发送邮件¶

Django provides wrappers for Python's email and smtplib modules to simplify composing and sending email. Django's email framework also supports swapping in different delivery mechanisms: you can direct email to the console or a file during development and an SMTP server or email service provider in production.

这些代码位于 django.core.mail 模块。

快速示例¶

使用 send_mail() 进行简单的邮件发送。例如，发送纯文本消息：

from django.core.mail import send_mail

send_mail(
    "Subject here",
    "Here is the message.",
    "from@example.com",
    ["to@example.com"],
)

When additional email sending functionality is needed, use the EmailMessage or EmailMultiAlternatives class. For example, to send a multipart email that includes both HTML and plain text versions with a specific template and custom headers, you can use the following approach:

from django.core.mail import EmailMultiAlternatives
from django.template.loader import render_to_string

# First, render the plain text content.
text_content = render_to_string(
    "templates/emails/my_email.txt",
    context={"my_variable": 42},
)

# Secondly, render the HTML content.
html_content = render_to_string(
    "templates/emails/my_email.html",
    context={"my_variable": 42},
)

# Then, create a multipart email instance.
msg = EmailMultiAlternatives(
    subject="Subject here",
    body=text_content,
    from_email="from@example.com",
    to=["to@example.com"],
    headers={"List-Unsubscribe": "<mailto:unsub@example.com>"},
)

# Lastly, attach the HTML content to the email instance and send.
msg.attach_alternative(html_content, "text/html")
msg.send()

Configuring email¶

New Django projects are not configured to send email by default. Instead, email is printed to the console as a development aid (for projects created with startproject) or results in a MailerDoesNotExist error (when the MAILERS setting isn't defined).

Use the MAILERS setting to tell Django how to send email. For example, to send through an SMTP server running on the local machine:

MAILERS = {
    "default": {
        "BACKEND": "django.core.mail.backends.smtp.EmailBackend",
        "OPTIONS": {
            "host": "localhost",
        },
    },
}

Django abstracts the email sending process into an "email backend" class. 邮件后端 lists the email backends that come with Django.

The example above uses Django's SMTP email backend, which sends using the standard SMTP protocol. This backend is useful for many production configurations, including SMTP servers in your own infrastructure and most commercial email service providers (ESPs). There are also third-party email backends available that integrate directly with ESP APIs or add other sending features.

During development or testing you often don't want to send email at all. Django's test runner automatically overrides the MAILERS configuration to substitute Django's memory email backend. This prevents test cases from sending real email and gives them access to the messages that would have been sent. 为了开发配置邮件 discusses some other approaches.

Changed in Django 6.1:

In earlier releases, Django defaulted to sending email through an SMTP server running on localhost, using the now-deprecated EMAIL_BACKEND and related settings.

Deprecated since version 6.1: Until Django 7.0, if the MAILERS setting is not defined then the earlier behavior still applies: Django will default to using an SMTP server on localhost (but will issue deprecation warnings). Starting in Django 7.0, attempts to send email without MAILERS defined will result in a MailerDoesNotExist error.

Existing projects can opt into the new behavior early by adding MAILERS to settings.py. See Migrating email to mailers.

Multiple mailers¶

Sometimes different types of email need to be sent in different ways: e.g., internal vs. external email, different SMTP servers for users in different regions, using different services for transactional notifications and bulk marketing email, etc.

The MAILERS setting can define multiple mail configurations. For example:

import os

MAILERS = {
    "default": {
        "BACKEND": "django.core.mail.backends.smtp.EmailBackend",
        "OPTIONS": {
            "host": "smtp.example.net",
            "use_tls": True,
            "username": os.environ["EMAIL_ACCOUNT_ID"],
            "password": os.environ["EMAIL_API_KEY"],
        },
    },
    "notifications": {
        "BACKEND": "example.third.party.EmailBackend",
        "OPTIONS": {
            "api_key": os.environ["THIRD_PARTY_API_KEY"],
            "region": "eu",
        },
    },
    "admin": {
        "BACKEND": "django.core.mail.backends.smtp.EmailBackend",
        "OPTIONS": {
            "host": "localhost",
        },
    },
}

This defines three mailer configurations:

"default" sends through an SMTP server at smtp.example.net with a TLS secured connection. It reads an account id and API key from environment variables and uses them as the SMTP authentication username and password. (Many SMTP services use some variation of this authentication scheme.)
"notifications" sends through a hypothetical commercial email service, using a third-party EmailBackend that connects directly to their API. (See Third-party backends for pointers on locating real, community maintained email backend packages.)
"admin" sends through an SMTP server running on localhost, with no other options required.

With this configuration, you can provide the using argument to Django's email sending functions to specify a particular mailer configuration:

from django.core.mail import send_mail

send_mail(
    "Account activated",
    "Congratulations, you're all ready to use our Django app!",
    "from@example.com",
    ["user@example.com"],
    using="notifications",
)

If using is not specified, Django uses the mailer defined for the "default" configuration.

With reusable apps or Django features that send email for you, there may be an option to use a specific mailer configuration. For example, Django's logging AdminEmailHandler allows specifying the mailer configuration in its using option.

Sending messages¶

django.core.mail provides functions for conveniently sending email, as well as classes for building and sending more complex email messages with attachments and multiple content types.

Note

通过 django.core.mail 发送的邮件的字符编码由 DEFAULT_CHARSET 设置项指定。

`send_mail()`¶

send_mail(subject, message, from_email, recipient_list, *, fail_silently=False, auth_user=None, auth_password=None, connection=None, html_message=None)[source]¶

django.core.mail.send_mail() sends a single email message.

参数 subject, message, from_email 和 recipient_list 是必须的。

subject: 一个字符串。
message: 一个字符串。
from_email ：字符串。如果为 None ，Django 将使用 DEFAULT_FROM_EMAIL 设置的值。
recipient_list: 一个字符串列表，每项都是一个邮箱地址。recipient_list 中的每个成员都可以在邮件的 "收件人:" 中看到其他的收件人。

The following parameters are optional, and must be given as keyword arguments if used.

fail_silently: A boolean, default False. If set True, send_mail() will suppress some errors during sending. (The exact exceptions ignored depend on the email backend in use.)
auth_user: 可选的用户名，用于验证登陆 SMTP 服务器。若未提供，Django 会使用 EMAIL_HOST_USER 指定的值。
auth_password: 可选的密码，用于验证登陆 SMTP 服务器。若未提供， Django 会使用 EMAIL_HOST_PASSWORD 指定的值。
connection: 可选参数，发送邮件使用的后端。若未指定，则使用默认的后端。查询邮件后端文档获取更多细节。
html_message: 若提供了 html_message，会使邮件成为 multipart/alternative 的实例， message 的内容类型则是 text/plain ，并且 html_message 的内容类型是 text/html 。
using: An optional MAILERS alias to use to send the mail. If unspecified, the default mailer configuration will be used.

fail_silently, auth_user, auth_password, and connection are not allowed with the using argument.

返回值会是成功发送的信息的数量（只能是 0 或 1 ，因为同时只能发送一条消息）。

Deprecated since version 6.0: Passing fail_silently and later parameters as positional arguments is deprecated.

Deprecated since version 6.1: The fail_silently, auth_user, auth_password, and connection arguments are deprecated. In most cases they can be replaced by using with an appropriate MAILERS configuration. See Replacing fail_silently, Replacing auth_user and auth_password, and Replacing get_connection() and connection arguments.

Changed in Django 6.1:

The using argument was added.

Older versions ignored fail_silently=True, auth_user, and auth_password when a connection was also provided. This now raises a TypeError.

`send_mass_mail()`¶

send_mass_mail(datatuple, *, fail_silently=False, auth_user=None, auth_password=None, connection=None, using=None)[source]¶

django.core.mail.send_mass_mail() 用于批量发送邮件。

datatuple 是一个元组，形式如下:

(subject, message, from_email, recipient_list)

fail_silently, auth_user, auth_password and connection have the same functions as in send_mail(). They must be given as keyword arguments if used, and are not allowed with the using argument.

The keyword argument using is an optional MAILERS alias to use to send the mail. If unspecified, the default mailer configuration will be used.

Each separate element of datatuple results in a separate email message. As in send_mail(), recipients in the same recipient_list will all see the other addresses in the email messages' "To:" field.

举个例子，以下代码会向两个不同的收件人列表发送两封不同的邮件，却复用了同一条连接:

message1 = (
    "Subject here",
    "Here is the message",
    "from@example.com",
    ["first@example.com", "other@example.com"],
)
message2 = (
    "Another Subject",
    "Here is another message",
    "from@example.com",
    ["second@test.com"],
)
send_mass_mail((message1, message2))

返回值是成功发送的消息的数量。

Deprecated since version 6.0: Passing fail_silently and later parameters as positional arguments is deprecated.

Changed in Django 6.1:

The using argument was added.

Older versions ignored fail_silently=True, auth_user, and auth_password when a connection was also provided. This now raises a TypeError.

`send_mass_mail()` vs. `send_mail()`¶

The main difference between send_mass_mail() and repeatedly calling send_mail() is that send_mail() opens a connection to the mail server each time it's executed, while send_mass_mail() uses a single connection for all of its messages. This makes send_mass_mail() slightly more efficient.

send_mail() with multiple to addresses sends a single email message, with john@example.com and jane@example.com both appearing in the "To:" field:

send_mail(
    "Subject",
    "Message.",
    "from@example.com",
    ["john@example.com", "jane@example.com"],
)

send_mass_mail() sends a separate message per datatuple element, so john@example.com and jane@example.com each receive their own email:

datatuple = (
    ("Subject", "Message.", "from@example.com", ["john@example.com"]),
    ("Subject", "Message.", "from@example.com", ["jane@example.com"]),
)
send_mass_mail(datatuple)

`mail_admins()`¶

mail_admins(subject, message, *, fail_silently=False, connection=None, html_message=None, using=None)[source]¶

django.core.mail.mail_admins() 是定义在 ADMINS 配置项中，用于向网站所有者快速发送邮件。

mail_admins() 在主题前面添加 EMAIL_SUBJECT_PREFIX 指定的前缀，默认是 "[Django] " 。

邮件头的 "发件人:" 由 SERVER_EMAIL 配置项指定。

创建这个方法是为了方便和可读性。

若提供了 html_message，会使邮件成为 multipart/alternative 的实例， message 的内容类型则是 text/plain ，并且 html_message 的内容类型是 text/html 。

The keyword argument using is an optional MAILERS alias to use to send the mail. If unspecified, the default mailer configuration will be used.

Deprecated since version 6.0: Passing fail_silently and later parameters as positional arguments is deprecated.

Deprecated since version 6.1: The fail_silently and connection arguments are deprecated. In most cases they can be replaced by using with an appropriate MAILERS configuration. See Replacing fail_silently and Replacing get_connection() and connection arguments.

Changed in Django 6.1:

The using argument was added.

Older versions ignored fail_silently=True when a connection was also provided. This now raises a TypeError.

`mail_managers()`¶

mail_managers(subject, message, *, fail_silently=False, connection=None, html_message=None, using=None)[source]¶

django.core.mail.mail_managers() 类似 mail_admins()，但它向 MANAGERS 指定的管理员们发送邮件。

The keyword argument using is an optional MAILERS alias to use to send the mail. If unspecified, the default mailer configuration will be used.

Deprecated since version 6.0: Passing fail_silently and later parameters as positional arguments is deprecated.

Changed in Django 6.1:

The using argument was added.

Older versions ignored fail_silently=True when a connection was also provided. This now raises a TypeError.

`EmailMessage` 类¶

Django's send_mail() and send_mass_mail() functions are actually thin wrappers that make use of the EmailMessage class.

Not all features of the EmailMessage class are available through the send_mail() and related wrapper functions. If you wish to use advanced features, such as BCC'ed recipients, file attachments, or multi-part email, you'll need to create EmailMessage instances directly.

Note

This is a design feature. send_mail() and related functions were originally the only interface Django provided. However, the list of parameters they accepted was slowly growing over time. It made sense to move to a more object-oriented design for email messages and retain the original functions only for backwards compatibility.

EmailMessage is responsible for creating the email message itself. The email backend is then responsible for sending the email.

For convenience, EmailMessage provides a send() method for sending a single email. If you need to send multiple messages, the email backend API provides an alternative.

class EmailMessage[source]¶

The EmailMessage class is initialized with the following parameters. All parameters are optional and can be set at any time prior to calling the send() method.

The first four parameters can be passed as positional or keyword arguments, but must be in the given order if positional arguments are used:

subject: 邮件的主题。
body: 邮件内容，需要为纯文本格式。
from_email: The sender's address. Both fred@example.com and "Fred" <fred@example.com> forms are supported (see Formatting email addresses). If omitted, the DEFAULT_FROM_EMAIL setting is used.
to: 一个包含收件人地址的列表或元组。

The following parameters must be given as keyword arguments if used:

cc: 一个包含收件人地址的列表或元组，指定“抄送”对象。
bcc: A list or tuple of addresses used for blind carbon copies when sending the email.
reply_to: 一个包含收件人地址的列表或元组，指定“回复”对象。
attachments: A list of attachments to put on the message. Each can be an instance of MIMEPart or EmailAttachment, or a tuple with attributes (filename, content, mimetype).

Changed in Django 6.0:
Support for MIMEPart objects in the attachments list was added.

Deprecated since version 6.0: Support for Python's legacy MIMEBase objects in attachments is deprecated. Use MIMEPart instead.
headers: 一个字典，包含邮件中额外的头信息。字典的关键字是头的名称，值为头的值。需要由调用者确保头名和值的正确性。对应的属性是 extra_headers 。
connection: An email backend instance. This parameter is ignored when using send_messages().

Deprecated since version 6.1: The connection argument is deprecated. Instead, define a MAILERS configuration with the desired connection options, and then call EmailMessage.send(using="...") with that configuration's alias. See Migrating email to mailers.

Deprecated since version 6.0: Passing all except the first four parameters as positional arguments is deprecated.

例如：

from django.core.mail import EmailMessage

email = EmailMessage(
    subject="Hello",
    body="Body goes here",
    from_email="from@example.com",
    to=["to1@example.com", "to2@example.com"],
    bcc=["bcc@example.com"],
    reply_to=["another@example.com"],
    headers={"Message-ID": "foo"},
)

这个类拥有以下方法：

send(fail_silently=False, *, using=None)[source]¶

Sends the message. Returns 1 if the message was sent successfully, otherwise 0. (An empty list of recipients returns 0 -- it will not raise an exception.)

The optional using keyword argument specifies a MAILERS alias to use to send the mail. If not given, the default mailer configuration will be used.

If a deprecated connection was specified when the email was constructed, that connection will be used. Providing both a connection and using will raise an error.

If the deprecated keyword argument fail_silently is True, certain backend-dependent exceptions while sending the message will be ignored. Providing both fail_silently and using will raise an error.

Changed in Django 6.1:

The using argument was added.

Older versions ignored fail_silently=True when a connection was also provided. This now raises a TypeError.

Deprecated since version 6.1: The fail_silently argument is deprecated. See Replacing fail_silently for alternatives.

message(*, policy=email.policy.default)[source]¶

Constructs and returns a Python email.message.EmailMessage object representing the message to be sent.

The keyword argument policy allows specifying the set of rules for updating and serializing the representation of the message. It must be an email.policy.Policy object. Defaults to email.policy.default. In certain cases you may want to use SMTP, SMTPUTF8 or a custom policy. For example, the SMTP email backend uses the SMTP policy to ensure \r\n line endings as required by the SMTP protocol.

If you ever need to extend Django's EmailMessage class, you'll probably want to override this method to put the content you want into the Python EmailMessage object.

Changed in Django 6.0:

The policy keyword argument was added and the return type was updated to an instance of EmailMessage.

recipients()[source]¶: Returns a list of all the recipients of the message, whether they're recorded in the to, cc or bcc attributes. This is another method you might need to override when subclassing, because the SMTP server needs to be told the full list of recipients when the message is sent. If you add another way to specify recipients in your class, they need to be returned from this method as well.

attach(filename, content, mimetype)[source]¶

attach(mimepart)

Creates a new attachment and adds it to the message. There are two ways to call attach():

You can pass it three arguments: filename, content and mimetype. filename is the name of the file attachment as it will appear in the email, content is the data that will be contained inside the attachment and mimetype is the optional MIME type for the attachment. If you omit mimetype, the MIME content type will be guessed from the filename of the attachment.

例如：
```
message.attach("design.png", img_data, "image/png")
```
If you specify a mimetype of message/rfc822, content can be a django.core.mail.EmailMessage or Python's email.message.EmailMessage or email.message.Message.

对于以 text/ 开头的 mimetype 类型，其内容应该是字符串。二进制数据将尝试以 UTF-8 解码，如果失败了，MIME 类型会被改为 application/octet-stream ，并不会修改数据内容。

Or for attachments requiring additional headers or parameters, you can pass attach() a single Python MIMEPart object. This will be attached directly to the resulting message. For example, to attach an inline image with a Content-ID:

import email.utils
from email.message import MIMEPart
from django.core.mail import EmailMultiAlternatives

message = EmailMultiAlternatives(...)
image_data_bytes = ...  # Load image as bytes

# Create a random Content-ID, including angle brackets
cid = email.utils.make_msgid()
inline_image = email.message.MIMEPart()
inline_image.set_content(
    image_data_bytes,
    maintype="image",
    subtype="png",  # or "jpeg", etc. depending on the image type
    disposition="inline",
    cid=cid,
)
message.attach(inline_image)
# Refer to Content-ID in HTML without angle brackets
message.attach_alternative(f'… <img src="cid:{cid[1:-1]}"> …', "text/html")

Python's email.contentmanager.set_content() documentation describes the supported arguments for MIMEPart.set_content().

Changed in Django 6.0:

Support for MIMEPart attachments was added.

Deprecated since version 6.0: Support for email.mime.base.MIMEBase attachments is deprecated. Use MIMEPart instead.

attach_file(path, mimetype=None)[source]¶

Creates a new attachment using a file from your filesystem. Call it with the path of the file to attach and, optionally, the MIME type to use for the attachment. If the MIME type is omitted, it will be guessed from the filename. You can use it like this:

message.attach_file("/images/weather_map.png")

For MIME types starting with text/, binary data is handled as in attach().

class EmailAttachment¶

A named tuple to store attachments to an email.

The named tuple has the following indexes:

filename
content
mimetype

发送可选的内容类型。¶

发送多个内容版本¶

It can be useful to include multiple versions of the content in an email; the classic example is to send both text and HTML versions of a message. With Django's email library, you can do this using the EmailMultiAlternatives class.

class EmailMultiAlternatives[source]¶

A subclass of EmailMessage that allows additional versions of the message body in the email via the attach_alternative() method. This directly inherits all methods (including the class initialization) from EmailMessage.

alternatives¶

A list of EmailAlternative named tuples. This is particularly useful in tests:

self.assertEqual(len(msg.alternatives), 1)
self.assertEqual(msg.alternatives[0].content, html_content)
self.assertEqual(msg.alternatives[0].mimetype, "text/html")

Alternatives should only be added using the attach_alternative() method, or passed to the constructor.

attach_alternative(content, mimetype)[source]¶

在电子邮件中附加消息正文的替代表示。

例如，要发送文本和 HTML 组合，你可以这样写：

from django.core.mail import EmailMultiAlternatives

subject = "hello"
from_email = "from@example.com"
to = "to@example.com"
text_content = "This is an important message."
html_content = "<p>This is an <strong>important</strong> message.</p>"
msg = EmailMultiAlternatives(subject, text_content, from_email, [to])
msg.attach_alternative(html_content, "text/html")
msg.send()

body_contains(text)[source]¶

Returns a boolean indicating whether the provided text is contained in the email body and in all attached MIME type text/* alternatives.

This can be useful when testing emails. For example:

def test_contains_email_content(self):
    subject = "Hello World"
    from_email = "from@example.com"
    to = "to@example.com"
    msg = EmailMultiAlternatives(subject, "I am content.", from_email, [to])
    msg.attach_alternative("<p>I am content.</p>", "text/html")

    self.assertIs(msg.body_contains("I am content"), True)
    self.assertIs(msg.body_contains("<p>I am content.</p>"), False)

class EmailAlternative¶

A named tuple to store alternative versions of email content.

The named tuple has the following indexes:

content
mimetype

更新默认内容类型¶

By default, the MIME type of the body parameter in an EmailMessage is "text/plain". It is good practice to leave this alone, because it guarantees that any recipient will be able to read the email, regardless of their mail client. However, if you are confident that your recipients can handle an alternative content type, you can use the content_subtype attribute on the EmailMessage class to change the main content type. The major type will always be "text", but you can change the subtype. For example:

msg = EmailMessage(subject, html_content, from_email, [to])
msg.content_subtype = "html"  # Main content is now text/html
msg.send()

Safely sending email¶

Any public website that can send email will eventually be targeted by attempts to abuse it for spam, phishing, or other malicious content. While a complete discussion of vulnerabilities in sending email is beyond the scope of Django's documentation, there are many references available on the web. Two good starting points are:

Princeton University's guidance on preventing email abuse in web forms. Although this is an internal reference for users of Princeton's Drupal Site Builder, nearly all of its advice applies equally to sites built with Django (or any web framework).
OWASP's Email Validation and Verification in Identity Systems Cheat Sheet. This primarily covers using email in authentication contexts. While many of its recommendations are handled by django.contrib.auth and other Django features, items like rate limiting and securing email change workflows are the developer's responsibility.

Thinking through how email might be abused (and taking steps to mitigate it) is especially important if your site can send to unverified addresses. Features like newsletter sign-up, contact forms that cc or auto-reply to the sender, and "share this page" can be attractive targets.

Formatting email addresses¶

Email addresses allow a "friendly" display name alongside the user@domain address. For example, you could include your company name in the DEFAULT_FROM_EMAIL setting:

DEFAULT_FROM_EMAIL = '"Example, Inc." <contact@example.com>'

The double quotes around "Example, Inc." are needed so the comma isn't read as separating two different addresses. A fixed address, written out by hand as in the example above, is safe, but composing one from variable parts (especially untrusted input) needs more care.

Warning

Never use string formatting to build an email address from variable parts. For example, f'"{name}" <{email}>' is unsafe.

Email address headers have complex syntax rules (much like HTML or SQL), so constructing them by combining strings creates an injection vulnerability. Even if you've validated the format of email, an attacker could exploit the name portion to inject additional addresses.

To avoid this, always use a well-tested library specifically meant to format email addresses, like Python's email.headerregistry.Address class (the replacement for the legacy formataddr() function, which does not support internationalized domain names).

For example, to include a user's full name when sending them email (where user is an instance of the default User model):

from django.core.mail import send_mail
from email.headerregistry import Address


def send_mail_to_user(user, subject, body, from_email=None):
    # Safely create an email address with the user's name.
    # (addr_spec is the technical term for the user@domain address.)
    address = Address(
        display_name=user.get_full_name(),
        addr_spec=user.email,
    )
    send_mail(subject, body, from_email, [address])

Django's built-in email backends support using Address objects directly in any address field, as shown here. So do many custom and third-party email backends. But if this causes a TypeError or other problem with a particular backend, use str(address) to convert the object to a safe, properly formatted string.

防止头注入¶

Email header injection is a security exploit in which an attacker manipulates email headers to change the intended sender or recipients, subject, or potentially even the entire visible message body.

One type of header injection exploits address header syntax. You are responsible for preventing this when constructing email addresses from user-supplied input, as described in Formatting email addresses above.

Another (perhaps better understood) attack, CRLF injection, uses carriage return and line feed characters to insert additional headers into the email. Django prevents this by raising a ValueError if those characters appear in any header field when trying to send the message.

Changed in Django 6.0:

Older versions raised django.core.mail.BadHeaderError for some invalid headers. This has been replaced with ValueError.

Django's CRLF protection relies on using Python's modern EmailPolicy in Django's EmailMessage.message(). Custom email backends that don't call that function, or that call it with the legacy compat32 policy, are responsible for implementing their own CRLF injection prevention.

Sending many messages efficiently¶

创建和关闭 SMTP 连接（或其它网络连接）是一项耗时的进程。如果你有很多封邮件要发送，复用连接就显得很有意义，而不是在每次发送邮件时创建和关闭连接。

There are two ways to tell an email backend to reuse a connection. Both involve obtaining an email backend instance from mail.mailers and using the backend's API.

The first approach is to use the backend's send_messages() method. This takes a list of EmailMessage (or subclass) instances, and sends them all using that single connection.

For example, if you have a function called get_notification_emails() that returns a list of EmailMessage objects representing some periodic email you wish to send out, you could send these emails using a single call to send_messages():

from django.core import mail

email_list = get_notification_emails()
# Use the default mailer. You could substitute
# mail.mailers["alias"] for a specific mailer.
backend = mail.mailers.default
backend.send_messages(email_list)

In this example, the call to send_messages() opens a connection on the backend, sends the list of messages, and then closes the connection again. (This is how send_mass_mail() is implemented.)

The second approach is to use the open() and close() methods on the email backend to manually control the connection. send_messages() will not open or close the connection if it is already open, so if you manually open the connection, you can control when it is closed. For example:

from django.core import mail

# Use the "notifications" mailer configuration.
backend = mail.mailers["notifications"]

# Manually open the connection.
backend.open()

# Construct an email message. (Passing None as the third argument
# uses settings.DEFAULT_FROM_EMAIL as the "From:" address.)
email1 = mail.EmailMessage("Hi", "Message", None, ["to1@example.com"])
# Send the email. The connection was already open, so send_messages()
# leaves it open after sending.
backend.send_messages([email1])

# Construct and send two more messages. The connection is still open.
email2 = mail.EmailMessage("Hi", "Message", None, ["to2@example.com"])
email3 = mail.EmailMessage("Hi", "Message", None, ["to3@example.com"])
backend.send_messages([email2, email3])

# Because we opened it, we need to manually close the connection.
backend.close()

When you manually open a backend's connection, you are responsible for ensuring it gets closed. The example above actually has a bug: if an exception occurs while sending the messages, the connection will not be closed. This can be fixed with a try-finally statement, but using the backend instance as a context manager is preferable, as it automatically calls open() and close() as needed.

This is equivalent to the previous example, but uses the backend as a context manager to avoid leaving the connection open on errors:

from django.core import mail

# Use mail.mailers[...] as a context manager.
with mail.mailers["notifications"] as backend:
    # The backend connection is automatically opened inside the context.
    email1 = mail.EmailMessage("Hi", "Message", None, ["to1@example.com"])
    backend.send_messages([email1])

    # The connection is still open, and is reused for the second send.
    email2 = mail.EmailMessage("Hi", "Message", None, ["to2@example.com"])
    email3 = mail.EmailMessage("Hi", "Message", None, ["to3@example.com"])
    backend.send_messages([email2, email3])

# After exiting the context (either normally or because of an error),
# the backend connection is automatically closed.

邮件后端¶

发送邮件的动作是由邮件后端执行的。

Django comes with several email backends. With the exception of the SMTP backend, these are mainly useful during testing and development. If the built-in backends don't meet your needs there are third-party packages available. You can also subclass one of the built-in backends to change its behavior, or even write your own email backend.

SMTP 后端¶

The SMTP email backend connects to an SMTP server to send email. To use it, set BACKEND to "django.core.mail.backends.smtp.EmailBackend".

The SMTP backend supports these OPTIONS:

"host" (required): the SMTP server hostname or IP address.
"port": the port number to connect to on the SMTP host. If omitted, uses the standard port for the connection protocol depending on the "use_tls" and "use_ssl" options: 587 for TLS, 465 for SSL, or 25 for an unsecured connection.
"username" and "password": set these if your server requires SMTP authentication ("SMTP AUTH" credentials, sometimes called SMTP login).

Although the username is often an email address, it should not be confused with default "From:" addresses. Those are defined by the DEFAULT_FROM_EMAIL and SERVER_EMAIL settings.
"use_tls" or "use_ssl": set one of these options to True to connect to the SMTP server using a secure protocol -- "use_tls" for explicit TLS or "use_ssl" for SSL (implicit TLS).
"ssl_certfile" and "ssl_keyfile": if the SMTP server's SSL/TLS connection requires client certificate authentication, use these options to specify the paths to a PEM-formatted certificate chain file and private key file. (The key file can be omitted if the certificate file includes the private key.)

These options are not intended for use with a private certificate authority or self-signed SMTP server certificate. See Private and self-signed SMTP server certificates below.

Note that these options don't result in checking certificate validity. They are passed to the underlying SSL connection. Refer to the documentation of Python's ssl.SSLContext.wrap_socket() method for details on how the certificate chain file and private key file are handled.
"timeout": the timeout (in seconds) for connecting to the SMTP server and other blocking operations. If not specified, the value is obtained from socket.getdefaulttimeout(), which defaults to no timeout (None) meaning SMTP operations can block indefinitely.
"fail_silently": set to True to ignore certain errors while sending a message. All OSErrors are ignored while opening the SMTP connection, and smtplib.SMTPException errors are ignored while communicating with the server. This will suppress both transient network glitches and also serious configuration problems. However, it does not ignore all errors, and problems with serializing the message will not fail silently. (This option is available for backward compatibility but is not recommended for typical use.)

举例：

MAILERS = {
    "default": {
        "BACKEND": "django.core.mail.backends.smtp.EmailBackend",
        "OPTIONS": {
            "host": "smtp.example.net",
            "use_tls": True,
            "username": "my-app",
            "password": os.environ["MY_APP_SMTP_PASSWORD"],
            "timeout": 10,
        },
    },
}

Deprecated since version 6.1: When the MAILERS setting is not defined, Django uses the SMTP backend as the default mailer (the default EMAIL_BACKEND), connecting to localhost on port 25. This behavior will be removed in Django 7.0, which will not have a default mailer configuration.

When the SMTP backend is used without MAILERS defined, the options listed above are obtained from the deprecated EMAIL_HOST, EMAIL_PORT, EMAIL_HOST_USER, EMAIL_HOST_PASSWORD, EMAIL_USE_TLS, EMAIL_USE_SSL, EMAIL_SSL_KEYFILE, EMAIL_SSL_CERTFILE, and EMAIL_TIMEOUT settings, respectively. (There is no setting equivalent to the "fail_silently" option.)

class backends.smtp.EmailBackend¶

Directly instantiating an EmailBackend class is not recommended. Use mailers to obtain a backend instance.

When constructed directly (without going through mailers), the SMTP EmailBackend class accepts the options listed above as keyword arguments. Default values come from the corresponding, deprecated EMAIL_* settings. host is not required and defaults to "localhost", and port defaults to 25 even if use_tls or use_ssl is True.

When the MAILERS setting is defined, attempting to directly create an SMTP EmailBackend will raise an AttributeError.

Deprecated since version 6.1: Directly constructing an instance of an EmailBackend class will be unsupported in Django 7.0. Undocumented use will result in different default argument handling compared to earlier releases.

Private and self-signed SMTP server certificates¶

If the SMTP server uses an SSL certificate from a private certificate authority (CA), the CA's root certificate should be added to the system CA bundle on the client (where Django is running). Likewise, if the server uses a self-signed certificate, it should be added to the client's system CA bundle so it can be trusted. (The SMTP backend's "ssl_certfile" option cannot be used for CA roots or self-signed certificates.)

Follow platform-specific instructions for adding to the system CA bundle. If modifying the system bundle is not possible or desired, an alternative is using OpenSSL's SSL_CERT_FILE or SSL_CERT_DIR environment variables to specify a custom certificate bundle.

For more complex scenarios, the SMTP backend can be subclassed to add root certificates to its ssl_context using ssl.SSLContext.load_verify_locations().

控制台后端¶

Instead of sending out real emails, the console backend writes the emails that would be sent to the standard output. To use it, set BACKEND to "django.core.mail.backends.console.EmailBackend".

The console backend supports these OPTIONS:

"stream": a stream-like object to write to. Defaults to stdout.
"fail_silently": set to True to ignore all errors while writing the message to the stream, including errors serializing the message. (This option is available for backward compatibility but is not recommended.)

该后端不是为了在生产环境使用的——出于方便的目的，让你在开发阶段使用。

Changed in Django 6.1:

The settings file created by startproject now defines MAILERS with the console backend as the default configuration.

文件后端¶

The file backend writes emails to a file. A new file is created for each new session that is opened on this backend. To use it, set BACKEND to "django.core.mail.backends.filebased.EmailBackend".

The file backend supports these OPTIONS:

"file_path" (required): the directory to which the files are written. Can be a string or a pathlib.Path object. If the directory does not exist, the file backend will attempt to create it.
"fail_silently": set to True to ignore all errors while writing the message to the file -- including errors serializing the message -- but not errors related to ensuring the file path directory exists. (This option is available for backward compatibility but is not recommended.)

该后端不是为了在生产环境使用的——出于方便的目的，让你在开发阶段使用。

Deprecated since version 6.1: When the file backend is used without the MAILERS setting defined, it will get its file_path option from the EMAIL_FILE_PATH setting.

内存后端¶

The 'locmem' backend stores messages in a special attribute of the django.core.mail module. The outbox attribute is created when the first message is sent. It's a list with an EmailMessage instance for each message that would be sent. Messages in the outbox are annotated with a sent_using attribute that identifies the MAILERS alias used to send the message.

To use the in-memory backend, set BACKEND to "django.core.mail.backends.locmem.EmailBackend". It does not support any OPTIONS.

Django's test runner automatically switches to this backend for testing.

该后端不是为了在生产环境使用的——出于方便的目的，让你在开发阶段使用。

Changed in Django 6.1:

The sent_using attribute was added to messages in the outbox.

虚拟后端¶

As the name suggests the dummy backend does nothing with your messages. To use it, set BACKEND to "django.core.mail.backends.dummy.EmailBackend". It does not support any OPTIONS.

该后端不是为了在生产环境使用的——出于方便的目的，让你在开发阶段使用。

Third-party backends¶

There are community-maintained solutions!

Django has a vibrant ecosystem. There are email backends highlighted on the Community Ecosystem page. The Django Packages Email grid has even more options for you!

Third-party email backends are available that:

Integrate directly with commercial email service providers' APIs (which often have extra functionality not available through SMTP).
Offload email sending to asynchronous task queues.
Add features to other email backends, such as enforcing do-not-send lists or logging sent messages.
Provide development and debugging tools, such as sandbox capture and in-browser email previews.

自定义邮件后端¶

If you need to change how emails are sent you can write your own email backend. To use a custom backend, set BACKEND to the Python import path for your backend class and OPTIONS to any __init__() keyword arguments your backend supports.

Custom email backends should subclass BaseEmailBackend that is located in the django.core.mail.backends.base module. A custom email backend must implement the send_messages(email_messages) method. This method receives a list of EmailMessage instances and returns the number of successfully delivered messages. If your backend has any concept of a persistent session or connection, you should also implement the open() and close() methods. Refer to smtp.EmailBackend for a reference implementation.

获取邮件后端的一个实例¶

The mailers factory in django.core.mail returns instances of email backends.

mailers¶

New in Django 6.1.

You can access the mailers configured in the MAILERS setting through a dict-like object: django.core.mail.mailers:

>>> from django.core.mail import mailers
>>> mailers["notifications"]

If the named key is not defined, a MailerDoesNotExist error will be raised. Other configuration problems will raise an InvalidMailer error.

mailers.default¶

New in Django 6.1.

As a shortcut, the default mailer can be accessed through django.core.mail.mailers.default:

>>> from django.core.mail import mailers
>>> mailers.default

This is equivalent to mailers["default"]. If no default mailer has been configured, a MailerDoesNotExist error will be raised.

Deprecated since version 6.1: If the MAILERS setting is not defined, mailers.default will create an email backend instance from the deprecated EMAIL_BACKEND and related settings. This supports backward compatibility with Django 6.0 and earlier.

This behavior (and those settings) will be removed in Django 7.0.

get_connection(backend=None, *, fail_silently=False, **kwargs)[source]¶

The deprecated django.core.mail.get_connection() function creates and returns an instance of an email backend. Its behavior depends on the MAILERS setting and how the function is called.

If the MAILERS setting is defined:

get_connection() with no arguments will return mailers.default.
get_connection(...) called with only fail_silently or other keyword arguments will create an instance of MAILERS["default"] with any keywords added to the default mailer's OPTIONS.
get_connection(backend, ...) with a backend import path will raise an error.

If the MAILERS setting is not defined:

get_connection() with no arguments will return an instance of the email backend specified in EMAIL_BACKEND.
If you specify the backend argument, an instance of that backend will be instantiated.
If the keyword argument fail_silently is True, certain backend-dependent exceptions during the email sending process will be silently ignored.
All other keyword arguments are passed directly to the constructor of the email backend.

Deprecated since version 6.0: Passing fail_silently as a positional argument is deprecated.

Deprecated since version 6.1: get_connection() is deprecated and will be removed in Django 7.0. Switch to mailers[alias]. See Replacing get_connection() and connection arguments for migration suggestions.

Email backend API¶

Instances of an email backend class have the following methods:

open() 创建一个发送邮件的长连接。
close() 关闭当前发送邮件的连接。
send_messages(email_messages) sends a list of EmailMessage objects. If the connection is not open, this call will implicitly open the connection, and close the connection afterward. If the connection is already open, it will be left open after mail has been sent.

A backend instance can also be used as a context manager, which will automatically call open() and close() as needed. An example is in Sending many messages efficiently.

为了开发配置邮件¶

曾经有很多次，你并不想 Django 真的发送邮件。举个例子，在开发网站时，你可能并不期望发送成千上万封邮件——但你想要确保这些邮件将会在正确的时间，包含正确的内容，发送给正确的人。

在本地开发中配置电子邮件的最简单方法是使用 console 电子邮件后端。该后端将所有电子邮件重定向到 stdout，允许您查看邮件的内容。

文件邮件后端在开发时也很有用——这个后端将每次 SMTP 连接的内容输出至一个文件，你可以在你闲暇时查看这个文件。

Another approach is to use a mocked SMTP server that receives the emails locally and displays them to the terminal, but does not actually send anything. The aiosmtpd package provides a way to accomplish this:

python -m pip install "aiosmtpd >= 1.4.5"

python -m aiosmtpd -n -l localhost:8025

This command will start a minimal SMTP server listening on port 8025 of localhost. This server prints to standard output all email headers and the email body. You then only need to set an SMTP backend's "host" and "port" OPTIONS accordingly. For a more detailed discussion of SMTP server options, see the documentation of the aiosmtpd module.

关于发送邮件的单元测试资料，参见测试文档中邮件服务章节。

发送邮件¶

快速示例¶

Configuring email¶

Multiple mailers¶

Sending messages¶

`send_mail()`¶

`send_mass_mail()`¶

`send_mass_mail()` vs. `send_mail()`¶

`mail_admins()`¶

`mail_managers()`¶

`EmailMessage` 类¶

发送可选的内容类型。¶

发送多个内容版本¶

更新默认内容类型¶

Safely sending email¶

Formatting email addresses¶

防止头注入¶

Sending many messages efficiently¶

邮件后端¶

SMTP 后端¶

Private and self-signed SMTP server certificates¶

控制台后端¶

文件后端¶

内存后端¶

虚拟后端¶

Third-party backends¶

自定义邮件后端¶

获取邮件后端的一个实例¶

Email backend API¶

为了开发配置邮件¶

附加信息

Support Django!

内容

获取帮助

下载：

Diamond and Platinum Members

发送邮件¶

快速示例¶

Configuring email¶

Multiple mailers¶

Sending messages¶

send_mail()¶

send_mass_mail()¶

send_mass_mail() vs. send_mail()¶

mail_admins()¶

mail_managers()¶

EmailMessage 类¶

发送可选的内容类型。¶

发送多个内容版本¶

更新默认内容类型¶

Safely sending email¶

Formatting email addresses¶

防止头注入¶

Sending many messages efficiently¶

邮件后端¶

SMTP 后端¶

Private and self-signed SMTP server certificates¶

控制台后端¶

文件后端¶

内存后端¶

虚拟后端¶

Third-party backends¶

自定义邮件后端¶

获取邮件后端的一个实例¶

Email backend API¶

为了开发配置邮件¶

附加信息

Support Django!

内容

获取帮助

下载：

Diamond and Platinum Members

`send_mail()`¶

`send_mass_mail()`¶

`send_mass_mail()` vs. `send_mail()`¶

`mail_admins()`¶

`mail_managers()`¶

`EmailMessage` 类¶