use tempfile for audio decoding

wechat/audio.py

@@ -2,6 +2,7 @@
 # -*- coding: UTF-8 -*-
 
 import os
+import tempfile
 import logging
 logger = logging.getLogger(__name__)
 
@@ -10,9 +11,6 @@ from .common.procutil import subproc_succ
 
 SILK_DECODER = os.path.join(os.path.dirname(__file__),
                             '../third-party/silk/decoder')
-if not os.path.exists(SILK_DECODER):
-    logger.error("Silk decoder is not compiled. Please see README.md.")
-    raise RuntimeError()
 
 def parse_wechat_audio_file(file_name):
     try:
@@ -25,7 +23,8 @@ def do_parse_wechat_audio_file(file_name):
     """ return a mp3 stored in base64 unicode string, and the duration"""
     if not file_name: return "", 0
 
-    mp3_file = os.path.join('/tmp',
+    with tempfile.TemporaryDirectory(prefix="wechatdump_audio") as temp:
+        mp3_file = os.path.join(temp,
                                 os.path.basename(file_name)[:-4] + '.mp3')
         with open(file_name, 'rb') as f:
             header = f.read(10)
@@ -45,7 +44,10 @@ def do_parse_wechat_audio_file(file_name):
             # signal = infile.get_signal().get_signalinfo()
             # duration = signal['length'] * 1.0 / signal['rate']
         elif b'SILK' in header:
-        raw_file = os.path.join('/tmp',
+            if not os.path.exists(SILK_DECODER):
+                raise RuntimeError("Silk decoder is not compiled. Please see README.md.")
+
+            raw_file = os.path.join(temp,
                                     os.path.basename(file_name)[:-4] + '.raw')
             cmd = '{0} {1} {2}'.format(SILK_DECODER, file_name, raw_file)
             out = subproc_succ(cmd)
@@ -54,15 +56,13 @@ def do_parse_wechat_audio_file(file_name):
                     duration = float(line[13:-3].strip())
                     break
             else:
-            raise RuntimeError("Error decoding silk audio file!")
+                raise RuntimeError("Error decoding silk audio file!" + out.decode('utf-8'))
 
             # TODO don't know how to do this with python
             subproc_succ('sox -r 24000 -e signed -b 16 -c 1 {} {}'.format(raw_file, mp3_file))
-        os.unlink(raw_file)
         else:
             raise NotImplementedError("Audio file format cannot be recognized.")
         mp3_string = get_file_b64(mp3_file)
-    os.unlink(mp3_file)
     return mp3_string, duration
 
 if __name__ == '__main__':