feat($message): support sending redered HTML in email

render HTML template via Jinjia2,
and then send it via email

BREAKING CHANGE: support sending redered HTML in email

home_guardian/message/email.py

@@ -1,52 +1,83 @@
-import datetime
 import smtplib
 from email.header import Header
+from email.mime.image import MIMEImage
 from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
 from typing import List
 
 from loguru import logger
 
 from home_guardian.configuration.application_configuration import application_conf
+from home_guardian.template.html_template import render_template
 
-mail_host: str = application_conf.get_string("email.mail_host")
-mail_user: str = application_conf.get_string("email.mail_user")
-mail_password: str = application_conf.get_string("email.mail_password")
-sender: str = f"{mail_user}{application_conf.get_string('email.mail_address_suffix')}"
-receivers: List[str] = application_conf.get_list("email.receivers")
+_mail_host: str = application_conf.get_string("email.mail_host")
+_mail_username: str = application_conf.get_string("email.mail_username")
+_mail_password: str = application_conf.get_string("email.mail_password")
+_sender: str = (
+    f"{_mail_username}{application_conf.get_string('email.mail_address_suffix')}"
+)
+_receivers: List[str] = application_conf.get_list("email.receivers")
 
 
-def build_message(receiver: str) -> MIMEMultipart:
+def build_message(
+    subject: str,
+    receiver: str,
+    template_name: str,
+    render_dict: dict,
+    picture_path: str,
+) -> MIMEMultipart:
+    """
+    Builds a message with the given subject, receiver, template name and render dict.
+
+    :param subject: The subject of the message.
+    :param receiver: The receiver of the message.
+    :param template_name: The name of the template to render.
+    :param render_dict: The render dict for the template.
+    :param picture_path: The path to the picture to attach.
+    """
     content: MIMEText = MIMEText(
-        "This is a email from Python "
-        + datetime.datetime.now().strftime("%Y-%m-%d %T"),
-        "plain",
-        "utf-8",
-    )
-    message: MIMEMultipart = MIMEMultipart()
-    message["Subject"] = Header(
-        "Emergency Security Alert, at "
-        + datetime.datetime.now().strftime("%Y-%m-%d %T"),
+        render_template(template_name, render_dict),
+        "html",
         "utf-8",
     )
-    message["From"] = Header(sender)
+    message: MIMEMultipart = MIMEMultipart("related")
+    message["Subject"] = Header(subject, "utf-8").encode()
+    message["From"] = Header(_sender)
     message["To"] = Header(receiver)
-    message["Cc"] = Header(sender)
+    message["Cc"] = Header(_sender)
     message.attach(content)
+    file = open(picture_path, "rb")
+    img_data = file.read()
+    file.close()
+    img = MIMEImage(img_data)
+    img.add_header("Content-ID", render_dict["content_id"])
+    message.attach(img)
     return message
 
 
-def send_email() -> None:
-    smtp: smtplib.SMTP = smtplib.SMTP(mail_host, 25)
-    smtp.connect(mail_host, 25)
-    smtp.login(sender, mail_password)
-    for receiver in receivers:
-        message: MIMEMultipart = build_message(receiver)
+def send_email(
+    subject: str, template_name: str, render_dict: dict, picture_path: str
+) -> None:
+    """
+    Sends an email with the given subject, template name and render dict.
+
+    :param subject: The subject of the message.
+    :param template_name: The name of the template to render.
+    :param render_dict: The render dict for the template.
+    :param picture_path: The path to the picture to attach.
+    """
+    smtp: smtplib.SMTP = smtplib.SMTP(_mail_host, 25)
+    smtp.connect(_mail_host, 25)
+    smtp.login(_sender, _mail_password)
+    for receiver in _receivers:
+        message: MIMEMultipart = build_message(
+            subject, receiver, template_name, render_dict, picture_path
+        )
+        logger.info(f"Sending email. receiver: {receiver}")
         try:
-            logger.info(f"Sending email. receiver: {receiver}")
-            smtp.sendmail(sender, [receiver], message.as_string())
+            smtp.sendmail(_sender, [receiver], message.as_string())
             logger.info(
-                f"Sent email successfully. {smtp}. receiver: {receiver}, message: {message}"
+                f"Sent email successfully. Receiver: {receiver}, subject: {subject}, template_name: {template_name}"
             )
         except smtplib.SMTPException:
             logger.exception("Exception occurred while sending email!")

home_guardian/resources/html_template/security_warning.html

@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <title>Security Warning: {{ subject }}</title>
+</head>
+<body>
+<p style="font-size:18px; font-family:Arial,serif; font-weight:bold">{{ content }}</p>
+<p style="font-size:15px; font-family:Arial,serif;">Warning time: {{ warning_time }}</p>
+<hr>
+<img src="cid:{{ content_id }}" alt="A capture">
+</body>
+</html>