1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
from django.apps import apps
from django.dispatch import Signal
from django.utils import six
class_prepared = Signal(providing_args=["class"])
class ModelSignal(Signal):
"""
Signal subclass that allows the sender to be lazily specified as a string
of the `app_label.ModelName` form.
"""
def __init__(self, *args, **kwargs):
super(ModelSignal, self).__init__(*args, **kwargs)
self.unresolved_references = {}
class_prepared.connect(self._resolve_references)
def _resolve_references(self, sender, **kwargs):
opts = sender._meta
reference = (opts.app_label, opts.object_name)
try:
receivers = self.unresolved_references.pop(reference)
except KeyError:
pass
else:
for receiver, weak, dispatch_uid in receivers:
super(ModelSignal, self).connect(
receiver, sender=sender, weak=weak, dispatch_uid=dispatch_uid
)
def connect(self, receiver, sender=None, weak=True, dispatch_uid=None):
if isinstance(sender, six.string_types):
try:
app_label, model_name = sender.split('.')
except ValueError:
raise ValueError(
"Specified sender must either be a model or a "
"model name of the 'app_label.ModelName' form."
)
try:
sender = apps.get_registered_model(app_label, model_name)
except LookupError:
ref = (app_label, model_name)
refs = self.unresolved_references.setdefault(ref, [])
refs.append((receiver, weak, dispatch_uid))
return
super(ModelSignal, self).connect(
receiver, sender=sender, weak=weak, dispatch_uid=dispatch_uid
)
pre_init = ModelSignal(providing_args=["instance", "args", "kwargs"], use_caching=True)
post_init = ModelSignal(providing_args=["instance"], use_caching=True)
pre_save = ModelSignal(providing_args=["instance", "raw", "using", "update_fields"],
use_caching=True)
post_save = ModelSignal(providing_args=["instance", "raw", "created", "using", "update_fields"], use_caching=True)
pre_delete = ModelSignal(providing_args=["instance", "using"], use_caching=True)
post_delete = ModelSignal(providing_args=["instance", "using"], use_caching=True)
m2m_changed = ModelSignal(
providing_args=["action", "instance", "reverse", "model", "pk_set", "using"],
use_caching=True,
)
pre_migrate = Signal(providing_args=["app_config", "verbosity", "interactive", "using"])
post_migrate = Signal(providing_args=["app_config", "verbosity", "interactive", "using"])
|