Email templates

ephios/core/dynamic_preferences_registry.py

@@ -36,7 +36,7 @@ class EventTypeRegistry(PerInstancePreferenceRegistry):
 @global_preferences_registry.register
 class OrganizationName(StringPreference):
     name = "organization_name"
-    verbose_name = _("Organization name")
+    verbose_name = _("Organization display name")
     default = ""
     section = general_global_section
     required = False

ephios/core/models/users.py

@@ -504,13 +504,21 @@ def notification_type(self):
 
     @property
     def subject(self):
+        """The subject of the notification."""
         return self.notification_type.get_subject(self)
 
-    def as_plaintext(self):
-        return self.notification_type.as_plaintext(self)
+    @property
+    def body(self):
+        """The body text of the notification."""
+        return self.notification_type.get_body(self)
 
     def as_html(self):
+        """The notification rendered as HTML."""
         return self.notification_type.as_html(self)
 
-    def get_url(self):
-        return self.notification_type.get_url(self)
+    def as_plaintext(self):
+        """The notification rendered as plaintext."""
+        return self.notification_type.as_plaintext(self)
+
+    def get_actions(self):
+        return self.notification_type.get_actions(self)

ephios/core/services/mail/cid.py

@@ -0,0 +1,106 @@
+import logging
+import os
+import re
+from email.mime.image import MIMEImage
+from urllib.parse import urljoin, urlparse
+
+import requests
+from bs4 import BeautifulSoup
+from django.conf import settings
+from django.core.mail import EmailMultiAlternatives, SafeMIMEMultipart
+
+logger = logging.getLogger(__name__)
+
+
+# The following code is based on the pretix implementation [source]
+# for embedding cid images in emails.
+# It is released under the Apache License 2.0.
+# If you did not receive a copy of the license, please refer to
+# https://www.apache.org/licenses/LICENSE-2.0.html
+#
+# source:
+# https://github.com/pretix/pretix/blob/a08272571b7b67a3f41e02cf05af8183e3f94a02/src/pretix/base/services/mail.py
+
+
+class CustomEmail(EmailMultiAlternatives):
+    def _create_mime_attachment(self, content, mimetype):
+        """
+        Convert the content, mimetype pair into a MIME attachment object.
+
+        If the mimetype is message/rfc822, content may be an
+        email.Message or EmailMessage object, as well as a str.
+        """
+        basetype, subtype = mimetype.split("/", 1)
+        if basetype == "multipart" and isinstance(content, SafeMIMEMultipart):
+            return content
+        return super()._create_mime_attachment(content, mimetype)
+
+
+def replace_images_with_cid_paths(body_html):
+    if body_html:
+        email = BeautifulSoup(body_html, "lxml")
+        cid_images = []
+        for image in email.findAll("img"):
+            original_image_src = image["src"]
+            try:
+                cid_id = "image_%s" % cid_images.index(original_image_src)
+            except ValueError:
+                cid_images.append(original_image_src)
+                cid_id = "image_%s" % (len(cid_images) - 1)
+            image["src"] = "cid:%s" % cid_id
+        return str(email), cid_images
+    else:
+        return body_html, []
+
+
+def attach_cid_images(msg, cid_images, verify_ssl=True):
+    if cid_images and len(cid_images) > 0:
+        msg.mixed_subtype = "mixed"
+        for key, image in enumerate(cid_images):
+            cid = "image_%s" % key
+            try:
+                mime_image = convert_image_to_cid(image, cid, verify_ssl)
+                if mime_image:
+                    msg.attach(mime_image)
+            except:
+                logger.exception("ERROR attaching CID image %s[%s]" % (cid, image))
+
+
+def encoder_linelength(msg):
+    """
+    RFC1341 mandates that base64 encoded data may not be longer than 76 characters per line
+    https://www.w3.org/Protocols/rfc1341/5_Content-Transfer-Encoding.html section 5.2
+    """
+    orig = msg.get_payload(decode=True).replace(b"\n", b"").replace(b"\r", b"")
+    max_length = 76
+    pieces = []
+    for i in range(0, len(orig), max_length):
+        chunk = orig[i : i + max_length]
+        pieces.append(chunk)
+    msg.set_payload(b"\r\n".join(pieces))
+
+
+def convert_image_to_cid(image_src, cid_id, verify_ssl=True):
+    image_src = image_src.strip()
+    try:
+        if image_src.startswith("data:image/"):
+            image_type, image_content = image_src.split(",", 1)
+            image_type = re.findall(r"data:image/(\w+);base64", image_type)[0]
+            mime_image = MIMEImage(image_content, _subtype=image_type, _encoder=encoder_linelength)
+            mime_image.add_header("Content-Transfer-Encoding", "base64")
+        elif image_src.startswith("data:"):
+            logger.exception("ERROR creating MIME element %s[%s]" % (cid_id, image_src))
+            return None
+        else:
+            # replaced normalize_image_url with these two lines
+            if "://" not in image_src:
+                image_src = urljoin(settings.GET_SITE_URL(), image_src)
+            path = urlparse(image_src).path
+            guess_subtype = os.path.splitext(path)[1][1:]
+            response = requests.get(image_src, verify=verify_ssl)
+            mime_image = MIMEImage(response.content, _subtype=guess_subtype)
+        mime_image.add_header("Content-ID", "<%s>" % cid_id)
+        return mime_image
+    except:
+        logger.exception("ERROR creating mime_image %s[%s]" % (cid_id, image_src))
+        return None

ephios/core/services/mail/send.py

@@ -0,0 +1,67 @@
+import logging
+
+from css_inline import css_inline
+from django.conf import settings
+from django.core.mail import SafeMIMEMultipart, SafeMIMEText
+
+from ephios.core.services.mail.cid import (
+    CustomEmail,
+    attach_cid_images,
+    replace_images_with_cid_paths,
+)
+
+logger = logging.getLogger(__name__)
+
+
+def send_mail(
+    to,
+    subject,
+    plaintext,
+    html=None,
+    from_email=None,
+    cc=None,
+    bcc=None,
+    is_autogenerated=True,
+):
+    headers = {}
+    if is_autogenerated:
+        headers["Auto-Submitted"] = "auto-generated"
+        # https://learn.microsoft.com/en-us/openspecs/exchange_server_protocols/ms-oxcmail/ced68690-498a-4567-9d14-5c01f974d8b1
+        headers["X-Auto-Response-Suppress"] = "OOF, NRN, AutoReply, RN"
+
+    email = CustomEmail(
+        to=to,
+        subject=subject,
+        body=prepare_plaintext(plaintext),
+        headers=headers,
+        from_email=from_email or settings.DEFAULT_FROM_EMAIL,
+        cc=cc,
+        bcc=bcc,
+    )
+    if html:
+        html_part = prepare_html_part(html)
+        email.attach_alternative(html_part, "multipart/related")
+    email.send()
+
+
+def prepare_plaintext(plaintext):
+    """
+    Prepare the given plaintext for inclusion in the email.
+    * Replace newlines with CRLF
+    """
+    return plaintext.replace("\n", "\r\n")
+
+
+def prepare_html_part(html):
+    """
+    Transform the given rendered HTML into a multipart/related MIME part.
+    * Inline CSS
+    * replace image URLs with cid: URLs
+    """
+    inliner = css_inline.CSSInliner()
+    html = inliner.inline(html)
+    html_part = SafeMIMEMultipart(_subtype="related", encoding=settings.DEFAULT_CHARSET)
+    cid_html, cid_images = replace_images_with_cid_paths(html)
+    html_part.attach(SafeMIMEText(cid_html, "html", settings.DEFAULT_CHARSET))
+    attach_cid_images(html_part, cid_images, verify_ssl=True)
+    return html_part

ephios/core/services/notifications/backends.py

@@ -3,11 +3,12 @@
 import traceback
 
 from django.conf import settings
-from django.core.mail import EmailMultiAlternatives, mail_admins
+from django.core.mail import mail_admins
 from django.utils.translation import gettext_lazy as _
 from webpush import send_user_notification
 
 from ephios.core.models.users import Notification
+from ephios.core.services.mail.send import send_mail
 
 logger = logging.getLogger(__name__)
 
@@ -94,13 +95,13 @@ def _get_mailaddress(cls, notification):
 
     @classmethod
     def send(cls, notification):
-        email = EmailMultiAlternatives(
+        send_mail(
             to=[cls._get_mailaddress(notification)],
             subject=notification.subject,
-            body=notification.as_plaintext(),
+            plaintext=notification.as_plaintext(),
+            html=notification.as_html(),
+            is_autogenerated=True,
         )
-        email.attach_alternative(notification.as_html(), "text/html")
-        email.send()
 
 
 class WebPushNotificationBackend(AbstractNotificationBackend):
@@ -111,11 +112,11 @@ class WebPushNotificationBackend(AbstractNotificationBackend):
     def send(cls, notification):
         payload = {
             "head": str(notification.subject),
-            "body": notification.as_plaintext(),
+            "body": notification.body,
             "icon": "/static/ephios/img/ephios-symbol-red.svg",
         }
-        if url := notification.get_url():
-            payload["url"] = url
+        if actions := notification.get_actions():
+            payload["url"] = actions[0][1]
         send_user_notification(user=notification.user, payload=payload, ttl=1000)