Django Debug Toolbar - Mail Panel

Testing and debugging e-mail while developing a Django app has never been pleasant. Sending e-mail to a file-based backend requires a user to click through obtusely-named files and does not provide a way to preview rendered HTML. Sending e-mail to a valid mailbox incurs a delay as the message is processed though a mail server, and clutters a developer's inbox.

The mail panel attempts to address these problems by providing a way to preview emails within the browser using django-debug-toolbar.

This mail panel is released under the Apache license. If you like it, please consider contributing!

Special thanks to @ShawnMilo for the code review.

Installation

To install the mail panel, first install this package with pip install django-mail-panel. Then add the mail_panel app after debug_toolbarto the INSTALLED_APPS setting:

INSTALLED_APPS = (
    ...
    'debug_toolbar',
    'mail_panel',
)

and add the panel DEBUG_TOOLBAR_PANELS:

DEBUG_TOOLBAR_PANELS = (
    ...
    'mail_panel.panels.MailToolbarPanel',
)

If you use the DEBUG_TOOLBAR_PANELS to custom order your panels:

    DEBUG_TOOLBAR_PANELS = [
        'debug_toolbar.panels.versions.VersionsPanel',
        'debug_toolbar.panels.timer.TimerPanel',
        'debug_toolbar.panels.settings.SettingsPanel',
        'debug_toolbar.panels.headers.HeadersPanel',
        'debug_toolbar.panels.request.RequestPanel',
        'debug_toolbar.panels.sql.SQLPanel',
        'debug_toolbar.panels.staticfiles.StaticFilesPanel',
        'debug_toolbar.panels.templates.TemplatesPanel',
        'debug_toolbar.panels.cache.CachePanel',
        'debug_toolbar.panels.signals.SignalsPanel',
        'debug_toolbar.panels.logging.LoggingPanel',
        'debug_toolbar.panels.redirects.RedirectsPanel',
        'mail_panel.panels.MailToolbarPanel',
    ]

Collect static and you'll be good to go.

./manage.py collectstatic

Configuration

After installation, you now need to redirect mail to the mail toolbar. Change your email backend to the following:

EMAIL_BACKEND = 'mail_panel.backend.MailToolbarBackend'

By default, mail toolbar stores messages for one day before removing them from cache. You can change this with the following setting:

MAIL_TOOLBAR_TTL = 86400  # 1 Day

Testing

To preview emails sent from your test suite, add the email backend override to your tests with the following:

from django.test.utils import override_settings

@override_settings(EMAIL_BACKEND='mail_panel.backend.MailToolbarBackend')
def test_send_email(self):
    # your code here

The backend works similarly to the standard email backend and code should not need to be reworked when using the MailToolbarBackend.

from django.core import mail

original_outbox = len(mail.outbox)
# Send mail ...
assert(len(mail.outbox) == original_outbox + 1)