Falcon supports before and after hooks. You install a hook simply by applying one of the decorators below, either to an individual responder or to an entire resource.
For example, consider this hook that validates a POST request for an image resource:
def validate_image_type(req, resp, resource, params):
if req.content_type not in ALLOWED_IMAGE_TYPES:
msg = 'Image type not allowed. Must be PNG, JPEG, or GIF'
raise falcon.HTTPBadRequest('Bad request', msg)
You would attach this hook to an on_post
responder like so:
@falcon.before(validate_image_type)
def on_post(self, req, resp):
pass
Or, suppose you had a hook that you would like to apply to all responders for a given resource. In that case, you would simply decorate the resource class:
@falcon.before(extract_project_id)
class Message(object):
def on_post(self, req, resp):
pass
def on_get(self, req, resp):
pass
Falcon middleware components <middleware>
can also be used to insert logic before and after requests. However, unlike hooks, middleware components <middleware>
are triggered globally for all requests.
falcon