Files
multi-seal-mail/server/app/mailer/sending/imap.py

342 lines
11 KiB
Python

from __future__ import annotations
import imaplib
import re
import socket
import ssl
import time
from dataclasses import dataclass
from app.mailer.campaign.models import ImapConfig, TransportSecurity
from app.mailer.dev.mock_mailbox import (
MOCK_IMAP_FOLDERS,
consume_fail_next_imap,
is_mock_imap_host,
record_imap_append,
)
class ImapConfigurationError(ValueError):
"""Raised when IMAP settings are incomplete or inconsistent."""
class ImapAppendError(RuntimeError):
"""Raised when APPENDing to Sent fails.
temporary=True means retrying later may help. temporary=False means the
configuration or mailbox choice probably needs user/admin attention.
"""
def __init__(self, message: str, *, temporary: bool | None = None):
super().__init__(message)
self.temporary = temporary
@dataclass(frozen=True, slots=True)
class ImapLoginTestResult:
host: str
port: int
security: str
authenticated: bool
@dataclass(frozen=True, slots=True)
class ImapMailboxInfo:
name: str
flags: list[str]
@dataclass(frozen=True, slots=True)
class ImapFolderListResult:
host: str
port: int
security: str
folders: list[ImapMailboxInfo]
detected_sent_folder: str | None = None
@dataclass(frozen=True, slots=True)
class ImapAppendResult:
host: str
port: int
security: str
folder: str
bytes_appended: int
response: str | None = None
def _require_imap_config(config: ImapConfig) -> tuple[str, int]:
if not config.enabled:
raise ImapConfigurationError("IMAP is disabled")
if not config.host:
raise ImapConfigurationError("IMAP host is required")
if not config.port:
raise ImapConfigurationError("IMAP port is required")
if bool(config.username) != bool(config.password):
raise ImapConfigurationError("IMAP username and password must be provided together, or both omitted")
return config.host, config.port
def _open_imap(config: ImapConfig) -> imaplib.IMAP4:
host, port = _require_imap_config(config)
context = ssl.create_default_context()
try:
if config.security == TransportSecurity.TLS:
client: imaplib.IMAP4 = imaplib.IMAP4_SSL(host=host, port=port, timeout=config.timeout_seconds, ssl_context=context)
else:
client = imaplib.IMAP4(host=host, port=port, timeout=config.timeout_seconds)
if config.security == TransportSecurity.STARTTLS:
typ, data = client.starttls(ssl_context=context)
if typ != "OK":
raise ImapAppendError(f"IMAP STARTTLS failed: {data!r}", temporary=True)
if config.username and config.password:
typ, data = client.login(config.username, config.password)
if typ != "OK":
raise ImapAppendError(f"IMAP login failed: {data!r}", temporary=False)
return client
except Exception:
try:
client.logout() # type: ignore[possibly-undefined]
except Exception:
pass
raise
def _decode_item(item: bytes | str | None) -> str:
if item is None:
return ""
if isinstance(item, bytes):
return item.decode("utf-8", errors="replace")
return item
def _unquote_imap_token(value: str) -> str:
value = value.strip()
if len(value) >= 2 and value[0] == '"' and value[-1] == '"':
value = value[1:-1]
value = value.replace('\\"', '"').replace('\\\\', '\\')
return value
def _extract_mailbox_name(list_response_line: bytes | str) -> tuple[str, set[str]] | None:
r"""Best-effort parser for IMAP LIST response lines.
RFC 3501 LIST responses contain attributes, hierarchy delimiter, then mailbox
name. Some servers quote both delimiter and mailbox::
(\HasNoChildren \Sent) "/" "Sent"
Others quote only the delimiter and leave the mailbox as an atom::
(\HasNoChildren \Sent) "/" Sent
The parser must therefore parse the delimiter token separately instead of
blindly taking the last quoted value.
"""
line = _decode_item(list_response_line).strip()
match = re.match(
r'^\((?P<flags>[^)]*)\)\s+'
r'(?P<delimiter>"(?:[^"\\]|\\.)*"|NIL|[^\s]+)\s+'
r'(?P<mailbox>.+?)\s*$',
line,
re.IGNORECASE,
)
if match:
flags = {part.lower() for part in match.group("flags").split()}
mailbox = _unquote_imap_token(match.group("mailbox"))
if mailbox:
return mailbox, flags
return None
# Fallback for non-standard server lines: prefer the final token.
parts = line.split(maxsplit=2)
if len(parts) >= 3:
flags_text = parts[0].strip("()")
flags = {part.lower() for part in flags_text.split()}
mailbox = _unquote_imap_token(parts[2])
if mailbox:
return mailbox, flags
return None
def _detect_sent_folder(parsed: list[tuple[str, set[str]]]) -> str | None:
for name, flags in parsed:
if "\\sent" in flags or "\\sentmail" in flags:
return name
common_names = [
"Sent",
"Sent Items",
"Sent Messages",
"Gesendet",
"Gesendete Elemente",
"INBOX.Sent",
"INBOX/Sent",
]
names = {name.lower(): name for name, _ in parsed}
for candidate in common_names:
if candidate.lower() in names:
return names[candidate.lower()]
return None
def discover_sent_folder(client: imaplib.IMAP4) -> str | None:
typ, data = client.list()
if typ != "OK" or not data:
return None
parsed: list[tuple[str, set[str]]] = []
for item in data:
extracted = _extract_mailbox_name(item)
if extracted:
parsed.append(extracted)
return _detect_sent_folder(parsed)
def _effective_sent_folder(*, config: ImapConfig, requested_folder: str | None, client: imaplib.IMAP4) -> str:
if requested_folder and requested_folder != "auto":
return requested_folder
if config.sent_folder and config.sent_folder != "auto":
return config.sent_folder
discovered = discover_sent_folder(client)
if discovered:
return discovered
raise ImapConfigurationError("Could not discover Sent folder; configure delivery.imap_append_sent.folder or server.imap.sent_folder")
def test_imap_login(*, imap_config: ImapConfig) -> ImapLoginTestResult:
"""Open an IMAP connection and authenticate if credentials are configured.
This is a side-effect-free connection test for the WebUI. It does not select
a mailbox and does not append any message.
"""
host, port = _require_imap_config(imap_config)
if is_mock_imap_host(imap_config.host):
return ImapLoginTestResult(
host=host,
port=port,
security=imap_config.security.value,
authenticated=bool(imap_config.username and imap_config.password),
)
client = _open_imap(imap_config)
try:
return ImapLoginTestResult(
host=host,
port=port,
security=imap_config.security.value,
authenticated=bool(imap_config.username and imap_config.password),
)
finally:
try:
client.logout()
except Exception:
pass
def list_imap_folders(*, imap_config: ImapConfig) -> ImapFolderListResult:
"""Return folders visible through IMAP LIST and the best sent-folder guess."""
host, port = _require_imap_config(imap_config)
if is_mock_imap_host(imap_config.host):
folders = [ImapMailboxInfo(name=str(item["name"]), flags=list(item.get("flags") or [])) for item in MOCK_IMAP_FOLDERS]
return ImapFolderListResult(
host=host,
port=port,
security=imap_config.security.value,
folders=folders,
detected_sent_folder="Sent",
)
client = _open_imap(imap_config)
try:
typ, data = client.list()
if typ != "OK":
raise ImapAppendError(f"IMAP folder listing failed: {data!r}", temporary=True)
parsed: list[tuple[str, set[str]]] = []
folders: list[ImapMailboxInfo] = []
for item in data or []:
extracted = _extract_mailbox_name(item)
if not extracted:
continue
name, flags = extracted
parsed.append((name, flags))
folders.append(ImapMailboxInfo(name=name, flags=sorted(flags)))
return ImapFolderListResult(
host=host,
port=port,
security=imap_config.security.value,
folders=folders,
detected_sent_folder=_detect_sent_folder(parsed),
)
finally:
try:
client.logout()
except Exception:
pass
def append_message_to_sent(
message_bytes: bytes,
*,
imap_config: ImapConfig,
folder: str | None = None,
) -> ImapAppendResult:
"""Append a sent MIME message to the configured IMAP Sent folder.
The SMTP send remains authoritative. APPEND is a separate best-effort step
and should not be used to decide whether an email was sent.
"""
host, port = _require_imap_config(imap_config)
if is_mock_imap_host(imap_config.host):
if consume_fail_next_imap():
raise ImapAppendError("Mock IMAP configured to fail the next append", temporary=False)
target_folder = folder or (imap_config.sent_folder if imap_config.sent_folder and imap_config.sent_folder != "auto" else "Sent")
record = record_imap_append(message_bytes, folder=target_folder, imap_host=imap_config.host)
return ImapAppendResult(
host=host,
port=port,
security=imap_config.security.value,
folder=target_folder,
bytes_appended=len(message_bytes),
response=f"mock append stored as {record.id}",
)
client: imaplib.IMAP4 | None = None
try:
client = _open_imap(imap_config)
target_folder = _effective_sent_folder(config=imap_config, requested_folder=folder, client=client)
internal_date = imaplib.Time2Internaldate(time.time())
typ, data = client.append(target_folder, "\\Seen", internal_date, message_bytes)
if typ != "OK":
raise ImapAppendError(f"IMAP APPEND failed for folder {target_folder!r}: {data!r}", temporary=False)
response = "; ".join(_decode_item(item) for item in (data or [])) or None
return ImapAppendResult(
host=host,
port=port,
security=imap_config.security.value,
folder=target_folder,
bytes_appended=len(message_bytes),
response=response,
)
except ImapAppendError:
raise
except (OSError, socket.timeout, imaplib.IMAP4.abort) as exc:
raise ImapAppendError(f"IMAP append failed: {exc}", temporary=True) from exc
except imaplib.IMAP4.error as exc:
raise ImapAppendError(f"IMAP append failed: {exc}", temporary=False) from exc
finally:
if client is not None:
try:
client.logout()
except Exception:
pass