Files
2026-01-23 22:00:12 +01:00

145 lines
5.5 KiB
Python

import os
import smtplib
from email.message import EmailMessage
def _truthy(v: str | None) -> bool:
if v is None:
return False
return v.strip().lower() in ("1", "true", "yes", "on")
def send_email(*, to_email: str, subject: str, body_text: str):
"""Send a plain-text email using SMTP settings from:
1) Admin-configured settings stored in the database (AppSettings) (highest priority)
2) Environment variables (fallback)
If you *do* want environment variables to override DB settings (e.g. in production),
set SMTP_OVERRIDE_DB=1.
Required configuration (either from DB or env):
- host
- username
- password
When using env vars, the names are:
- SMTP_HOST
- SMTP_PORT
- SMTP_USERNAME
- SMTP_PASSWORD
- SMTP_FROM (defaults to SMTP_USERNAME)
Optional:
- SMTP_STARTTLS (default: "1")
- SMTP_TIMEOUT_SECONDS (default: "10")
- SMTP_DEBUG (default: "0") - set to 1 to print SMTP conversation to console
"""
# Load DB settings (best-effort). If the DB has a complete SMTP config, we will use
# it even if environment variables are present.
#
# This fixes the common deployment situation where a .env/.flaskenv provides SMTP_*
# values that unintentionally override admin-configured settings.
db_defaults: dict[str, object] = {}
try:
# Local import to avoid import cycles and to keep this module lightweight.
from flask import current_app
from .extensions import db
from .models import AppSettings
# Only try if app context exists (send_email is called inside requests/CLI normally).
# Accessing the LocalProxy will raise if there is no active app context.
current_app._get_current_object()
s = db.session.get(AppSettings, 1)
if s:
db_defaults = {
"host": s.smtp_host,
"port": s.smtp_port,
"username": s.smtp_username,
"password": s.smtp_password,
"from_email": s.smtp_from,
"starttls": s.smtp_starttls,
"timeout": s.smtp_timeout_seconds,
"debug": s.smtp_debug,
}
except Exception:
# Best-effort; if DB isn't ready we fall back to env vars only.
db_defaults = {}
# DB-first selection rules:
# - If *any* SMTP field is configured in DB, treat DB as authoritative (and do NOT
# silently mix in env vars). This avoids confusion where partial DB config still
# results in env vars being used.
# - Env override is only possible with SMTP_OVERRIDE_DB=1.
override_db = _truthy(os.environ.get("SMTP_OVERRIDE_DB"))
db_config_present = bool(
db_defaults.get("host")
or db_defaults.get("username")
or db_defaults.get("password")
or db_defaults.get("from_email")
or (db_defaults.get("port") is not None)
)
if db_config_present and not override_db:
config_source = "db"
host = str(db_defaults.get("host") or "") or None
port = int(db_defaults.get("port") or 587)
username = str(db_defaults.get("username") or "") or None
password = str(db_defaults.get("password") or "") or None
from_email = (str(db_defaults.get("from_email")) if db_defaults.get("from_email") else None) or username
starttls = bool(db_defaults.get("starttls") if db_defaults.get("starttls") is not None else True)
timeout = float(db_defaults.get("timeout") or 10)
debug = bool(db_defaults.get("debug") or False)
else:
config_source = "env"
host = os.environ.get("SMTP_HOST")
port = int(os.environ.get("SMTP_PORT") or 587)
username = os.environ.get("SMTP_USERNAME")
password = os.environ.get("SMTP_PASSWORD")
from_email = os.environ.get("SMTP_FROM") or username
starttls = _truthy(os.environ.get("SMTP_STARTTLS")) if os.environ.get("SMTP_STARTTLS") is not None else True
timeout = float(os.environ.get("SMTP_TIMEOUT_SECONDS") or 10)
debug = _truthy(os.environ.get("SMTP_DEBUG")) if os.environ.get("SMTP_DEBUG") is not None else False
missing = []
if not host:
missing.append("host")
if not username:
missing.append("username")
if not password:
missing.append("password")
if not from_email:
missing.append("from_email")
if missing:
raise RuntimeError(
f"Missing SMTP configuration ({config_source}): "
+ ", ".join(missing)
+ ". Configure it in Admin → Settings (or set SMTP_* environment variables)."
)
msg = EmailMessage()
msg["From"] = from_email
msg["To"] = to_email
msg["Subject"] = subject
# Helps when SMTP providers force the authenticated mailbox as envelope sender,
# but still allow replies to go to the desired address.
if from_email and username and from_email != username:
msg["Reply-To"] = from_email
msg.set_content(body_text)
with smtplib.SMTP(host, port, timeout=timeout) as smtp:
if debug:
smtp.set_debuglevel(1)
print(f"[email_utils] Using SMTP config from: {config_source}")
smtp.ehlo()
if starttls:
smtp.starttls()
smtp.ehlo()
smtp.login(username, password)
# Pass explicit envelope-from to avoid falling back to the authenticated user.
# Note: some SMTP providers will still override this for anti-spoofing.
smtp.send_message(msg, from_addr=from_email, to_addrs=[to_email])