Add a method to move messages to IMAPlib

[mcepl]

BPO	33327
Nosy	@mcepl
PRs	WIP: bpo-33327: Add IMAP4.move_messages() method. #19072

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-04-21.19:10:03.702>
labels = ['3.8', 'type-feature', 'library']
title = 'Add a method to move messages to IMAPlib'
updated_at = <Date 2021-09-19.23:36:53.735>
user = 'https://github.com/mcepl'

bugs.python.org fields:

activity = <Date 2021-09-19.23:36:53.735>
actor = 'mcepl'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2018-04-21.19:10:03.702>
creator = 'mcepl'
dependencies = []
files = []
hgrepos = []
issue_num = 33327
keywords = ['patch']
message_count = 6.0
messages = ['315578', '321952', '372955', '372966', '372967', '402188']
nosy_count = 2.0
nosy_names = ['mcepl', 'frispete']
pr_nums = ['19072']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue33327'
versions = ['Python 3.8']

Linked PRs

• gh-77508: Add imaplib.IMAP4.move method #153121

[mcepl]

I am in the process of writing script working with IMAP first time using Python 3 for it (unfortunately, most of servers where I run other code is so ancient that even Python 2.7 is a stretch), and it is really nice experience so far. Many problems which are dealt with on the StackExchange with arcane workarounds are now resolved in email or imaplib libraries. Thank you, everybody!

However, it seems to me that few higher level commands could greatly improve useability of imaplib library. For example, moving messages (not fault of imaplib) is still horrible mess. In the end I had to write this monstrosity just to make moving messages working:

 Capas = collections.namedtuple('Capas', ['MOVE', 'UIDPLUS'])

 def __login(self, host='localhost', username=None, password=None, ssl=None):
 self.box = imaplib.IMAP4_SSL(host=host)
 ok, data = self.box.login(username, password)
 if ok != 'OK':
 raise IOError('Cannot login with credentials %s' %
 str((host, username, password,)))

 ok, data = box.capability()
 capas = data[0].decode()
 box.features_present = Capas._make(['MOVE' in capas, 'UIDPLUS' in capas])

 def move_messages(self, target, messages):
 if self.box.features_present.MOVE:
 ok, data = self.box.uid('MOVE', '%s %s' % (messages, target))
 if ok != 'OK':
 raise IOError('Cannot move messages to folder %s' % target)
 elif self.box.features_present.UIDPLUS:
 ok, data = self.box.uid('COPY', '%s %s' % (messages, target))
 if ok != 'OK':
 raise IOError('Cannot copy messages to folder %s' % target)
 ok, data = self.box.uid('STORE',
 r'+FLAGS.SILENT (\DELETED) %s' % messages)
 if ok != 'OK':
 raise IOError('Cannot delete messages.')
 ok, data = self.box.uid('EXPUNGE', messages)
 if ok != 'OK':
 raise IOError('Cannot expunge messages.')
 else:
 ok, data = self.box.uid('COPY', '%s %s' % (messages, target))
 if ok != 'OK':
 raise IOError('Cannot copy messages to folder %s' % target)
 ok, data = self.box.uid('STORE',
 r'+FLAGS.SILENT (\DELETED) %s' % messages)
 if ok != 'OK':
 raise IOError('Cannot delete messages.')

It would be nice if some capabilities detection (see bpo-18921) was embedded into login method, and if some version of move_messages was included in imaplib itself.

[vstinner]

See also bpo-33336: [imaplib] MOVE is a legal command.

[frispete]

If I'm not mistaken, this is applied to the openSUSE TW version of Python.
For some reason, this seems to not play well with <instance>.uid('move',...)
on a cyrus imap server (v2.4.19). Is that to be expected?

2020-07-03 18:04:05 INFO: [imap_reorg] move b'10399' from 2017-01-01 06:30:35+02:00 to INBOX.2017
Traceback (most recent call last):
 File "./imap_reorg.py", line 431, in <module>
 sys.exit(main())
 File "./imap_reorg.py", line 425, in main
 return process()
 File "./imap_reorg.py", line 133, in trace_and_call
 result = func(*args, **kwargs)
 File "./imap_reorg.py", line 358, in process
 ret |= reorg.run_expr(expr)
 File "./imap_reorg.py", line 345, in run_expr
 return method(*args)
 File "./imap_reorg.py", line 328, in yearly
 ret = self.imap.uid('move', uid, dest)
 File "/usr/lib64/python3.8/imaplib.py", line 881, in uid
 typ, dat = self._simple_command(name, command, *args)
 File "/usr/lib64/python3.8/imaplib.py", line 1205, in _simple_command
 return self._command_complete(name, self._command(name, *args))
 File "/usr/lib64/python3.8/imaplib.py", line 1030, in _command_complete
 raise self.error('%s command error: %s %s' % (name, typ, data))
imaplib.error: UID command error: BAD [b'Unrecognized UID subcommand']

[mcepl]

1. no this has not been included anywhere, just in the unfinished PR on GitHub
2. only thing which I was fighting to get into Python (and I did) was https://bugs.python.org/issue33336 but that’s another issue (without this whole discussion here would not be even possible), it is now part of the upstream Python
3. are you certain that the IMAP server in question supports MOVE command? (have you noticed all that business with CAPABILITIES and particularly the UID one?)

[mcepl]

Sorry, UIDPLUS capability.

[mcepl]

Hans-Peter Jansen (frispete)

imaplib.error: UID command error: BAD [b'Unrecognized UID subcommand']

You missed the fix for https://bugs.python.org/issue33336