Add email channel via Mailgun for Ask Simba
Users can now receive a unique email address (ask+<token>@domain) and interact with Simba by sending emails. Inbound emails hit a Mailgun webhook, are authenticated via HMAC token lookup, processed through the LangChain agent, and replied to via the Mailgun API. - Extract shared SIMBA_SYSTEM_PROMPT to blueprints/conversation/prompts.py - Add email_enabled and email_hmac_token fields to User model - Create blueprints/email with webhook, signature validation, rate limiting - Add admin endpoints to enable/disable email per user - Update AdminPanel with Email column, toggle, and copy-address button - Add Mailgun env vars to .env.example - Include database migration for new fields Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
ryan
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blueprints/email/__init__.py
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blueprints/email/__init__.py
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import os
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import hmac
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import hashlib
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import logging
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import functools
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import time
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from collections import defaultdict
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import httpx
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from quart import Blueprint, request
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from blueprints.users.models import User
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from blueprints.conversation.logic import (
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get_conversation_for_user,
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add_message_to_conversation,
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get_conversation_transcript,
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)
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from blueprints.conversation.agents import main_agent
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from blueprints.conversation.prompts import SIMBA_SYSTEM_PROMPT
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from .helpers import generate_email_token, get_user_email_address # noqa: F401
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email_blueprint = Blueprint("email_api", __name__, url_prefix="/api/email")
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logger = logging.getLogger(__name__)
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# Rate limiting: per-sender message timestamps
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_rate_limit_store: dict[str, list[float]] = defaultdict(list)
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RATE_LIMIT_MAX = int(os.getenv("EMAIL_RATE_LIMIT_MAX", "5"))
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RATE_LIMIT_WINDOW = int(os.getenv("EMAIL_RATE_LIMIT_WINDOW", "300"))
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MAX_MESSAGE_LENGTH = 2000
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# --- Mailgun signature validation ---
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def validate_mailgun_signature(f):
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"""Decorator to validate Mailgun webhook signatures."""
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@functools.wraps(f)
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async def decorated_function(*args, **kwargs):
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if os.getenv("MAILGUN_SIGNATURE_VALIDATION", "true").lower() == "false":
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return await f(*args, **kwargs)
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signing_key = os.getenv("MAILGUN_WEBHOOK_SIGNING_KEY")
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if not signing_key:
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logger.error("MAILGUN_WEBHOOK_SIGNING_KEY not set — rejecting request")
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return "", 406
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form_data = await request.form
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timestamp = form_data.get("timestamp", "")
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token = form_data.get("token", "")
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signature = form_data.get("signature", "")
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if not timestamp or not token or not signature:
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logger.warning("Missing Mailgun signature fields")
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return "", 406
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expected = hmac.new(
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signing_key.encode(),
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f"{timestamp}{token}".encode(),
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hashlib.sha256,
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).hexdigest()
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if not hmac.compare_digest(expected, signature):
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logger.warning("Invalid Mailgun signature")
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return "", 406
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return await f(*args, **kwargs)
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return decorated_function
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# --- Rate limiting ---
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def _check_rate_limit(sender: str) -> bool:
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"""Check if a sender has exceeded the rate limit.
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Returns True if the request is allowed, False if rate-limited.
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"""
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now = time.monotonic()
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cutoff = now - RATE_LIMIT_WINDOW
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timestamps = _rate_limit_store[sender]
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_rate_limit_store[sender] = [t for t in timestamps if t > cutoff]
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if len(_rate_limit_store[sender]) >= RATE_LIMIT_MAX:
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return False
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_rate_limit_store[sender].append(now)
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return True
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# --- Send reply via Mailgun API ---
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async def send_email_reply(to: str, subject: str, body: str, in_reply_to: str | None = None):
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"""Send a reply email via the Mailgun API."""
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api_key = os.getenv("MAILGUN_API_KEY")
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domain = os.getenv("MAILGUN_DOMAIN")
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if not api_key or not domain:
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logger.error("MAILGUN_API_KEY or MAILGUN_DOMAIN not configured")
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return
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data = {
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"from": f"Simba <simba@{domain}>",
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"to": to,
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"subject": f"Re: {subject}" if not subject.startswith("Re:") else subject,
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"text": body,
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}
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if in_reply_to:
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data["h:In-Reply-To"] = in_reply_to
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async with httpx.AsyncClient() as client:
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resp = await client.post(
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f"https://api.mailgun.net/v3/{domain}/messages",
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auth=("api", api_key),
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data=data,
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)
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if resp.status_code != 200:
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logger.error(f"Mailgun send failed ({resp.status_code}): {resp.text}")
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else:
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logger.info(f"Sent email reply to {to}")
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# --- Webhook route ---
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@email_blueprint.route("/webhook", methods=["POST"])
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@validate_mailgun_signature
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async def webhook():
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"""Handle inbound emails forwarded by Mailgun."""
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form_data = await request.form
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sender = form_data.get("sender", "")
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recipient = form_data.get("recipient", "")
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body = form_data.get("stripped-text", "")
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subject = form_data.get("subject", "(no subject)")
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message_id = form_data.get("Message-Id", "")
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# Extract token from recipient: ask+<token>@domain
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local_part = recipient.split("@")[0] if "@" in recipient else ""
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if "+" not in local_part:
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logger.info(f"Ignoring email to {recipient} — no token in address")
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return "", 200
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token = local_part.split("+", 1)[1]
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# Lookup user by token
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user = await User.filter(email_hmac_token=token, email_enabled=True).first()
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if not user:
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logger.info(f"No user found for email token {token}")
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return "", 200
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# Rate limit
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if not _check_rate_limit(sender):
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logger.warning(f"Rate limit exceeded for email sender {sender}")
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return "", 200
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# Clean up body
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body = (body or "").strip()
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if not body:
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logger.info(f"Ignoring empty email from {sender}")
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return "", 200
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if len(body) > MAX_MESSAGE_LENGTH:
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body = body[:MAX_MESSAGE_LENGTH]
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logger.info(f"Truncated long email from {sender} to {MAX_MESSAGE_LENGTH} chars")
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logger.info(f"Processing email from {sender} for user {user.username}: {body[:100]}")
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# Get or create conversation
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try:
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conversation = await get_conversation_for_user(user=user)
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await conversation.fetch_related("messages")
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except Exception as e:
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logger.error(f"Failed to get conversation for user {user.username}: {e}")
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return "", 200
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# Add user message
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await add_message_to_conversation(
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conversation=conversation,
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message=body,
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speaker="user",
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user=user,
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)
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# Build messages payload
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try:
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messages = await conversation.messages.all()
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recent_messages = list(messages)[-10:]
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messages_payload = [{"role": "system", "content": SIMBA_SYSTEM_PROMPT}]
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for msg in recent_messages[:-1]:
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role = "user" if msg.speaker == "user" else "assistant"
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messages_payload.append({"role": role, "content": msg.text})
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messages_payload.append({"role": "user", "content": body})
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logger.info(f"Invoking LangChain agent with {len(messages_payload)} messages")
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response = await main_agent.ainvoke({"messages": messages_payload})
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response_text = response.get("messages", [])[-1].content
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except Exception as e:
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logger.error(f"Error invoking agent for email: {e}")
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response_text = "Sorry, I'm having trouble thinking right now."
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# Save response
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await add_message_to_conversation(
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conversation=conversation,
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message=response_text,
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speaker="simba",
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user=user,
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)
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# Send reply email
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await send_email_reply(
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to=sender,
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subject=subject,
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body=response_text,
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in_reply_to=message_id,
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)
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return "", 200
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14
blueprints/email/helpers.py
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14
blueprints/email/helpers.py
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@@ -0,0 +1,14 @@
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import hmac
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import hashlib
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def generate_email_token(user_id: str, secret: str) -> str:
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"""Generate a 16-char hex HMAC token for a user's email address."""
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return hmac.new(
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secret.encode(), str(user_id).encode(), hashlib.sha256
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).hexdigest()[:16]
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def get_user_email_address(token: str, domain: str) -> str:
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"""Return the routable email address for a given token."""
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return f"ask+{token}@{domain}"
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