类型错误：“EmailMultiAlternatives”类型的对象没有 len()

Question

Django 应用程序，仅在工作日使用脚本（使用 runscript）发送电子邮件。 尝试使用 Google 的 STMP。

这是相关脚本：

import os, django
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "labschedule.settings")
django.setup()
import datetime
from datetime import date
import smtplib
from django.template.loader import render_to_string
from django.core.mail import EmailMultiAlternatives
from labschedule import settings

def run():
    today = date.today()
    subject = "Daily Report for %s" % today
    to = [settings.EMAIL_ADMIN]
    from_email = 'blahblah@gmail.com' # My email

    reservations = Event.objects.filter(day=today).order_by('cart')
    last = Event.objects.latest('day')
    if today >= today + datetime.timedelta(days=5):
        countdown = last - datetime.timedelta(today)
        warning = "Hey! You run out of open slots in %s days" % countdown
    else:
        warning = None

    ctx = ({
        'reservations' : reservations, 'warning' : warning, 'cart_choice' : cart_choice
    })
    html_content = render_to_string('schedule/email.html', ctx)
    text_content = render_to_string('schedule/email.html', ctx)
    msg = EmailMultiAlternatives(subject, text_content, to=to, from_email=from_email)
    msg.attach_alternative(html_content, "text/html")
    weekend = set([5, 6])  # Python week starts on Monday as 0
    if today.weekday() not in weekend and settings.DAILY_EMAIL == True:
        server = smtplib.SMTP_SSL('smtp.gmail.com', 465)
        server.ehlo()
        server.login(settings.gmail_user, settings.gmail_password)
        server.sendmail(from_email, to, msg)
        server.close()

        print ('Email sent!')
    else:
        pass

我主要在这里学习了教程。

我收到的错误：

TypeError: object of type 'EmailMultiAlternatives' has no len()

我是新手，我知道这很愚蠢，非常感谢任何帮助。

编辑：追溯

Traceback (most recent call last):
  File "/home/mrsaltz/labschedule/manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django/core/management/__init__.py", line 363, in execute_from_comm
and_line
    utility.execute()
  File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django/core/management/__init__.py", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django_extensions/management/email_notifications.py", line 63, in r
un_from_argv
    super(EmailNotificationCommand, self).run_from_argv(argv)
  File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django_extensions/management/email_notifications.py", line 75, in e
xecute
    super(EmailNotificationCommand, self).execute(*args, **options)
  File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django_extensions/management/utils.py", line 58, in inner
    ret = func(self, *args, **kwargs)
  File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django_extensions/management/commands/runscript.py", line 165, in h
andle
    run_script(mod, *script_args)
  File "/home/mrsaltz/.virtualenvs/scheduler/lib/python3.5/site-packages/django_extensions/management/commands/runscript.py", line 77, in ru
n_script
    mod.run(*script_args)
  File "/home/mrsaltz/labschedule/scripts/daily_email.py", line 40, in run
    server.sendmail(from_email, to, msg)
  File "/usr/lib/python3.5/smtplib.py", line 853, in sendmail
    esmtp_opts.append("size=%d" % len(msg))
TypeError: object of type 'EmailMultiAlternatives' has no len()

Answer 1

SMTP_SSL.send()需要一个字节串而不是 EmailMultiAlternatives 的实例

你不应该在这里混杂。 EmailMultiAlternatives 是来自 Django 的类，但 smtplib 来自 Python 标准库。 EmailMultiAlternatives 应该与 Django 邮件库一起使用 - 此外，它还负责所有 SMTP 连接和登录逻辑。

所有这些都包含在您已经链接到的文档页面中：您应该遵循它。

Answer 2

to (email) 的参数不是作为单个电子邮件填充的，而是用于电子邮件列表。 你应该改变：

msg = EmailMultiAlternatives(subject, text_content, to=to, from_email=from_email)

到

msg = EmailMultiAlternatives(subject, text_content, from_email, [to])

有关更多信息，请参阅此文档。