aiosmtplib¶

Overview¶

aiosmtplib is an asynchronous SMTP client for use with asyncio.

Quickstart¶

import asyncio
from email.mime.text import MIMEText

import aiosmtplib

loop = asyncio.get_event_loop()
smtp = aiosmtplib.SMTP(hostname="127.0.0.1", port=1025, loop=loop)
loop.run_until_complete(smtp.connect())

message = MIMEText("Sent via aiosmtplib")
message["From"] = "root@localhost"
message["To"] = "somebody@example.com"
message["Subject"] = "Hello World!"

loop.run_until_complete(smtp.send_message(message))

Requirements¶

Python 3.5.2+, compiled with SSL support, is required.

Connecting to an SMTP Server¶

Initialize a new SMTP instance, then await its SMTP.connect() coroutine. Initializing an instance does not automatically connect to the server, as that is a blocking operation.

client = SMTP()

loop = asyncio.get_event_loop()
loop.run_until_complete(client.connect(hostname="localhost", port=25))

Connecting over TLS/SSL¶

If an SMTP server supports direct connection via TLS/SSL, pass use_tls=True when initializing the SMTP instance (or when calling SMTP.connect()).

loop = asyncio.get_event_loop()
smtp = aiosmtplib.SMTP(hostname="smtp.gmail.com", port=465, loop=loop, use_tls=True)
loop.run_until_complete(smtp.connect())

STARTTLS connections¶

Many SMTP servers support the STARTTLS extension over port 587. When using STARTTLS, the initial connection is made over plaintext, and after connecting a STARTTLS command is sent which initiates the upgrade to a secure connection. To connect to a server that uses STARTTLS, set use_tls to False when connecting, and call SMTP.starttls() on the client.

loop = asyncio.get_event_loop()
smtp = aiosmtplib.SMTP(hostname="smtp.gmail.com", port=587, loop=loop, use_tls=False)
loop.run_until_complete(smtp.connect())
loop.run_until_complete(smtp.starttls())

Connecting via async context manager¶

Instances of the SMTP class can also be used as an async context manager, which will automatically connect/disconnect on entry/exit.

async def send_message():
    message = MIMEText("Sent via aiosmtplib")
    message["From"] = "root@localhost"
    message["To"] = "somebody@example.com"
    message["Subject"] = "Hello World!"

    async with aiosmtplib.SMTP(hostname="127.0.0.1", port=1025, loop=loop):
        await smtp.send_message(message)

loop.run_until_complete(send_message())

Sending Messages¶

`SMTP.send_message()`¶

This is the simplest API, and is the recommended way to send messages, as it makes it easy to set headers correctly and handle multi part messages. For details on creating email.message.Message objects, see the stdlib documentation examples.

Use SMTP.send_message() to send email.message.Message objects, including email.mime subclasses such as email.mime.text.MIMEText.

from email.mime.text import MIMEText

message = MIMEText("Sent via aiosmtplib")
message["From"] = "root@localhost"
message["To"] = "somebody@example.com"
message["Subject"] = "Hello World!"

loop = asyncio.get_event_loop()
loop.run_until_complete(smtp.send_message(message))

Pass email.mime.multipart.MIMEMultipart objects to SMTP.send_message() to send messages with both HTML text and plain text alternatives.

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

message = MIMEMultipart("alternative")
message["From"] = "root@localhost"
message["To"] = "somebody@example.com"
message["Subject"] = "Hello World!"

message.attach(MIMEText("hello", "plain", "utf-8"))
message.attach(MIMEText("<html><body><h1>Hello</h1></body></html>", "html", "utf-8"))

loop = asyncio.get_event_loop()
loop.run_until_complete(smtp.send_message(message))

`SMTP.sendmail()`¶

Use SMTP.sendmail() to send raw messages. Note that when using this method, you must format the message headers yourself.

sender = "root@localhost"
recipients = ["somebody@example.com"]
message = """To: somebody@example.com
From: root@localhost
Subject: Hello World!

Sent via aiosmtplib
"""

loop = asyncio.get_event_loop()
loop.run_until_complete(smtp.sendmail(sender, recipients, message))

Timeouts¶

All commands accept a timeout keyword argument of a numerical value in seconds. This value is used for all socket operations, and will raise SMTPTimeoutError if exceeded. Timeout values passed to SMTP.__init__() or SMTP.connect() will be used as the default value for commands executed on the connection.

The default timeout is 60 seconds.

Parallel Execution¶

SMTP is a sequential protocol. Multiple commands must be sent to send an email, and they must be sent in the correct sequence. As a consequence of this, executing multiple SMTP.sendmail() tasks in parallel (i.e. with asyncio.gather()) is not any more efficient than executing in sequence, as the client must wait until one mail is sent before beginning the next.

If you have a lot of emails to send, consider creating multiple connections (SMTP instances) and splitting the work between them.

Bug reporting¶

Bug reports (and feature requests) are welcome via Github issues.

API Reference¶

The SMTP Class¶

class aiosmtplib.SMTP(*args, **kwargs)[source]¶

Main SMTP client class.

Basic usage:

>>> loop = asyncio.get_event_loop()
>>> smtp = aiosmtplib.SMTP(hostname="127.0.0.1", port=1025, loop=loop)
>>> loop.run_until_complete(smtp.connect())
(220, ...)
>>> sender = "root@localhost"
>>> recipients = ["somebody@localhost"]
>>> message = "Hello World"
>>> send = smtp.sendmail(sender, recipients, "Hello World")
>>> loop.run_until_complete(send)
({}, 'OK')

__init__(*args, **kwargs)[source]¶

Parameters:	hostname – Server name (or IP) to connect to port – Server port. Defaults to `25` if `use_tls` is `False`, `465` if `use_tls` is `True`. source_address – The hostname of the client. Defaults to the result of `socket.getfqdn()`. Note that this call blocks. timeout – Default timeout value for the connection, in seconds. Defaults to 60. loop – event loop to run on. If not set, uses `asyncio.get_event_loop()`. use_tls – If True, make the initial connection to the server over TLS/SSL. Note that if the server supports STARTTLS only, this should be False. validate_certs – Determines if server certificates are validated. Defaults to True. client_cert – Path to client side certificate, for TLS verification. client_key – Path to client side key, for TLS verification. tls_context – An existing `ssl.SSLContext`, for TLS verification. Mutually exclusive with `client_cert`/ `client_key`. cert_bundle – Path to certificate bundle, for TLS verification.
Raises:	ValueError – mutually exclusive options provided
Return type:	`None`

auth_crammd5(username, password, timeout=<Default.token: 0>)¶

CRAM-MD5 auth uses the password as a shared secret to MD5 the server’s response.

Example:

250 AUTH CRAM-MD5
auth cram-md5
334 PDI0NjA5LjEwNDc5MTQwNDZAcG9wbWFpbC5TcGFjZS5OZXQ+
dGltIGI5MTNhNjAyYzdlZGE3YTQ5NWI0ZTZlNzMzNGQzODkw

Return type:	`SMTPResponse`

auth_login(username, password, timeout=<Default.token: 0>)¶

LOGIN auth sends the Base64 encoded username and password in sequence.

Example:

250 AUTH LOGIN PLAIN CRAM-MD5
auth login avlsdkfj
334 UGFzc3dvcmQ6
avlsdkfj

Note that there is an alternate version sends the username as a separate command:

250 AUTH LOGIN PLAIN CRAM-MD5
auth login
334 VXNlcm5hbWU6
avlsdkfj
334 UGFzc3dvcmQ6
avlsdkfj

However, since most servers seem to support both, we send the username with the initial request.

Return type:	`SMTPResponse`

auth_plain(username, password, timeout=<Default.token: 0>)¶

PLAIN auth encodes the username and password in one Base64 encoded string. No verification message is required.

Example:

220-esmtp.example.com
AUTH PLAIN dGVzdAB0ZXN0AHRlc3RwYXNz
235 ok, go ahead (#2.0.0)

Return type:	`SMTPResponse`

close()¶

Makes sure we reset ESMTP state on close.

Return type:	`None`

connect(hostname=None, port=None, source_address=<Default.token: 0>, timeout=<Default.token: 0>, loop=None, use_tls=None, validate_certs=None, client_cert=<Default.token: 0>, client_key=<Default.token: 0>, tls_context=<Default.token: 0>, cert_bundle=<Default.token: 0>)¶

Initialize a connection to the server. Options provided to connect() take precedence over those used to initialize the class.

Parameters:	hostname – Server name (or IP) to connect to port – Server port. Defaults to 25 if `use_tls` is False, 465 if `use_tls` is True. source_address – The hostname of the client. Defaults to the result of `socket.getfqdn()`. Note that this call blocks. timeout – Default timeout value for the connection, in seconds. Defaults to 60. loop – event loop to run on. If not set, uses `asyncio.get_event_loop()`. use_tls – If True, make the initial connection to the server over TLS/SSL. Note that if the server supports STARTTLS only, this should be False. validate_certs – Determines if server certificates are validated. Defaults to True. client_cert – Path to client side certificate, for TLS. client_key – Path to client side key, for TLS. tls_context – An existing `ssl.SSLContext`, for TLS. Mutually exclusive with `client_cert`/`client_key`. cert_bundle – Path to certificate bundle, for TLS verification.
Raises:	ValueError – mutually exclusive options provided
Return type:	`SMTPResponse`

data(message, timeout=<Default.token: 0>)¶

Send an SMTP DATA command, followed by the message given. This method transfers the actual email content to the server.

Raises:	SMTPDataError – on unexpected server response code SMTPServerDisconnected – connection lost
Return type:	`SMTPResponse`

ehlo(hostname=None, timeout=<Default.token: 0>)¶

Send the SMTP EHLO command. Hostname to send for this command defaults to the FQDN of the local host.

Raises:	SMTPHeloError – on unexpected server response code
Return type:	`SMTPResponse`

execute_command(*args, timeout=<Default.token: 0>)¶

Check that we’re connected, if we got a timeout value, and then pass the command to the protocol.

Raises:	SMTPServerDisconnected – connection lost
Return type:	`SMTPResponse`

expn(address, timeout=<Default.token: 0>)¶

Send an SMTP EXPN command, which expands a mailing list. Not many servers support this command.

Raises:	SMTPResponseException – on unexpected server response code
Return type:	`SMTPResponse`

get_transport_info(key)¶

Get extra info from the transport. Supported keys:

peername

socket

sockname

compression

cipher

peercert

sslcontext

sslobject

Raises:	SMTPServerDisconnected – connection lost
Return type:	`Any`

helo(hostname=None, timeout=<Default.token: 0>)¶

Send the SMTP HELO command. Hostname to send for this command defaults to the FQDN of the local host.

Raises:	SMTPHeloError – on unexpected server response code
Return type:	`SMTPResponse`

help(timeout=<Default.token: 0>)¶

Send the SMTP HELP command, which responds with help text.

Raises:	SMTPResponseException – on unexpected server response code
Return type:	`str`

is_connected¶

Check if our transport is still connected.

Return type:	`bool`

is_ehlo_or_helo_needed¶

Check if we’ve already received a response to an EHLO or HELO command.

Return type:	`bool`

login(username, password, timeout=<Default.token: 0>)¶

Tries to login with supported auth methods.

Some servers advertise authentication methods they don’t really support, so if authentication fails, we continue until we’ve tried all methods.

Return type:	`SMTPResponse`

mail(sender, options=None, timeout=<Default.token: 0>)¶

Send an SMTP MAIL command, which specifies the message sender and begins a new mail transfer session (“envelope”).

Raises:	SMTPSenderRefused – on unexpected server response code
Return type:	`SMTPResponse`

noop(timeout=<Default.token: 0>)¶

Send an SMTP NOOP command, which does nothing.

Raises:	SMTPResponseException – on unexpected server response code
Return type:	`SMTPResponse`

quit(timeout=<Default.token: 0>)¶

Send the SMTP QUIT command, which closes the connection. Also closes the connection from our side after a response is received.

Raises:	SMTPResponseException – on unexpected server response code
Return type:	`SMTPResponse`

rcpt(recipient, options=None, timeout=<Default.token: 0>)¶

Send an SMTP RCPT command, which specifies a single recipient for the message. This command is sent once per recipient and must be preceded by ‘MAIL’.

Raises:	SMTPRecipientRefused – on unexpected server response code
Return type:	`SMTPResponse`

rset(timeout=<Default.token: 0>)¶

Send an SMTP RSET command, which resets the server’s envelope (the envelope contains the sender, recipient, and mail data).

Raises:	SMTPResponseException – on unexpected server response code
Return type:	`SMTPResponse`

send_message(message, sender=None, recipients=None, mail_options=None, rcpt_options=None, timeout=<Default.token: 0>)[source]¶

Sends an email.message.Message object.

Arguments are as for sendmail(), except that message is an email.message.Message object. If sender is None or recipients is None, these arguments are taken from the headers of the Message as described in RFC 2822. Regardless of the values of sender and recipients, any Bcc field (or Resent-Bcc field, when the Message is a resent) of the Message object will not be transmitted. The Message object is then serialized using email.generator.Generator and sendmail() is called to transmit the message.

‘Resent-Date’ is a mandatory field if the Message is resent (RFC 2822 Section 3.6.6). In such a case, we use the ‘Resent-*’ fields. However, if there is more than one ‘Resent-‘ block there’s no way to unambiguously determine which one is the most recent in all cases, so rather than guess we raise a ValueError in that case.

Raises:	ValueError – on more than one Resent header block SMTPRecipientsRefused – delivery to all recipients failed SMTPResponseException – on invalid response
Return type:	`Tuple`[`Dict`[`str`, `SMTPResponse`], `str`]

send_message_sync(message, sender=None, recipients=None, mail_options=None, rcpt_options=None, timeout=<Default.token: 0>)[source]¶

Synchronous version of send_message(). This method starts the event loop to connect, send the message, and disconnect.

Return type:	`Tuple`[`Dict`[`str`, `SMTPResponse`], `str`]

sendmail(sender, recipients, message, mail_options=None, rcpt_options=None, timeout=<Default.token: 0>)[source]¶

This command performs an entire mail transaction.

The arguments are:

sender: The address sending this mail.
recipients: A list of addresses to send this mail to. A bare

string will be treated as a list with 1 address.
message: The message string to send.
mail_options: List of options (such as ESMTP 8bitmime) for the

MAIL command.
rcpt_options: List of options (such as DSN commands) for all the

RCPT commands.

message must be a string containing characters in the ASCII range. The string is encoded to bytes using the ascii codec, and lone \r and \n characters are converted to \r\n characters.

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

This method will return normally if the mail is accepted for at least one recipient. It returns a tuple consisting of:

an error 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.

the message sent by the server in response to the DATA command

(often containing a message id)

Example:

>>> loop = asyncio.get_event_loop()
>>> smtp = aiosmtplib.SMTP(hostname="127.0.0.1", port=1025)
>>> loop.run_until_complete(smtp.connect())
(220, ...)
>>> recipients = ["one@one.org", "two@two.org", "3@three.org"]
>>> message = "From: Me@my.org\nSubject: testing\nHello World"
>>> send_coro = smtp.sendmail("me@my.org", recipients, message)
>>> loop.run_until_complete(send_coro)
({}, 'OK')
>>> loop.run_until_complete(smtp.quit())
(221, Bye)

In the above example, the message was accepted for delivery for all three addresses. If delivery had been only successful to two of the three addresses, and one was rejected, the response would look something like:

(
    {"nobody@three.org": (550, "User unknown")},
    "Written safely to disk. #902487694.289148.12219.",
)

If delivery is not successful to any addresses, SMTPRecipientsRefused is raised.

If SMTPResponseException is raised by this method, we try to send an RSET command to reset the server envelope automatically for the next attempt.

Raises:	SMTPRecipientsRefused – delivery to all recipients failed SMTPResponseException – on invalid response
Return type:	`Tuple`[`Dict`[`str`, `SMTPResponse`], `str`]

sendmail_sync(sender, recipients, message, mail_options=None, rcpt_options=None, timeout=<Default.token: 0>)[source]¶

Synchronous version of sendmail(). This method starts the event loop to connect, send the message, and disconnect.

Return type:	`Tuple`[`Dict`[`str`, `SMTPResponse`], `str`]

source_address¶

Get the system hostname to be sent to the SMTP server. Simply caches the result of socket.getfqdn().

Return type:	`str`

starttls(server_hostname=None, validate_certs=None, client_cert=<Default.token: 0>, client_key=<Default.token: 0>, cert_bundle=<Default.token: 0>, tls_context=<Default.token: 0>, timeout=<Default.token: 0>)¶

Puts the connection to the SMTP server into TLS mode.

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

If the server supports TLS, this will encrypt the rest of the SMTP session. If you provide the keyfile and certfile parameters, the identity of the SMTP server and client can be checked (if validate_certs is True). You can also provide a custom SSLContext object. If no certs or SSLContext is given, and TLS config was provided when initializing the class, STARTTLS will use to that, otherwise it will use the Python defaults.

Raises:	SMTPException – server does not support STARTTLS SMTPServerDisconnected – connection lost ValueError – invalid options provided
Return type:	`SMTPResponse`

supported_auth_methods¶

Get all AUTH methods supported by the both server and by us.

Return type:	`List`[`str`]

supports_extension(extension)¶

Tests if the server supports the ESMTP service extension given.

Return type:	`bool`

vrfy(address, timeout=<Default.token: 0>)¶

Send an SMTP VRFY command, which tests an address for validity. Not many servers support this command.

Raises:	SMTPResponseException – on unexpected server response code
Return type:	`SMTPResponse`

Server Responses¶

class aiosmtplib.response.SMTPResponse[source]¶

NamedTuple of server response code and server response message.

code and message can be accessed via attributes or indexes:

>>> response = SMTPResponse(200, "OK")
>>> response.message
'OK'
>>> response[0]
200
>>> response.code
200

Status Codes¶

class aiosmtplib.status.SMTPStatus[source]¶

Defines SMTP statuses for code readability.

access_denied = 530¶

auth_continue = 334¶

auth_failed = 535¶

auth_successful = 235¶

bad_command_sequence = 503¶

cannot_vrfy = 252¶

closing = 221¶

command_not_implemented = 502¶

completed = 250¶

domain_does_not_accept_mail = 521¶

domain_unavailable = 421¶

error_processing = 451¶

help_message = 214¶

insufficient_storage = 452¶

invalid_response = -1¶

mailbox_does_not_exist = 550¶

mailbox_name_invalid = 553¶

mailbox_unavailable = 450¶

parameter_not_implemented = 504¶

ready = 220¶

start_input = 354¶

storage_exceeded = 552¶

syntax_error = 555¶

system_status_ok = 211¶

transaction_failed = 554¶

unrecognized_command = 500¶

unrecognized_parameters = 501¶

user_not_local = 551¶

will_forward = 251¶

Exceptions¶

exception aiosmtplib.errors.SMTPAuthenticationError(code, message)[source]¶

Bases: aiosmtplib.errors.SMTPResponseException

Server refused our AUTH request; may be caused by invalid credentials.

exception aiosmtplib.errors.SMTPConnectError(message)[source]¶

Bases: aiosmtplib.errors.SMTPException, ConnectionError

An error occurred while connecting to the SMTP server.

exception aiosmtplib.errors.SMTPDataError(code, message)[source]¶

Bases: aiosmtplib.errors.SMTPResponseException

Server refused DATA content.

exception aiosmtplib.errors.SMTPException(message)[source]¶

Bases: Exception

Base class for all SMTP exceptions.

exception aiosmtplib.errors.SMTPHeloError(code, message)[source]¶

Bases: aiosmtplib.errors.SMTPResponseException

Server refused HELO or EHLO.

exception aiosmtplib.errors.SMTPNotSupported(code, message)[source]¶

Bases: aiosmtplib.errors.SMTPResponseException

A command or argument sent to the SMTP server is not supported.

exception aiosmtplib.errors.SMTPRecipientRefused(code, message, recipient)[source]¶

Bases: aiosmtplib.errors.SMTPResponseException

SMTP server refused a message recipient.

exception aiosmtplib.errors.SMTPRecipientsRefused(recipients)[source]¶

Bases: aiosmtplib.errors.SMTPException

SMTP server refused multiple recipients.

exception aiosmtplib.errors.SMTPResponseException(code, message)[source]¶

Bases: aiosmtplib.errors.SMTPException

Base class for all server responses with error codes.

exception aiosmtplib.errors.SMTPSenderRefused(code, message, sender)[source]¶

Bases: aiosmtplib.errors.SMTPResponseException

SMTP server refused the message sender.

exception aiosmtplib.errors.SMTPServerDisconnected(message)[source]¶

Bases: aiosmtplib.errors.SMTPException, ConnectionError

The connection was lost unexpectedly, or a command was run that requires a connection.

exception aiosmtplib.errors.SMTPTimeoutError(message)[source]¶

Bases: aiosmtplib.errors.SMTPException, concurrent.futures._base.TimeoutError

A timeout occurred while performing a network operation.

Changelog¶

1.0.6¶

Bugfix: Set default timeout to 60 seconds as per documentation (previously it was unlimited).

1.0.5¶

Bugfix: Connection is now closed if an error response is recieved immediately after connecting.

1.0.4¶

Bugfix: Badly encoded server response messages are now decoded to utf-8, with error chars escaped.
Cleanup: Removed handling for exceptions not raised by asyncio (in SMTPProtocol._readline)

1.0.3¶

Bugfix: Removed buggy close connection on __del__
Bugfix: Fixed old style auth method parsing in ESMPT response.
Bugfix: Cleanup transport on exception in connect method.
Cleanup: Simplified SMTPProtocol.connection_made, __main__

1.0.2¶

Bugfix: Close connection lock on on SMTPServerDisconnected
Feature: Added cert_bundle argument to connection init, connect and starttls methods
Bugfix: Disconnected clients would raise SMTPResponseException: (-1 …) instead of SMTPServerDisconnected

1.0.1¶

Bugfix: Commands were getting out of order when using the client as a context manager within a task
Bugfix: multiple tasks calling connect would get confused
Bugfix: EHLO/HELO responses were being saved even after disconnect
Bugfix: RuntimeError on client cleanup if event loop was closed
Bugfix: CRAM-MD5 auth was not working
Bugfix: AttributeError on STARTTLS under uvloop

1.0.0¶

Initial feature complete release with stable API; future changes will be documented here.

aiosmtplib¶

Overview¶

Quickstart¶

Requirements¶

Connecting to an SMTP Server¶

Connecting over TLS/SSL¶

STARTTLS connections¶

Connecting via async context manager¶

Sending Messages¶

`SMTP.send_message()`¶

`SMTP.sendmail()`¶

Timeouts¶

Parallel Execution¶

Bug reporting¶

API Reference¶

The SMTP Class¶

Server Responses¶

Status Codes¶

Exceptions¶

Changelog¶

1.0.6¶

1.0.5¶

1.0.4¶

1.0.3¶

1.0.2¶

1.0.1¶

1.0.0¶

Indices and tables¶

Table of Contents

Related Topics

aiosmtplib¶

Overview¶

Quickstart¶

Requirements¶

Connecting to an SMTP Server¶

Connecting over TLS/SSL¶

STARTTLS connections¶

Connecting via async context manager¶

Sending Messages¶

SMTP.send_message()¶

SMTP.sendmail()¶

Timeouts¶

Parallel Execution¶

Bug reporting¶

API Reference¶

The SMTP Class¶

Server Responses¶

Status Codes¶

Exceptions¶

Changelog¶

1.0.6¶

1.0.5¶

1.0.4¶

1.0.3¶

1.0.2¶

1.0.1¶

1.0.0¶

Indices and tables¶

`SMTP.send_message()`¶

`SMTP.sendmail()`¶