Queue server

As shown in the general usage document, you can create subclasses of the Server class to define how you want to handle received messages. A very common pattern is to use a Queue to share messages between the controlling thread and the server thread. These are nice because, unlike a mailbox based server, no sorting is required to get the messages out of the server in the same order they are sent.

First, you need a queue.

>>> try:
...     from queue import Empty, Queue
... except ImportError:
...     # Python 2
...     from Queue import Empty, Queue
>>> queue = Queue()

Then you need a server.

>>> from lazr.smtptest.server import QueueServer
>>> server = QueueServer('localhost', 9025, queue)

Finally, you need a controller.

>>> from lazr.smtptest.controller import Controller
>>> controller = Controller(server)

Now, start the SMTP server.

>>> controller.start()

Send the server a bunch of messages.

>>> import smtplib
>>> smtpd = smtplib.SMTP()
>>> code, helo = smtpd.connect('localhost', 9025)
>>> print(code, str(helo))
220 ... Python SMTP proxy version ...

>>> smtpd.sendmail('iperson@example.com', ['jperson@example.com'], """\
... From: Irie Person <iperson@example.com>
... To: Jeff Person <jperson@example.com>
... Subject: A test
... Message-ID: <elephant>
...
... This is a test.
... """)
{}

>>> smtpd.sendmail('kperson@example.com', ['lperson@example.com'], """\
... From: Kari Person <kperson@example.com>
... To: Liam Person <lperson@example.com>
... Subject: A test
... Message-ID: <falcon>
...
... This is a test.
... """)
{}

>>> smtpd.sendmail('mperson@example.com', ['nperson@example.com'], """\
... From: Mary Person <mperson@example.com>
... To: Neal Person <nperson@example.com>
... Subject: A test
... Message-ID: <goat>
...
... This is a test.
... """)
{}

All of these messages are available in the queue.

>>> while True:
...     try:
...         message = queue.get_nowait()
...     except Empty:
...         break
...     print(message['message-id'])
<elephant>
<falcon>
<goat>

We’re done with the controller.

>>> controller.stop()

Queue controller

An even more convenient interface, is to use the QueueController.

>>> from lazr.smtptest.controller import QueueController
>>> controller = QueueController('localhost', 9025)
>>> controller.start()

>>> smtpd = smtplib.SMTP()
>>> code, helo = smtpd.connect('localhost', 9025)
>>> print(code, str(helo))
220 ... Python SMTP proxy version ...

We now have an SMTP server that we can send some messages to.

>>> smtpd.sendmail('operson@example.com', ['pperson@example.com'], """\
... From: Onua Person <operson@example.com>
... To: Paul Person <pperson@example.com>
... Subject: A test
... Message-ID: <horse>
...
... This is a test.
... """)
{}

>>> smtpd.sendmail('qperson@example.com', ['rperson@example.com'], """\
... From: Quay Person <qperson@example.com>
... To: Raul Person <rperson@example.com>
... Subject: A test
... Message-ID: <iguana>
...
... This is a test.
... """)
{}

>>> smtpd.sendmail('sperson@example.com', ['tperson@example.com'], """\
... From: Sean Person <sperson@example.com>
... To: Thom Person <tperson@example.com>
... Subject: A test
... Message-ID: <jackel>
...
... This is a test.
... """)
{}

And we can dump out all the messages from the controller.

>>> for message in controller:
...     print(message['message-id'])
<horse>
<iguana>
<jackel>

We can send more messages and view them too.

>>> smtpd.sendmail('uperson@example.com', ['vperson@example.com'], """\
... From: Umma Person <uperson@example.com>
... To: Vern Person <vperson@example.com>
... Subject: A test
... Message-ID: <kangaroo>
...
... This is a test.
... """)
{}

>>> for message in controller:
...     print(message['message-id'])
<kangaroo>

Resetting

Queue servers support a RSET (reset) method, which empties the queue.

>>> smtpd.sendmail('wperson@example.com', ['xperson@example.com'], """\
... From: Wynn Person <wperson@example.com>
... To: Xerx Person <xperson@example.com>
... Subject: A test
... Message-ID: <llama>
...
... This is a test.
... """)
{}

>>> smtpd.sendmail('yperson@example.com', ['zperson@example.com'], """\
... From: Yikes Person <yperson@example.com>
... To: Zell Person <zperson@example.com>
... Subject: A test
... Message-ID: <moose>
...
... This is a test.
... """)
{}

>>> controller.queue.qsize()
2
>>> controller.reset()
>>> controller.queue.qsize()
0

Clean up

We’re done with this controller.

>>> controller.stop()