Using EmailMessage with an attached email file crashes due to non-ASCII

Using Django Mystery Errors
1

Given a basic email setup like below, when I try to send the message, I get the following traceback:

Traceback (most recent call last):
  File "/usr/src/paperless/src/documents/signals/handlers.py", line 989, in email_action
    n_messages = email.send()
                 ^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/django/core/mail/message.py", line 301, in send
    return self.get_connection(fail_silently).send_messages([self])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/django/core/mail/backends/smtp.py", line 136, in send_messages
    sent = self._send(message)
           ^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/django/core/mail/backends/smtp.py", line 156, in _send
    from_email, recipients, message.as_bytes(linesep="\r\n")
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/django/core/mail/message.py", line 148, in as_bytes
    g.flatten(self, unixfrom=unixfrom, linesep=linesep)
  File "/usr/local/lib/python3.12/email/generator.py", line 117, in flatten
    self._write(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 182, in _write
    self._dispatch(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 219, in _dispatch
    meth(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 286, in _handle_multipart
    g.flatten(part, unixfrom=False, linesep=self._NL)
  File "/usr/local/lib/python3.12/email/generator.py", line 117, in flatten
    self._write(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 182, in _write
    self._dispatch(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 219, in _dispatch
    meth(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 372, in _handle_message
    g.flatten(msg.get_payload(0), unixfrom=False, linesep=self._NL)
  File "/usr/local/lib/python3.12/email/generator.py", line 117, in flatten
    self._write(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 182, in _write
    self._dispatch(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 219, in _dispatch
    meth(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 446, in _handle_text
    super(BytesGenerator,self)._handle_text(msg)
  File "/usr/local/lib/python3.12/email/generator.py", line 263, in _handle_text
    self._write_lines(payload)
  File "/usr/local/lib/python3.12/email/generator.py", line 156, in _write_lines
    self.write(line)
  File "/usr/local/lib/python3.12/email/generator.py", line 420, in write
    self._fp.write(s.encode('ascii', 'surrogateescape'))

                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 UnicodeEncodeError: 'ascii' codec can't encode characters in position 10-15: ordinal not in range(128)

email = EmailMessage(
    subject=subject,
    body=body,
    to=action.email.to.split(","),
)
email.attach_file(original_file)
n_messages = email.send()

The attached file is itself an eml file, which contains UTF8 content in the body. As far as I can figure, the s.encode('ascii', 'surrogateescape') is hardcoded. Has anyone worked around this? It seems like sending UTF8 content should be pretty easy.

2

Hi, I sugest you try

email.attach("file.eml", original_file, "message/rfc822")

insted of

email.attach_file(original_file)

With attach method we can pass the MIME Type of the file.

3

Interesting idea, I had tried attach_file, which can optionally take the MIME type, and providing that didn’t change anything.

So email.attach_file(original_file, "message/rfc822") didn’t work, nor did email.attach(original_file.name, original_file.read_bytes(), "message/rfc822")

4

Try to set the content type and charset explicitly:

email = EmailMessage(
    subject=subject,
    body=body,
    to=action.email.to.split(","),
)
email.content_subtype = 'plain'
email.encoding = 'utf-8'
email.attach_file(original_file)
n_messages = email.send()