# IMAP folder support # Copyright (C) 2002-2012 John Goerzen & contributors # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA import email import random import binascii import re import time from sys import exc_info from .Base import BaseFolder from offlineimap import imaputil, imaplibutil, OfflineImapError from offlineimap.imaplib2 import MonthNames class IMAPFolder(BaseFolder): def __init__(self, imapserver, name, repository): name = imaputil.dequote(name) self.sep = imapserver.delim super(IMAPFolder, self).__init__(name, repository) self.expunge = repository.getexpunge() self.root = None # imapserver.root self.imapserver = imapserver self.messagelist = None self.randomgenerator = random.Random() #self.ui is set in BaseFolder def selectro(self, imapobj, force = False): """Select this folder when we do not need write access. Prefer SELECT to EXAMINE if we can, since some servers (Courier) do not stabilize UID validity until the folder is selected. .. todo: Still valid? Needs verification :param: Enforce new SELECT even if we are on that folder already. :returns: raises :exc:`OfflineImapError` severity FOLDER on error""" try: imapobj.select(self.getfullname(), force = force) except imapobj.readonly: imapobj.select(self.getfullname(), readonly = True, force = force) def suggeststhreads(self): return 1 def waitforthread(self): self.imapserver.connectionwait() def getcopyinstancelimit(self): return 'MSGCOPY_' + self.repository.getname() def get_uidvalidity(self): """Retrieve the current connections UIDVALIDITY value UIDVALIDITY value will be cached on the first call. :returns: The UIDVALIDITY as (long) number.""" if hasattr(self, '_uidvalidity'): # use cached value if existing return self._uidvalidity imapobj = self.imapserver.acquireconnection() try: # SELECT (if not already done) and get current UIDVALIDITY self.selectro(imapobj) typ, uidval = imapobj.response('UIDVALIDITY') assert uidval != [None] and uidval != None, \ "response('UIDVALIDITY') returned [None]!" self._uidvalidity = long(uidval[-1]) return self._uidvalidity finally: self.imapserver.releaseconnection(imapobj) def quickchanged(self, statusfolder): # An IMAP folder has definitely changed if the number of # messages or the UID of the last message have changed. Otherwise # only flag changes could have occurred. retry = True # Should we attempt another round or exit? while retry: retry = False imapobj = self.imapserver.acquireconnection() try: # Select folder and get number of messages restype, imapdata = imapobj.select(self.getfullname(), True, True) except OfflineImapError as e: # retry on dropped connections, raise otherwise self.imapserver.releaseconnection(imapobj, True) if e.severity == OfflineImapError.ERROR.FOLDER_RETRY: retry = True else: raise finally: self.imapserver.releaseconnection(imapobj) # 1. Some mail servers do not return an EXISTS response # if the folder is empty. 2. ZIMBRA servers can return # multiple EXISTS replies in the form 500, 1000, 1500, # 1623 so check for potentially multiple replies. if imapdata == [None]: return True maxmsgid = 0 for msgid in imapdata: maxmsgid = max(long(msgid), maxmsgid) # Different number of messages than last time? if maxmsgid != statusfolder.getmessagecount(): return True return False def cachemessagelist(self): maxage = self.config.getdefaultint("Account %s" % self.accountname, "maxage", -1) maxsize = self.config.getdefaultint("Account %s" % self.accountname, "maxsize", -1) self.messagelist = {} imapobj = self.imapserver.acquireconnection() try: res_type, imapdata = imapobj.select(self.getfullname(), True, True) if imapdata == [None] or imapdata[0] == '0': # Empty folder, no need to populate message list return # By default examine all UIDs in this folder msgsToFetch = '1:*' if (maxage != -1) | (maxsize != -1): search_cond = "("; if(maxage != -1): #find out what the oldest message is that we should look at oldest_struct = time.gmtime(time.time() - (60*60*24*maxage)) if oldest_struct[0] < 1900: raise OfflineImapError("maxage setting led to year %d. " "Abort syncing." % oldest_struct[0], OfflineImapError.ERROR.REPO) search_cond += "SINCE %02d-%s-%d" % ( oldest_struct[2], MonthNames[oldest_struct[1]], oldest_struct[0]) if(maxsize != -1): if(maxage != -1): # There are two conditions, add space search_cond += " " search_cond += "SMALLER %d" % maxsize search_cond += ")" res_type, res_data = imapobj.search(None, search_cond) if res_type != 'OK': raise OfflineImapError("SEARCH in folder [%s]%s failed. " "Search string was '%s'. Server responded '[%s] %s'" % ( self.getrepository(), self, search_cond, res_type, res_data), OfflineImapError.ERROR.FOLDER) # Result UIDs are seperated by space, coalesce into ranges msgsToFetch = imaputil.uid_sequence(res_data[0].split()) if not msgsToFetch: return # No messages to sync # Get the flags and UIDs for these. single-quotes prevent # imaplib2 from quoting the sequence. res_type, response = imapobj.fetch("'%s'" % msgsToFetch, '(FLAGS UID)') if res_type != 'OK': raise OfflineImapError("FETCHING UIDs in folder [%s]%s failed. " "Server responded '[%s] %s'" % ( self.getrepository(), self, res_type, response), OfflineImapError.ERROR.FOLDER) finally: self.imapserver.releaseconnection(imapobj) for messagestr in response: # looks like: '1 (FLAGS (\\Seen Old) UID 4807)' or None if no msg # Discard initial message number. if messagestr == None: continue messagestr = messagestr.split(' ', 1)[1] options = imaputil.flags2hash(messagestr) if not 'UID' in options: self.ui.warn('No UID in message with options %s' %\ str(options), minor = 1) else: uid = long(options['UID']) flags = imaputil.flagsimap2maildir(options['FLAGS']) rtime = imaplibutil.Internaldate2epoch(messagestr) self.messagelist[uid] = {'uid': uid, 'flags': flags, 'time': rtime} def getmessagelist(self): return self.messagelist def getmessage(self, uid): """Retrieve message with UID from the IMAP server (incl body) :returns: the message body or throws and OfflineImapError (probably severity MESSAGE) if e.g. no message with this UID could be found. """ imapobj = self.imapserver.acquireconnection() try: fails_left = 2 # retry on dropped connection while fails_left: try: imapobj.select(self.getfullname(), readonly = True) res_type, data = imapobj.uid('fetch', str(uid), '(BODY.PEEK[])') fails_left = 0 except imapobj.abort as e: # Release dropped connection, and get a new one self.imapserver.releaseconnection(imapobj, True) imapobj = self.imapserver.acquireconnection() self.ui.error(e, exc_info()[2]) fails_left -= 1 if not fails_left: raise e if data == [None] or res_type != 'OK': #IMAP server says bad request or UID does not exist severity = OfflineImapError.ERROR.MESSAGE reason = "IMAP server '%s' failed to fetch message UID '%d'."\ "Server responded: %s %s" % (self.getrepository(), uid, res_type, data) if data == [None]: #IMAP server did not find a message with this UID reason = "IMAP server '%s' does not have a message "\ "with UID '%s'" % (self.getrepository(), uid) raise OfflineImapError(reason, severity) # data looks now e.g. [('320 (UID 17061 BODY[] # {2565}','msgbody....')] we only asked for one message, # and that msg is in data[0]. msbody is in [0][1] data = data[0][1].replace("\r\n", "\n") if len(data)>200: dbg_output = "%s...%s" % (str(data)[:150], str(data)[-50:]) else: dbg_output = data self.ui.debug('imap', "Returned object from fetching %d: '%s'" % (uid, dbg_output)) finally: self.imapserver.releaseconnection(imapobj) return data def getmessagetime(self, uid): return self.messagelist[uid]['time'] def getmessageflags(self, uid): return self.messagelist[uid]['flags'] def generate_randomheader(self, content): """Returns a unique X-OfflineIMAP header Generate an 'X-OfflineIMAP' mail header which contains a random unique value (which is based on the mail content, and a random number). This header allows us to fetch a mail after APPENDing it to an IMAP server and thus find out the UID that the server assigned it. :returns: (headername, headervalue) tuple, consisting of strings headername == 'X-OfflineIMAP' and headervalue will be a random string """ headername = 'X-OfflineIMAP' # We need a random component too. If we ever upload the same # mail twice (e.g. in different folders), we would still need to # get the UID for the correct one. As we won't have too many # mails with identical content, the randomness requirements are # not extremly critial though. # compute unsigned crc32 of 'content' as unique hash # NB: crc32 returns unsigned only starting with python 3.0 headervalue = str( binascii.crc32(content) & 0xffffffff ) + '-' headervalue += str(self.randomgenerator.randint(0,9999999999)) return (headername, headervalue) def savemessage_addheader(self, content, headername, headervalue): self.ui.debug('imap', 'savemessage_addheader: called to add %s: %s' % (headername, headervalue)) insertionpoint = content.find("\r\n\r\n") self.ui.debug('imap', 'savemessage_addheader: insertionpoint = %d' % insertionpoint) leader = content[0:insertionpoint] self.ui.debug('imap', 'savemessage_addheader: leader = %s' % repr(leader)) if insertionpoint == 0 or insertionpoint == -1: newline = '' insertionpoint = 0 else: newline = "\r\n" newline += "%s: %s" % (headername, headervalue) self.ui.debug('imap', 'savemessage_addheader: newline = ' + repr(newline)) trailer = content[insertionpoint:] self.ui.debug('imap', 'savemessage_addheader: trailer = ' + repr(trailer)) return leader + newline + trailer def savemessage_searchforheader(self, imapobj, headername, headervalue): self.ui.debug('imap', 'savemessage_searchforheader called for %s: %s' % \ (headername, headervalue)) # Now find the UID it got. headervalue = imapobj._quote(headervalue) try: matchinguids = imapobj.uid('search', 'HEADER', headername, headervalue)[1][0] except imapobj.error as err: # IMAP server doesn't implement search or had a problem. self.ui.debug('imap', "savemessage_searchforheader: got IMAP error '%s' while attempting to UID SEARCH for message with header %s" % (err, headername)) return 0 self.ui.debug('imap', 'savemessage_searchforheader got initial matchinguids: ' + repr(matchinguids)) if matchinguids == '': self.ui.debug('imap', "savemessage_searchforheader: UID SEARCH for message with header %s yielded no results" % headername) return 0 matchinguids = matchinguids.split(' ') self.ui.debug('imap', 'savemessage_searchforheader: matchinguids now ' + \ repr(matchinguids)) if len(matchinguids) != 1 or matchinguids[0] == None: raise ValueError("While attempting to find UID for message with " "header %s, got wrong-sized matchinguids of %s" %\ (headername, str(matchinguids))) return long(matchinguids[0]) def savemessage_fetchheaders(self, imapobj, headername, headervalue): """ We fetch all new mail headers and search for the right X-OfflineImap line by hand. The response from the server has form: ( 'OK', [ ( '185 (RFC822.HEADER {1789}', '... mail headers ...' ), ' UID 2444)', ( '186 (RFC822.HEADER {1789}', '... 2nd mail headers ...' ), ' UID 2445)' ] ) We need to locate the UID just after mail headers containing our X-OfflineIMAP line. Returns UID when found, 0 when not found. """ self.ui.debug('imap', 'savemessage_fetchheaders called for %s: %s' % \ (headername, headervalue)) # run "fetch X:* rfc822.header" # since we stored the mail we are looking for just recently, it would # not be optimal to fetch all messages. So we'll find highest message # UID in our local messagelist and search from there (exactly from # UID+1). That works because UIDs are guaranteed to be unique and # ascending. if self.getmessagelist(): start = 1+max(self.getmessagelist().keys()) else: # Folder was empty - start from 1 start = 1 # Imaplib quotes all parameters of a string type. That must not happen # with the range X:*. So we use bytearray to stop imaplib from getting # in our way result = imapobj.uid('FETCH', bytearray('%d:*' % start), 'rfc822.header') if result[0] != 'OK': raise OfflineImapError('Error fetching mail headers: ' + '. '.join(result[1]), OfflineImapError.ERROR.MESSAGE) result = result[1] found = 0 for item in result: if found == 0 and type(item) == type( () ): # Walk just tuples if re.search("(?:^|\\r|\\n)%s:\s*%s(?:\\r|\\n)" % (headername, headervalue), item[1], flags=re.IGNORECASE): found = 1 elif found == 1: if type(item) == type (""): uid = re.search("UID\s+(\d+)", item, flags=re.IGNORECASE) if uid: return int(uid.group(1)) else: self.ui.warn("Can't parse FETCH response, can't find UID: %s", result.__repr__()) else: self.ui.warn("Can't parse FETCH response, we awaited string: %s", result.__repr__()) return 0 def getmessageinternaldate(self, content, rtime=None): """Parses mail and returns an INTERNALDATE string It will use information in the following order, falling back as an attempt fails: - rtime parameter - Date header of email We return None, if we couldn't find a valid date. In this case the IMAP server will use the server local time when appening (per RFC). Note, that imaplib's Time2Internaldate is inherently broken as it returns localized date strings which are invalid for IMAP servers. However, that function is called for *every* append() internally. So we need to either pass in `None` or the correct string (in which case Time2Internaldate() will do nothing) to append(). The output of this function is designed to work as input to the imapobj.append() function. TODO: We should probably be returning a bytearray rather than a string here, because the IMAP server will expect plain ASCII. However, imaplib.Time2INternaldate currently returns a string so we go with the same for now. :param rtime: epoch timestamp to be used rather than analyzing the email. :returns: string in the form of "DD-Mmm-YYYY HH:MM:SS +HHMM" (including double quotes) or `None` in case of failure (which is fine as value for append).""" if rtime is None: message = email.message_from_string(content) # parsedate returns a 9-tuple that can be passed directly to # time.mktime(); Will be None if missing or not in a valid # format. Note that indexes 6, 7, and 8 of the result tuple are # not usable. datetuple = email.utils.parsedate(message.get('Date')) if datetuple is None: #could not determine the date, use the local time. return None #make it a real struct_time, so we have named attributes datetuple = time.struct_time(datetuple) else: #rtime is set, use that instead datetuple = time.localtime(rtime) try: # Check for invalid dates if datetuple[0] < 1981: raise ValueError # Check for invalid dates datetuple_check = time.localtime(time.mktime(datetuple)) if datetuple[:2] != datetuple_check[:2]: raise ValueError except (ValueError, OverflowError): # Argh, sometimes it's a valid format but year is 0102 # or something. Argh. It seems that Time2Internaldate # will rause a ValueError if the year is 0102 but not 1902, # but some IMAP servers nonetheless choke on 1902. self.ui.debug('imap', "Message with invalid date %s. Server will use local time." \ % datetuple) return None #produce a string representation of datetuple that works as #INTERNALDATE num2mon = {1:'Jan', 2:'Feb', 3:'Mar', 4:'Apr', 5:'May', 6:'Jun', 7:'Jul', 8:'Aug', 9:'Sep', 10:'Oct', 11:'Nov', 12:'Dec'} #tm_isdst coming from email.parsedate is not usable, we still use it here, mhh if datetuple.tm_isdst == '1': zone = -time.altzone else: zone = -time.timezone offset_h, offset_m = divmod(zone//60, 60) internaldate = '"%02d-%s-%04d %02d:%02d:%02d %+03d%02d"' \ % (datetuple.tm_mday, num2mon[datetuple.tm_mon], datetuple.tm_year, \ datetuple.tm_hour, datetuple.tm_min, datetuple.tm_sec, offset_h, offset_m) return internaldate def savemessage(self, uid, content, flags, rtime): """Save the message on the Server This backend always assigns a new uid, so the uid arg is ignored. This function will update the self.messagelist dict to contain the new message after sucessfully saving it. :param rtime: A timestamp to be used as the mail date :returns: the UID of the new message as assigned by the server. If the message is saved, but it's UID can not be found, it will return 0. If the message can't be written (folder is read-only for example) it will return -1.""" self.ui.debug('imap', 'savemessage: called') # already have it, just save modified flags if uid > 0 and self.uidexists(uid): self.savemessageflags(uid, flags) return uid retry_left = 2 # succeeded in APPENDING? imapobj = self.imapserver.acquireconnection() try: while retry_left: # UIDPLUS extension provides us with an APPENDUID response. use_uidplus = 'UIDPLUS' in imapobj.capabilities # get the date of the message, so we can pass it to the server. date = self.getmessageinternaldate(content, rtime) content = re.sub("(?200: dbg_output = "%s...%s" % (content[:150], content[-50:]) else: dbg_output = content self.ui.debug('imap', "savemessage: date: %s, content: '%s'" % (date, dbg_output)) try: # Select folder for append and make the box READ-WRITE imapobj.select(self.getfullname()) except imapobj.readonly: # readonly exception. Return original uid to notify that # we did not save the message. (see savemessage in Base.py) self.ui.msgtoreadonly(self, uid, content, flags) return uid # Clean out existing APPENDUID responses and do APPEND try: imapobj.response('APPENDUID') # flush APPENDUID responses typ, dat = imapobj.append(self.getfullname(), imaputil.flagsmaildir2imap(flags), date, content) retry_left = 0 # Mark as success except imapobj.abort as e: # connection has been reset, release connection and retry. retry_left -= 1 self.imapserver.releaseconnection(imapobj, True) imapobj = self.imapserver.acquireconnection() if not retry_left: raise OfflineImapError("Saving msg in folder '%s', " "repository '%s' failed (abort). Server reponded: %s\n" "Message content was: %s" % (self, self.getrepository(), str(e), dbg_output), OfflineImapError.ERROR.MESSAGE) self.ui.error(e, exc_info()[2]) except imapobj.error as e: # APPEND failed # If the server responds with 'BAD', append() # raise()s directly. So we catch that too. # drop conn, it might be bad. self.imapserver.releaseconnection(imapobj, True) imapobj = None raise OfflineImapError("Saving msg folder '%s', repo '%s'" "failed (error). Server reponded: %s\nMessage content was: " "%s" % (self, self.getrepository(), str(e), dbg_output), OfflineImapError.ERROR.MESSAGE) # get the new UID, default to 0 (=unknown) uid = 0 if use_uidplus: # get new UID from the APPENDUID response, it could look # like OK [APPENDUID 38505 3955] APPEND completed with # 38505 being folder UIDvalidity and 3955 the new UID. typ, resp = imapobj.response('APPENDUID') if resp == [None] or resp == None: self.ui.warn("Server supports UIDPLUS but got no APPENDUID " "appending a message.") else: uid = long(resp[-1].split(' ')[1]) if uid == 0: self.ui.warn("savemessage: Server supports UIDPLUS, but" " we got no usable uid back. APPENDUID reponse was " "'%s'" % str(resp)) else: # Don't support UIDPLUS # Checkpoint. Let it write out stuff, etc. Eg searches for # just uploaded messages won't work if we don't do this. typ, dat = imapobj.check() assert(typ == 'OK') uid = self.savemessage_searchforheader(imapobj, headername, headervalue) # If everything failed up to here, search the message # manually TODO: rather than inserting and searching for our # custom header, we should be searching the Message-ID and # compare the message size... if uid == 0: self.ui.debug('imap', 'savemessage: attempt to get new UID ' 'UID failed. Search headers manually.') uid = self.savemessage_fetchheaders(imapobj, headername, headervalue) self.ui.warn('imap', "savemessage: Searching mails for new " "Message-ID failed. Could not determine new UID.") finally: self.imapserver.releaseconnection(imapobj) if uid: # avoid UID FETCH 0 crash happening later on self.messagelist[uid] = {'uid': uid, 'flags': flags} self.ui.debug('imap', 'savemessage: returning new UID %d' % uid) return uid def savemessageflags(self, uid, flags): """Change a message's flags to `flags`.""" imapobj = self.imapserver.acquireconnection() try: try: imapobj.select(self.getfullname()) except imapobj.readonly: self.ui.flagstoreadonly(self, [uid], flags) return result = imapobj.uid('store', '%d' % uid, 'FLAGS', imaputil.flagsmaildir2imap(flags)) assert result[0] == 'OK', 'Error with store: ' + '. '.join(result[1]) finally: self.imapserver.releaseconnection(imapobj) result = result[1][0] if not result: self.messagelist[uid]['flags'] = flags else: flags = imaputil.flags2hash(imaputil.imapsplit(result)[1])['FLAGS'] self.messagelist[uid]['flags'] = imaputil.flagsimap2maildir(flags) def addmessageflags(self, uid, flags): self.addmessagesflags([uid], flags) def addmessagesflags_noconvert(self, uidlist, flags): self.processmessagesflags('+', uidlist, flags) def addmessagesflags(self, uidlist, flags): """This is here for the sake of UIDMaps.py -- deletemessages must add flags and get a converted UID, and if we don't have noconvert, then UIDMaps will try to convert it twice.""" self.addmessagesflags_noconvert(uidlist, flags) def deletemessageflags(self, uid, flags): self.deletemessagesflags([uid], flags) def deletemessagesflags(self, uidlist, flags): self.processmessagesflags('-', uidlist, flags) def processmessagesflags(self, operation, uidlist, flags): if len(uidlist) > 101: # Hack for those IMAP ervers with a limited line length self.processmessagesflags(operation, uidlist[:100], flags) self.processmessagesflags(operation, uidlist[100:], flags) return imapobj = self.imapserver.acquireconnection() try: try: imapobj.select(self.getfullname()) except imapobj.readonly: self.ui.flagstoreadonly(self, uidlist, flags) return r = imapobj.uid('store', imaputil.uid_sequence(uidlist), operation + 'FLAGS', imaputil.flagsmaildir2imap(flags)) assert r[0] == 'OK', 'Error with store: ' + '. '.join(r[1]) r = r[1] finally: self.imapserver.releaseconnection(imapobj) # Some IMAP servers do not always return a result. Therefore, # only update the ones that it talks about, and manually fix # the others. needupdate = list(uidlist) for result in r: if result == None: # Compensate for servers that don't return anything from # STORE. continue attributehash = imaputil.flags2hash(imaputil.imapsplit(result)[1]) if not ('UID' in attributehash and 'FLAGS' in attributehash): # Compensate for servers that don't return a UID attribute. continue flagstr = attributehash['FLAGS'] uid = long(attributehash['UID']) self.messagelist[uid]['flags'] = imaputil.flagsimap2maildir(flagstr) try: needupdate.remove(uid) except ValueError: # Let it slide if it's not in the list pass for uid in needupdate: if operation == '+': self.messagelist[uid]['flags'] |= flags elif operation == '-': self.messagelist[uid]['flags'] -= flags def change_message_uid(self, uid, new_uid): """Change the message from existing uid to new_uid If the backend supports it. IMAP does not and will throw errors.""" raise OfflineImapError('IMAP backend cannot change a messages UID from ' '%d to %d' % (uid, new_uid), OfflineImapError.ERROR.MESSAGE) def deletemessage(self, uid): self.deletemessages_noconvert([uid]) def deletemessages(self, uidlist): self.deletemessages_noconvert(uidlist) def deletemessages_noconvert(self, uidlist): # Weed out ones not in self.messagelist uidlist = [uid for uid in uidlist if self.uidexists(uid)] if not len(uidlist): return self.addmessagesflags_noconvert(uidlist, set('T')) imapobj = self.imapserver.acquireconnection() try: try: imapobj.select(self.getfullname()) except imapobj.readonly: self.ui.deletereadonly(self, uidlist) return if self.expunge: assert(imapobj.expunge()[0] == 'OK') finally: self.imapserver.releaseconnection(imapobj) for uid in uidlist: del self.messagelist[uid]