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.
This patch represents a squashed series of changes from both Jameson
Graef Rollins and Daniel Kahn Gillmor (dkg), though dkg is primarily
responsible for any remaining bugs.
Thanks to Sean Whitton for useful and significant feedback.
Signed-off-by: Jameson Graef Rollins <jroll...@finestructure.net>
Signed-off-by: Daniel Kahn Gillmor <d...@fifthhorseman.net>
---
Makefile | 4 +-
debian/control | 2 +
debian/mailscripts.bash-completion | 1 +
debian/mailscripts.install | 1 +
debian/mailscripts.manpages | 1 +
imap-dl | 278 +++++++++++++++++++++++++++++
imap-dl.1.pod | 88 +++++++++
7 files changed, 374 insertions(+), 1 deletion(-)
create mode 100755 imap-dl
create mode 100644 imap-dl.1.pod
diff --git a/Makefile b/Makefile
index af30616..ec3d851 100644
--- a/Makefile
+++ b/Makefile
@@ -1,15 +1,17 @@
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
-COMPLETIONS=completions/bash/email-print-mime-structure
+COMPLETIONS=completions/bash/email-print-mime-structure
completions/bash/imap-dl
all: $(MANPAGES) $(COMPLETIONS)
check:
./tests/email-print-mime-structure.sh
mypy --strict ./email-print-mime-structure
+ mypy --strict ./imap-dl
clean:
rm -f $(MANPAGES)
diff --git a/debian/control b/debian/control
index bc8268a..21afa45 100644
--- a/debian/control
+++ b/debian/control
@@ -77,3 +77,5 @@ Description: collection of scripts for manipulating e-mail on
Debian
email-print-mime-structure -- tree view of a message's MIME structure
.
email-extract-openpgp-certs -- extract OpenPGP certificates from a message
+ .
+ imap-dl -- download messages from an IMAP mailbox to a maildir
diff --git a/debian/mailscripts.bash-completion
b/debian/mailscripts.bash-completion
index 435576f..657de01 100644
--- a/debian/mailscripts.bash-completion
+++ b/debian/mailscripts.bash-completion
@@ -1 +1,2 @@
completions/bash/email-print-mime-structure
+completions/bash/imap-dl
diff --git a/debian/mailscripts.install b/debian/mailscripts.install
index 2c060df..3739c49 100644
--- a/debian/mailscripts.install
+++ b/debian/mailscripts.install
@@ -1,5 +1,6 @@
email-extract-openpgp-certs /usr/bin
email-print-mime-structure /usr/bin
+imap-dl /usr/bin
maildir-import-patch /usr/bin
mbox2maildir /usr/bin
mdmv /usr/bin
diff --git a/debian/mailscripts.manpages b/debian/mailscripts.manpages
index 1de088f..a915617 100644
--- a/debian/mailscripts.manpages
+++ b/debian/mailscripts.manpages
@@ -1,5 +1,6 @@
email-extract-openpgp-certs.1
email-print-mime-structure.1
+imap-dl.1
maildir-import-patch.1
mbox2maildir.1
mdmv.1
diff --git a/imap-dl b/imap-dl
new file mode 100755
index 0000000..30f2c2f
--- /dev/null
+++ b/imap-dl
@@ -0,0 +1,278 @@
+#!/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)
diff --git a/imap-dl.1.pod b/imap-dl.1.pod
new file mode 100644
index 0000000..9fb77c3
--- /dev/null
+++ b/imap-dl.1.pod
@@ -0,0 +1,88 @@
+=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 were 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 otherwise it will terminate with an error. It should not
+lose e-mail messages.
+
+If there's any interest in supporting other similarly simple 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.
+
+In addition to parts of the standard B<getmail> configuration,
+B<imap-dl> supports the following keywords in the config file:
+
+B<options.on_size_mismatch> can be set to B<error>, B<none>, or
+B<warn>. This governs what to do when the remote IMAP server claims a
+different size in the message summary list than the actual message
+retrieval (default: B<error>).
+
+=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 use just 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.
--
2.24.1
