收到电子邮件时触发脚本

Question

每次我的网络服务器在特定帐户上收到电子邮件时，我都需要触发 python 脚本。我还需要将电子邮件作为参数传递给脚本。我的网络服务器正在使用 Dovecot。我该怎么做？

Answer 1

我建议您查看Twisted，特别是它的IMAP 和POP 协议和客户端模块。

举个例子：

#!/usr/bin/env python

# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.


"""
Simple IMAP4 client which displays the subjects of all messages in a
particular mailbox.
"""
import sys

from twisted.internet import protocol
from twisted.internet import ssl
from twisted.internet import defer
from twisted.internet import stdio
from twisted.mail import imap4
from twisted.protocols import basic
from twisted.python import util
from twisted.python import log 

class TrivialPrompter(basic.LineReceiver):
    from os import linesep as delimiter

    promptDeferred = None

    def prompt(self, msg):
        assert self.promptDeferred is None
        self.display(msg)
        self.promptDeferred = defer.Deferred()
        return self.promptDeferred

    def display(self, msg):
        self.transport.write(msg)

    def lineReceived(self, line):
        if self.promptDeferred is None:
            return
        d, self.promptDeferred = self.promptDeferred, None
        d.callback(line)

class SimpleIMAP4Client(imap4.IMAP4Client):
    """
    A client with callbacks for greeting messages from an IMAP server.
    """
    greetDeferred = None

    def serverGreeting(self, caps):
        self.serverCapabilities = caps
        if self.greetDeferred is not None:
            d, self.greetDeferred = self.greetDeferred, None
            d.callback(self)

class SimpleIMAP4ClientFactory(protocol.ClientFactory):
    usedUp = False

    protocol = SimpleIMAP4Client

    def __init__(self, username, onConn):
        self.ctx = ssl.ClientContextFactory()

        self.username = username
        self.onConn = onConn

    def buildProtocol(self, addr):
        """
        Initiate the protocol instance. Since we are building a simple IMAP
        client, we don't bother checking what capabilities the server has. We
        just add all the authenticators twisted.mail has.  Note: Gmail no
        longer uses any of the methods below, it's been using XOAUTH since
        2010.
        """
        assert not self.usedUp
        self.usedUp = True

        p = self.protocol(self.ctx)
        p.factory = self
        p.greetDeferred = self.onConn

        p.registerAuthenticator(imap4.PLAINAuthenticator(self.username))
        p.registerAuthenticator(imap4.LOGINAuthenticator(self.username))
        p.registerAuthenticator(
                imap4.CramMD5ClientAuthenticator(self.username))

        return p

    def clientConnectionFailed(self, connector, reason):
        d, self.onConn = self.onConn, None
        d.errback(reason)



def cbServerGreeting(proto, username, password):
    """
    Initial callback - invoked after the server sends us its greet message.
    """
    # Hook up stdio
    tp = TrivialPrompter()
    stdio.StandardIO(tp)

    # And make it easily accessible
    proto.prompt = tp.prompt
    proto.display = tp.display

    # Try to authenticate securely
    return proto.authenticate(password
        ).addCallback(cbAuthentication, proto
        ).addErrback(ebAuthentication, proto, username, password
        )

def ebConnection(reason):
    """
    Fallback error-handler. If anything goes wrong, log it and quit.
    """
    log.startLogging(sys.stdout)
    log.err(reason)
    return reason

def cbAuthentication(result, proto):
    """
    Callback after authentication has succeeded.

    Lists a bunch of mailboxes.
    """
    return proto.list("", "*"
        ).addCallback(cbMailboxList, proto
        )


def ebAuthentication(failure, proto, username, password):
    """
    Errback invoked when authentication fails.

    If it failed because no SASL mechanisms match, offer the user the choice
    of logging in insecurely.

    If you are trying to connect to your Gmail account, you will be here!
    """
    failure.trap(imap4.NoSupportedAuthentication)
    return proto.prompt(
        "No secure authentication available. Login insecurely? (y/N) "
        ).addCallback(cbInsecureLogin, proto, username, password
        )


def cbInsecureLogin(result, proto, username, password):
    """
    Callback for "insecure-login" prompt.
    """
    if result.lower() == "y":
        # If they said yes, do it.
        return proto.login(username, password
            ).addCallback(cbAuthentication, proto
            )
    return defer.fail(Exception("Login failed for security reasons."))


def cbMailboxList(result, proto):
    """
    Callback invoked when a list of mailboxes has been retrieved.
    """
    result = [e[2] for e in result]
    s = '\n'.join(['%d. %s' % (n + 1, m) for (n, m) in zip(range(len(result)), result)])
    if not s:
        return defer.fail(Exception("No mailboxes exist on server!"))
    return proto.prompt(s + "\nWhich mailbox? [1] "
        ).addCallback(cbPickMailbox, proto, result
        )


def cbPickMailbox(result, proto, mboxes):
    """
    When the user selects a mailbox, "examine" it.
    """
    mbox = mboxes[int(result or '1') - 1]
    return proto.examine(mbox
        ).addCallback(cbExamineMbox, proto
        )


def cbExamineMbox(result, proto):
    """
    Callback invoked when examine command completes.

    Retrieve the subject header of every message in the mailbox.
    """
    return proto.fetchSpecific('1:*',
                               headerType='HEADER.FIELDS',
                               headerArgs=['SUBJECT'],
        ).addCallback(cbFetch, proto
        )


def cbFetch(result, proto):
    """
    Finally, display headers.
    """
    if result:
        keys = result.keys()
        keys.sort()
        for k in keys:
            proto.display('%s %s' % (k, result[k][0][2]))
    else:
        print "Hey, an empty mailbox!"

    return proto.logout()


def cbClose(result):
    """
    Close the connection when we finish everything.
    """
    from twisted.internet import reactor
    reactor.stop()


def main():
    hostname = raw_input('IMAP4 Server Hostname: ')
    port = raw_input('IMAP4 Server Port (the default is 143, 993 uses SSL): ')
    username = raw_input('IMAP4 Username: ')
    password = util.getPassword('IMAP4 Password: ')

    onConn = defer.Deferred(
        ).addCallback(cbServerGreeting, username, password
        ).addErrback(ebConnection
        ).addBoth(cbClose)

    factory = SimpleIMAP4ClientFactory(username, onConn)

    from twisted.internet import reactor
    if port == '993':
        reactor.connectSSL(hostname, int(port), factory, ssl.ClientContextFactory())
    else:
        if not port:
            port = 143
        reactor.connectTCP(hostname, int(port), factory)
    reactor.run()


if __name__ == '__main__':
    main()

当您从您正在检查的 IMAP 文件夹中检测到一封新电子邮件时，您只需在子流程中调用您的 Python 脚本...在这里您还可以使用 Twisted 的流程处理作为记录在这里：https://twistedmatrix.com/documents/13.0.0/core/howto/process.html

祝你好运！

Answer 2

如果 IMAP 服务器支持 IDLE 命令，它可能会通知您有关新消息的信息。如果它不支持它，那么您可以使用 stdlib (code example to retrieve messages from a time period) 中的 imaplib 定期轮询收件箱。

imaplib 不支持 IDLE 命令，但可以轻松添加，例如 imapidle:

from imapidle import imaplib

m = imaplib.IMAP4_SSL('imap.gmail.com')
m.login('robert', 'pa55w0rd')
m.select()
for uid, msg in m.idle(): # yield new messages
    print msg

另见How do I enable push-notification for IMAP (Gmail) using Python imaplib?