nimforum mirror - Streaming HTTP request with timeout?

perturbation2 (orginal) [2018-10-01T05:00:40+02:00] view original

I'm streaming audio (Internet radio) from an HTTP(S) endpoint, and wanting to capture 30 seconds of it (it's streaming in real time, and will continue sending data for as long as the connection is open).

import httpclient
import asyncdispatch
from portaudio as p import nil

const
  URL = "http://icecast.maxxwave.co.uk/lcr_aac"
  TIMEOUT_SECONDS = 30
  USER_AGENT = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36"
  OUTPUT_AAC = "output.aac"

proc check(err: p.TError|p.TErrorCode) =
  if cast[p.TErrorCode](err) != p.NoError:
    raise newException(Exception, $p.GetErrorText(err))


proc requestAACWithTimeout(client: AsyncHttpClient, url: string, timeout: int = TIMEOUT_SECONDS) {.async.} =
  let resp = await client.get(url)
  
  let outFile = open(OUTPUT_AAC, fmWrite)
  defer:
    outFile.close()
    client.close()
  
  let timeout = sleepAsync(timeout * 1_000)
  
  while not timeout.finished():
    let (hasData, bodyChunk) = await resp.bodyStream.read()
    
    if hasData:
      outFile.write(bodyChunk)
  
  resp.bodyStream.complete()
  
  # Any lingering data
  let bodyChunk = await resp.bodyStream.readAll()
  
  if bodyChunk.len > 0:
    outFile.write(bodyChunk)


proc main() =
  check p.Initialize()
  
  defer:
    check p.Terminate()
  
  let client = newAsyncHttpClient(userAgent = USER_AGENT)
  
  try:
    waitFor client.requestAACWithTimeout(URL)
  except Exception as e:
    echo "Error getting request"
    raise e
  
  echo "Ran successfully"
  
  # TODO: Convert from AAC to WAV

when isMainModule:
  main()

The above works, but is a little awkward - I'm reading from the AsyncResponse stream until a timeout future completes, and then writing any remaining elements to the file. I'm wondering if there's a better of doing this. (It would also be nice if I could write the end of the AAC stream cleanly (mplayer and ffmpeg complain about 'missing end element'), but that's not essential for my purposes - I just want to sample a small snippet of audio regularly).

In reading the HTTP Client timeouts section, the timeout seems to be for connection and so:

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4260 :: Streaming HTTP request with timeout?