feat: add backend/smtp_client.py

backend/smtp_client.py

@@ -0,0 +1,59 @@
+"""SMTP 발송: smtplib STARTTLS + Sent 폴더 자동 저장"""
+import smtplib, ssl, asyncio
+from email.mime.multipart import MIMEMultipart
+from email.mime.text import MIMEText
+from email.mime.base import MIMEBase
+from email import encoders
+from email.utils import formatdate
+from typing import Optional
+
+SMTP_HOST = "localhost"
+SMTP_PORT = 587
+
+
+async def send_mail(
+    username: str, password: str,
+    to: str, subject: str, body: str,
+    cc: Optional[str] = None, bcc: Optional[str] = None,
+    is_html: bool = False,
+    attachments: Optional[list] = None,
+) -> bytes:
+    """발송 성공 시 raw 메시지 바이트 반환 (Sent 폴더 저장용)"""
+    msg = MIMEMultipart("alternative" if is_html else "mixed")
+    msg["From"] = username
+    msg["To"] = to
+    msg["Subject"] = subject
+    msg["Date"] = formatdate(localtime=True)
+    if cc: msg["Cc"] = cc
+
+    msg.attach(MIMEText(body, "html" if is_html else "plain", "utf-8"))
+
+    if attachments:
+        for name, data, ctype in attachments:
+            part = MIMEBase(*ctype.split("/", 1))
+            part.set_payload(data)
+            encoders.encode_base64(part)
+            part.add_header("Content-Disposition", "attachment", filename=name)
+            msg.attach(part)
+
+    recipients = [r.strip() for r in to.split(",")]
+    if cc: recipients += [r.strip() for r in cc.split(",")]
+    if bcc: recipients += [r.strip() for r in bcc.split(",")]
+
+    raw_bytes = msg.as_bytes()
+    user_short = username.split("@")[0]
+
+    def _do():
+        ctx = ssl.create_default_context()
+        ctx.check_hostname = False
+        ctx.verify_mode = ssl.CERT_NONE
+        s = smtplib.SMTP(SMTP_HOST, SMTP_PORT, timeout=15)
+        s.ehlo()
+        s.starttls(context=ctx)
+        s.ehlo()
+        s.login(user_short, password)
+        s.sendmail(username, recipients, raw_bytes)
+        s.quit()
+
+    await asyncio.get_event_loop().run_in_executor(None, _do)
+    return raw_bytes