我正在翻新一个python脚本，用于检查IMAP是否有新电子邮件，如果有新邮件则会发送推送通知。问题是每隔几个小时我就会崩溃。起初我无法真正理解发生了什么，但后来我发现M.debug = 4给了我一个很好的输出，但我仍然无法理解导致问题的原因。我已经将我的脚本和调试输出从正常行为发布到崩溃，希望在python中有更好理解的人可以告诉我发生了什么以及如何解决它。
修改
我按照以下答案的建议编辑了我的代码：
while True:
try:
[call function that does all your logic]
except imaplib2.IMAP4.abort:
print("Disconnected. Trying again.")
或者这个：
while True:
try:
[call function that does all your logic]
except (imaplib2.IMAP4.abort, imaplib2.IMAP4.error) as e:
print("Disconnected. Trying again.")
但是我在一段不确定的时间后仍然会遇到崩溃，而且异常永远不会被抓住。 print("Disconnected. Trying again.")永远不会执行。
代码：
#!/usr/local/bin/python2.7
print "Content-type: text/html\r\n\r\n";
import socket, ssl, json, struct, re
import imaplib2, time
from threading import *
# enter gmail login details here
USER="username@gmail.com"
PASSWORD="password"
# enter device token here
deviceToken = 'my device token x x x x x'
deviceToken = deviceToken.replace(' ','').decode('hex')
currentBadgeNum = -1
def getUnseen():
(resp, data) = M.status("INBOX", '(UNSEEN)')
print data
return int(re.findall("UNSEEN (\d)*\)", data[0])[0])
def sendPushNotification(badgeNum):
global currentBadgeNum, deviceToken
if badgeNum != currentBadgeNum:
currentBadgeNum = badgeNum
thePayLoad = {
'aps': {
'alert':'Hello world!',
'sound':'',
'badge': badgeNum,
},
'test_data': { 'foo': 'bar' },
}
theCertfile = 'certif.pem'
theHost = ('gateway.push.apple.com', 2195)
data = json.dumps(thePayLoad)
theFormat = '!BH32sH%ds' % len(data)
theNotification = struct.pack(theFormat, 0, 32, deviceToken, len(data), data)
ssl_sock = ssl.wrap_socket(socket.socket(socket.AF_INET, socket.SOCK_STREAM), certfile=theCertfile)
ssl_sock.connect(theHost)
ssl_sock.write(theNotification)
ssl_sock.close()
print "Sent Push alert."
# This is the threading object that does all the waiting on
# the event
class Idler(object):
def __init__(self, conn):
self.thread = Thread(target=self.idle)
self.M = conn
self.event = Event()
def start(self):
self.thread.start()
def stop(self):
# This is a neat trick to make thread end. Took me a
# while to figure that one out!
self.event.set()
def join(self):
self.thread.join()
def idle(self):
# Starting an unending loop here
while True:
# This is part of the trick to make the loop stop
# when the stop() command is given
if self.event.isSet():
return
self.needsync = False
# A callback method that gets called when a new
# email arrives. Very basic, but that's good.
def callback(args):
if not self.event.isSet():
self.needsync = True
self.event.set()
# Do the actual idle call. This returns immediately,
# since it's asynchronous.
self.M.idle(callback=callback)
# This waits until the event is set. The event is
# set by the callback, when the server 'answers'
# the idle call and the callback function gets
# called.
self.event.wait()
# Because the function sets the needsync variable,
# this helps escape the loop without doing
# anything if the stop() is called. Kinda neat
# solution.
if self.needsync:
self.event.clear()
self.dosync()
# The method that gets called when a new email arrives.
# Replace it with something better.
def dosync(self):
print "Got an event!"
numUnseen = getUnseen()
sendPushNotification(numUnseen)
# Had to do this stuff in a try-finally, since some testing
# went a little wrong.....
while True:
try:
# Set the following two lines to your creds and server
M = imaplib2.IMAP4_SSL("imap.gmail.com")
M.login(USER, PASSWORD)
M.debug = 4
# We need to get out of the AUTH state, so we just select
# the INBOX.
M.select("INBOX")
numUnseen = getUnseen()
sendPushNotification(numUnseen)
typ, data = M.fetch(1, '(RFC822)')
raw_email = data[0][1]
import email
email_message = email.message_from_string(raw_email)
print email_message['Subject']
#print M.status("INBOX", '(UNSEEN)')
# Start the Idler thread
idler = Idler(M)
idler.start()
# Sleep forever, one minute at a time
while True:
time.sleep(60)
except imaplib2.IMAP4.abort:
print("Disconnected. Trying again.")
finally:
# Clean up.
#idler.stop() #Commented out to see the real error
#idler.join() #Commented out to see the real error
#M.close() #Commented out to see the real error
# This is important!
M.logout()
... ... ...
43:54.43 imap.gmail.com handler _request_pop(continuation, (True, 'idling')) = CHPJ127
43:54.43 imap.gmail.com handler None:CHPJ127.ready.set
43:54.43 Thread-4 continuation => True, idling
43:54.43 Thread-4 server IDLE started, timeout in 1740.00 secs
43:54.43 Thread-4 state_change_pending.release
57:13.60 imap.gmail.com reader < * BYE System error\r\n
57:13.63 imap.gmail.com handler server IDLE finished
57:13.63 imap.gmail.com handler BYE response: System error
57:13.63 imap.gmail.com writer > DONE\r\n
**57:13.63 imap.gmail.com handler terminating: 'connection terminated'**
57:13.63 imap.gmail.com writer finished
57:13.63 imap.gmail.com handler last 20 log messages:
51:49.77 Thread-4 [sync] IDLE ()
20:50.18 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
20:50.51 Thread-4 [sync] IDLE ()
49:50.79 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
49:51.02 Thread-4 [sync] IDLE ()
18:51.33 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
18:51.49 Thread-4 [sync] IDLE ()
47:51.80 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
47:51.96 Thread-4 [sync] IDLE ()
16:52.26 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
16:52.63 Thread-4 [sync] IDLE ()
45:53.08 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
45:53.24 Thread-4 [sync] IDLE ()
14:53.54 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
14:53.69 Thread-4 [sync] IDLE ()
43:53.96 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
43:54.17 Thread-4 [sync] IDLE ()
57:13.63 imap.gmail.com handler BYE response: System error
57:13.63 imap.gmail.com handler terminating: 'connection terminated'
57:13.63 imap.gmail.com writer finished
Got an event!
57:13.63 imap.gmail.com handler state_change_free.set
57:13.63 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
57:13.63 imap.gmail.com handler finished
57:13.63 Thread-4 state_change_pending.acquire
57:13.63 Thread-4 state_change_pending.release
Exception in thread Thread-4:
Traceback (most recent call last):
File "/usr/local/lib/python2.7/threading.py", line 551, in __bootstrap_inner
self.run()
File "/usr/local/lib/python2.7/threading.py", line 504, in run
self.__target(*self.__args, **self.__kwargs)
File "shaserver.py", line 111, in idle
self.dosync()
File "shaserver.py", line 117, in dosync
numUnseen = getUnseen()
File "shaserver.py", line 35, in getUnseen
(resp, data) = M.status("INBOX", '(UNSEEN)')
File "/home/boombe/lib/python2.7/imaplib2/imaplib2.py", line 1121, in status
return self._simple_command(name, mailbox, names, **kw)
File "/home/boombe/lib/python2.7/imaplib2/imaplib2.py", line 1607, in _simple_command
return self._command_complete(self._command(name, *args), kw)
File "/home/boombe/lib/python2.7/imaplib2/imaplib2.py", line 1295, in _command
self._check_bye()
File "/home/boombe/lib/python2.7/imaplib2/imaplib2.py", line 1229, in _check_bye
raise self.abort(bye[-1])
abort: System error
57:13.70 imap.gmail.com reader finished
... ... ...
有时我会这样：
03:09.29 Thread-4 [sync] IDLE ()
05:53.25 imap.gmail.com reader socket error: <type 'exceptions.IOError'> - Error Hang up
05:53.25 imap.gmail.com reader finished
05:53.26 imap.gmail.com handler terminating: "socket error: <type 'exceptions.IOError'> - Error Hang up"
05:53.26 imap.gmail.com handler last 20 log messages:
07:07.66 Thread-4 [sync] IDLE ()
36:07.78 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
36:07.83 Thread-4 [async] SEARCH ('ALL',)
36:07.88 Thread-4 [async] FETCH ('1', '(RFC822.HEADER)')
36:08.09 Thread-4 [sync] IDLE ()
05:08.19 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
05:08.25 Thread-4 [async] SEARCH ('ALL',)
05:08.42 Thread-4 [async] FETCH ('1', '(RFC822.HEADER)')
05:08.48 Thread-4 [sync] IDLE ()
34:08.58 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
34:08.68 Thread-4 [async] SEARCH ('ALL',)
34:08.79 Thread-4 [async] FETCH ('1', '(RFC822.HEADER)')
34:08.94 Thread-4 [sync] IDLE ()
03:09.05 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
03:09.16 Thread-4 [async] SEARCH ('ALL',)
03:09.21 Thread-4 [async] FETCH ('1', '(RFC822.HEADER)')
03:09.29 Thread-4 [sync] IDLE ()
05:53.25 imap.gmail.com reader socket error: <type 'exceptions.IOError'> - Error Hang up
05:53.25 imap.gmail.com reader finished
05:53.26 imap.gmail.com handler terminating: "socket error: <type 'exceptions.IOError'> - Error Hang up"
05:53.26 imap.gmail.com writer finished
Got an event!
05:53.26 Thread-4 [async] STATUS ('INBOX', '(UNSEEN)')
05:53.26 Thread-4 state_change_pending.acquire
05:53.26 Thread-4 server IDLE finished
05:53.26 Thread-4 state_change_pending.release
05:53.26 Thread-4 _get_untagged_response(READ-ONLY) => ['']
05:53.26 imap.gmail.com handler state_change_free.set
05:53.26 imap.gmail.com handler finished
Exception in thread Thread-4:
Traceback (most recent call last):
File "/usr/local/lib/python2.7/threading.py", line 551, in __bootstrap_inner
self.run()
File "/usr/local/lib/python2.7/threading.py", line 504, in run
self.__target(*self.__args, **self.__kwargs)
File "shaserver.py", line 229, in idle
self.dosync()
File "shaserver.py", line 235, in dosync
numUnseen = getUnseen()
File "shaserver.py", line 150, in getUnseen
(resp, data) = M.status("INBOX", '(UNSEEN)')
File "/home/boombe/lib/python2.7/imaplib2/imaplib2.py", line 1121, in status
return self._simple_command(name, mailbox, names, **kw)
File "/home/boombe/lib/python2.7/imaplib2/imaplib2.py", line 1607, in _simple_command
return self._command_complete(self._command(name, *args), kw)
File "/home/boombe/lib/python2.7/imaplib2/imaplib2.py", line 1305, in _command
raise self.abort('connection closed')
abort: connection closed
答案 0 :(得分：1)
那是因为异常被抛出到另一个线程和另一个没有被except块保护的地方。只需查看回溯 - 您将看到它在threading.py内开始（并且那里没有异常处理）。继续使用dosync和getUnseen方法 - 再次，无异常处理。
这就解释了为什么你的try / except块无效 - 这是因为你明确要求在另一个线程中执行该代码。还有待解释的是，为什么你首先得到例外。一个原因可能是您正在达到通常与IDLE命令相关联的超时 - 请参阅RFC 2177了解详细信息（这是一个简短的读取），它会告诉您，您应该打破每29分钟空转一次。另一种可能性是gmail根本不喜欢你 - 也许他们不喜欢维持连接时间太长的客户端。但是，我没有数据来支持这种推测。
但最重要的问题仍然存在 - 你为什么要使用线程呢？作为从头开始实现和IMAP client的人（顺便说一句，它多年前在Python中开始），我完全相信线程是不需要有效地谈论IMAP。在您的特定用例中，您似乎只为IDLE命令运行一个线程，同时将主线程的时间花费在无限wait中。这本身就是我不明白的东西，但也许你有一些重要的原因 - 也许你真的需要将一些IMAP处理卸载到另一个线程。但是，在这种情况下，请考虑将任何 IMAP相关活动移动到该线程 - 因为现在，您的一个线程正在执行初始SELECT和一些数据获取，并且仅在此之后它将IMAP连接转移到IDLE的另一个线程。那只是邪恶。
对于线程的基本需求 - 一个对我有用的架构正在利用IMAP协议的异步性质。我不确定它与imaplib2库有多好，也许它不支持真正的异步IMAP处理。在这种情况下，我强烈考虑只是在一种无聊的阻塞同步方式中使用IMAP，其中每个操作都真正等待命令的完成。是的，其中一些会运行很长时间 - 如果你绝对需要进行某些活动，例如等待IDLE在29分钟后完成，然后将IMAP处理推迟到另一个线程可能是个好主意。但是你应该非常肯定这是你在走这条路之前真正需要的。
答案 1 :(得分：0)
我从头开始构建相同的应用程序并收到完全相同的错误（BYE响应异常）。
这是通过包装
解决的 self.M.idle(callback=callback)
使用try except，然后在某处保存异常（例如，在Idler的属性中）。
这个保存的异常会在主线程中持续扫描（即每秒睡眠和唤醒），如果存在，则在主线程中引发以便正确处理（即按照指示重新创建的imap连接）在imaplib2库中。）
BYE响应为什么会发生这种情况？我的猜测是，当一个连接被不清洁地关闭时（例如，使用kill信号，这样就不会进行清理），服务器之前不会从连接接收到NOOP信号，并决定关闭该信道。但现在是新程序接收到“关闭通道”信号。
为什么我推测这个？一旦我实施了BYE imaplib2.abort异常捕获并杀死捕获信号（SIGTERM等），imaplib2.abort异常就完全停止了。
注意：您还可以在我的github中找到这两种解决方案的确切实现：https://www.github.com/Elijas/email-notifier
答案 2 :(得分：-1)
从您的跟踪中，它看起来远程端发送了一个未经请求的BYE命令，因为它想要出于某种原因关闭连接。
您可能必须使脚本更加健壮，以处理连接失败和BYE命令。
例如，您应该将最高级别更改为循环：
while True:
try:
[call function that does all your logic]
except imaplib2.IMAP4.abort:
print("Disconnected. Trying again.")
此外，您需要更新回调（）以查看它的参数。如果IDLE返回错误，因为您异步使用它，它将向callback（）报告错误。您需要在那里处理异常。 （注意，它不会在回调中引发错误，只会在参数中返回错误。
来自imaplib2s文档：
If 'callback' is provided then the command is asynchronous, so after
the command is queued for transmission, the call returns immediately
with the tuple (None, None).
The result will be posted by invoking "callback" with one arg, a tuple:
callback((result, cb_arg, None))
or, if there was a problem:
callback((None, cb_arg, (exception class, reason)))
这意味着你的回电需要查看它的参数：
def callback(args):
result, arg, exc = args
if result is None:
print("There was an error during IDLE:", str(exc))
self.error = exc
self.event.set()
else:
self.needsync = True
self.event.set()
现在您可以检查您的闲人话题中是否有错误。然后在你坐的主线程中，每次60秒，你可以设置某种标志来指示你是否已经断开连接。