python - 如何处理 imaplib2 错误

Question

我有一个使用 imap IDLE 协议(protocol)检查 gmail 帐户的脚本。为此，我使用 imaplib2，托管 here .每隔一段时间，它就会抛出一个未处理的异常:

  Traceback (most recent call last):
  File "C:\Python27\lib\site-packages\imaplib2\imaplib2.py", line 1830, in _reader
    raise IOError("Too many read 0")
IOError: Too many read 0

(来自发布链接的第 1839 行)

这是有问题的部分(中途):

  def _reader(self):

    threading.currentThread().setName(self.identifier + 'reader')

    if __debug__: self._log(1, 'starting using select')

    line_part = ''

    rxzero = 0
    terminate = False

    while not (terminate or self.Terminate):
        if self.state == LOGOUT:
            timeout = 1
        else:
            timeout = self.read_poll_timeout
        try:
            r,w,e = select.select([self.read_fd], [], [], timeout)
            if __debug__: self._log(5, 'select => %s, %s, %s' % (r,w,e))
            if not r:                                       # Timeout
                continue

            data = self.read(self.read_size)                # Drain ssl buffer if present
            start = 0
            dlen = len(data)
            if __debug__: self._log(5, 'rcvd %s' % dlen)
            if dlen == 0:
                rxzero += 1
                if rxzero > 5:
                    raise IOError("Too many read 0") # <- This is the error I'm
                time.sleep(0.1)                      #    getting
            else:
                rxzero = 0
            while True:
                stop = data.find('\n', start)
                if stop < 0:
                    line_part += data[start:]
                    break
                stop += 1
                line_part, start, line = \
                    '', stop, line_part + data[start:stop]
                if __debug__: self._log(4, '< %s' % line)
                self.inq.put(line)
                if self.TerminateReader:
                    terminate = True
        except:
            reason = 'socket error: %s - %s' % sys.exc_info()[:2]
            if __debug__:
                if not self.Terminate:
                    self._print_log()
                    if self.debug: self.debug += 4          # Output all
                    self._log(1, reason)
            self.inq.put((self.abort, reason))
            break

我无法从脚本中捕获此错误，因为 imaplib2 为其 _reader 和 _writer 函数创建了单独的线程。我不太明白这个错误，所以我的问题是我应该修改 imaplib2 源代码以忽略这个错误还是改变它的条件还是什么？

谢谢

Answer 1

我从 imaplib2 收到了各种错误，包括 errno 10054 连接被强制关闭和太多读取 0。这些错误会导致我的程序挂起大约半小时。为了解决这些问题，我使用多处理在单独的进程中完成工作并实现了事件检查。如果一段时间内没有事件，则主进程终止(我知道，不理想)子进程并产生另一个。这是一些相关的代码。

def MasterRun():
    from multiprocessing import Value

    counter = Value("I", 0)

    last = counter.value
    elapsed = 0
    interval = 1

    TIMEOUT = 90

    proc = _make_process(counter)
    # value < 0 signals process quit naturally
    while counter.value >= 0:
        if counter.value != last:
            elapsed = 0
            last = counter.value
        if elapsed >= TIMEOUT or not proc.is_alive():
            print "terminating process reason: %s\n" % \
                  ("no activity time was exceeded" if proc.is_alive() else "process committed suicide")
            proc.terminate()
            proc.join(25)
            proc = _make_process(counter)
            proc.start()
            elapsed = 0

        sleep(interval)
        elapsed += interval
    proc.join(25)

def _make_process(counter):
    from multiprocessing import Process
    print "spawning child process"
    proc = Process(target=_make_instance, args=(counter, ))
    proc.daemon = True
    proc.start()
    return proc