django.dispatch.dispatcher.Signal

class documentation

class Signal:

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Base class for all signals

Internal attributes:

receivers
{ receiverkey (id) : weakref(receiver) }
Method __init__ Create a new signal.
Method ​_clear​_dead​_receivers Undocumented
Method ​_live​_receivers Filter sequence of receivers to get resolved, live receivers.
Method ​_remove​_receiver Undocumented
Method connect Connect receiver to sender for signal.
Method disconnect Disconnect receiver from sender for signal.
Method has​_listeners Undocumented
Method send Send signal from sender to all connected receivers.
Method send​_robust Send signal from sender to all connected receivers catching errors.
Instance Variable ​_dead​_receivers Undocumented
Instance Variable lock Undocumented
Instance Variable receivers Undocumented
Instance Variable sender​_receivers​_cache Undocumented
Instance Variable use​_caching Undocumented
def __init__(self, use_caching=False):
Create a new signal.
def _clear_dead_receivers(self):

Undocumented

def _live_receivers(self, sender):

Filter sequence of receivers to get resolved, live receivers.

This checks for weak references and resolves them, then returning only live receivers.

def _remove_receiver(self, receiver=None):

Undocumented

def connect(self, receiver, sender=None, weak=True, dispatch_uid=None):

Connect receiver to sender for signal.

Arguments:

receiver

A function or an instance method which is to receive signals. Receivers must be hashable objects.

If weak is True, then receiver must be weak referenceable.

Receivers must be able to accept keyword arguments.

If a receiver is connected with a dispatch_uid argument, it will not be added if another receiver was already connected with that dispatch_uid.

sender
The sender to which the receiver should respond. Must either be a Python object, or None to receive events from any sender.
weak
Whether to use weak references to the receiver. By default, the module will attempt to use weak references to the receiver objects. If this parameter is false, then strong references will be used.
dispatch_uid
An identifier used to uniquely identify a particular instance of a receiver. This will usually be a string, though it may be anything hashable.
def disconnect(self, receiver=None, sender=None, dispatch_uid=None):

Disconnect receiver from sender for signal.

If weak references are used, disconnect need not be called. The receiver will be removed from dispatch automatically.

Arguments:

receiver
The registered receiver to disconnect. May be none if dispatch_uid is specified.
sender
The registered sender to disconnect
dispatch_uid
the unique identifier of the receiver to disconnect
def has_listeners(self, sender=None):

Undocumented

def send(self, sender, **named):

Send signal from sender to all connected receivers.

If any receiver raises an error, the error propagates back through send, terminating the dispatch loop. So it's possible that all receivers won't be called if an error is raised.

Arguments:

sender
The sender of the signal. Either a specific object or None.
named
Named arguments which will be passed to receivers.

Return a list of tuple pairs [(receiver, response), ... ].

def send_robust(self, sender, **named):

Send signal from sender to all connected receivers catching errors.

Arguments:

sender
The sender of the signal. Can be any Python object (normally one registered with a connect if you actually want something to occur).
named
Named arguments which will be passed to receivers.

Return a list of tuple pairs [(receiver, response), ... ].

If any receiver raises an error (specifically any subclass of Exception), return the error instance as the result for that receiver.

_dead_receivers: bool =

Undocumented

lock =

Undocumented

receivers =

Undocumented

sender_receivers_cache =

Undocumented

use_caching =

Undocumented