Question

I’m trying to work with applescript for retrieving BPM values of songs. Eventually I’d like to implement it with a game. Here’s my code:

import os
import time
import sys


def getBPM():
    iTunesInstruct = """'
    tell application "iTunes"
    set k to get bpm of current track
    end tell
    return k
    '"""
    bpm = os.system('arch -i386 osascript -e ' + iTunesInstruct )
    #bpm =90

    bpm = int(bpm)
    bpm = round(bpm)

    if bpm > 250:
        bpm = 200
    return bpm


def getBeatSecond(bpm):
    bps = float(bpm) / 60
    #raw_input(bps)
    return float(bps)

i = 0

beatMatch = True

while True:
    beat = 1 / getBeatSecond(getBPM()) # BPS Beat divided by a second.

    if beatMatch:
        time.sleep(beat)
        print beat
    else:
        raw_input('Go??')
    i += 1
    if i > 50:
        break

But this seems to only work once… it got the BPM of the song I was listening to, saw it was 94, and then it seems on the second iteration it thought it was 0, and then it divided by 0 and died. What’s going on?

Answer 1

os.system doesn’t wait for the command completes.

90 = is the result of osascript , 0 = no error, is the exit status (os.system).

Use subprocess.Popen

from subprocess import Popen, PIPE

def getBPM():
    cmd = "arch -i386 osascript -e " + """'tell application "iTunes" to return bpm of current track'"""
    bpm, tError = Popen(cmd, shell=True, stdin=PIPE, stdout=PIPE, stderr=PIPE).communicate()
    if bpm > 250:
        return = 200
    return int(bpm)