Webhooks allow to register an url to a specific event (or alls) and the event will be posted on this URL. Each events can triger a post on a given url.
for example to listen all create events on http://echohttp.com/echo you can add this line in the webhooks sections of the gaffer setting file:
[webhooks]
create = http://echohttp.com/echo you
Or programatically:
from gaffer.manager import Manager
from gaffer.webhooks import WebHooks
hooks = [("create", "http://echohttp.com/echo you ")
webhooks = WebHooks(hooks=hooks)
manager = Manager()
manager.start(apps=[webhooks])
This gaffer application is started like other applications in the manager. All Gaffer events are supported.