About tgext.mailer

tgext.mailer is a TurboGears2 extension for sending emails with transaction manager integration. Whenever the transaction manager provided with TurboGears commits the transaction all the emails are sent, when the transaction is abort the mails are discarded.

While there are other extensions available for sending emails on TurboGears, like TurboMail. Those are not bound to the transaction manager, have a more complex structure or are not actively maintained anymore. This lead to the birth of tgext.mailer.

tgext.mailer code is adapted from the pyramid_mailer project which uses repoze.sendmail to perform actual email delivery.

Installing

tgext.mailer can be installed from pypi:

pip install tgext.mailer

should just work for most of the users.

Enabling

To enable tgext.mailer put inside your application config/app_cfg.py the following:

import tgext.mailer
tgext.mailer.plugme(base_config)

or you can use tgext.pluggable when available:

from tgext.pluggable import plug
plug(base_config, 'tgext.mailer')

tgext.mailer will then load the options from your application configuration file, refer to the Configuration File Options section for a complete list of available options.

Sending Emails

Sending emails is performed through the mailer object, each request has its own mailer object, which is in charge of sending only the emails of that request. If you don't pass any request to the get_mailer call, the application wide mailer is returned (Do not use it inside a request):

from tgext.mailer import get_mailer
mailer = get_mailer(request)

To send a message, you must first create a tgext.mailer.message.Message instance:

from tgext.mailer import Message

message = Message(subject="hello world",
                  sender="admin@mysite.com",
                  recipients=["john.doe@gmail.com"],
                  body="Hi John!")

The Message is then passed to the Mailer instance. You can either send the message right away:

mailer.send(message)

or add it to your mail queue (a maildir on disk):

mailer.send_to_queue(message)

If you want to send the email without registering it on the transaction manager, to make sure it gets sent even in case of transaction failures, use:

mailer.send_immediately(message)

Configuration File Options

The available settings are listed below. Place them under [app:main] in your configuration *.ini file.

Setting	Default	Description
mail.debugmailer	False	Store emails on disk for debugging
mail.host	localhost	SMTP host
mail.port	25	SMTP port
mail.username	None	SMTP username
mail.password	None	SMTP password
mail.tls	False	Use TLS
mail.ssl	False	Use SSL
mail.keyfile	None	SSL key file
mail.certfile	None	SSL certificate file
mail.queue_path	None	Location of maildir
mail.default_sender	None	Default from address
mail.debug	0	SMTP debug level

In test units that have to check for sent email, make sure to set mail.debugmailer to "dummy" it will save outgoing emails in mailer.output instead of actually sending them.

Transactions

If you are using transaction management then tgext.mailer will only send the emails (or add them to the mail queue) when the transactions are committed.

For example:

import transaction

from tgext.mailer.mailer import Mailer
from tgext.mailer import Message

mailer = Mailer()
message = Message(subject="hello world",
                  sender="admin@mysite.com",
                  recipients=["john.doe@gmail.com"],
                  body="Hi John!")

mailer.send(message)
transaction.commit()

The email is not actually sent until the transaction is committed.

Usually TurboGears will automatically commit the transaction for your at the end of the request so you don't need to explicitly commit or abort within code that sends mail. Instead, if an exception is raised, the transaction will implicitly be aborted and mail will not be sent; otherwise it will be committed, and mail will be sent.

If you use the Application wide email manager it is usually best practice to only use send_immediately method, to avoid registering the same mail manager in multiple transactions.

Attachments

Attachments are added using the tgext.mailer.message.Attachment class:

from tgext.mailer import Attachment
from tgext.mailer import Message

message = Message()

photo_data = open("photo.jpg", "rb").read()
attachment = Attachment("photo.jpg", "image/jpg", photo_data)

message.attach(attachment)

You can pass the data either as a string or file object, so the above code could be rewritten:

from tgext.mailer import Attachment
from tgext.mailer import Message

message = Message()

attachment = Attachment("photo.jpg", "image/jpg",
                        open("photo.jpg", "rb"))

message.attach(attachment)

A transfer encoding can be specified via the transfer_encoding option. Supported options are currently base64 (the default) and quoted-printable.

You can also pass an attachment as the body and/or html arguments to specify Content-Transfer-Encoding or other Attachment attributes:

from tgext.mailer import Attachment
from tgext.mailer import Message

body = Attachment(data="hello, arthur",
                  transfer_encoding="quoted-printable")
html = Attachment(data="<p>hello, arthur</p>",
                  transfer_encoding="quoted-printable")
message = Message(body=body, html=html)