Update 2026-05-13 16:43:53
This commit is contained in:
yi
@@ -0,0 +1,552 @@
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"""Email channel implementation using IMAP polling + SMTP replies."""
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import asyncio
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import html
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import imaplib
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import re
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import smtplib
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import ssl
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from datetime import date
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from email import policy
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from email.header import decode_header, make_header
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from email.message import EmailMessage
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from email.parser import BytesParser
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from email.utils import parseaddr
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from typing import Any
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from loguru import logger
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from pydantic import Field
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from nanobot.bus.events import OutboundMessage
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from nanobot.bus.queue import MessageBus
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from nanobot.channels.base import BaseChannel
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from nanobot.config.schema import Base
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class EmailConfig(Base):
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"""Email channel configuration (IMAP inbound + SMTP outbound)."""
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enabled: bool = False
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consent_granted: bool = False
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imap_host: str = ""
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imap_port: int = 993
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imap_username: str = ""
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imap_password: str = ""
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imap_mailbox: str = "INBOX"
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imap_use_ssl: bool = True
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smtp_host: str = ""
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smtp_port: int = 587
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smtp_username: str = ""
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smtp_password: str = ""
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smtp_use_tls: bool = True
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smtp_use_ssl: bool = False
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from_address: str = ""
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auto_reply_enabled: bool = True
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poll_interval_seconds: int = 30
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mark_seen: bool = True
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max_body_chars: int = 12000
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subject_prefix: str = "Re: "
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allow_from: list[str] = Field(default_factory=list)
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# Email authentication verification (anti-spoofing)
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verify_dkim: bool = True # Require Authentication-Results with dkim=pass
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verify_spf: bool = True # Require Authentication-Results with spf=pass
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class EmailChannel(BaseChannel):
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"""
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Email channel.
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Inbound:
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- Poll IMAP mailbox for unread messages.
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- Convert each message into an inbound event.
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Outbound:
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- Send responses via SMTP back to the sender address.
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"""
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name = "email"
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display_name = "Email"
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_IMAP_MONTHS = (
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"Jan",
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"Feb",
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"Mar",
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"Apr",
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"May",
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"Jun",
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"Jul",
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"Aug",
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"Sep",
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"Oct",
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"Nov",
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"Dec",
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)
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_IMAP_RECONNECT_MARKERS = (
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"disconnected for inactivity",
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"eof occurred in violation of protocol",
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"socket error",
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"connection reset",
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"broken pipe",
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"bye",
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)
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_IMAP_MISSING_MAILBOX_MARKERS = (
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"mailbox doesn't exist",
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"select failed",
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"no such mailbox",
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"can't open mailbox",
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"does not exist",
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)
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@classmethod
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def default_config(cls) -> dict[str, Any]:
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return EmailConfig().model_dump(by_alias=True)
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def __init__(self, config: Any, bus: MessageBus):
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if isinstance(config, dict):
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config = EmailConfig.model_validate(config)
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super().__init__(config, bus)
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self.config: EmailConfig = config
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self._last_subject_by_chat: dict[str, str] = {}
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self._last_message_id_by_chat: dict[str, str] = {}
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self._processed_uids: set[str] = set() # Capped to prevent unbounded growth
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self._MAX_PROCESSED_UIDS = 100000
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async def start(self) -> None:
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"""Start polling IMAP for inbound emails."""
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if not self.config.consent_granted:
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logger.warning(
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"Email channel disabled: consent_granted is false. "
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"Set channels.email.consentGranted=true after explicit user permission."
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)
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return
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if not self._validate_config():
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return
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self._running = True
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if not self.config.verify_dkim and not self.config.verify_spf:
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logger.warning(
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"Email channel: DKIM and SPF verification are both DISABLED. "
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"Emails with spoofed From headers will be accepted. "
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"Set verify_dkim=true and verify_spf=true for anti-spoofing protection."
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)
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logger.info("Starting Email channel (IMAP polling mode)...")
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poll_seconds = max(5, int(self.config.poll_interval_seconds))
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while self._running:
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try:
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inbound_items = await asyncio.to_thread(self._fetch_new_messages)
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for item in inbound_items:
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sender = item["sender"]
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subject = item.get("subject", "")
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message_id = item.get("message_id", "")
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if subject:
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self._last_subject_by_chat[sender] = subject
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if message_id:
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self._last_message_id_by_chat[sender] = message_id
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await self._handle_message(
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sender_id=sender,
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chat_id=sender,
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content=item["content"],
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metadata=item.get("metadata", {}),
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)
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except Exception as e:
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logger.error("Email polling error: {}", e)
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await asyncio.sleep(poll_seconds)
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async def stop(self) -> None:
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"""Stop polling loop."""
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self._running = False
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async def send(self, msg: OutboundMessage) -> None:
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"""Send email via SMTP."""
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if not self.config.consent_granted:
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logger.warning("Skip email send: consent_granted is false")
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return
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if not self.config.smtp_host:
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logger.warning("Email channel SMTP host not configured")
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return
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to_addr = msg.chat_id.strip()
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if not to_addr:
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logger.warning("Email channel missing recipient address")
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return
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# Determine if this is a reply (recipient has sent us an email before)
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is_reply = to_addr in self._last_subject_by_chat
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force_send = bool((msg.metadata or {}).get("force_send"))
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# autoReplyEnabled only controls automatic replies, not proactive sends
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if is_reply and not self.config.auto_reply_enabled and not force_send:
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logger.info("Skip automatic email reply to {}: auto_reply_enabled is false", to_addr)
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return
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base_subject = self._last_subject_by_chat.get(to_addr, "nanobot reply")
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subject = self._reply_subject(base_subject)
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if msg.metadata and isinstance(msg.metadata.get("subject"), str):
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override = msg.metadata["subject"].strip()
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if override:
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subject = override
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email_msg = EmailMessage()
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email_msg["From"] = self.config.from_address or self.config.smtp_username or self.config.imap_username
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email_msg["To"] = to_addr
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email_msg["Subject"] = subject
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email_msg.set_content(msg.content or "")
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in_reply_to = self._last_message_id_by_chat.get(to_addr)
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if in_reply_to:
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email_msg["In-Reply-To"] = in_reply_to
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email_msg["References"] = in_reply_to
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try:
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await asyncio.to_thread(self._smtp_send, email_msg)
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except Exception as e:
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logger.error("Error sending email to {}: {}", to_addr, e)
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raise
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def _validate_config(self) -> bool:
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missing = []
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if not self.config.imap_host:
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missing.append("imap_host")
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if not self.config.imap_username:
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missing.append("imap_username")
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if not self.config.imap_password:
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missing.append("imap_password")
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if not self.config.smtp_host:
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missing.append("smtp_host")
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if not self.config.smtp_username:
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missing.append("smtp_username")
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if not self.config.smtp_password:
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missing.append("smtp_password")
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if missing:
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logger.error("Email channel not configured, missing: {}", ', '.join(missing))
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return False
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return True
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def _smtp_send(self, msg: EmailMessage) -> None:
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timeout = 30
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if self.config.smtp_use_ssl:
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with smtplib.SMTP_SSL(
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self.config.smtp_host,
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self.config.smtp_port,
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timeout=timeout,
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) as smtp:
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smtp.login(self.config.smtp_username, self.config.smtp_password)
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smtp.send_message(msg)
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return
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with smtplib.SMTP(self.config.smtp_host, self.config.smtp_port, timeout=timeout) as smtp:
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if self.config.smtp_use_tls:
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smtp.starttls(context=ssl.create_default_context())
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smtp.login(self.config.smtp_username, self.config.smtp_password)
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smtp.send_message(msg)
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def _fetch_new_messages(self) -> list[dict[str, Any]]:
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"""Poll IMAP and return parsed unread messages."""
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return self._fetch_messages(
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search_criteria=("UNSEEN",),
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mark_seen=self.config.mark_seen,
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dedupe=True,
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limit=0,
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)
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def fetch_messages_between_dates(
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self,
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start_date: date,
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end_date: date,
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limit: int = 20,
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) -> list[dict[str, Any]]:
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"""
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Fetch messages in [start_date, end_date) by IMAP date search.
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This is used for historical summarization tasks (e.g. "yesterday").
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"""
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if end_date <= start_date:
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return []
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return self._fetch_messages(
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search_criteria=(
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"SINCE",
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self._format_imap_date(start_date),
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"BEFORE",
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self._format_imap_date(end_date),
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),
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mark_seen=False,
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dedupe=False,
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limit=max(1, int(limit)),
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)
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def _fetch_messages(
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self,
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search_criteria: tuple[str, ...],
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mark_seen: bool,
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dedupe: bool,
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limit: int,
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) -> list[dict[str, Any]]:
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messages: list[dict[str, Any]] = []
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cycle_uids: set[str] = set()
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for attempt in range(2):
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try:
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self._fetch_messages_once(
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search_criteria,
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mark_seen,
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dedupe,
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limit,
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messages,
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cycle_uids,
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)
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return messages
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except Exception as exc:
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if attempt == 1 or not self._is_stale_imap_error(exc):
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raise
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logger.warning("Email IMAP connection went stale, retrying once: {}", exc)
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return messages
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def _fetch_messages_once(
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self,
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search_criteria: tuple[str, ...],
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mark_seen: bool,
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dedupe: bool,
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limit: int,
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messages: list[dict[str, Any]],
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cycle_uids: set[str],
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) -> None:
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"""Fetch messages by arbitrary IMAP search criteria."""
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mailbox = self.config.imap_mailbox or "INBOX"
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if self.config.imap_use_ssl:
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client = imaplib.IMAP4_SSL(self.config.imap_host, self.config.imap_port)
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else:
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client = imaplib.IMAP4(self.config.imap_host, self.config.imap_port)
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try:
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client.login(self.config.imap_username, self.config.imap_password)
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try:
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status, _ = client.select(mailbox)
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except Exception as exc:
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if self._is_missing_mailbox_error(exc):
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logger.warning("Email mailbox unavailable, skipping poll for {}: {}", mailbox, exc)
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return messages
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raise
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if status != "OK":
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logger.warning("Email mailbox select returned {}, skipping poll for {}", status, mailbox)
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return messages
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status, data = client.search(None, *search_criteria)
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if status != "OK" or not data:
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return messages
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ids = data[0].split()
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if limit > 0 and len(ids) > limit:
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ids = ids[-limit:]
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for imap_id in ids:
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status, fetched = client.fetch(imap_id, "(BODY.PEEK[] UID)")
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if status != "OK" or not fetched:
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continue
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raw_bytes = self._extract_message_bytes(fetched)
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if raw_bytes is None:
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continue
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uid = self._extract_uid(fetched)
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if uid and uid in cycle_uids:
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continue
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if dedupe and uid and uid in self._processed_uids:
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continue
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parsed = BytesParser(policy=policy.default).parsebytes(raw_bytes)
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sender = parseaddr(parsed.get("From", ""))[1].strip().lower()
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if not sender:
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continue
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# --- Anti-spoofing: verify Authentication-Results ---
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spf_pass, dkim_pass = self._check_authentication_results(parsed)
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if self.config.verify_spf and not spf_pass:
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logger.warning(
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"Email from {} rejected: SPF verification failed "
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"(no 'spf=pass' in Authentication-Results header)",
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sender,
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)
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continue
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if self.config.verify_dkim and not dkim_pass:
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logger.warning(
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"Email from {} rejected: DKIM verification failed "
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"(no 'dkim=pass' in Authentication-Results header)",
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sender,
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)
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continue
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subject = self._decode_header_value(parsed.get("Subject", ""))
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date_value = parsed.get("Date", "")
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message_id = parsed.get("Message-ID", "").strip()
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body = self._extract_text_body(parsed)
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if not body:
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body = "(empty email body)"
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body = body[: self.config.max_body_chars]
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content = (
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f"[EMAIL-CONTEXT] Email received.\n"
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f"From: {sender}\n"
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f"Subject: {subject}\n"
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f"Date: {date_value}\n\n"
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f"{body}"
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)
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metadata = {
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"message_id": message_id,
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"subject": subject,
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"date": date_value,
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"sender_email": sender,
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"uid": uid,
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}
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messages.append(
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{
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"sender": sender,
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"subject": subject,
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"message_id": message_id,
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"content": content,
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"metadata": metadata,
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}
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)
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if uid:
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cycle_uids.add(uid)
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if dedupe and uid:
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self._processed_uids.add(uid)
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# mark_seen is the primary dedup; this set is a safety net
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if len(self._processed_uids) > self._MAX_PROCESSED_UIDS:
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# Evict a random half to cap memory; mark_seen is the primary dedup
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self._processed_uids = set(list(self._processed_uids)[len(self._processed_uids) // 2:])
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|
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if mark_seen:
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client.store(imap_id, "+FLAGS", "\\Seen")
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finally:
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try:
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client.logout()
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except Exception:
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pass
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@classmethod
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def _is_stale_imap_error(cls, exc: Exception) -> bool:
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message = str(exc).lower()
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return any(marker in message for marker in cls._IMAP_RECONNECT_MARKERS)
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||||
|
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@classmethod
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def _is_missing_mailbox_error(cls, exc: Exception) -> bool:
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message = str(exc).lower()
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return any(marker in message for marker in cls._IMAP_MISSING_MAILBOX_MARKERS)
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||||
|
||||
@classmethod
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||||
def _format_imap_date(cls, value: date) -> str:
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"""Format date for IMAP search (always English month abbreviations)."""
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month = cls._IMAP_MONTHS[value.month - 1]
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return f"{value.day:02d}-{month}-{value.year}"
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||||
|
||||
@staticmethod
|
||||
def _extract_message_bytes(fetched: list[Any]) -> bytes | None:
|
||||
for item in fetched:
|
||||
if isinstance(item, tuple) and len(item) >= 2 and isinstance(item[1], (bytes, bytearray)):
|
||||
return bytes(item[1])
|
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return None
|
||||
|
||||
@staticmethod
|
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def _extract_uid(fetched: list[Any]) -> str:
|
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for item in fetched:
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if isinstance(item, tuple) and item and isinstance(item[0], (bytes, bytearray)):
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||||
head = bytes(item[0]).decode("utf-8", errors="ignore")
|
||||
m = re.search(r"UID\s+(\d+)", head)
|
||||
if m:
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||||
return m.group(1)
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||||
return ""
|
||||
|
||||
@staticmethod
|
||||
def _decode_header_value(value: str) -> str:
|
||||
if not value:
|
||||
return ""
|
||||
try:
|
||||
return str(make_header(decode_header(value)))
|
||||
except Exception:
|
||||
return value
|
||||
|
||||
@classmethod
|
||||
def _extract_text_body(cls, msg: Any) -> str:
|
||||
"""Best-effort extraction of readable body text."""
|
||||
if msg.is_multipart():
|
||||
plain_parts: list[str] = []
|
||||
html_parts: list[str] = []
|
||||
for part in msg.walk():
|
||||
if part.get_content_disposition() == "attachment":
|
||||
continue
|
||||
content_type = part.get_content_type()
|
||||
try:
|
||||
payload = part.get_content()
|
||||
except Exception:
|
||||
payload_bytes = part.get_payload(decode=True) or b""
|
||||
charset = part.get_content_charset() or "utf-8"
|
||||
payload = payload_bytes.decode(charset, errors="replace")
|
||||
if not isinstance(payload, str):
|
||||
continue
|
||||
if content_type == "text/plain":
|
||||
plain_parts.append(payload)
|
||||
elif content_type == "text/html":
|
||||
html_parts.append(payload)
|
||||
if plain_parts:
|
||||
return "\n\n".join(plain_parts).strip()
|
||||
if html_parts:
|
||||
return cls._html_to_text("\n\n".join(html_parts)).strip()
|
||||
return ""
|
||||
|
||||
try:
|
||||
payload = msg.get_content()
|
||||
except Exception:
|
||||
payload_bytes = msg.get_payload(decode=True) or b""
|
||||
charset = msg.get_content_charset() or "utf-8"
|
||||
payload = payload_bytes.decode(charset, errors="replace")
|
||||
if not isinstance(payload, str):
|
||||
return ""
|
||||
if msg.get_content_type() == "text/html":
|
||||
return cls._html_to_text(payload).strip()
|
||||
return payload.strip()
|
||||
|
||||
@staticmethod
|
||||
def _check_authentication_results(parsed_msg: Any) -> tuple[bool, bool]:
|
||||
"""Parse Authentication-Results headers for SPF and DKIM verdicts.
|
||||
|
||||
Returns:
|
||||
A tuple of (spf_pass, dkim_pass) booleans.
|
||||
"""
|
||||
spf_pass = False
|
||||
dkim_pass = False
|
||||
for ar_header in parsed_msg.get_all("Authentication-Results") or []:
|
||||
ar_lower = ar_header.lower()
|
||||
if re.search(r"\bspf\s*=\s*pass\b", ar_lower):
|
||||
spf_pass = True
|
||||
if re.search(r"\bdkim\s*=\s*pass\b", ar_lower):
|
||||
dkim_pass = True
|
||||
return spf_pass, dkim_pass
|
||||
|
||||
@staticmethod
|
||||
def _html_to_text(raw_html: str) -> str:
|
||||
text = re.sub(r"<\s*br\s*/?>", "\n", raw_html, flags=re.IGNORECASE)
|
||||
text = re.sub(r"<\s*/\s*p\s*>", "\n", text, flags=re.IGNORECASE)
|
||||
text = re.sub(r"<[^>]+>", "", text)
|
||||
return html.unescape(text)
|
||||
|
||||
def _reply_subject(self, base_subject: str) -> str:
|
||||
subject = (base_subject or "").strip() or "nanobot reply"
|
||||
prefix = self.config.subject_prefix or "Re: "
|
||||
if subject.lower().startswith("re:"):
|
||||
return subject
|
||||
return f"{prefix}{subject}"
|
||||
Reference in New Issue
Block a user