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dev (3.14)pre (3.13)3.12.73.113.103.93.83.73.63.53.43.33.23.13.02.72.6

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TABLE OF CONTENTS

 * smtplib — SMTP protocol client
   * SMTP Objects
   * SMTP Example

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SMTPLIB — SMTP PROTOCOL CLIENT¶

Source code: Lib/smtplib.py

--------------------------------------------------------------------------------

The smtplib module defines an SMTP client session object that can be used to
send mail to any internet machine with an SMTP or ESMTP listener daemon. For
details of SMTP and ESMTP operation, consult RFC 821 (Simple Mail Transfer
Protocol) and RFC 1869 (SMTP Service Extensions).

Availability: not Emscripten, not WASI.

This module does not work or is not available on WebAssembly platforms
wasm32-emscripten and wasm32-wasi. See WebAssembly platforms for more
information.

class smtplib.SMTP(host='', port=0, local_hostname=None, [timeout,
]source_address=None)¶

An SMTP instance encapsulates an SMTP connection. It has methods that support a
full repertoire of SMTP and ESMTP operations. If the optional host and port
parameters are given, the SMTP connect() method is called with those parameters
during initialization. If specified, local_hostname is used as the FQDN of the
local host in the HELO/EHLO command. Otherwise, the local hostname is found
using socket.getfqdn(). If the connect() call returns anything other than a
success code, an SMTPConnectError is raised. The optional timeout parameter
specifies a timeout in seconds for blocking operations like the connection
attempt (if not specified, the global default timeout setting will be used). If
the timeout expires, TimeoutError is raised. The optional source_address
parameter allows binding to some specific source address in a machine with
multiple network interfaces, and/or to some specific source TCP port. It takes a
2-tuple (host, port), for the socket to bind to as its source address before
connecting. If omitted (or if host or port are '' and/or 0 respectively) the OS
default behavior will be used.

For normal use, you should only require the initialization/connect, sendmail(),
and SMTP.quit() methods. An example is included below.

The SMTP class supports the with statement. When used like this, the SMTP QUIT
command is issued automatically when the with statement exits. E.g.:

>>>

>>> from smtplib import SMTP
>>> with SMTP("domain.org") as smtp:
...     smtp.noop()
...
(250, b'Ok')
>>>




All commands will raise an auditing event smtplib.SMTP.send with arguments self
and data, where data is the bytes about to be sent to the remote host.



Changed in version 3.3: Support for the with statement was added.

Changed in version 3.3: source_address argument was added.

Added in version 3.5: The SMTPUTF8 extension (RFC 6531) is now supported.

Changed in version 3.9: If the timeout parameter is set to be zero, it will
raise a ValueError to prevent the creation of a non-blocking socket.

class smtplib.SMTP_SSL(host='', port=0, local_hostname=None, *, [timeout,
]context=None, source_address=None)¶

An SMTP_SSL instance behaves exactly the same as instances of SMTP. SMTP_SSL
should be used for situations where SSL is required from the beginning of the
connection and using starttls() is not appropriate. If host is not specified,
the local host is used. If port is zero, the standard SMTP-over-SSL port (465)
is used. The optional arguments local_hostname, timeout and source_address have
the same meaning as they do in the SMTP class. context, also optional, can
contain a SSLContext and allows configuring various aspects of the secure
connection. Please read Security considerations for best practices.

Changed in version 3.3: context was added.

Changed in version 3.3: The source_address argument was added.

Changed in version 3.4: The class now supports hostname check with
ssl.SSLContext.check_hostname and Server Name Indication (see ssl.HAS_SNI).

Changed in version 3.9: If the timeout parameter is set to be zero, it will
raise a ValueError to prevent the creation of a non-blocking socket

Changed in version 3.12: The deprecated keyfile and certfile parameters have
been removed.

class smtplib.LMTP(host='', port=LMTP_PORT, local_hostname=None,
source_address=None[, timeout])¶

The LMTP protocol, which is very similar to ESMTP, is heavily based on the
standard SMTP client. It’s common to use Unix sockets for LMTP, so our connect()
method must support that as well as a regular host:port server. The optional
arguments local_hostname and source_address have the same meaning as they do in
the SMTP class. To specify a Unix socket, you must use an absolute path for
host, starting with a ‘/’.

Authentication is supported, using the regular SMTP mechanism. When using a Unix
socket, LMTP generally don’t support or require any authentication, but your
mileage might vary.

Changed in version 3.9: The optional timeout parameter was added.

A nice selection of exceptions is defined as well:

exception smtplib.SMTPException¶

Subclass of OSError that is the base exception class for all the other
exceptions provided by this module.

Changed in version 3.4: SMTPException became subclass of OSError

exception smtplib.SMTPServerDisconnected¶

This exception is raised when the server unexpectedly disconnects, or when an
attempt is made to use the SMTP instance before connecting it to a server.

exception smtplib.SMTPResponseException¶

Base class for all exceptions that include an SMTP error code. These exceptions
are generated in some instances when the SMTP server returns an error code. The
error code is stored in the smtp_code attribute of the error, and the smtp_error
attribute is set to the error message.

exception smtplib.SMTPSenderRefused¶

Sender address refused. In addition to the attributes set by on all
SMTPResponseException exceptions, this sets ‘sender’ to the string that the SMTP
server refused.

exception smtplib.SMTPRecipientsRefused¶

All recipient addresses refused. The errors for each recipient are accessible
through the attribute recipients, which is a dictionary of exactly the same sort
as SMTP.sendmail() returns.

exception smtplib.SMTPDataError¶

The SMTP server refused to accept the message data.

exception smtplib.SMTPConnectError¶

Error occurred during establishment of a connection with the server.

exception smtplib.SMTPHeloError¶

The server refused our HELO message.

exception smtplib.SMTPNotSupportedError¶

The command or option attempted is not supported by the server.

Added in version 3.5.

exception smtplib.SMTPAuthenticationError¶

SMTP authentication went wrong. Most probably the server didn’t accept the
username/password combination provided.

See also

RFC 821 - Simple Mail Transfer Protocol

Protocol definition for SMTP. This document covers the model, operating
procedure, and protocol details for SMTP.

RFC 1869 - SMTP Service Extensions

Definition of the ESMTP extensions for SMTP. This describes a framework for
extending SMTP with new commands, supporting dynamic discovery of the commands
provided by the server, and defines a few additional commands.


SMTP OBJECTS¶

An SMTP instance has the following methods:

SMTP.set_debuglevel(level)¶

Set the debug output level. A value of 1 or True for level results in debug
messages for connection and for all messages sent to and received from the
server. A value of 2 for level results in these messages being timestamped.

Changed in version 3.5: Added debuglevel 2.

SMTP.docmd(cmd, args='')¶

Send a command cmd to the server. The optional argument args is simply
concatenated to the command, separated by a space.

This returns a 2-tuple composed of a numeric response code and the actual
response line (multiline responses are joined into one long line.)

In normal operation it should not be necessary to call this method explicitly.
It is used to implement other methods and may be useful for testing private
extensions.

If the connection to the server is lost while waiting for the reply,
SMTPServerDisconnected will be raised.

SMTP.connect(host='localhost', port=0)¶

Connect to a host on a given port. The defaults are to connect to the local host
at the standard SMTP port (25). If the hostname ends with a colon (':') followed
by a number, that suffix will be stripped off and the number interpreted as the
port number to use. This method is automatically invoked by the constructor if a
host is specified during instantiation. Returns a 2-tuple of the response code
and message sent by the server in its connection response.

Raises an auditing event smtplib.connect with arguments self, host, port.

SMTP.helo(name='')¶

Identify yourself to the SMTP server using HELO. The hostname argument defaults
to the fully qualified domain name of the local host. The message returned by
the server is stored as the helo_resp attribute of the object.

In normal operation it should not be necessary to call this method explicitly.
It will be implicitly called by the sendmail() when necessary.

SMTP.ehlo(name='')¶

Identify yourself to an ESMTP server using EHLO. The hostname argument defaults
to the fully qualified domain name of the local host. Examine the response for
ESMTP option and store them for use by has_extn(). Also sets several
informational attributes: the message returned by the server is stored as the
ehlo_resp attribute, does_esmtp is set to True or False depending on whether the
server supports ESMTP, and esmtp_features will be a dictionary containing the
names of the SMTP service extensions this server supports, and their parameters
(if any).

Unless you wish to use has_extn() before sending mail, it should not be
necessary to call this method explicitly. It will be implicitly called by
sendmail() when necessary.

SMTP.ehlo_or_helo_if_needed()¶

This method calls ehlo() and/or helo() if there has been no previous EHLO or
HELO command this session. It tries ESMTP EHLO first.

SMTPHeloError

The server didn’t reply properly to the HELO greeting.

SMTP.has_extn(name)¶

Return True if name is in the set of SMTP service extensions returned by the
server, False otherwise. Case is ignored.

SMTP.verify(address)¶

Check the validity of an address on this server using SMTP VRFY. Returns a tuple
consisting of code 250 and a full RFC 822 address (including human name) if the
user address is valid. Otherwise returns an SMTP error code of 400 or greater
and an error string.

Note

Many sites disable SMTP VRFY in order to foil spammers.

SMTP.login(user, password, *, initial_response_ok=True)¶

Log in on an SMTP server that requires authentication. The arguments are the
username and the password to authenticate with. If there has been no previous
EHLO or HELO command this session, this method tries ESMTP EHLO first. This
method will return normally if the authentication was successful, or may raise
the following exceptions:

SMTPHeloError

The server didn’t reply properly to the HELO greeting.

SMTPAuthenticationError

The server didn’t accept the username/password combination.

SMTPNotSupportedError

The AUTH command is not supported by the server.

SMTPException

No suitable authentication method was found.

Each of the authentication methods supported by smtplib are tried in turn if
they are advertised as supported by the server. See auth() for a list of
supported authentication methods. initial_response_ok is passed through to
auth().

Optional keyword argument initial_response_ok specifies whether, for
authentication methods that support it, an “initial response” as specified in
RFC 4954 can be sent along with the AUTH command, rather than requiring a
challenge/response.

Changed in version 3.5: SMTPNotSupportedError may be raised, and the
initial_response_ok parameter was added.

SMTP.auth(mechanism, authobject, *, initial_response_ok=True)¶

Issue an SMTP AUTH command for the specified authentication mechanism, and
handle the challenge response via authobject.

mechanism specifies which authentication mechanism is to be used as argument to
the AUTH command; the valid values are those listed in the auth element of
esmtp_features.

authobject must be a callable object taking an optional single argument:

data = authobject(challenge=None)


If optional keyword argument initial_response_ok is true, authobject() will be
called first with no argument. It can return the RFC 4954 “initial response”
ASCII str which will be encoded and sent with the AUTH command as below. If the
authobject() does not support an initial response (e.g. because it requires a
challenge), it should return None when called with challenge=None. If
initial_response_ok is false, then authobject() will not be called first with
None.

If the initial response check returns None, or if initial_response_ok is false,
authobject() will be called to process the server’s challenge response; the
challenge argument it is passed will be a bytes. It should return ASCII str data
that will be base64 encoded and sent to the server.

The SMTP class provides authobjects for the CRAM-MD5, PLAIN, and LOGIN
mechanisms; they are named SMTP.auth_cram_md5, SMTP.auth_plain, and
SMTP.auth_login respectively. They all require that the user and password
properties of the SMTP instance are set to appropriate values.

User code does not normally need to call auth directly, but can instead call the
login() method, which will try each of the above mechanisms in turn, in the
order listed. auth is exposed to facilitate the implementation of authentication
methods not (or not yet) supported directly by smtplib.

Added in version 3.5.

SMTP.starttls(*, context=None)¶

Put the SMTP connection in TLS (Transport Layer Security) mode. All SMTP
commands that follow will be encrypted. You should then call ehlo() again.

If keyfile and certfile are provided, they are used to create an ssl.SSLContext.

Optional context parameter is an ssl.SSLContext object; This is an alternative
to using a keyfile and a certfile and if specified both keyfile and certfile
should be None.

If there has been no previous EHLO or HELO command this session, this method
tries ESMTP EHLO first.

Changed in version 3.12: The deprecated keyfile and certfile parameters have
been removed.

SMTPHeloError

The server didn’t reply properly to the HELO greeting.

SMTPNotSupportedError

The server does not support the STARTTLS extension.

RuntimeError

SSL/TLS support is not available to your Python interpreter.

Changed in version 3.3: context was added.

Changed in version 3.4: The method now supports hostname check with
SSLContext.check_hostname and Server Name Indicator (see HAS_SNI).

Changed in version 3.5: The error raised for lack of STARTTLS support is now the
SMTPNotSupportedError subclass instead of the base SMTPException.

SMTP.sendmail(from_addr, to_addrs, msg, mail_options=(), rcpt_options=())¶

Send mail. The required arguments are an RFC 822 from-address string, a list of
RFC 822 to-address strings (a bare string will be treated as a list with 1
address), and a message string. The caller may pass a list of ESMTP options
(such as 8bitmime) to be used in MAIL FROM commands as mail_options. ESMTP
options (such as DSN commands) that should be used with all RCPT commands can be
passed as rcpt_options. (If you need to use different ESMTP options to different
recipients you have to use the low-level methods such as mail(), rcpt() and
data() to send the message.)

Note

The from_addr and to_addrs parameters are used to construct the message envelope
used by the transport agents. sendmail does not modify the message headers in
any way.

msg may be a string containing characters in the ASCII range, or a byte string.
A string is encoded to bytes using the ascii codec, and lone \r and \n
characters are converted to \r\n characters. A byte string is not modified.

If there has been no previous EHLO or HELO command this session, this method
tries ESMTP EHLO first. If the server does ESMTP, message size and each of the
specified options will be passed to it (if the option is in the feature set the
server advertises). If EHLO fails, HELO will be tried and ESMTP options
suppressed.

This method will return normally if the mail is accepted for at least one
recipient. Otherwise it will raise an exception. That is, if this method does
not raise an exception, then someone should get your mail. If this method does
not raise an exception, it returns a dictionary, with one entry for each
recipient that was refused. Each entry contains a tuple of the SMTP error code
and the accompanying error message sent by the server.

If SMTPUTF8 is included in mail_options, and the server supports it, from_addr
and to_addrs may contain non-ASCII characters.

This method may raise the following exceptions:

SMTPRecipientsRefused

All recipients were refused. Nobody got the mail. The recipients attribute of
the exception object is a dictionary with information about the refused
recipients (like the one returned when at least one recipient was accepted).

SMTPHeloError

The server didn’t reply properly to the HELO greeting.

SMTPSenderRefused

The server didn’t accept the from_addr.

SMTPDataError

The server replied with an unexpected error code (other than a refusal of a
recipient).

SMTPNotSupportedError

SMTPUTF8 was given in the mail_options but is not supported by the server.

Unless otherwise noted, the connection will be open even after an exception is
raised.

Changed in version 3.2: msg may be a byte string.

Changed in version 3.5: SMTPUTF8 support added, and SMTPNotSupportedError may be
raised if SMTPUTF8 is specified but the server does not support it.

SMTP.send_message(msg, from_addr=None, to_addrs=None, mail_options=(),
rcpt_options=())¶

This is a convenience method for calling sendmail() with the message represented
by an email.message.Message object. The arguments have the same meaning as for
sendmail(), except that msg is a Message object.

If from_addr is None or to_addrs is None, send_message fills those arguments
with addresses extracted from the headers of msg as specified in RFC 5322:
from_addr is set to the Sender field if it is present, and otherwise to the From
field. to_addrs combines the values (if any) of the To, Cc, and Bcc fields from
msg. If exactly one set of Resent-* headers appear in the message, the regular
headers are ignored and the Resent-* headers are used instead. If the message
contains more than one set of Resent-* headers, a ValueError is raised, since
there is no way to unambiguously detect the most recent set of Resent- headers.

send_message serializes msg using BytesGenerator with \r\n as the linesep, and
calls sendmail() to transmit the resulting message. Regardless of the values of
from_addr and to_addrs, send_message does not transmit any Bcc or Resent-Bcc
headers that may appear in msg. If any of the addresses in from_addr and
to_addrs contain non-ASCII characters and the server does not advertise SMTPUTF8
support, an SMTPNotSupported error is raised. Otherwise the Message is
serialized with a clone of its policy with the utf8 attribute set to True, and
SMTPUTF8 and BODY=8BITMIME are added to mail_options.

Added in version 3.2.

Added in version 3.5: Support for internationalized addresses (SMTPUTF8).

SMTP.quit()¶

Terminate the SMTP session and close the connection. Return the result of the
SMTP QUIT command.

Low-level methods corresponding to the standard SMTP/ESMTP commands HELP, RSET,
NOOP, MAIL, RCPT, and DATA are also supported. Normally these do not need to be
called directly, so they are not documented here. For details, consult the
module code.


SMTP EXAMPLE¶

This example prompts the user for addresses needed in the message envelope (‘To’
and ‘From’ addresses), and the message to be delivered. Note that the headers to
be included with the message must be included in the message as entered; this
example doesn’t do any processing of the RFC 822 headers. In particular, the
‘To’ and ‘From’ addresses must be included in the message headers explicitly:

import smtplib

def prompt(title):
    return input(title).strip()

from_addr = prompt("From: ")
to_addrs  = prompt("To: ").split()
print("Enter message, end with ^D (Unix) or ^Z (Windows):")

# Add the From: and To: headers at the start!
lines = [f"From: {from_addr}", f"To: {', '.join(to_addrs)}", ""]
while True:
    try:
        line = input()
    except EOFError:
        break
    else:
        lines.append(line)

msg = "\r\n".join(lines)
print("Message length is", len(msg))

server = smtplib.SMTP("localhost")
server.set_debuglevel(1)
server.sendmail(from_addr, to_addrs, msg)
server.quit()


Note

In general, you will want to use the email package’s features to construct an
email message, which you can then send via send_message(); see email: Examples.




TABLE OF CONTENTS

 * smtplib — SMTP protocol client
   * SMTP Objects
   * SMTP Example

PREVIOUS TOPIC

imaplib — IMAP4 protocol client

NEXT TOPIC

uuid — UUID objects according to RFC 4122


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