Work in progress: added a daemon to encode wav files.

Also added a toy client that can talk to the daemon, for testing purposes.

mp3wavcfg.py

+socketpath = "/home/ceder/rgit/mp3wavweb/.socket"
 BASE = '/home/ceder/tmp/2014/sample'

wav2mp3c.py

+#!/usr/bin/env python3
+
+import sys
+import multiprocessing.connection
+
+import mp3wavcfg
+
+try:
+    c = multiprocessing.connection.Client(mp3wavcfg.socketpath, 'AF_UNIX')
+except FileNotFoundError:
+    sys.stderr.write("no daemon running?\n")
+    sys.exit(1)
+c.send(("encode", "2009/12 - December/13"))
+while True:
+    msg = c.recv()
+    if msg[0] != "progress":
+        break
+    print("%s%%" % msg[1])
+print(msg)

wav2mp3d.py

+#!/usr/bin/env python3
+
+import re
+import os
+import sys
+import subprocess
+import multiprocessing
+import multiprocessing.connection
+
+import mp3wavcfg
+
+def listener_fileno(self):
+    return self._listener._socket.fileno()
+
+queue = []
+progress = 0.0
+proc = None
+
+def work():
+    global proc
+    global queue
+
+    setattr(multiprocessing.connection.Listener, "fileno", listener_fileno)
+
+    server = multiprocessing.connection.Listener(
+        mp3wavcfg.socketpath, 'AF_UNIX', 3)
+
+    clients = []
+
+    while True:
+        pending = [server] + clients
+        if proc is not None:
+            pending.append(proc.sentinel)
+        ready = multiprocessing.connection.wait(pending)
+        for sock in ready:
+            if sock is server:
+                clients.append(sock.accept())
+            elif proc is not None and sock is proc.sentinel:
+                proc.join()
+                if proc.exitcode == 0:
+                    queue[0][1].send(("done", queue[0][0]))
+                else:
+                    queue[0][1].send(("fail", queue[0][0]))
+                proc = None
+                queue = queue[1:]
+                start_encoding()
+            else:
+                try:
+                    msg = sock.recv()
+                except EOFError:
+                    clients.remove(sock)
+                else:
+                    handle_message(sock, msg)
+
+def exists(fn):
+    return os.path.isfile(os.path.join(mp3wavcfg.BASE, fn))
+
+def handle_message(client, msg):
+    global queue
+    global progress
+
+    if msg[0] == "ping":
+        client.send(("pong", ))
+    elif msg[0] == "peek":
+        client.send(("status", [q[0] for q in queue], progress))
+    elif msg[0] == "encode":
+        fn = msg[1]
+        if exists(fn + ".wav"):
+            if exists(fn + ".mp3"):
+                client.send(("already-there", fn))
+            else:
+                queue.append((fn, client))
+                start_encoding()
+        else:
+            client.send(("enofile", fn))
+    elif msg[0] == "progress":
+        progress = msg[1]
+        queue[0][1].send(("progress", progress))
+    else:
+        client.send(("badreq", msg[0]))
+
+def start_encoding():
+    global proc
+    global queue
+
+    if proc is not None:
+        return
+    if len(queue) == 0:
+        return
+    proc = multiprocessing.Process(target=encode, args=(queue[0][0], ))
+    proc.start()
+
+def encode(fn):
+    c = multiprocessing.connection.Client(mp3wavcfg.socketpath, 'AF_UNIX')
+    cmd = ["lame", "--preset", "standard", "--nohist",
+           os.path.join(mp3wavcfg.BASE, fn + ".wav")]
+    lame = subprocess.Popen(args=cmd, bufsize=0, stdin=subprocess.DEVNULL,
+                            stderr=subprocess.PIPE)
+    percent_match = re.compile(".*\\(([0-9]+)%\\)")
+
+    while True:
+        msg = lame.stderr.read(100)
+        if len(msg) == 0:
+            break
+        m = percent_match.search(str(msg))
+        if m is not None:
+            c.send(("progress", m.group(1)))
+    x = lame.wait()
+    sys.exit(x)
+
+if __name__ == '__main__':
+    work()