How to Email a Django FileField as an Attachment?

I would just not supply a content type and let the recipient's email client work it out. Unless it will be something unusual it shouldn't be a problem.

RFC2616 states:

If and only if the media type is not given by a Content-Type field, the recipient MAY attempt to guess the media type via inspection of its content and/or the name extension(s) of the URI used to identify the resource.

but... If you want to specify it then storing the content type on upload is a very good idea. It should be noted that django's own docs say to verify the data from users

If you are on a *unix OS you could try to guess/inspect it:

import subprocess
subprocess.check_output(['file', '-b', '--mime', filename]) 

(from How to find the mime type of a file in python? )

I am using django-storages and so .path raises

NotImplementedError: This backend doesn't support absolute paths.

To avoid this, I simply open the file, read it, guess the mimetype and close it later, but having to use .attach instead of .attach_file magic.

from mimetypes import guess_type
from os.path import basename


f = model.filefield
f.open()
# msg.attach(filename, content, mimetype)
msg.attach(basename(f.name), f.read(), guess_type(f.name)[0])
f.close()

Another approach:

from django.core.mail.message import EmailMessage

msg = EmailMessage(subject=my_subject, body=my_email_body, 
      from_email=settings.DEFAULT_FROM_EMAIL, to=[to_addressed])
msg.attach_file(self.my_filefield.path) # self.my_filefield.file for Django < 1.7
msg.send(fail_silently=not(settings.DEBUG))

Attaching a models.FileField file to an email message is nice and simple in Django:

from django.core.mail import EmailMultiAlternatives
kwargs = dict(
    to=to,
    from_email=from_addr,
    subject=subject,
    body=text_content,
    alternatives=((html_content, 'text/html'),)
)
message = EmailMultiAlternatives(**kwargs)
message.attach_file(model_instance.filefield.path)
message.send()