feat: multipart ticket email with embedded QR, structured resend result

Port of upstream v1.6.8's delivery layer, wave-free: `_deliver_ticket_
notifications` sends text + HTML (the HTML embeds the ticket QR PNG from
this extension on the LNbits host — built from lnbits_baseurl on purpose,
since ticket_base_url may point at a separate web app) and returns a
`TicketResendResult` with per-channel attempted/sent/error. The SMTP
session runs via asyncio.to_thread so a slow relay cannot stall the event
loop while a batch of tickets settles. Resend keeps bypassing the
per-event email opt-in (organizer asked explicitly) and is email-only.
Our nsec-DM Nostr path is kept (upstream went NIP-05-only).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EYwoAkZZmXMMmaBp4WGUBo

services.py

@@ -1,14 +1,16 @@
 from __future__ import annotations
 
 import asyncio
+import smtplib
 from asyncio.tasks import create_task
+from email.mime.multipart import MIMEMultipart
+from email.mime.text import MIMEText
+from html import escape
 
 from lnbits.core.models.users import UserNotifications
 from lnbits.core.services.nostr import send_nostr_dm
-from lnbits.core.services.notifications import (
-    send_email_notification,
-    send_user_notification,
-)
+from lnbits.core.services.notifications import send_user_notification
+from lnbits.helpers import is_valid_email_address
 from lnbits.settings import settings
 from lnbits.utils.nostr import normalize_private_key, normalize_public_key
 from lnurl import execute
@@ -21,7 +23,7 @@ from .crud import (
     update_event,
     update_ticket,
 )
-from .models import Event, Ticket
+from .models import Event, NotificationDeliveryResult, Ticket, TicketResendResult
 from .nostr_hooks import publish_or_delete_nostr_event
 
 DEFAULT_NOSTR_RELAYS = [
@@ -80,40 +82,13 @@ async def _send_ticket_notification(ticket: Ticket) -> None:
         logger.warning(f"Event {ticket.event} not found for ticket notification.")
         return
 
-    subject, message = _ticket_notification_message(ticket, event)
-    updated = False
-
-    if (
-        event.extra.email_notifications
-        and settings.lnbits_email_notifications_enabled
-        and ticket.email
-    ):
-        try:
-            await send_email_notification([ticket.email], message, subject)
-            ticket.extra.email_notification_sent = True
-            updated = True
-        except Exception as exc:
-            logger.warning(f"Failed to email ticket {ticket.id}: {exc}")
-
-    if (
-        event.extra.nostr_notifications
-        and settings.is_nostr_notifications_configured()
-        and ticket.extra.nostr_identifier
-    ):
-        try:
-            await _send_nostr_ticket_notification(
-                ticket.extra.nostr_identifier, message
-            )
-            ticket.extra.nostr_notification_sent = True
-            updated = True
-        except Exception as exc:
-            logger.warning(f"Failed to send nostr DM for ticket {ticket.id}: {exc}")
-
-    if updated:
-        await update_ticket(ticket)
+    await _deliver_ticket_notifications(ticket, event)
 
 
-async def resend_ticket_email_notification(ticket: Ticket) -> Ticket:
+async def resend_ticket_email_notification(ticket: Ticket) -> TicketResendResult:
+    """Organizer-triggered re-delivery of the ticket email. Bypasses the
+    per-event `email_notifications` opt-in (the organizer asked explicitly)
+    but still needs the instance mailer and an address on the ticket."""
     event = await get_event(ticket.event)
     if not event:
         raise ValueError("Event does not exist.")
@@ -122,10 +97,7 @@ async def resend_ticket_email_notification(ticket: Ticket) -> Ticket:
     if not ticket.email:
         raise ValueError("Ticket does not have an email address.")
 
-    subject, message = _ticket_notification_message(ticket, event)
-    await send_email_notification([ticket.email], message, subject)
-    ticket.extra.email_notification_sent = True
-    return await update_ticket(ticket)
+    return await _deliver_ticket_notifications(ticket, event, email=True, nostr=False)
 
 
 def _ticket_notification_message(ticket: Ticket, event: Event) -> tuple[str, str]:
@@ -142,6 +114,149 @@ def _ticket_notification_message(ticket: Ticket, event: Event) -> tuple[str, str
     return subject, f"{body}\n\nOpen it here: {ticket_url}"
 
 
+def _ticket_delivery_message(ticket: Ticket, base_message: str) -> str:
+    return f"{base_message}\n\nTicket image: {_ticket_image_url(ticket)}"
+
+
+def _ticket_email_html_message(ticket: Ticket, base_message: str) -> str:
+    text_message = _ticket_delivery_message(ticket, base_message)
+    html_message = f"<p>{escape(text_message).replace(chr(10), '<br />')}</p>"
+    image_url = escape(_ticket_image_url(ticket), quote=True)
+    return (
+        f"{html_message}"
+        f'<p><img src="{image_url}" alt="Ticket QR code" '
+        'style="max-width: 300px; height: auto;" /></p>'
+    )
+
+
+def _ticket_notification_payload(ticket: Ticket, event: Event) -> tuple[str, str, str]:
+    subject, base_message = _ticket_notification_message(ticket, event)
+    text_message = _ticket_delivery_message(ticket, base_message)
+    html_message = _ticket_email_html_message(ticket, base_message)
+    return subject, text_message, html_message
+
+
+async def _deliver_ticket_notifications(
+    ticket: Ticket,
+    event: Event,
+    *,
+    email: bool | None = None,
+    nostr: bool | None = None,
+) -> TicketResendResult:
+    """Send the ticket by every configured channel and report per-channel
+    outcome (upstream v1.6.8 shape). `email` / `nostr` override the event's
+    opt-ins when not None; the instance-level prerequisites always apply."""
+    subject, text_message, html_message = _ticket_notification_payload(ticket, event)
+    updated = False
+
+    email_wanted = event.extra.email_notifications if email is None else email
+    nostr_wanted = event.extra.nostr_notifications if nostr is None else nostr
+    result = TicketResendResult(
+        ticket=ticket,
+        email=NotificationDeliveryResult(
+            attempted=bool(
+                email_wanted
+                and settings.lnbits_email_notifications_enabled
+                and ticket.email
+            )
+        ),
+        nostr=NotificationDeliveryResult(
+            attempted=bool(
+                nostr_wanted
+                and settings.is_nostr_notifications_configured()
+                and ticket.extra.nostr_identifier
+            )
+        ),
+    )
+
+    if result.email.attempted:
+        try:
+            assert ticket.email
+            await _send_ticket_email_notification(
+                [ticket.email], text_message, subject, html_message
+            )
+            ticket.extra.email_notification_sent = True
+            result.email.sent = True
+            updated = True
+        except Exception as exc:
+            logger.warning(f"Failed to email ticket {ticket.id}: {exc}")
+            result.email.error = str(exc)
+
+    if result.nostr.attempted:
+        try:
+            identifier = ticket.extra.nostr_identifier
+            assert identifier
+            await _send_nostr_ticket_notification(identifier, text_message)
+            ticket.extra.nostr_notification_sent = True
+            result.nostr.sent = True
+            updated = True
+        except Exception as exc:
+            logger.warning(f"Failed to send nostr DM for ticket {ticket.id}: {exc}")
+            result.nostr.error = str(exc)
+
+    if updated:
+        result.ticket = await update_ticket(ticket)
+    return result
+
+
+async def _send_ticket_email_notification(
+    to_emails: list[str],
+    message: str,
+    subject: str,
+    html_message: str | None = None,
+) -> None:
+    """Multipart (text + HTML) ticket email through the instance SMTP
+    settings. Core's `send_email_notification` is plain-text only, which is
+    why this lives here (ported from upstream v1.6.8). The blocking smtplib
+    session runs in a worker thread so a slow relay cannot stall the event
+    loop while a batch of tickets settles."""
+    if not settings.lnbits_email_notifications_enabled:
+        raise ValueError("Email notifications are disabled")
+    from_email = settings.lnbits_email_notifications_email
+    if not is_valid_email_address(from_email):
+        raise ValueError(f"Invalid from email address: {from_email}")
+    if not to_emails:
+        raise ValueError("No email addresses provided")
+    for address in to_emails:
+        if not is_valid_email_address(address):
+            raise ValueError(f"Invalid email address: {address}")
+
+    msg = MIMEMultipart("alternative")
+    msg["From"] = from_email
+    msg["To"] = ", ".join(to_emails)
+    msg["Subject"] = subject
+    msg.attach(MIMEText(message, "plain"))
+    if html_message:
+        msg.attach(MIMEText(html_message, "html"))
+
+    username = settings.lnbits_email_notifications_username or from_email
+    await asyncio.to_thread(
+        _smtp_send,
+        settings.lnbits_email_notifications_server,
+        settings.lnbits_email_notifications_port,
+        username,
+        settings.lnbits_email_notifications_password,
+        from_email,
+        to_emails,
+        msg.as_string(),
+    )
+
+
+def _smtp_send(
+    server: str,
+    port: int,
+    username: str,
+    password: str,
+    from_email: str,
+    to_emails: list[str],
+    payload: str,
+) -> None:
+    with smtplib.SMTP(server, port, timeout=30) as smtp_server:
+        smtp_server.starttls()
+        smtp_server.login(username, password)
+        smtp_server.sendmail(from_email, to_emails, payload)
+
+
 async def _send_nostr_ticket_notification(identifier: str, message: str) -> None:
     if "@" in identifier:
         await send_user_notification(
@@ -161,6 +276,14 @@ def _ticket_url(ticket: Ticket) -> str:
     return f"{base_url}/events/ticket/{ticket.id}"
 
 
+def _ticket_image_url(ticket: Ticket) -> str:
+    """The QR PNG is served by THIS extension on the LNbits host, so it is
+    built from `lnbits_baseurl` even when `ticket_base_url` points at a
+    separate web app (deviation from upstream, which assumes both are the
+    same host)."""
+    return f"{settings.lnbits_baseurl.rstrip('/')}/events/api/v1/qr/{ticket.id}"
+
+
 async def refund_tickets(event_id: str):
     """
     Refund tickets for an event that has not met the minimum ticket requirement.