Signals

Wagtail’s PageRevision and Page implement Signals from django.dispatch. Signals are useful for creating side-effects from page publish/unpublish events.

For example, you could use signals to send publish notifications to a messaging service, or POST messages to another app that’s consuming the API, such as a static site generator.

page_published

This signal is emitted from a PageRevision when a revision is set to published.

sender:The page class instance:The specific Page instance. revision:The PageRevision that was published kwargs:Any other arguments passed to page_published.send().

To listen to a signal, implement page_published.connect(receiver, sender, **kwargs). Here’s a simple example showing how you might notify your team when something is published:

from wagtail.core.signals import page_published
import urllib
import urllib2


# Let everyone know when a new page is published
def send_to_slack(sender, **kwargs):
    instance = kwargs['instance']
    url = 'https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX'
    values = {
        "text" : "%s was published by %s " % (instance.title, instance.owner.username),
        "channel": "#publish-notifications",
        "username": "the squid of content",
        "icon_emoji": ":octopus:"
    }

    data = urllib.urlencode(values)
    req = urllib2.Request(url, data)
    response = urllib2.urlopen(req)

# Register a receiver
page_published.connect(send_to_slack)

Receiving specific model events

Sometimes you’re not interested in receiving signals for every model, or you want to handle signals for specific models in different ways. For instance, you may wish to do something when a new blog post is published:

from wagtail.core.signals import page_published
from mysite.models import BlogPostPage

# Do something clever for each model type
def receiver(sender, **kwargs):
    # Do something with blog posts
    pass

# Register listeners for each page model class
page_published.connect(receiver, sender=BlogPostPage)

Wagtail provides access to a list of registered page types through the get_page_models() function in wagtail.core.models.

Read the Django documentation for more information about specifying senders.

page_unpublished

This signal is emitted from a Page when the page is unpublished.

sender:The page class instance:The specific Page instance. kwargs:Any other arguments passed to page_unpublished.send()