CSV File Attachment Error: 'bytes' object has no attribute 'encode'

Question

I need to create a CSV file and send it as an email attachment. I want to create the file in memory so that it does not actually occupy space in my file system. I seem to have it nearly working except I get an error when I try to send the email: 'bytes' object has no attribute 'encode' Any ideas what's going wrong?

    from django.core.mail import EmailMultiAlternatives
    import csv, io

    csvfile = io.StringIO()
    fieldnames = ['user_id', 'user_name', 'user_forecast', 'is_correct', 'correct_answer',
        'forecast_to_event_seconds']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

    writer.writeheader()
    for f in forecasts:
        writer.writerow({'user_id': f.profile.id, 'user_name': f.profile.name,
            'user_forecast': f.answer_text, 'is_correct': f.is_correct, 'correct_answer': correct_answer, 
            'forecast_to_event_seconds': (event_end-f.created_on).total_seconds()})

    # Send email with CSV attachment
    subject='Data'
    to=["[email protected]",]
    from_email=from_email
    context={'group': group.replace('-', ' '), 'question': poll.question, 'site': Site.objects.get_current(),
        'STATIC_URL': settings.STATIC_URL}
    template='polls/notifications/castie_data.txt'
    message = render_to_string('polls/notifications/castie_data.txt', context)

    msg = EmailMultiAlternatives(subject, message, to=to, from_email=from_email)
    msg.attach_alternative(render_to_string('polls/notifications/castie_data.html', context), 'text/html')

    file_name = "%s-%s.csv" % (group, poll.question.replace(' ', '-'))
    msg.attach_file(file_name, 'text/csv')
    msg.content_subtype = "html"
    msg.send()

Full Traceback:

Environment:

Request Method: POST Request URL: http://localhost:8000/poll/81e21783370b46218d6e26d1366b97b8/close/

Django Version: 1.7.7 Python Version: 3.4.3

Traceback: File "/Users/s/.virtualenvs/c/lib/python3.4/site-packages/django/core/handlers/base.py" in get_response 111. response = wrapped_callback(request, *callback_args, **callback_kwargs) File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/contrib/auth/decorators.py" in _wrapped_view 21. return view_func(request, *args, **kwargs) File "/Users/stephaniesocias/git/cassie/cassie-app/polls/views.py" in close_poll 101. create_send_data(poll.id) File "/Users/stephaniesocias/git/cassie/cassie-app/polls/tasks.py" in create_send_data 455. msg.send() File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/message.py" in send 286. return self.get_connection(fail_silently).send_messages([self]) File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/backends/smtp.py" in send_messages 99. sent = self._send(message) File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/backends/smtp.py" in _send 113. message = email_message.message() File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/message.py" in message 253. msg = self._create_message(msg) File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/message.py" in _create_message 409. return self._create_attachments(self._create_alternatives(msg)) File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/message.py" in _create_attachments 325. msg.attach(self._create_attachment(*attachment)) File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/message.py" in _create_attachment 367. attachment = self._create_mime_attachment(content, mimetype) File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/message.py" in _create_mime_attachment 338. attachment = SafeMIMEText(content, subtype, encoding) File "/Users/stephaniesocias/.virtualenvs/cassie/lib/python3.4/site-packages/django/core/mail/message.py" in init 175. MIMEText.init(self, text, subtype, None) File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/email/mime/text.py" in init 33. try:

Exception Type: AttributeError at /poll/81e21783370b46218d6e26d1366b97b8/close/ Exception Value: 'bytes' object has no attribute 'encode'

Please show the full traceback. It looks as if you are not using your stringio buffer as you are still using attach_file(filename, 'text/csv'). — Alasdair
The full traceback should say the line of your code that is throwing the error as well. As I was saying in the previous comment, have a think about your code as well, since you are writing to a stringio buffer but not using it. — Alasdair
@Alasdair Added more traceback info; hmm I've never used the StringIO buffer so that is where I must be going wrong. How do I go about attaching something from the buffer? — steph

steph steph · Accepted Answer · 2015-10-27T19:54:39

Not the most elegant solution but it works:

    import csv, io
    csvfile = io.StringIO()
    fieldnames = ['user_id', 'user_name', 'user_forecast', 'is_correct', 'correct_answer',
        'forecast_to_event_seconds', 'answer_types']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

    writer.writeheader()
    for f in forecasts:
        writer.writerow({'user_id': f.profile.id, 'user_name': f.profile.name,
            'user_forecast': f.answer_text, 'is_correct': f.is_correct, 'correct_answer': correct_answer, 
            'forecast_to_event_seconds': (event_end-f.created_on).total_seconds(), 'answer_types': poll.answer_type})

    # Send email with CSV attachment
    subject='Data'
    to=["[email protected]",]
    from_email=from_email
    context={'group': group.replace('-', ' '), 'question': poll.question, 'site': Site.objects.get_current(),
        'STATIC_URL': settings.STATIC_URL}
    template='polls/notifications/castie_data.txt'
    message = render_to_string('polls/notifications/castie_data.txt', context)

    msg = EmailMultiAlternatives(subject, message, to=to, from_email=from_email)
    msg.attach_alternative(render_to_string('polls/notifications/castie_data.html', context), 'text/html')

    file_name = "%s-%s.csv" % (group, poll.question.replace(' ', '-'))
    csv_file = csvfile.getvalue()
    msg.attach(file_name, csv_file,'text/csv')
    msg.content_subtype = "html"
    msg.send()

CSV File Attachment Error: 'bytes' object has no attribute 'encode'

1 Answers