Python source code: Raspberry Pi streaming radio player -- improved pipe handling

Streamer.py

from evdev import InputDevice,ecodes,KeyEvent
import subprocess32 as subp
import select
import re
import sys
import time
import logging

Media = {'KEY_KP7' : ['Classical',False,['mplayer','--quiet','-playlist','http://stream2137.init7.net/listen.pls']],
         'KEY_KP8' : ['Jazz',False,['mplayer','--quiet','-playlist','http://stream2138.init7.net/listen.pls']],
         'KEY_KP9' : ['WMHT',False,['mplayer','--quiet','http://live.str3am.com:2070/wmht1']],
         'KEY_KP4' : ['Classic 1000',True,['mplayer','--quiet','-playlist','http://listen.radionomy.com/1000classicalhits.m3u']],
         'KEY_KP5' : ['DCNY 911',False,['mplayer','--quiet','-playlist','http://www.broadcastify.com/scripts/playlists/1/12305/-5857889408.m3u']],
         'KEY_KP6' : ['WAMC',False,['mplayer','--quiet','http://pubint.ic.llnwd.net/stream/pubint_wamc']],
         'KEY_KP1' : ['60s',True,['mplayer','--quiet','-playlist','http://listen.radionomy.com/all60sallthetime-keepfreemusiccom.m3u']],
         'KEY_KP2' : ['50-70s',True,['mplayer','--quiet','-playlist','http://listen.radionomy.com/golden-50-70s-hits.m3u']],
         'KEY_KP3' : ['Soft Rock',True,['mplayer','--quiet','-playlist','http://listen.radionomy.com/softrockradio.m3u']],
         'KEY_KP0' : ['Zen',True,['mplayer','--quiet','-playlist','http://listen.radionomy.com/zen-for-you.m3u']]
}

CurrentKC = 'KEY_KP3'

Controls = {'KEY_KPSLASH' : '//////',
            'KEY_KPASTERISK' : '******',
            'KEY_KPENTER' : ' ',
            'KEY_KPMINUS' : '<',
            'KEY_KPPLUS' : '>',
            'KEY_VOLUMEUP' : '*',
            'KEY_VOLUMEDOWN' : '/'
}

MuteStrings = ["TargetSpot","[Unknown]","Advert:","+++","---","SRR","Srr","ZEN FOR"]

MuteDelay = 8.0         # delay before non-music track; varies with buffering
UnMuteDelay = 7.5       # delay after non-music track
Muted = False           # keep track of muted state

MixerChannel = 'PCM'     # which amixer thing to use

logging.basicConfig(format='%(asctime)s %(levelname)s:%(message)s',filename='/tmp/Streamer.log',level=logging.INFO)
logger = logging.getLogger()

# set up event inputs and polling objects
# This requires some udev magic to create the symlinks

k = InputDevice('/dev/input/keypad')
k.grab()

kp = select.poll()
kp.register(k.fileno(),select.POLLIN + select.POLLPRI + select.POLLERR)

v = InputDevice('/dev/input/volume')
v.grab()

vp = select.poll()
vp.register(v.fileno(),select.POLLIN + select.POLLPRI + select.POLLERR)

# set up file for output tracing

lw = open('/tmp/mp.log','w')    # mplayer piped output

# set the mixer output low enough that the initial stream won't wake the dead

subp.call(['amixer','sset',MixerChannel,'10'])

# Start the player with the default stream, set up for polling

print 'Starting mplayer on',Media[CurrentKC][0],' -> ',Media[CurrentKC][-1][-1]
logging.info('Starting mplayer on %s -> %s',Media[CurrentKC][0],Media[CurrentKC][-1][-1])
p = subp.Popen(Media[CurrentKC][-1],
                     stdin=subp.PIPE,stdout=subp.PIPE,stderr=subp.STDOUT)

pp = select.poll()            # this may be valid for other invocations, but is not pretty
pp.register(p.stdout.fileno(),select.POLLIN + select.POLLPRI + select.POLLERR)

print ' ... running'

#--------------------
#--- Play the streams

while True:

# pluck next line from mplayer and decode it

  if [] != pp.poll(10):
    text = p.stdout.readline()
    
    if 'ICY Info: ' in text:        # these lines may contain track names
      lw.write(text)
      lw.flush()

      trkinfo = text.split(';')     # also splits at semicolon embedded in track name
#      logging.info('Raw split line: %s', trkinfo)
      for ln in trkinfo:
        if 'StreamTitle' in ln:     # this part contains a track name
          NeedMute = False          # assume a listenable track
          if 2 == ln.count("'"):    # exactly two single quotes = probably none embedded in track name
            trkhit = re.search(r"StreamTitle='(.*)'",ln)
            if trkhit:                # true for valid search results
              TrackName = trkhit.group(1)   # the string between the two quotes
              print 'Track name: ', TrackName
              logging.info('Track name: [%s]', TrackName)
              if Media[CurrentKC][1] and ( (len(TrackName) == 0) or any(m in TrackName for m in MuteStrings) ) :
                  NeedMute = True
            else:
              print ' ... semicolon in track name: ', ln
              logging.info('Semicolon in track name: [' + ln + ']')
          else:
            print ' ... quotes in track name: ', ln
            logging.info('Quotes in track name: [' + ln + ']')
          if NeedMute:
            print ' ... muting:',
            if Media[CurrentKC][1] and not Muted:
              time.sleep(MuteDelay)           # brute-force assumption about buffer leadtime
            subp.call(['amixer','-q','sset',MixerChannel,'mute'])
            Muted = True
            print 'done'
            logging.info('Track muted')
          else:
            print ' ... unmuting:',
            if Muted:
              if Media[CurrentKC][1]:
                time.sleep(UnMuteDelay)         # another brute-force timing assumption
              Muted = False
            subp.call(['amixer','-q','sset',MixerChannel,'unmute'])
            print 'done'
            logging.info('Track unmuted')

    elif 'Exiting.' in text:                # mplayer just imploded
      lw.write(text)
      lw.flush()
      print 'Got EOF / stream cutoff'
      logging.info('EOF or stream cutoff')
      print ' ... killing dead mplayer'
      pp.unregister(p.stdout.fileno())
      p.terminate()     #    p.kill()
      p.wait()
  #    print ' ... flushing pipes'
  #    lw.truncate(0)
      print ' ... discarding keys'
      while [] != kp.poll(0):
        kev = k.read
      print ' ... restarting mplayer: ',Media[CurrentKC][0]
      logging.info('Restarting mplayer')
      p = subp.Popen(Media[CurrentKC][-1],
                          stdin=subp.PIPE,stdout=subp.PIPE,stderr=subp.STDOUT)
      pp.register(p.stdout.fileno(),select.POLLIN + select.POLLPRI + select.POLLERR)
      print ' ... running'
      logging.info(' ... running')

  
# accept pending events from volume control knob

  if [] != vp.poll(10):
    vev = v.read()
    lw.write('Volume')
    lw.flush()
    for e in vev:
      if e.type == ecodes.EV_KEY:
        kc = KeyEvent(e).keycode

#        print 'Volume kc: ',kc

        if kc in Controls:
          print 'Vol Control: ',kc
          try:
            p.stdin.write(Controls[kc])
          except Exception as e:
            print "Can't send control: ",e
            print ' ... restarting player: ',Media[CurrentKC][0]
            logging.info('Error sending volume, restarting player')
            pp.unregister(p.stdout.fileno())
            p = subp.Popen(Media[CurrentKC][-1],
                                 stdin=subp.PIPE,stdout=subp.PIPE,stderr=subp.STDOUT)
            pp.register(p.stdout.fileno(),select.POLLIN + select.POLLPRI + select.POLLERR)
            print ' ... running'
            logging.info(' ... running')


# accept pending events from keypad

  if [] != kp.poll(10):
    kev = k.read()
    lw.write("Keypad")
    lw.flush()
    for e in kev:
      if e.type == ecodes.EV_KEY:
        kc = KeyEvent(e).keycode

        if kc == 'KEY_NUMLOCK':                           # discard these, as we don't care
          continue

#        print 'Got: ',kc

        if (kc == 'KEY_BACKSPACE') and (KeyEvent(e).keystate == KeyEvent.key_hold):
          if True:
            print 'Backspace = shutdown!'
            p.kill()
            logging.shutdown()
            q = subp.call(['sudo','shutdown','-P','now'])
            q.wait()
            time.sleep(5)
            print "Oddly, we did not die..."
          else:
            print 'BS = bail from main!'
            logging.shutdown()
            sys.exit(0)
          break

        if KeyEvent(e).keystate != KeyEvent.key_down:     # discard key up & other rubbish
          continue

        if kc in Controls:
          print 'Control:', kc
          try:
            p.stdin.write(Controls[kc])
          except Exception as e:
            print "Can't send control: ",e
            print ' ... restarting player: ',Media[CurrentKC][0]
            logging.info('Error sending controls, restarting player')
            pp.unregister(p.stdout.fileno())
            p.terminate()     #    p.kill()
            p.wait()
            p = subp.Popen(Media[CurrentKC][-1],
                                 stdin=subp.PIPE,stdout=subp.PIPE,stderr=subp.STDOUT)
            pp.register(p.stdout.fileno(),select.POLLIN + select.POLLPRI + select.POLLERR)
            print ' ... running'
            logging.info(' ... running')

        if kc in Media:
          print 'Switching stream to ',Media[kc][0],' -> ',Media[kc][-1][-1]
          logging.info('Switching stream: ' + Media[kc][0] + ' -> ' + Media[kc][-1][-1])
          CurrentKC = kc
          print ' ... halting player'
          try:
            p.communicate(input='q')
          except Exception as e:
            print 'Perhaps mplayer died?',e
            print ' ... killing it for sure'
            pp.unregister(p.stdout.fileno())
            p.terminate()     #    p.kill()
            p.wait()
#          print ' ... flushing pipes'
#          lw.truncate(0)
          print ' ... restarting player: ',Media[CurrentKC][0]
          p = subp.Popen(Media[CurrentKC][-1],
                               stdin=subp.PIPE,stdout=subp.PIPE,stderr=subp.STDOUT)
          pp.register(p.stdout.fileno(),select.POLLIN + select.POLLPRI + select.POLLERR)
          print ' ... running' 
          logging.info(' ... running')

print 'Out of loop!'
logging.shutdown()

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