当我需要在Python中发送邮件时，我使用mailgun API，它在发送邮件时遇到了很多麻烦。他们有一个很棒的应用程序/api，可以让你每月发送5000封免费电子邮件。

发送电子邮件是这样的:

def send_simple_message():
    return requests.post(
        "https://api.mailgun.net/v3/YOUR_DOMAIN_NAME/messages",
        auth=("api", "YOUR_API_KEY"),
        data={"from": "Excited User <mailgun@YOUR_DOMAIN_NAME>",
              "to": ["bar@example.com", "YOU@YOUR_DOMAIN_NAME"],
              "subject": "Hello",
              "text": "Testing some Mailgun awesomness!"})

您还可以跟踪事件和更多信息，参见快速入门指南。

我编写了一个简单的函数send_email()，用于使用smtplib和电子邮件包发送电子邮件(链接到我的文章)。它还使用dotenv包来加载发件人的电子邮件和密码(请不要在代码中保密!)我正在使用Gmail电子邮件服务。密码是应用程序密码(这里是谷歌文档如何生成应用程序密码)。

import os
import smtplib
from email.message import EmailMessage
from dotenv import load_dotenv
_ = load_dotenv()


def send_email(to, subject, message):
    try:
        email_address = os.environ.get("EMAIL_ADDRESS")
        email_password = os.environ.get("EMAIL_PASSWORD")

        if email_address is None or email_password is None:
            # no email address or password
            # something is not configured properly
            print("Did you set email address and password correctly?")
            return False

        # create email
        msg = EmailMessage()
        msg['Subject'] = subject
        msg['From'] = email_address
        msg['To'] = to
        msg.set_content(message)

        # send email
        with smtplib.SMTP_SSL('smtp.gmail.com', 465) as smtp:
            smtp.login(email_address, email_password)
            smtp.send_message(msg)
        return True
    except Exception as e:
        print("Problem during send email")
        print(str(e))
    return False

以上方法对于简单的电子邮件发送是可行的。如果您正在寻找更高级的功能，例如HTML内容或附件，当然可以手工编码，但我建议使用现有的包，例如yagmail。

Gmail每天限制500封邮件。对于每天发送许多电子邮件，请考虑事务性电子邮件服务提供商，如Amazon SES, MailGun, MailJet或SendGrid。

它可能会在你的信息中添加标签。在你把它传递给sendMail之前打印出消息。

我对发送电子邮件的包选项不满意，我决定制作并开源我自己的电子邮件发送器。它易于使用，并支持高级用例。

如何安装:

pip install redmail

用法:

from redmail import EmailSender
email = EmailSender(
    host="<SMTP HOST ADDRESS>",
    port=<PORT NUMBER>,
)

email.send(
    sender="me@example.com",
    receivers=["you@example.com"],
    subject="An example email",
    text="Hi, this is text body.",
    html="<h1>Hi,</h1><p>this is HTML body</p>"
)

如果您的服务器需要用户和密码，只需将user_name和密码传递给EmailSender。

我在send方法中包含了很多特性:

包含附件 将图像直接包含到HTML主体中 金贾的模板 漂亮的HTML表格开箱即用

文档: https://red-mail.readthedocs.io/en/latest/

源代码:https://github.com/Miksus/red-mail

我建议您使用标准包email和smtplib一起发送电子邮件。请看下面的例子(摘自Python文档)。注意，如果遵循这种方法，“简单”任务确实很简单，而更复杂的任务(如附加二进制对象或发送纯/HTML多部分消息)将很快完成。

# Import smtplib for the actual sending function
import smtplib

# Import the email modules we'll need
from email.mime.text import MIMEText

# Open a plain text file for reading.  For this example, assume that
# the text file contains only ASCII characters.
with open(textfile, 'rb') as fp:
    # Create a text/plain message
    msg = MIMEText(fp.read())

# me == the sender's email address
# you == the recipient's email address
msg['Subject'] = 'The contents of %s' % textfile
msg['From'] = me
msg['To'] = you

# Send the message via our own SMTP server, but don't include the
# envelope header.
s = smtplib.SMTP('localhost')
s.sendmail(me, [you], msg.as_string())
s.quit()

要将电子邮件发送到多个目的地，您还可以遵循Python文档中的示例:

# Import smtplib for the actual sending function
import smtplib

# Here are the email package modules we'll need
from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart

# Create the container (outer) email message.
msg = MIMEMultipart()
msg['Subject'] = 'Our family reunion'
# me == the sender's email address
# family = the list of all recipients' email addresses
msg['From'] = me
msg['To'] = ', '.join(family)
msg.preamble = 'Our family reunion'

# Assume we know that the image files are all in PNG format
for file in pngfiles:
    # Open the files in binary mode.  Let the MIMEImage class automatically
    # guess the specific image type.
    with open(file, 'rb') as fp:
        img = MIMEImage(fp.read())
    msg.attach(img)

# Send the email via our own SMTP server.
s = smtplib.SMTP('localhost')
s.sendmail(me, family, msg.as_string())
s.quit()

如您所见，MIMEText对象中的报头To必须是由逗号分隔的电子邮件地址组成的字符串。另一方面，sendmail函数的第二个参数必须是一个字符串列表(每个字符串都是一个电子邮件地址)。

所以，如果你有三个电子邮件地址:person1@example.com, person2@example.com和person3@example.com，你可以这样做(明显的部分省略了):

to = ["person1@example.com", "person2@example.com", "person3@example.com"]
msg['To'] = ",".join(to)
s.sendmail(me, to, msg.as_string())

"，".join(to)部分从列表中生成一个单独的字符串，用逗号分隔。

从你的问题中，我猜你还没有读过Python教程——如果你想在Python中有所了解，这是必须的——标准库的文档大部分都很出色。

使用gmail的另一个实现让我们说:

import smtplib

def send_email(email_address: str, subject: str, body: str):
"""
send_email sends an email to the email address specified in the
argument.

Parameters
----------
email_address: email address of the recipient
subject: subject of the email
body: body of the email
"""

server = smtplib.SMTP('smtp.gmail.com', 587)
server.starttls()
server.login("email_address", "password")
server.sendmail("email_address", email_address,
                "Subject: {}\n\n{}".format(subject, body))
server.quit()