How to set IMAP flags using Twisted

Question

How do you delete messages using imap4.IMAP4Client? I cannot get the "deleted" tag correctly applied for using the "expunge" method.

I keep getting the following error:

Failure: twisted.mail.imap4.IMAP4Exception: Invalid system flag \

Sample code would be appreciated. This is what I have so far:

from twisted.internet import protocol, reactor
from twisted.mail import imap4

#Variables for connection
username = 'user@host.com'
password = 'mypassword'
host = 'imap.host.com'
port = 143

class IMAP4LocalClient(imap4.IMAP4Client):
    def connectionMade(self):
        self.login(username,password).addCallbacks(self._getMessages, self._ebLogin)

    #reports any connection errors
    def connectionLost(self,reason):
        reactor.stop()

    #drops the connection
    def _ebLogin(self,result):
        print result
        self.transport.loseConnection()

    def _programUtility(self,result):
        print result
        return self.logout()

    def _cbExpungeMessage(self,result):
        return self.expunge().addCallback(self._programUtility)

    def _cbDeleteMessage(self,result):
        return self.setFlags("1:5",flags=r"\\Deleted",uid=False).addCallback(self._cbExpungeMessage)

    #gets the mailbox list
    def _getMessages(self,result):
        return self.list("","*").addCallback(self._cbPickMailbox)

    #selects the inbox desired    
    def _cbPickMailbox(self,result):
        mbox='INBOX.Trash'
        return self.select(mbox).addCallback(self._cbExamineMbox)

    def _cbExamineMbox(self,result):
        return self.fetchMessage("1:*",uid=False).addCallback(self._cbDeleteMessage)

class IMAP4ClientFactory(protocol.ClientFactory):
    def buildProtocol(self,addr):
        return IMAP4LocalClient()

    def clientConnectionFailed(self,connector,reason):
        print reason
        reactor.stop()


reactor.connectTCP(host,port,IMAP4ClientFactory())
reactor.run()

Changed to:

def _cbDeleteMessage(self,result):
    return self.setFlags("1:5",flags=['\\Deleted'],uid=False).addCallback(self._cbExpungeMessage)

thanks to Jean-Paul Calderone and it worked, setFlags requires a list, not just a string.

Answer 1

I think there are two problems here.

First, you're passing a string as the flags parameter to setFlags. Notice the documentation for that parameter: The flags to set (type: Any iterable of str). Try a list containing one string, instead.

Second, \\Deleted is probably not a flag the server you're interacting with supports. The standard deleted flag in IMAP4 is \Deleted.