallow exceptions (at least make that discard an echo) unless you have a really good reason. Probably you're getting some other error without knowing it

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• demetera (orginal) [2023-02-21T13:30:51+01:00] view original

  Thanks for your feedback, meanwhile this code is just a probing version, while I'm using lldb debugger. I was mostly interested in the correctness of the method I apply here.

  The stream I want to fetch is : http://live.advailo.com/audio/mp3/icecast.audio And I'm getting zeros in buffer.

  Another stream is : http://uk2.internet-radio.com:8171/stream It's freezing on retrieving bodyStream (apparently because port isn't 80)

  let res = client.get(radioURL).bodyStream
  Run

  Unfortunately, I don't know (yet) how to catch possible exceptions for the streams.

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• sky_khan (orginal) [2023-02-22T00:59:18+01:00] view original

  Well, I dont really know Nim well. Actually I havent used it at all for the last few years. I just visit the forum sometimes to follow the news.

  Anyway, this time I've tried to download from those URLs with wget. It says

   request sent, awaiting response... 200 OK
   Length: unspecified [audio/mpeg]
  Run

  I suspect that your example doesnt work because content-length is not determined for live audio. I mean, probably this use case is not supported by Nim's stdlib but as I said, I dont know Nim well, so I'm not really sure if thats the case or how to fix it, sorry

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• demetera (orginal) [2023-02-23T20:50:21+01:00] view original

  Managed to solve the problem using net sockets. Raw code (Control+C interrupts recording and closes stream and socket) without catching exceptions and async:

  import std/[net,streams,strutils]
  
  const Url = "uk2.internet-radio.com"
  const Port = Port(8171)
  const BufSize = 1024
  let sock = newSocket()
  var meta : seq[string]
  var data : string
  let fs = newFileStream("radio.mp3", fmWrite)
  
  sock.connect(Url, Port)
  
  let req = "GET /stream HTTP/1.0\r\nHost:uk2.internet-radio.com\r\n\r\n"
  sock.send(req)
  
  proc controlC() {.noconv.} =
    fs.close()
    sock.close()
    echo "Stopping recording. Exiting"
    quit(0)
  
  setControlCHook(controlC)
  
  while true:
    while true: # Collecting metadata
      data = sock.recvLine().strip()
      if data.len > 0:
        meta.add(data)
      else:
        echo "Metadata: ",meta
        break
    echo "Starting recording"
    while true: # Main loop to fetch the stream chunks
      discard sock.recv(data, BufSize)
      fs.write(data)
  Run

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