Hi Sean-- Thanks for the extensive review. I've revised imap-dl, taking it into account, and have attached the revised version here. You can also find it on my imap-dl-v2 branch on salsa.
I've adopted all of the suggested revisions in pretty straightforward
ways except for the comments below.
On Thu 2020-01-23 12:24:31 -0700, Sean Whitton wrote:
> Is there really no documentation from the IMAP library you're using
> about the closeparens?
I've dug further into imaplib, and i've pushed the typeshed folks toward
annotating imaplib further based on those findings. We now expect the
response to the uids() call to be a list of items that alternates
between Tuple[bytes,bytes] and b')'.
>> + fname = mdst.add(f[1].replace(b'\r\n', b'\n'))
>
> Could a message contain a mixture of UNIX and Windows line endings, such
> that this line corrupts the message? If not, please write a comment
> saying why it is always safe to perform this replacement.
I know of no way to have this create an actual corruption, unless the
message itself doesn't actually have line endings at all (e.g. an 8-bit
attachment in a MIME message) but i don't have anything like that handy
and i've never seen it in practice.
> Maybe python has a e-mail message processing library with a function to
> transform line endings safely?
not that i know of, but if you want to point me to something specific
i'd be happy to adopt it. I suppose we could round-trip the blob
through some function of email.message, but i'm not sure that's useful
or necessary.
>> + if delete:
>> + logging.info('trying to delete %d messages from IMAP store',
>> len(fetched))
>> + resp = imap.uid('STORE', ','.join(map(str, fetched.keys())),
>> '+FLAGS', r'(\Deleted)')
>> + if resp[0] != 'OK':
>> + raise Exception('failed to set \\Deleted flag: %s'%(resp))
>> + resp = imap.expunge()
>
> Not a blocker, but it would be nice if the user could request that the
> expunge step be skipped.
this is a pretty subtle distinction -- you want to set the Deleted flag
but not expunge? can you describe the use case?
> Also, will imap-dl skip messages with the deleted flag? Do you think it
> should?
I don't think it should -- the use case at the moment is just to fetch
all messages that exist in the inbox. Why should it treat any flag
differently?
--dkg
#!/usr/bin/python3 # PYTHON_ARGCOMPLETE_OK # -*- 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/>. DESCRIPTION = '''A simple replacement for a minimalist use of getmail. In particular, if you use getmail to reach an IMAP server as though it were 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 similarly simple 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 re import sys import ssl import enum import time import imaplib import logging import mailbox import os.path import argparse import statistics import configparser from typing import Dict, List, Union, Tuple try: import argcomplete #type: ignore except ImportError: argcomplete = None class Splitter(object): def __init__(self, name:str, match:bytes): self._splitter = re.compile(match) self._name = name def breakup(self, line:bytes) -> Dict[str,int]: match = self._splitter.match(line) if not match: raise Exception(f'malformed {self._name} line {line!r}') ret:Dict[str,int] = {} i:str for i in ['id', 'uid', 'size']: ret[i] = int(match[i]) return ret OnSizeMismatch = enum.Enum('OnSizeMismatch', 'warn error none') # b'1 (UID 160 RFC822.SIZE 1867)' -> {id: 1, uid: 160, size: 1867} _summary_re = rb'^(?P<id>[0-9]+) \(UID (?P<uid>[0-9]+) RFC822.SIZE (?P<size>[0-9]+)\)$' summary_splitter = Splitter('summary', _summary_re) # b'1 (UID 160 BODY[] {1867}' -> {id: 1, uid: 160, size: 1867} _fetch_re = rb'^(?P<id>[0-9]+) \(UID (?P<uid>[0-9]+) (FLAGS \([\\A-Za-z ]*\) )?BODY\[\] \{(?P<size>[0-9]+)\}$' fetch_splitter = Splitter('fetch', _fetch_re) def scan_msgs(configfile:str, verbose:bool) -> None: conf = configparser.ConfigParser() conf.read_file(open(configfile, 'r')) oldloglevel = logging.getLogger().getEffectiveLevel() conf_verbose = conf.getint('options', 'verbose', fallback=1) if conf_verbose > 1: verbose = True if verbose: logging.getLogger().setLevel(logging.INFO) logging.info('pulling from config file %s', configfile) delete = conf.getboolean('options', 'delete', fallback=False) read_all = conf.getboolean('options', 'read_all', fallback=True) if not read_all: raise NotImplementedError('imap-dl only supports options.read_all=True, got False') rtype = conf.get('retriever', 'type', fallback='SimpleIMAPSSLRetriever') if rtype.lower() != 'simpleimapsslretriever': raise NotImplementedError(f'imap-dl only supports retriever.type=SimpleIMAPSSLRetriever, got {rtype}') # FIXME: handle `retriever.record_mailbox` dtype = conf.get('destination', 'type', fallback='Maildir') if dtype.lower() != 'maildir': raise NotImplementedError(f'imap-dl only supports destination.type=Maildir, got {dtype}') dst = conf.get('destination', 'path') dst = os.path.expanduser(dst) if os.path.exists(dst) and not os.path.isdir(dst): raise Exception('expected destination directory, but %s is not a directory'%(dst,)) mdst:mailbox.Maildir = mailbox.Maildir(dst, create=True) ca_certs = conf.get('retriever', 'ca_certs', fallback=None) on_size_mismatch_str:str = conf.get('options', 'on_size_mismatch', fallback='error').lower() try: on_size_mismatch:OnSizeMismatch = OnSizeMismatch.__members__[on_size_mismatch_str] except KeyError: raise Exception(f'options.on_size_mismatch value should be one of:\n' '{list(OnSizeMismatch.__members__.keys())}\n' '(found "{on_size_mismatch_str}")') ctx = ssl.create_default_context(cafile=ca_certs) server:str = conf.get('retriever', 'server') with imaplib.IMAP4_SSL(host=server, #type: ignore port=int(conf.get('retriever', 'port', fallback=993)), ssl_context=ctx) as imap: username:str = conf.get('retriever', 'username') logging.info('Logging in as %s', username) resp:Tuple[str, List[Union[bytes,Tuple[bytes,bytes]]]] resp = imap.login(username, conf.get('retriever', 'password')) if resp[0] != 'OK': raise Exception(f'login failed with {resp} as user {username} on {server}') if verbose: # only enable debugging after login to avoid leaking credentials in the log imap.debug = 4 logging.info("capabilities reported: %s", ', '.join(imap.capabilities)) resp = imap.select(readonly=not delete) if resp[0] != 'OK': raise Exception(f'selection failed: {resp}') if len(resp[1]) != 1: raise Exception(f'expected exactly one EXISTS response from select, got {resp[1]}') data:Union[bytes,Tuple[bytes,bytes]] = resp[1][0] if not isinstance(data, bytes): raise Exception(f'expected bytes in response to SELECT, got {data}') n:int = int(data) if n == 0: logging.info('No messages to retrieve') else: pull_msgs(imap, n, mdst, on_size_mismatch, delete) logging.getLogger().setLevel(oldloglevel) def pull_msgs(imap:imaplib.IMAP4_SSL, n:int, mdst:mailbox.Maildir, on_size_mismatch:OnSizeMismatch, delete:bool) -> None: sizes_mismatched:List[int] = [] resp:Tuple[str, List[Union[bytes,Tuple[bytes,bytes]]]] resp = imap.fetch('1:%d'%(n), '(UID RFC822.SIZE)') if resp[0] != 'OK': raise Exception(f'initial FETCH 1:{n} not OK ({resp})') pending:List[Dict[str,int]] = [] for data in resp[1]: if not isinstance(data, bytes): raise TypeError(f'Expected bytes, got {type(data)}') pending.append(summary_splitter.breakup(data)) sizes:Dict[int,int] = {} for m in pending: sizes[m['uid']] = m['size'] fetched:Dict[int,int] = {} uids = ','.join(map(str, sorted([x['uid'] for x in pending]))) totalbytes = sum([x['size'] for x in pending]) logging.info('Fetching %d messages, expecting %d bytes of message content', len(pending), totalbytes) # FIXME: sort by size? # FIXME: fetch in batches or singly instead of all-at-once? # FIXME: rolling deletion? # FIXME: asynchronous work? before = time.perf_counter() resp = imap.uid('FETCH', uids, '(UID BODY.PEEK[])') after = time.perf_counter() if resp[0] != 'OK': raise Exception('UID fetch failed {resp[0]}') expected_objects:int = len(pending) * 2 if len(resp[1]) != expected_objects: raise Exception(f'expected {expected_objects} responses for fetch, got {len(resp[1])}') for n in range(0, expected_objects, 2): # expected response is one "fetch" line, followed by a close-paren item data = resp[1][n] if not isinstance(data, tuple) or len(data) != 2: raise Exception(f'expected 2-part tuple, got {type(data)}') closeparen = resp[1][n+1] if not isinstance(closeparen, bytes) or closeparen != b')': raise Exception('Expected close parenthesis after message fetch') m = fetch_splitter.breakup(data[0]) if m['size'] != len(data[1]): raise Exception(f'expected {m["size"]} octets, got {len(data[1])}') if m['size'] != sizes[m['uid']]: if on_size_mismatch == OnSizeMismatch.warn: if len(sizes_mismatched) == 0: logging.warning('size mismatch: summary said %d octets, fetch sent %d', sizes[m['uid']], m['size']) elif len(sizes_mismatched) == 1: logging.warning('size mismatch: (mismatches after the first suppressed until summary)') sizes_mismatched.append(sizes[m['uid']] - m['size']) elif on_size_mismatch == OnSizeMismatch.error: raise Exception(f"size mismatch: summary said {sizes[m['uid']]} octets, " "fetch sent {m['size']}\n" "(set options.on_size_mismatch to none or warn to avoid hard failure)") # convert any CRLF line-endings to UNIX standard line- # endings: fname = mdst.add(data[1].replace(b'\r\n', b'\n')) 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[m['uid']] = m['size'] if sizes: logging.warning('unhandled UIDs: %s', sizes) logging.info('%d bytes of %d messages fetched in %g seconds (~%g KB/s)', sum(fetched.values()), len(fetched), after - before, sum(fetched.values())/((after - before)*1024)) if on_size_mismatch == OnSizeMismatch.warn and len(sizes_mismatched) > 1: logging.warning('%d size mismatches out of %d messages (mismatches in bytes: mean %f, stddev %f)', len(sizes_mismatched), len(fetched), statistics.mean(sizes_mismatched), statistics.stdev(sizes_mismatched)) if delete: logging.info('trying to delete %d messages from IMAP store', len(fetched)) resp = imap.uid('STORE', ','.join(map(str, fetched.keys())), '+FLAGS', r'(\Deleted)') if resp[0] != 'OK': raise Exception(f'failed to set \\Deleted flag: {resp}') resp = imap.expunge() if resp[0] != 'OK': raise Exception(f'failed to expunge! {resp}') else: logging.info('not deleting any messages, since options.delete is not set') if __name__ == '__main__': parser = argparse.ArgumentParser( description=DESCRIPTION, formatter_class=argparse.RawDescriptionHelpFormatter, ) parser.add_argument( 'config', nargs='+', metavar='CONFIG', help="configuration file") parser.add_argument( '-v', '--verbose', action='store_true', help="verbose log output") if argcomplete: argcomplete.autocomplete(parser) elif '_ARGCOMPLETE' in os.environ: logging.error('Argument completion requested but the "argcomplete" ' 'module is not installed. ' 'Maybe you want to "apt install python3-argcomplete"') sys.exit(1) args = parser.parse_args() if args.verbose: logging.getLogger().setLevel(logging.INFO) errs = {} for confname in args.config: try: scan_msgs(confname, args.verbose) except imaplib.IMAP4.error as e: logging.error('IMAP failure for config file %s: %s', confname, e) errs[confname] = e if errs: exit(1)
signature.asc
Description: PGP signature
