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--- fw:djangoadv [2014/06/02 16:58]
alfred [Signals in Django]
+++ fw:djangoadv [2020/05/09 09:25] (actual)
@@ Línea 103: / Línea 103: @@
 ==== Defining and sending signals ====
+Signals are ''django.dispatch.Signal([providing_args=list])'' instances. ''providing_args'' is a list of the names of arguments the signal will provide to listeners. To declare a ''pizza_done'' signal which provides receivers with toppics and size arguments:
+<code python>
+import django.dispatch
+pizza_done = django.dispatch.Signal(providing_args=["toppings", "size"])
+</code>
+To send a signal, call either ''Signal.send()'' or ''Signal.send_robust()''. Both return a list of tuple pairs ''[(receiver, response), ... ]''. They differ in how exceptions raised by receiver functions. ''send()'' does not catch any exceptions raised by receivers; it simply allows errors to propagate. Whereas ''send_robust()'' catches all errors derived from Python’s Exception class, and ensures all receivers are notified of the signal.
+<code python>
+class PizzaStore(object):
+    ...
+    def send_pizza(self, toppings, size):
+        pizza_done.send(sender=self.__class__, toppings=toppings, size=size)
+</code>
+To disconnect a receiver from a signal, call ''Signal.disconnect()''.

Programming