IMAP implementation

This is a very limited implementation of IMAPv4rev1 (rfc3501). But this
is sufficient for mutt, isync and thunderbird clients.

Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
       - name: "Check mypy"
         run: |
           mypy --non-interactive --install-types -c 'import tabulate'
-          mypy --strict jiramail/*.py
+          find jiramail -type f -name '*.py' -a \! -name '*_tab.py' | xargs -r mypy --strict
 
       - name: "Check pylint"
         run: pylint --disable=R --disable=W0603,W0621,W0718 --disable=C0103,C0114,C0115,C0116,C0301,C0415,C3001 jiramail/*.py

jiramail/__init__.py

@@ -79,19 +79,29 @@ def __init__(self, path: str):
         logger.debug("openning the mailbox `%s' ...", path)
 
         self.mbox = mailbox.mbox(path)
+        self.path = os.path.abspath(os.path.expanduser(path))
+        self.n_msgs = 0
         self.msgid = {}
 
         for key in self.mbox.iterkeys():
             mail = self.mbox.get_message(key)
             if "Message-Id" in mail:
                 msg_id = mail.get("Message-Id")
                 self.msgid[msg_id] = True
+            self.n_msgs += 1
 
         logger.info("mailbox is ready")
 
     def get_message(self, key: str) -> mailbox.mboxMessage:
         return self.mbox.get_message(key)
 
+    def del_message(self, key: str) -> None:
+        mail = self.get_message(key)
+        msg_id = mail.get("Message-Id")
+
+        self.mbox.remove(key)
+        del self.msgid[msg_id]
+
     def update_message(self, key: str, mail: email.message.Message) -> None:
         self.mbox.update([(key, mail)])
 
@@ -105,6 +115,9 @@ def append(self, mail: email.message.Message) -> None:
     def iterkeys(self) -> Iterator[Any]:
         return self.mbox.iterkeys()
 
+    def sync(self) -> None:
+        self.mbox.flush()
+
     def close(self) -> None:
         self.mbox.close()
 

jiramail/auth.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-3.0-or-later
+# Copyright (C) 2023  Alexey Gladkov <gladkov.alexey@gmail.com>
+
+__author__ = 'Alexey Gladkov <gladkov.alexey@gmail.com>'
+
+import base64
+import binascii
+import hashlib
+import hmac
+import os
+import random
+import time
+
+from typing import Callable, Tuple, Any
+
+import jiramail
+
+logger = jiramail.logger
+
+def cram_md5(user: str, password: str, interact: Callable[[Any, str], str], data: Any) -> Tuple[bool, str]:
+    pid = os.getpid()
+    now = time.time_ns()
+    rnd = random.randrange(2**32 - 1)
+    shared = f"<{pid}.{now}.{rnd}@jiramail>"
+
+    line = interact(data, base64.b64encode(shared.encode()).decode())
+
+    try:
+        buf = base64.standard_b64decode(line).decode()
+    except binascii.Error:
+        return (False, "couldn't decode your credentials")
+
+    fields = buf.split(" ")
+
+    if len(fields) != 2:
+        return (False, "wrong number of fields in the token")
+
+    hexdigest = hmac.new(password.encode(),
+                         shared.encode(),
+                         hashlib.md5).hexdigest()
+
+    if hmac.compare_digest(user, fields[0]) and hmac.compare_digest(hexdigest, fields[1]):
+        return (True, "authentication successful")
+
+    return (False, "authenticate failure")

jiramail/command.py

@@ -38,6 +38,11 @@ def cmd_smtp(cmdargs: argparse.Namespace) -> int:
     return jiramail.smtp.main(cmdargs)
 
 
+def cmd_imap(cmdargs: argparse.Namespace) -> int:
+    import jiramail.imap
+    return jiramail.imap.main(cmdargs)
+
+
 def add_common_arguments(parser: argparse.ArgumentParser) -> None:
     parser.add_argument("-v", "--verbose",
                         dest="verbose", action='count', default=0,
@@ -184,6 +189,19 @@ def setup_parser() -> argparse.ArgumentParser:
                      help="path to mailbox to store a reply messages with the status of command execution.")
     add_common_arguments(sp4)
 
+    # jiramail imap
+    sp5_description = """\
+imap server
+"""
+    sp5 = subparsers.add_parser("imap",
+                                description=sp3_description,
+                                help=sp5_description,
+                                epilog=epilog,
+                                add_help=False)
+    sp5.set_defaults(func=cmd_imap)
+    add_common_arguments(sp5)
+
+
     return parser