我正在更新一个python脚本,它检查IMAP中是否有新的电子邮件,如果有新的电子邮件,则发送一个推送通知。问题是每隔几个小时我就有一次车祸。一开始我真的不明白到底发生了什么,但后来我发现M.debug = 4
给了我一个很好的输出,但我仍然不明白是什么导致了这个问题。我已经发布了我的脚本和从正常行为到崩溃的调试输出,希望对python有更好理解的人可以告诉我发生了什么,以及如何修复它。在
编辑:
我已经按照答案中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:
^{pr2}$但在一段不确定的时间后,我还是会崩溃,而且这个例外永远不会被发现。print("Disconnected. Trying again.")
永远不会执行。在
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()
。。。 ... ... 在
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
。。。 ... ... 在
有时我会发现:
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
我已经从头开始构建相同的应用程序,并且收到了完全相同的错误(除了
BYE
响应)。如何在Thread-4中捕捉异常
这可以通过包装来解决
self.M.idle(callback=callback)
,然后将异常保存在某个地方(例如在
Idler
的属性中)。这个保存的异常会在主线程中不断地进行扫描(即每隔一秒左右就会休眠和唤醒一次),如果存在,则会在主线程中引发以正确处理(即按照imaplib2库中的说明重新创建imap连接)。
如何避免来自服务器的
BYE
响应为什么会这样?我的推测是,当一个连接不干净地关闭时(例如,使用kill信号,这样就不会进行清理),服务器就不会接收到来自连接的
NOOP
信号,而是决定关闭通道。但现在是新程序接收“关闭通道”信号。我为什么要猜测这个?一旦我实现了}异常就完全停止了。
BYE
imaplib2.abort
异常捕捉和终止信号捕获(SIGTERM
,等等),那么{注意:您还可以在我的github中找到这两个解决方案的精确实现:https://www.github.com/Elijas/email-notifier
这是因为异常被抛出到另一个线程和另一个不受
except
块保护的地方。只需看看回溯跟踪,就会发现它是从threading.py
开始的(其中没有异常处理)。再次通过dosync
和getUnseen
方法继续,没有异常处理。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会首先得到例外。一个原因可能是您遇到了与IDLE
命令相关联的超时,有关详细信息,请参见RFC 2177(这是一个简短的阅读),它将告诉您应该每隔29分钟中断一次空闲。另一种可能是gmail根本不喜欢你,也许他们不想维持那些连接时间太长的客户。不过,我没有推测数据。但最重要的问题仍然是为什么要使用线程?作为一个从零开始实现和IMAP client的人(顺便说一句,它是在很多年前用Python实现的),我完全确信线程是而不是来高效地讨论IMAP的。在您的特定用例中,您似乎只为
IDLE
命令运行一个线程,而将主线程的时间花在无休止的wait
中。这本身是我不明白的,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,请考虑将任何与IMAP相关的活动移动到该线程,因为现在,您的一个线程正在执行初始的SELECT
和一些数据获取,并且只有在这之后,它才将IMAP连接传输到IDLE
的另一个线程。那真是邪恶。对于线程化的基本需求,一个对我来说很好的架构就是利用IMAP协议的异步特性。我不确定它在
imaplib2
库中能发挥多好,也许它不支持真正的异步IMAP处理。在这种情况下,我强烈考虑只在borin中使用IMAP,阻塞同步方式,在这种方式下,每个操作都真正等待命令的完成。是的,如果您确实需要在29分钟后执行某个活动(例如等待该活动在29分钟后完成),则其中一些将运行很长时间,然后将IMAP处理推迟到另一个线程可能是个好主意。但你应该非常确定这是你真正需要的,在你走那条路之前。从您的跟踪中,它看起来远程端向您发送了一个未经请求的BYE命令,因为它出于某种原因想关闭连接。
您可能需要使脚本更加健壮,以处理连接失败和BYE命令。
例如,应将顶层更改为循环:
另外,还需要更新callback()来查看它的参数。如果IDLE由于异步使用而返回错误,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,只会返回参数中的错误。
来自imaplib2s文档:
^{pr2}$这意味着您的回拨需要查看它的参数:
现在您可以检查您的惰轮螺纹是否有错误。然后在你的主线程中,你可以一次坐着睡觉60秒,你可以设置一些标志来指示你是否已经断开连接。
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