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API Documentation

All public API members can (and should) be imported from blinker:

from blinker import ANY, signal

Basic Signals

base.ANY
Token for “any sender”.
base.receiver_connected

Sent by a Signal after a receiver connects.

Argument:

the Signal that was connected to
Parameters:
  • receiver_arg – the connected receiver
  • sender_arg – the sender to connect to
  • weak_arg – true if the connection to receiver_arg is a weak reference
class blinker.base.Signal(doc=None)

A notification emitter.

Parameter:doc – optional. If provided, will be assigned to the signal’s __doc__ attribute.
ANY
An ANY convenience synonym, allows Signal.ANY without an additional import.
receivers

A mapping of connected receivers.

The values of this mapping are not meaningful outside of the internal Signal implementation, however the boolean value of the mapping is useful as an extremely efficient check to see if any receivers are connected to the signal.

connect(receiver, sender=ANY, weak=True)

Connect receiver to signal events sent by sender.

Parameters:
  • receiver – A callable. Will be invoked by send() with sender= as a single positional argument and any **kwargs that were provided to a call to send().
  • sender – Any object or ANY, defaults to ANY. Restricts notifications delivered to receiver to only those send() emissions sent by sender. If ANY, the receiver will always be notified. A receiver may be connected to multiple sender values on the same Signal through multiple calls to connect().
  • weak – If true, the Signal will hold a weakref to receiver and automatically disconnect when receiver goes out of scope or is garbage collected. Defaults to True.
disconnect(receiver, sender=ANY)

Disconnect receiver from this signal’s events.

Parameters:
  • receiver – a previously connected callable
  • sender – a specific sender to disconnect from, or ANY to disconnect from all senders. Defaults to ANY.
has_receivers_for(sender)

True if there is probably a receiver for sender.

Performs an optimistic check only. Does not guarantee that all weakly referenced receivers are still alive. See receivers_for() for a stronger search.

receivers_for(sender)
Iterate all live receivers listening for sender.
send(*sender, **kwargs)

Emit this signal on behalf of sender, passing on **kwargs.

Returns a list of 2-tuples, pairing receivers with their return value. The ordering of receiver notification is undefined.

Parameters:
  • *sender – Any object or None. If omitted, synonymous with None. Only accepts one positional argument.
  • **kwargs – Data to be sent to receivers.

Named Signals

blinker.base.signal(name, doc=None)

Return the NamedSignal name, creating it if required.

Repeated calls to this function will return the same signal object. Signals are created in a global Namespace.

class blinker.base.NamedSignal(name, doc=None)

Bases: blinker.base.Signal

A named generic notification emitter.

name
The name of this signal.
class blinker.base.Namespace(*args, **kw)

Bases: weakref.WeakValueDictionary

A mapping of signal names to signals.

signal(name, doc=None)

Return the NamedSignal name, creating it if required.

Repeated calls to this function will return the same signal object.