1from datetime import datetime
2
3from django.conf import settings
4from django.db.models.expressions import Func
5from django.db.models.fields import (
6 DateField,
7 DateTimeField,
8 DurationField,
9 Field,
10 IntegerField,
11 TimeField,
12)
13from django.db.models.lookups import (
14 Transform,
15 YearExact,
16 YearGt,
17 YearGte,
18 YearLt,
19 YearLte,
20)
21from django.utils import timezone
22
23
24class TimezoneMixin:
25 tzinfo = None
26
27 def get_tzname(self):
28 # Timezone conversions must happen to the input datetime *before*
29 # applying a function. 2015-12-31 23:00:00 -02:00 is stored in the
30 # database as 2016-01-01 01:00:00 +00:00. Any results should be
31 # based on the input datetime not the stored datetime.
32 tzname = None
33 if settings.USE_TZ:
34 if self.tzinfo is None:
35 tzname = timezone.get_current_timezone_name()
36 else:
37 tzname = timezone._get_timezone_name(self.tzinfo)
38 return tzname
39
40
41class Extract(TimezoneMixin, Transform):
42 lookup_name = None
43 output_field = IntegerField()
44
45 def __init__(self, expression, lookup_name=None, tzinfo=None, **extra):
46 if self.lookup_name is None:
47 self.lookup_name = lookup_name
48 if self.lookup_name is None:
49 raise ValueError("lookup_name must be provided")
50 self.tzinfo = tzinfo
51 super().__init__(expression, **extra)
52
53 def as_sql(self, compiler, connection):
54 sql, params = compiler.compile(self.lhs)
55 lhs_output_field = self.lhs.output_field
56 if isinstance(lhs_output_field, DateTimeField):
57 tzname = self.get_tzname()
58 sql, params = connection.ops.datetime_extract_sql(
59 self.lookup_name, sql, tuple(params), tzname
60 )
61 elif self.tzinfo is not None:
62 raise ValueError("tzinfo can only be used with DateTimeField.")
63 elif isinstance(lhs_output_field, DateField):
64 sql, params = connection.ops.date_extract_sql(
65 self.lookup_name, sql, tuple(params)
66 )
67 elif isinstance(lhs_output_field, TimeField):
68 sql, params = connection.ops.time_extract_sql(
69 self.lookup_name, sql, tuple(params)
70 )
71 elif isinstance(lhs_output_field, DurationField):
72 if not connection.features.has_native_duration_field:
73 raise ValueError(
74 "Extract requires native DurationField database support."
75 )
76 sql, params = connection.ops.time_extract_sql(
77 self.lookup_name, sql, tuple(params)
78 )
79 else:
80 # resolve_expression has already validated the output_field so this
81 # assert should never be hit.
82 assert False, "Tried to Extract from an invalid type."
83 return sql, params
84
85 def resolve_expression(
86 self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False
87 ):
88 copy = super().resolve_expression(
89 query, allow_joins, reuse, summarize, for_save
90 )
91 field = getattr(copy.lhs, "output_field", None)
92 if field is None:
93 return copy
94 if not isinstance(field, (DateField, DateTimeField, TimeField, DurationField)):
95 raise ValueError(
96 "Extract input expression must be DateField, DateTimeField, "
97 "TimeField, or DurationField."
98 )
99 # Passing dates to functions expecting datetimes is most likely a mistake.
100 if type(field) is DateField and copy.lookup_name in (
101 "hour",
102 "minute",
103 "second",
104 ):
105 raise ValueError(
106 "Cannot extract time component '%s' from DateField '%s'."
107 % (copy.lookup_name, field.name)
108 )
109 if isinstance(field, DurationField) and copy.lookup_name in (
110 "year",
111 "iso_year",
112 "month",
113 "week",
114 "week_day",
115 "iso_week_day",
116 "quarter",
117 ):
118 raise ValueError(
119 "Cannot extract component '%s' from DurationField '%s'."
120 % (copy.lookup_name, field.name)
121 )
122 return copy
123
124
125class ExtractYear(Extract):
126 lookup_name = "year"
127
128
129class ExtractIsoYear(Extract):
130 """Return the ISO-8601 week-numbering year."""
131
132 lookup_name = "iso_year"
133
134
135class ExtractMonth(Extract):
136 lookup_name = "month"
137
138
139class ExtractDay(Extract):
140 lookup_name = "day"
141
142
143class ExtractWeek(Extract):
144 """
145 Return 1-52 or 53, based on ISO-8601, i.e., Monday is the first of the
146 week.
147 """
148
149 lookup_name = "week"
150
151
152class ExtractWeekDay(Extract):
153 """
154 Return Sunday=1 through Saturday=7.
155
156 To replicate this in Python: (mydatetime.isoweekday() % 7) + 1
157 """
158
159 lookup_name = "week_day"
160
161
162class ExtractIsoWeekDay(Extract):
163 """Return Monday=1 through Sunday=7, based on ISO-8601."""
164
165 lookup_name = "iso_week_day"
166
167
168class ExtractQuarter(Extract):
169 lookup_name = "quarter"
170
171
172class ExtractHour(Extract):
173 lookup_name = "hour"
174
175
176class ExtractMinute(Extract):
177 lookup_name = "minute"
178
179
180class ExtractSecond(Extract):
181 lookup_name = "second"
182
183
184DateField.register_lookup(ExtractYear)
185DateField.register_lookup(ExtractMonth)
186DateField.register_lookup(ExtractDay)
187DateField.register_lookup(ExtractWeekDay)
188DateField.register_lookup(ExtractIsoWeekDay)
189DateField.register_lookup(ExtractWeek)
190DateField.register_lookup(ExtractIsoYear)
191DateField.register_lookup(ExtractQuarter)
192
193TimeField.register_lookup(ExtractHour)
194TimeField.register_lookup(ExtractMinute)
195TimeField.register_lookup(ExtractSecond)
196
197DateTimeField.register_lookup(ExtractHour)
198DateTimeField.register_lookup(ExtractMinute)
199DateTimeField.register_lookup(ExtractSecond)
200
201ExtractYear.register_lookup(YearExact)
202ExtractYear.register_lookup(YearGt)
203ExtractYear.register_lookup(YearGte)
204ExtractYear.register_lookup(YearLt)
205ExtractYear.register_lookup(YearLte)
206
207ExtractIsoYear.register_lookup(YearExact)
208ExtractIsoYear.register_lookup(YearGt)
209ExtractIsoYear.register_lookup(YearGte)
210ExtractIsoYear.register_lookup(YearLt)
211ExtractIsoYear.register_lookup(YearLte)
212
213
214class Now(Func):
215 template = "CURRENT_TIMESTAMP"
216 output_field = DateTimeField()
217
218 def as_postgresql(self, compiler, connection, **extra_context):
219 # PostgreSQL's CURRENT_TIMESTAMP means "the time at the start of the
220 # transaction". Use STATEMENT_TIMESTAMP to be cross-compatible with
221 # other databases.
222 return self.as_sql(
223 compiler, connection, template="STATEMENT_TIMESTAMP()", **extra_context
224 )
225
226 def as_mysql(self, compiler, connection, **extra_context):
227 return self.as_sql(
228 compiler, connection, template="CURRENT_TIMESTAMP(6)", **extra_context
229 )
230
231 def as_sqlite(self, compiler, connection, **extra_context):
232 return self.as_sql(
233 compiler,
234 connection,
235 template="STRFTIME('%%%%Y-%%%%m-%%%%d %%%%H:%%%%M:%%%%f', 'NOW')",
236 **extra_context,
237 )
238
239 def as_oracle(self, compiler, connection, **extra_context):
240 return self.as_sql(
241 compiler, connection, template="LOCALTIMESTAMP", **extra_context
242 )
243
244
245class TruncBase(TimezoneMixin, Transform):
246 kind = None
247 tzinfo = None
248
249 def __init__(
250 self,
251 expression,
252 output_field=None,
253 tzinfo=None,
254 **extra,
255 ):
256 self.tzinfo = tzinfo
257 super().__init__(expression, output_field=output_field, **extra)
258
259 def as_sql(self, compiler, connection):
260 sql, params = compiler.compile(self.lhs)
261 tzname = None
262 if isinstance(self.lhs.output_field, DateTimeField):
263 tzname = self.get_tzname()
264 elif self.tzinfo is not None:
265 raise ValueError("tzinfo can only be used with DateTimeField.")
266 if isinstance(self.output_field, DateTimeField):
267 sql, params = connection.ops.datetime_trunc_sql(
268 self.kind, sql, tuple(params), tzname
269 )
270 elif isinstance(self.output_field, DateField):
271 sql, params = connection.ops.date_trunc_sql(
272 self.kind, sql, tuple(params), tzname
273 )
274 elif isinstance(self.output_field, TimeField):
275 sql, params = connection.ops.time_trunc_sql(
276 self.kind, sql, tuple(params), tzname
277 )
278 else:
279 raise ValueError(
280 "Trunc only valid on DateField, TimeField, or DateTimeField."
281 )
282 return sql, params
283
284 def resolve_expression(
285 self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False
286 ):
287 copy = super().resolve_expression(
288 query, allow_joins, reuse, summarize, for_save
289 )
290 field = copy.lhs.output_field
291 # DateTimeField is a subclass of DateField so this works for both.
292 if not isinstance(field, (DateField, TimeField)):
293 raise TypeError(
294 "%r isn't a DateField, TimeField, or DateTimeField." % field.name
295 )
296 # If self.output_field was None, then accessing the field will trigger
297 # the resolver to assign it to self.lhs.output_field.
298 if not isinstance(copy.output_field, (DateField, DateTimeField, TimeField)):
299 raise ValueError(
300 "output_field must be either DateField, TimeField, or DateTimeField"
301 )
302 # Passing dates or times to functions expecting datetimes is most
303 # likely a mistake.
304 class_output_field = (
305 self.__class__.output_field
306 if isinstance(self.__class__.output_field, Field)
307 else None
308 )
309 output_field = class_output_field or copy.output_field
310 has_explicit_output_field = (
311 class_output_field or field.__class__ is not copy.output_field.__class__
312 )
313 if type(field) is DateField and (
314 isinstance(output_field, DateTimeField)
315 or copy.kind in ("hour", "minute", "second", "time")
316 ):
317 raise ValueError(
318 "Cannot truncate DateField '%s' to %s."
319 % (
320 field.name,
321 (
322 output_field.__class__.__name__
323 if has_explicit_output_field
324 else "DateTimeField"
325 ),
326 )
327 )
328 elif isinstance(field, TimeField) and (
329 isinstance(output_field, DateTimeField)
330 or copy.kind in ("year", "quarter", "month", "week", "day", "date")
331 ):
332 raise ValueError(
333 "Cannot truncate TimeField '%s' to %s."
334 % (
335 field.name,
336 (
337 output_field.__class__.__name__
338 if has_explicit_output_field
339 else "DateTimeField"
340 ),
341 )
342 )
343 return copy
344
345 def convert_value(self, value, expression, connection):
346 if isinstance(self.output_field, DateTimeField):
347 if not settings.USE_TZ:
348 pass
349 elif value is not None:
350 value = value.replace(tzinfo=None)
351 value = timezone.make_aware(value, self.tzinfo)
352 elif not connection.features.has_zoneinfo_database:
353 raise ValueError(
354 "Database returned an invalid datetime value. Are time "
355 "zone definitions for your database installed?"
356 )
357 elif isinstance(value, datetime):
358 if value is None:
359 pass
360 elif isinstance(self.output_field, DateField):
361 value = value.date()
362 elif isinstance(self.output_field, TimeField):
363 value = value.time()
364 return value
365
366
367class Trunc(TruncBase):
368 def __init__(
369 self,
370 expression,
371 kind,
372 output_field=None,
373 tzinfo=None,
374 **extra,
375 ):
376 self.kind = kind
377 super().__init__(expression, output_field=output_field, tzinfo=tzinfo, **extra)
378
379
380class TruncYear(TruncBase):
381 kind = "year"
382
383
384class TruncQuarter(TruncBase):
385 kind = "quarter"
386
387
388class TruncMonth(TruncBase):
389 kind = "month"
390
391
392class TruncWeek(TruncBase):
393 """Truncate to midnight on the Monday of the week."""
394
395 kind = "week"
396
397
398class TruncDay(TruncBase):
399 kind = "day"
400
401
402class TruncDate(TruncBase):
403 kind = "date"
404 lookup_name = "date"
405 output_field = DateField()
406
407 def as_sql(self, compiler, connection):
408 # Cast to date rather than truncate to date.
409 sql, params = compiler.compile(self.lhs)
410 tzname = self.get_tzname()
411 return connection.ops.datetime_cast_date_sql(sql, tuple(params), tzname)
412
413
414class TruncTime(TruncBase):
415 kind = "time"
416 lookup_name = "time"
417 output_field = TimeField()
418
419 def as_sql(self, compiler, connection):
420 # Cast to time rather than truncate to time.
421 sql, params = compiler.compile(self.lhs)
422 tzname = self.get_tzname()
423 return connection.ops.datetime_cast_time_sql(sql, tuple(params), tzname)
424
425
426class TruncHour(TruncBase):
427 kind = "hour"
428
429
430class TruncMinute(TruncBase):
431 kind = "minute"
432
433
434class TruncSecond(TruncBase):
435 kind = "second"
436
437
438DateTimeField.register_lookup(TruncDate)
439DateTimeField.register_lookup(TruncTime)