437 lines
16 KiB
ReStructuredText
437 lines
16 KiB
ReStructuredText
:mod:`smtplib` --- SMTP protocol client
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=======================================
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.. module:: smtplib
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:synopsis: SMTP protocol client (requires sockets).
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.. sectionauthor:: Eric S. Raymond <esr@snark.thyrsus.com>
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.. index::
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pair: SMTP; protocol
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single: Simple Mail Transfer Protocol
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**Source code:** :source:`Lib/smtplib.py`
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--------------
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The :mod:`smtplib` module defines an SMTP client session object that can be used
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to send mail to any Internet machine with an SMTP or ESMTP listener daemon. For
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details of SMTP and ESMTP operation, consult :rfc:`821` (Simple Mail Transfer
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Protocol) and :rfc:`1869` (SMTP Service Extensions).
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.. class:: SMTP(host='', port=0, local_hostname=None[, timeout])
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A :class:`SMTP` instance encapsulates an SMTP connection. It has methods
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that support a full repertoire of SMTP and ESMTP operations. If the optional
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host and port parameters are given, the SMTP :meth:`connect` method is called
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with those parameters during initialization. An :exc:`SMTPConnectError` is
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raised if the specified host doesn't respond correctly. The optional
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*timeout* parameter specifies a timeout in seconds for blocking operations
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like the connection attempt (if not specified, the global default timeout
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setting will be used).
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For normal use, you should only require the initialization/connect,
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:meth:`sendmail`, and :meth:`quit` methods. An example is included below.
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The :class:`SMTP` class supports the :keyword:`with` statement. When used
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like this, the SMTP ``QUIT`` command is issued automatically when the
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:keyword:`with` statement exits. E.g.::
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>>> from smtplib import SMTP
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>>> with SMTP("domain.org") as smtp:
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... smtp.noop()
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...
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(250, b'Ok')
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>>>
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.. versionchanged:: 3.3
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Support for the :keyword:`with` statement was added.
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.. class:: SMTP_SSL(host='', port=0, local_hostname=None, keyfile=None, certfile=None[, timeout], context=None)
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A :class:`SMTP_SSL` instance behaves exactly the same as instances of
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:class:`SMTP`. :class:`SMTP_SSL` should be used for situations where SSL is
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required from the beginning of the connection and using :meth:`starttls` is
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not appropriate. If *host* is not specified, the local host is used. If
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*port* is zero, the standard SMTP-over-SSL port (465) is used. *keyfile*
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and *certfile* are also optional, and can contain a PEM formatted private key
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and certificate chain file for the SSL connection. *context* also optional, can contain
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a SSLContext, and is an alternative to keyfile and certfile; If it is specified both
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keyfile and certfile must be None. The optional *timeout*
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parameter specifies a timeout in seconds for blocking operations like the
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connection attempt (if not specified, the global default timeout setting
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will be used).
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.. versionchanged:: 3.3
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*context* was added.
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.. class:: LMTP(host='', port=LMTP_PORT, local_hostname=None)
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The LMTP protocol, which is very similar to ESMTP, is heavily based on the
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standard SMTP client. It's common to use Unix sockets for LMTP, so our :meth:`connect`
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method must support that as well as a regular host:port server. To specify a
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Unix socket, you must use an absolute path for *host*, starting with a '/'.
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Authentication is supported, using the regular SMTP mechanism. When using a Unix
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socket, LMTP generally don't support or require any authentication, but your
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mileage might vary.
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A nice selection of exceptions is defined as well:
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.. exception:: SMTPException
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Base exception class for all exceptions raised by this module.
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.. exception:: SMTPServerDisconnected
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This exception is raised when the server unexpectedly disconnects, or when an
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attempt is made to use the :class:`SMTP` instance before connecting it to a
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server.
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.. exception:: SMTPResponseException
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Base class for all exceptions that include an SMTP error code. These exceptions
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are generated in some instances when the SMTP server returns an error code. The
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error code is stored in the :attr:`smtp_code` attribute of the error, and the
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:attr:`smtp_error` attribute is set to the error message.
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.. exception:: SMTPSenderRefused
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Sender address refused. In addition to the attributes set by on all
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:exc:`SMTPResponseException` exceptions, this sets 'sender' to the string that
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the SMTP server refused.
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.. exception:: SMTPRecipientsRefused
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All recipient addresses refused. The errors for each recipient are accessible
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through the attribute :attr:`recipients`, which is a dictionary of exactly the
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same sort as :meth:`SMTP.sendmail` returns.
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.. exception:: SMTPDataError
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The SMTP server refused to accept the message data.
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.. exception:: SMTPConnectError
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Error occurred during establishment of a connection with the server.
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.. exception:: SMTPHeloError
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The server refused our ``HELO`` message.
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.. exception:: SMTPAuthenticationError
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SMTP authentication went wrong. Most probably the server didn't accept the
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username/password combination provided.
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.. seealso::
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:rfc:`821` - Simple Mail Transfer Protocol
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Protocol definition for SMTP. This document covers the model, operating
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procedure, and protocol details for SMTP.
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:rfc:`1869` - SMTP Service Extensions
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Definition of the ESMTP extensions for SMTP. This describes a framework for
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extending SMTP with new commands, supporting dynamic discovery of the commands
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provided by the server, and defines a few additional commands.
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.. _smtp-objects:
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SMTP Objects
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------------
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An :class:`SMTP` instance has the following methods:
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.. method:: SMTP.set_debuglevel(level)
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Set the debug output level. A true value for *level* results in debug messages
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for connection and for all messages sent to and received from the server.
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.. method:: SMTP.connect(host='localhost', port=0)
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Connect to a host on a given port. The defaults are to connect to the local
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host at the standard SMTP port (25). If the hostname ends with a colon (``':'``)
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followed by a number, that suffix will be stripped off and the number
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interpreted as the port number to use. This method is automatically invoked by
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the constructor if a host is specified during instantiation.
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.. method:: SMTP.docmd(cmd, args='')
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Send a command *cmd* to the server. The optional argument *args* is simply
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concatenated to the command, separated by a space.
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This returns a 2-tuple composed of a numeric response code and the actual
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response line (multiline responses are joined into one long line.)
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In normal operation it should not be necessary to call this method explicitly.
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It is used to implement other methods and may be useful for testing private
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extensions.
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If the connection to the server is lost while waiting for the reply,
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:exc:`SMTPServerDisconnected` will be raised.
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.. method:: SMTP.helo(name='')
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Identify yourself to the SMTP server using ``HELO``. The hostname argument
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defaults to the fully qualified domain name of the local host.
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The message returned by the server is stored as the :attr:`helo_resp` attribute
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of the object.
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In normal operation it should not be necessary to call this method explicitly.
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It will be implicitly called by the :meth:`sendmail` when necessary.
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.. method:: SMTP.ehlo(name='')
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Identify yourself to an ESMTP server using ``EHLO``. The hostname argument
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defaults to the fully qualified domain name of the local host. Examine the
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response for ESMTP option and store them for use by :meth:`has_extn`.
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Also sets several informational attributes: the message returned by
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the server is stored as the :attr:`ehlo_resp` attribute, :attr:`does_esmtp`
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is set to true or false depending on whether the server supports ESMTP, and
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:attr:`esmtp_features` will be a dictionary containing the names of the
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SMTP service extensions this server supports, and their
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parameters (if any).
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Unless you wish to use :meth:`has_extn` before sending mail, it should not be
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necessary to call this method explicitly. It will be implicitly called by
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:meth:`sendmail` when necessary.
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.. method:: SMTP.ehlo_or_helo_if_needed()
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This method call :meth:`ehlo` and or :meth:`helo` if there has been no
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previous ``EHLO`` or ``HELO`` command this session. It tries ESMTP ``EHLO``
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first.
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:exc:`SMTPHeloError`
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The server didn't reply properly to the ``HELO`` greeting.
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.. method:: SMTP.has_extn(name)
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Return :const:`True` if *name* is in the set of SMTP service extensions returned
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by the server, :const:`False` otherwise. Case is ignored.
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.. method:: SMTP.verify(address)
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Check the validity of an address on this server using SMTP ``VRFY``. Returns a
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tuple consisting of code 250 and a full :rfc:`822` address (including human
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name) if the user address is valid. Otherwise returns an SMTP error code of 400
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or greater and an error string.
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.. note::
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Many sites disable SMTP ``VRFY`` in order to foil spammers.
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.. method:: SMTP.login(user, password)
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Log in on an SMTP server that requires authentication. The arguments are the
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username and the password to authenticate with. If there has been no previous
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``EHLO`` or ``HELO`` command this session, this method tries ESMTP ``EHLO``
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first. This method will return normally if the authentication was successful, or
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may raise the following exceptions:
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:exc:`SMTPHeloError`
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The server didn't reply properly to the ``HELO`` greeting.
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:exc:`SMTPAuthenticationError`
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The server didn't accept the username/password combination.
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:exc:`SMTPException`
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No suitable authentication method was found.
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.. method:: SMTP.starttls(keyfile=None, certfile=None, context=None)
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Put the SMTP connection in TLS (Transport Layer Security) mode. All SMTP
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commands that follow will be encrypted. You should then call :meth:`ehlo`
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again.
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If *keyfile* and *certfile* are provided, these are passed to the :mod:`socket`
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module's :func:`ssl` function.
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Optional *context* parameter is a :class:`ssl.SSLContext` object; This is an alternative to
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using a keyfile and a certfile and if specified both *keyfile* and *certfile* should be None.
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If there has been no previous ``EHLO`` or ``HELO`` command this session,
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this method tries ESMTP ``EHLO`` first.
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:exc:`SMTPHeloError`
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The server didn't reply properly to the ``HELO`` greeting.
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:exc:`SMTPException`
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The server does not support the STARTTLS extension.
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:exc:`RuntimeError`
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SSL/TLS support is not available to your Python interpreter.
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.. versionchanged:: 3.3
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*context* was added.
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.. method:: SMTP.sendmail(from_addr, to_addrs, msg, mail_options=[], rcpt_options=[])
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Send mail. The required arguments are an :rfc:`822` from-address string, a list
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of :rfc:`822` to-address strings (a bare string will be treated as a list with 1
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address), and a message string. The caller may pass a list of ESMTP options
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(such as ``8bitmime``) to be used in ``MAIL FROM`` commands as *mail_options*.
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ESMTP options (such as ``DSN`` commands) that should be used with all ``RCPT``
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commands can be passed as *rcpt_options*. (If you need to use different ESMTP
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options to different recipients you have to use the low-level methods such as
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:meth:`mail`, :meth:`rcpt` and :meth:`data` to send the message.)
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.. note::
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The *from_addr* and *to_addrs* parameters are used to construct the message
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envelope used by the transport agents. ``sendmail`` does not modify the
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message headers in any way.
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msg may be a string containing characters in the ASCII range, or a byte
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string. A string is encoded to bytes using the ascii codec, and lone ``\r``
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and ``\n`` characters are converted to ``\r\n`` characters. A byte string
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is not modified.
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If there has been no previous ``EHLO`` or ``HELO`` command this session, this
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method tries ESMTP ``EHLO`` first. If the server does ESMTP, message size and
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each of the specified options will be passed to it (if the option is in the
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feature set the server advertises). If ``EHLO`` fails, ``HELO`` will be tried
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and ESMTP options suppressed.
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This method will return normally if the mail is accepted for at least one
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recipient. Otherwise it will raise an exception. That is, if this method does
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not raise an exception, then someone should get your mail. If this method does
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not raise an exception, it returns a dictionary, with one entry for each
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recipient that was refused. Each entry contains a tuple of the SMTP error code
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and the accompanying error message sent by the server.
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This method may raise the following exceptions:
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:exc:`SMTPRecipientsRefused`
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All recipients were refused. Nobody got the mail. The :attr:`recipients`
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attribute of the exception object is a dictionary with information about the
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refused recipients (like the one returned when at least one recipient was
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accepted).
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:exc:`SMTPHeloError`
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The server didn't reply properly to the ``HELO`` greeting.
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:exc:`SMTPSenderRefused`
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The server didn't accept the *from_addr*.
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:exc:`SMTPDataError`
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The server replied with an unexpected error code (other than a refusal of a
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recipient).
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Unless otherwise noted, the connection will be open even after an exception is
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raised.
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.. versionchanged:: 3.2 *msg* may be a byte string.
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.. method:: SMTP.send_message(msg, from_addr=None, to_addrs=None, \
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mail_options=[], rcpt_options=[])
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This is a convenience method for calling :meth:`sendmail` with the message
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represented by an :class:`email.message.Message` object. The arguments have
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the same meaning as for :meth:`sendmail`, except that *msg* is a ``Message``
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object.
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If *from_addr* is ``None`` or *to_addrs* is ``None``, ``send_message`` fills
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those arguments with addresses extracted from the headers of *msg* as
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specified in :rfc:`2822`\: *from_addr* is set to the :mailheader:`Sender`
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field if it is present, and otherwise to the :mailheader:`From` field.
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*to_adresses* combines the values (if any) of the :mailheader:`To`,
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:mailheader:`Cc`, and :mailheader:`Bcc` fields from *msg*. If exactly one
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set of :mailheader:`Resent-*` headers appear in the message, the regular
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headers are ignored and the :mailheader:`Resent-*` headers are used instead.
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If the message contains more than one set of :mailheader:`Resent-*` headers,
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a :exc:`ValueError` is raised, since there is no way to unambiguously detect
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the most recent set of :mailheader:`Resent-` headers.
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``send_message`` serializes *msg* using
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:class:`~email.generator.BytesGenerator` with ``\r\n`` as the *linesep*, and
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calls :meth:`sendmail` to transmit the resulting message. Regardless of the
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values of *from_addr* and *to_addrs*, ``send_message`` does not transmit any
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:mailheader:`Bcc` or :mailheader:`Resent-Bcc` headers that may appear
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in *msg*.
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.. versionadded:: 3.2
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.. method:: SMTP.quit()
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Terminate the SMTP session and close the connection. Return the result of
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the SMTP ``QUIT`` command.
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Low-level methods corresponding to the standard SMTP/ESMTP commands ``HELP``,
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``RSET``, ``NOOP``, ``MAIL``, ``RCPT``, and ``DATA`` are also supported.
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Normally these do not need to be called directly, so they are not documented
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here. For details, consult the module code.
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.. _smtp-example:
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SMTP Example
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------------
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This example prompts the user for addresses needed in the message envelope ('To'
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and 'From' addresses), and the message to be delivered. Note that the headers
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to be included with the message must be included in the message as entered; this
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example doesn't do any processing of the :rfc:`822` headers. In particular, the
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'To' and 'From' addresses must be included in the message headers explicitly. ::
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import smtplib
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def prompt(prompt):
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return input(prompt).strip()
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fromaddr = prompt("From: ")
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toaddrs = prompt("To: ").split()
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print("Enter message, end with ^D (Unix) or ^Z (Windows):")
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# Add the From: and To: headers at the start!
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msg = ("From: %s\r\nTo: %s\r\n\r\n"
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% (fromaddr, ", ".join(toaddrs)))
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while True:
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try:
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line = input()
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except EOFError:
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break
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if not line:
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break
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msg = msg + line
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print("Message length is", len(msg))
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server = smtplib.SMTP('localhost')
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server.set_debuglevel(1)
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server.sendmail(fromaddr, toaddrs, msg)
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server.quit()
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.. note::
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In general, you will want to use the :mod:`email` package's features to
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construct an email message, which you can then send
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via :meth:`~smtplib.SMTP.send_message`; see :ref:`email-examples`.
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