fix: Support Django 6 updated EmailMessage

src/postmarker/models/emails.py

@@ -3,6 +3,7 @@
 import os
 from base64 import b64encode
 from email.header import decode_header
+from email.message import EmailMessage
 from email.mime.base import MIMEBase
 from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
@@ -37,6 +38,42 @@ def prepare_attachments(attachment):
         }
         if len(attachment) == 4:
             result["ContentID"] = attachment[3]
+    elif isinstance(attachment, EmailMessage):
+        # Handle EmailMessage objects (from email.message module)
+        # These can come from Django's message.message() or deconstruct_multipart
+        payload = attachment.get_payload(decode=True)
+        if payload is None:
+            # For multipart or string payloads
+            payload = attachment.get_payload()
+        if isinstance(payload, bytes):
+            content = b64encode(payload).decode()
+        elif isinstance(payload, str):
+            content = b64encode(payload.encode('utf-8')).decode()
+        else:
+            # For multipart messages, serialize the entire message
+            content = b64encode(attachment.as_bytes()).decode()
+
+        content_type = attachment.get_content_type()
+        filename = attachment.get_filename()
+        if filename is None:
+            # Generate filename based on content type
+            if content_type == "message/rfc822":
+                filename = "message.eml"
+            else:
+                filename = "attachment.txt"
+
+        result = {
+            "Name": filename,
+            "Content": content,
+            "ContentType": content_type,
+        }
+        content_id = attachment.get("Content-ID")
+        if content_id:
+            if content_id.startswith("<") and content_id.endswith(">"):
+                content_id = content_id[1:-1]
+            if (attachment.get("Content-Disposition") or "").startswith("inline"):
+                content_id = "cid:%s" % content_id
+            result["ContentID"] = content_id
     elif isinstance(attachment, MIMEBase):
         payload = attachment.get_payload()
         content_type = attachment.get_content_type()
@@ -76,15 +113,23 @@ def deconstruct_multipart_recursive(seen, text, html, attachments, message):
     if message in seen:
         return
     seen.add(message)
-    if isinstance(message, MIMEMultipart):
+    if message.is_multipart():
         for part in message.walk():
             deconstruct_multipart_recursive(seen, text, html, attachments, part)
     else:
         content_type = message.get_content_type()
         if content_type == "text/plain" and not text:
-            text.append(message.get_payload(decode=True).decode("utf8"))
+            # Use get_content() for EmailMessage, fall back to get_payload for MIME
+            if isinstance(message, EmailMessage):
+                text.append(message.get_content())
+            else:
+                text.append(message.get_payload(decode=True).decode("utf8"))
         elif content_type == "text/html" and not html:
-            html.append(message.get_payload(decode=True).decode("utf8"))
+            # Use get_content() for EmailMessage, fall back to get_payload for MIME
+            if isinstance(message, EmailMessage):
+                html.append(message.get_content())
+            else:
+                html.append(message.get_payload(decode=True).decode("utf8"))
         else:
             # Ignore underlying messages inside `message/rfc822` payload, because the message itself will be passed
             # as an attachment
@@ -285,7 +330,7 @@ def _construct_email(self, email, **extra):
         """Converts incoming data to properly structured dictionary."""
         if isinstance(email, dict):
             email = Email(manager=self._manager, **email)
-        elif isinstance(email, (MIMEText, MIMEMultipart)):
+        elif isinstance(email, (EmailMessage, MIMEText, MIMEMultipart)):
             email = Email.from_mime(email, self._manager)
         elif not isinstance(email, Email):
             raise ValueError
@@ -348,7 +393,7 @@ def send(
     ):
         """Sends a single email.
 
-        :param message: :py:class:`Email` or ``email.mime.text.MIMEText`` instance.
+        :param message: :py:class:`Email`, ``email.message.EmailMessage``, or ``email.mime.text.MIMEText`` instance.
         :param str From: The sender email address.
         :param To: Recipient's email address.
                    Multiple recipients could be specified as a list or string with comma separated values.
@@ -391,10 +436,10 @@ def send(
                 Attachments=Attachments,
                 MessageStream=MessageStream,
             )
-        elif isinstance(message, (MIMEText, MIMEMultipart)):
+        elif isinstance(message, (EmailMessage, MIMEText, MIMEMultipart)):
             message = Email.from_mime(message, self)
         elif not isinstance(message, Email):
-            raise TypeError("message should be either Email or MIMEText or MIMEMultipart instance")
+            raise TypeError("message should be either Email, EmailMessage, MIMEText or MIMEMultipart instance")
         return message.send()
 
     def send_with_template(