-
Notifications
You must be signed in to change notification settings - Fork 16
/
__init__.py
430 lines (314 loc) · 13 KB
/
__init__.py
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
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
import copy
import collections
from itertools import chain
from django.core.exceptions import ValidationError
from django.db import models, transaction
from django.db.models.base import ModelBase
from django.utils.translation import ugettext_lazy as _
from django.utils.encoding import force_text
from chamber.exceptions import PersistenceException
from chamber.patch import Options
from chamber.shortcuts import change_and_save, change, bulk_change_and_save
from .fields import * # NOQA exposing classes and functions as a module API
from .signals import dispatcher_post_save, dispatcher_pre_save
def many_to_many_field_to_dict(field, instance):
if instance.pk is None:
# If the object doesn't have a primary key yet, just use an empty
# list for its m2m fields. Calling f.value_from_object will raise
# an exception.
return []
else:
# MultipleChoiceWidget needs a list of pks, not object instances.
return list(field.value_from_object(instance).values_list('pk', flat=True))
def should_exclude_field(field, fields, exclude):
return (fields and field.name not in fields) or (exclude and field.name in exclude)
def field_to_dict(field, instance):
"""
Converts a model field to a dictionary
"""
# avoid a circular import
from django.db.models.fields.related import ManyToManyField
return (many_to_many_field_to_dict(field, instance) if isinstance(field, ManyToManyField)
else field.value_from_object(instance))
def model_to_dict(instance, fields=None, exclude=None):
"""
The same implementation as django model_to_dict but editable fields are allowed
"""
return {
field.name: field_to_dict(field, instance)
for field in chain(instance._meta.concrete_fields, instance._meta.many_to_many) # pylint: disable=W0212
if not should_exclude_field(field, fields, exclude)
}
ValueChange = collections.namedtuple('ValueChange', ('initial', 'current'))
class ChangedFields:
"""
Class stores changed fields and its initial and current values.
"""
def __init__(self, initial_dict):
self._initial_dict = initial_dict
@property
def initial_values(self):
return self._initial_dict
@property
def current_values(self):
raise NotImplementedError
@property
def diff(self):
d1 = self.initial_values
d2 = self.current_values
return {k: ValueChange(v, d2[k]) for k, v in d1.items() if v != d2[k]}
def __setitem__(self, key, item):
raise AttributeError('Object is readonly')
def __getitem__(self, key):
return self.diff[key]
def __repr__(self):
return repr(self.diff)
def __len__(self):
return len(self.diff)
def __delitem__(self, key):
raise AttributeError('Object is readonly')
def clear(self):
raise AttributeError('Object is readonly')
def has_key(self, k):
return k in self.diff
def has_any_key(self, *keys):
return bool(set(self.keys()) & set(keys))
def update(self, *args, **kwargs):
raise AttributeError('Object is readonly')
def keys(self):
return self.diff.keys()
def values(self):
return self.diff.values()
def items(self):
return self.diff.items()
def pop(self, *args, **kwargs):
raise AttributeError('Object is readonly')
def __cmp__(self, dictionary):
return cmp(self.diff, dictionary)
def __contains__(self, item):
return item in self.diff
def __iter__(self):
return iter(self.diff)
def __str__(self):
return repr(self.diff)
class DynamicChangedFields(ChangedFields):
"""
Dynamic changed fields are changed with the instance changes.
"""
def __init__(self, instance):
super(DynamicChangedFields, self).__init__(self._get_instance_dict(instance))
self.instance = instance
def _get_instance_dict(self, instance):
return model_to_dict(instance, fields=(field.name for field in instance._meta.fields))
@property
def current_values(self):
return self._get_instance_dict(self.instance)
def get_static_changes(self):
return StaticChangedFields(self.initial_values, self.current_values)
class StaticChangedFields(ChangedFields):
"""
Static changed fields are immutable. The origin instance changes will not have an affect.
"""
def __init__(self, initial_dict, current_dict):
super(StaticChangedFields, self).__init__(initial_dict)
self._current_dict = current_dict
@property
def current_values(self):
return self._current_dict
class ComparableModelMixin:
def equals(self, obj, comparator):
"""
Use comparator for evaluating if objects are the same
"""
return comparator.compare(self, obj)
class Comparator:
def compare(self, a, b):
"""
Return True if objects are same otherwise False
"""
raise NotImplementedError
class AuditModel(models.Model):
created_at = models.DateTimeField(verbose_name=_('created at'), null=False, blank=False, auto_now_add=True,
db_index=True)
changed_at = models.DateTimeField(verbose_name=_('changed at'), null=False, blank=False, auto_now=True,
db_index=True)
class Meta:
abstract = True
class Signal:
def __init__(self, obj):
self.connected_functions = []
self.obj = obj
def connect(self, fun):
self.connected_functions.append(fun)
def send(self):
[fun(self.obj) for fun in self.connected_functions]
class SmartQuerySet(models.QuerySet):
def fast_distinct(self):
"""
Because standard distinct used on the all fields are very slow and works only with PostgreSQL database
this method provides alternative to the standard distinct method.
:return: qs with unique objects
"""
return self.model.objects.filter(pk__in=self.values_list('pk', flat=True))
def change_and_save(self, **chaned_fields):
"""
Changes a given `changed_fields` on each object in the queryset, saves objects
and returns the changed objects in the queryset.
"""
bulk_change_and_save(self, **chaned_fields)
return self.filter()
class SmartModelBase(ModelBase):
"""
Smart model meta class that register dispatchers to the post or pre save signals.
"""
def __new__(cls, name, bases, attrs):
new_cls = super(SmartModelBase, cls).__new__(cls, name, bases, attrs)
for dispatcher in new_cls.dispatchers:
dispatcher.connect(new_cls)
return new_cls
class SmartModel(AuditModel, metaclass=SmartModelBase):
objects = SmartQuerySet.as_manager()
dispatchers = []
def __init__(self, *args, **kwargs):
super(SmartModel, self).__init__(*args, **kwargs)
self.changed_fields = DynamicChangedFields(self)
self.post_save = Signal(self)
@property
def has_changed(self):
return bool(self.changed_fields)
@property
def initial_values(self):
return self.changed_fields.initial_values
def full_clean(self, exclude=None, *args, **kwargs):
errors = {}
for field in self._meta.fields:
if (not exclude or field.name not in exclude) and hasattr(self, 'clean_{}'.format(field.name)):
try:
getattr(self, 'clean_{}'.format(field.name))()
except ValidationError as er:
errors[field.name] = er
if errors:
raise ValidationError(errors)
super(SmartModel, self).full_clean(exclude=exclude, *args, **kwargs)
def _clean_save(self, *args, **kwargs):
self._persistence_clean(*args, **kwargs)
def _clean_delete(self, *args, **kwargs):
self._persistence_clean(*args, **kwargs)
def _clean_pre_save(self, *args, **kwargs):
self._clean_save(*args, **kwargs)
def _clean_pre_delete(self, *args, **kwargs):
self._clean_delete(*args, **kwargs)
def _clean_post_save(self, *args, **kwargs):
self._clean_save(*args, **kwargs)
def _clean_post_delete(self, *args, **kwargs):
self._clean_delete(*args, **kwargs)
def _persistence_clean(self, *args, **kwargs):
exclude = kwargs.pop('exclude', None)
try:
self.full_clean(exclude=exclude)
except ValidationError as er:
if hasattr(er, 'error_dict'):
raise PersistenceException(', '.join(
('%s: %s' % (key, ', '.join(map(force_text, val))) for key, val in er.message_dict.items())))
else:
raise PersistenceException(', '.join(map(force_text, er.messages)))
def _get_save_extra_kwargs(self):
return {}
def _pre_save(self, *args, **kwargs):
pass
def _call_pre_save(self, *args, **kwargs):
self._pre_save(*args, **kwargs)
def _save(self, is_cleaned_pre_save=None, is_cleaned_post_save=None, force_insert=False, force_update=False,
using=None, update_fields=None, *args, **kwargs):
is_cleaned_pre_save = (
self._smart_meta.is_cleaned_pre_save if is_cleaned_pre_save is None else is_cleaned_pre_save
)
is_cleaned_post_save = (
self._smart_meta.is_cleaned_post_save if is_cleaned_post_save is None else is_cleaned_post_save
)
origin = self.__class__
change = not self._state.adding
kwargs.update(self._get_save_extra_kwargs())
self._call_pre_save(change, self.changed_fields, *args, **kwargs)
if is_cleaned_pre_save:
self._clean_pre_save(*args, **kwargs)
dispatcher_pre_save.send(sender=origin, instance=self, change=change,
changed_fields=self.changed_fields.get_static_changes(),
*args, **kwargs)
super(SmartModel, self).save(force_insert=force_insert, force_update=force_update, using=using,
update_fields=update_fields)
self._call_post_save(change, self.changed_fields, *args, **kwargs)
if is_cleaned_post_save:
self._clean_post_save(*args, **kwargs)
dispatcher_post_save.send(sender=origin, instance=self, change=change,
changed_fields=self.changed_fields.get_static_changes(),
*args, **kwargs)
self.post_save.send()
def _post_save(self, *args, **kwargs):
pass
def _call_post_save(self, *args, **kwargs):
self._post_save(*args, **kwargs)
def save(self, *args, **kwargs):
if self._smart_meta.is_save_atomic:
with transaction.atomic():
self._save(*args, **kwargs)
else:
self._save(*args, **kwargs)
self.changed_fields = DynamicChangedFields(self)
def _pre_delete(self, *args, **kwargs):
pass
def _delete(self, is_cleaned_pre_delete=None, is_cleaned_post_delete=None, *args, **kwargs):
is_cleaned_pre_delete = (
self._smart_meta.is_cleaned_pre_delete if is_cleaned_pre_delete is None else is_cleaned_pre_delete
)
is_cleaned_post_delete = (
self._smart_meta.is_cleaned_post_delete if is_cleaned_post_delete is None else is_cleaned_post_delete
)
self._pre_delete(*args, **kwargs)
if is_cleaned_pre_delete:
self._clean_pre_delete(*args, **kwargs)
super(SmartModel, self).delete(*args, **kwargs)
self._post_delete(*args, **kwargs)
if is_cleaned_post_delete:
self._clean_post_delete(*args, **kwargs)
def _post_delete(self, *args, **kwargs):
pass
def delete(self, *args, **kwargs):
if self._smart_meta.is_delete_atomic:
with transaction.atomic():
self._delete(*args, **kwargs)
else:
self._delete(*args, **kwargs)
def refresh_from_db(self, *args, **kwargs):
super().refresh_from_db(*args, **kwargs)
return self
def change(self, **changed_fields):
"""
Changes a given `changed_fields` on this object and returns itself.
:param changed_fields: fields to change
:return: self
"""
change(self, **changed_fields)
return self
def change_and_save(self, **changed_fields):
"""
Changes a given `changed_fields` on this object, saves it and returns itself.
:param changed_fields: fields to change
:return: self
"""
change_and_save(self, **changed_fields)
return self
class Meta:
abstract = True
class SmartOptions(Options):
meta_class_name = 'SmartMeta'
meta_name = '_smart_meta'
model_class = SmartModel
attributes = {
'is_cleaned_pre_save': True,
'is_cleaned_post_save': False,
'is_cleaned_pre_delete': False,
'is_cleaned_post_delete': False,
'is_save_atomic': False,
'is_delete_atomic': False,
}