Package: mailscripts Severity: wishlist Version: 0.11-1 Tags: patch upstream
Please consider adding imap-dl to mailscripts (see attached patch). This is a simple downloader that pulls from IMAP-over-TLS and deposits in a Maildir. It is in python3, and makes use of only the modern stdlib. This allows those of us who use getmail to treat a remote IMAP store as a POP message store to no longer depend on getmail (which is python2-only at the time of this writing). --dkg
From 0f17fac791cb6b2fd656b85d97c28f432571e750 Mon Sep 17 00:00:00 2001 From: Daniel Kahn Gillmor <d...@fifthhorseman.net> Date: Sun, 15 Sep 2019 19:55:07 -0400 Subject: [PATCH] Add imap-dl, a simple imap downloader getmail upstream appears to have no plans to convert to python3 in the near future. Some of us use only a minimal subset of features of getmail, and it would be nice to have something simpler, with the main complexity offloaded to the modern python3 stdlib. Signed-off-by: Daniel Kahn Gillmor <d...@fifthhorseman.net> --- Makefile | 1 + imap-dl | 196 ++++++++++++++++++++++++++++++++++++++++++++++++++ imap-dl.1.pod | 80 +++++++++++++++++++++ 3 files changed, 277 insertions(+) create mode 100755 imap-dl create mode 100644 imap-dl.1.pod diff --git a/Makefile b/Makefile index 352f6f0..860ec27 100644 --- a/Makefile +++ b/Makefile @@ -1,5 +1,6 @@ MANPAGES=mdmv.1 mbox2maildir.1 \ notmuch-slurp-debbug.1 notmuch-extract-patch.1 maildir-import-patch.1 \ + imap-dl.1 \ email-extract-openpgp-certs.1 \ email-print-mime-structure.1 \ notmuch-import-patch.1 diff --git a/imap-dl b/imap-dl new file mode 100755 index 0000000..97fa4a8 --- /dev/null +++ b/imap-dl @@ -0,0 +1,196 @@ +#!/usr/bin/python3 +# -*- coding: utf-8 -*- + +# Copyright (C) 2019 Daniel Kahn Gillmor +# +# 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 3 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, see <https://www.gnu.org/licenses/>. + +'''A simple replacement for a minimalist use of getmail. + +Usage: + + imap-dl [-v|--verbose] configfile… + +In particular, if you use getmail to reach an IMAP server as though it +was POP (retrieving from the server and optionally deleting), you can +point this script to the getmail config and it should do the same +thing. + +It tries to ensure that the configuration file is of the expected +type, and will terminate raising an exception, and it should not lose +messages. + +If there's any interest in supporting other use cases for getmail, +patches are welcome. + +If you've never used getmail, you can make the simplest possible +config file like so: + +---------- +[retriever] +server = mail.example.net +username = foo +password = sekr1t! + +[destination] +path = /home/foo/Maildir + +[options] +delete = True +---------- +''' + +import configparser +import sys +import ssl +import imaplib +import re +import logging +import mailbox +import os.path + +_summary_splitter = re.compile(rb'^(?P<id>[0-9]+) \(UID (?P<uid>[0-9]+) RFC822.SIZE (?P<size>[0-9]+)\)$') +def break_fetch_summary(line): + '''b'1 (UID 160 RFC822.SIZE 1867)' -> {id: 1, uid: 160, size: 1867}''' + match = _summary_splitter.match(line) + if not match: + raise Exception('malformed summary line %s'%(line)) + ret = {} + for i in ['id', 'uid', 'size']: + ret[i] = int(match[i]) + return ret + +_fetch_splitter = re.compile(rb'^(?P<id>[0-9]+) \(UID (?P<uid>[0-9]+) (FLAGS \([\\A-Za-z ]*\) )?BODY\[\] \{(?P<size>[0-9]+)\}$') +def break_fetch(line): + '''b'1 (UID 160 BODY[] {1867}' -> {id: 1, uid: 160, size: 1867}''' + match = _fetch_splitter.match(line) + if not match: + raise Exception('malformed fetch line %s'%(line)) + ret = {} + for i in ['id', 'uid', 'size']: + ret[i] = int(match[i]) + return ret + +def pull_msgs(configfile): + logging.info('pulling from config file %s'%(configfile,)) + conf = configparser.ConfigParser() + conf.read_file(open(configfile, 'r')) + delete = conf.get('options', 'delete', fallback='False') + if not isinstance(delete, bool): + if delete.lower() in ['true', 'yes', '1']: + delete = True + elif delete.lower() not in ['false', 'no', '0']: + logging.warning('options.delete has unknown value %s, treating as false'%(delete,)) + delete = False + rtype = conf.get('retreiver', 'type', fallback='SimpleIMAPSSLRetriever') + if rtype.lower() != 'simpleimapsslretriever': + raise Exception('Expected retriever.type to be SimpleIMAPSSLRetriever, got %s'%(rtype,)) + # FIXME: handle `retriever.record_mailbox` + # FIXME: handle leading ~-style globbing for destination.type + dtype = conf.get('destination', 'type', fallback='Maildir') + if dtype.lower() != 'maildir': + raise Exception('expected destination.type to be Maildir, got %s'%( + dtype)) + dst = conf.get('destination', 'path') + if not os.path.isdir(dst): + raise Exception('expected destination directory, but %s is not a directory'%(dst,)) + ca_certs = conf.get('retriever', 'ca_certs', fallback=None) + ctx = ssl.create_default_context(cafile=ca_certs) + mdst = mailbox.Maildir(dst) + with imaplib.IMAP4_SSL(host=conf.get('retriever', 'server'), + port=conf.get('retriever', 'port', fallback=993), + ssl_context=ctx) as imap: + resp = imap.login(conf.get('retriever', 'username'), + conf.get('retriever', 'password')) + if resp[0] != 'OK': + raise Exception('login failed with %s as user %s on %s'%( + resp, + conf.get('retriever', 'username'), + conf.get('retriever', 'server'))) + resp = imap.select() + if resp[0] != 'OK': + raise Exception('selection failed: %s'%(resp,)) + if len(resp[1]) != 1: + raise Exception('expected exactly one EXISTS response from select, got %s'%(resp[1])) + n = int(resp[1][0]) + if n == 0: + logging.info('No messages to retrieve') + return + resp = imap.fetch('1:%d'%(n), '(UID RFC822.SIZE)') + if resp[0] != 'OK': + raise Exception('initial FETCH 1:%d not OK (%s)'%(n, resp)) + pending = list(map(break_fetch_summary, resp[1])) + sizes = {} + for m in pending: + sizes[m['uid']] = m['size'] + fetched = set() + uids = ','.join(map(lambda x: str(x['uid']), sorted(pending, key=lambda x: x['uid']))) + totalbytes = sum([x['size'] for x in pending]) + logging.info('Fetching %d messages, for a total of %d bytes'%( + len(pending), totalbytes)) + # FIXME: sort by size? + # FIXME: fetch in batches or singly instead of all-at-once? + # FIXME: rolling deletion? + # FIXME: asynchronous work? + resp = imap.uid('fetch', uids, '(UID BODY[])') + if resp[0] != 'OK': + raise Exception('UID fetch failed %s'%(resp[0])) + for f in resp[1]: + # these objects are weirdly structured. i don't know why + # these trailing close-parens show up. so this is very + # ad-hoc and nonsense + if isinstance(f, bytes): + if f != b')': + raise Exception('got bytes object of length %d but expected simple closeparen'%(len(f),)) + elif isinstance(f, tuple): + if len(f) != 2: + raise Exception('expected 2-part tuple, got %d-part'%( + len(f))) + m = break_fetch(f[0]) + if m['size'] != len(f[1]): + raise Exception('expected %d octets, got %d'%( + m['size'], len(f[1]))) + if m['size'] != sizes[m['uid']]: + raise Exception('summary said %d octets, fetch sent %d'%( + sizes[m['uid']], m['size'])) + fname = mdst.add(f[1]) + logging.info('stored message %d/%d (uid %d, %d bytes) in %s'%( + len(fetched) + 1, len(pending), m['uid'], m['size'], fname)) + del sizes[m['uid']] + fetched.add(m['uid']) + if sizes: + logging.warning('unhandled UIDs: %s'%(sizes)) + if delete: + logging.info('trying to delete %d messages from IMAP store'%(len(fetched))) + resp = imap.uid('STORE', ','.join(map(str, fetched)), '+FLAGS', r'(\Deleted)') + if resp[0] != 'OK': + raise Exception('failed to set \\Deleted flag: %s'%(resp)) + resp = imap.expunge() + if resp[0] != 'OK': + raise Exception('failed to expunge! %s'%(resp)) + else: + logging.info('not deleting any messages, since delete=True') + +if __name__ == '__main__': + args = sys.argv[1:] + for varg in ['-v', '--verbose']: + while varg in args: + logging.getLogger().setLevel(logging.INFO) + args.remove(varg) + + if not args: + logging.error('no config files supplied, must supply at least one') + exit(1) + for confname in args: + pull_msgs(confname) diff --git a/imap-dl.1.pod b/imap-dl.1.pod new file mode 100644 index 0000000..4afdaf0 --- /dev/null +++ b/imap-dl.1.pod @@ -0,0 +1,80 @@ +=encoding utf8 + +=head1 NAME + +imap-dl -- a simple replacement for a minimalist user of getmail + +=head1 SYNOPSIS + +B<imap-dl> [B<-v>|B<--verbose>}] B<configfile>... + +=head1 DESCRIPTION + +If you use getmail to reach an IMAP server as though it was POP +(retrieving from the server, storing it in a maildir and optionally +deleting), you can point this script to the getmail config and it +should do the same thing. + +It tries to ensure that the configuration file is of the expected +type, and will terminate raising an exception, and it should not lose +messages. + +If there's any interest in supporting other use cases for getmail, +patches are welcome. + +=head1 OPTIONS + +B<-v> or B<--verbose> causes B<imap-dl> to print more details +about what it is doing. + +=head1 EXAMPLE CONFIG + +If you've never used getmail, you can make the simplest possible +config file like so: + +=over 4 + + [retriever] + server = mail.example.net + username = foo + password = sekr1t! + + [destination] + path = /home/foo/Maildir + + [options] + delete = True + +=back + +=head1 LIMITATIONS + +B<imap-dl> is currently deliberately minimal. It is designed to be +used by someone who treats their IMAP mailbox like a POP server. + +It works with IMAP-over-TLS only, and it just fetches all messages +from the default IMAP folder. It does not support all the various +features of getmail. + +B<imap-dl> is deliberately implemented in a modern version of python3, +and tries to just use the standard library. It will not be backported +to python2. + +B<imap-dl> uses imaplib, which means that it does synchronous calls to +the imap server. A more clever implementation would use asynchronous +python to avoid latency/roundtrips. + +B<imap-dl> does not know how to wait and listen for new mail using +IMAP IDLE. This would be a nice additional feature. + +B<imap-dl> does not yet know how to deliver to an MDA (or to +B<notmuch-insert>). This would be a nice thing to be able to do. + +=head1 SEE ALSO + +https://tools.ietf.org/html/rfc3501, http://pyropus.ca/software/getmail/ + +=head1 AUTHOR + +B<imap-dl> and this manpage were written by Daniel Kahn Gillmor, +inspired by some functionality from the getmail project. -- 2.23.0
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