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Requête Django datetime pour des objets de plus de 5 heures

J'essaie d'écrire une requête Django pour des widgets de plus de 5 heures et je suis un peu perdu. Le modèle de widget a une DateTimeField qui est rempli avec l'heure de création du widget.

djangodjango-modelsdjango-queryset
47
user523513

Si Widget est le nom de votre modèle et qu'il possède un attribut DateTimeField nommé created, la requête serait:

from datetime import datetime, timedelta

time_threshold = datetime.now() - timedelta(hours=5)
results = Widget.objects.filter(created__lt=time_threshold)

Notez que created__lt signifie "créé est inférieur à".

110
David Robinson
now = datetime.datetime.now()
earlier = now - datetime.timedelta(hours=5)
MyModel.objects.filter(my_date_field__range=(earlier,now))

Cela devrait faire l'affaire.

13
Josh Smeaton

si settings.USE_TZ = True et settings.TIME_ZONE est défini

from Django.utils import timezone
five_h_ago = timezone.now()-timezone.timedelta(hours=5)
example.object.filter(datetimefield__lt=five_h_ago)
3
tao.song

L’approche la plus simple a déjà été abordée dans d’autres réponses: il suffit de filtrer les enregistrements dont la date est antérieure à cinq heures. Voici un exemple complet qui trouve des enregistrements créés il y a au moins cinq secondes:

# Tested with Django 1.11.15 and Python 3.6.
import logging
import sys
from datetime import datetime, timedelta
from time import sleep

import Django
from Django.apps import apps
from Django.apps.config import AppConfig
from Django.conf import settings
from Django.db import connections, models, DEFAULT_DB_ALIAS
from Django.db.models.base import ModelBase

NAME = 'udjango'
DB_FILE = NAME + '.db'


def main():
    setup()
    logger = logging.getLogger(__name__)

    class Widget(models.Model):
        name = models.CharField(max_length=200)
        date_created = models.DateTimeField(auto_now_add=True)

        def __str__(self):
            return self.name

    syncdb(Widget)

    Widget.objects.create(name='spline')
    sleep(1)
    Widget.objects.create(name='reticulator')
    sleep(1)
    Widget.objects.create(name='tardis')
    sleep(5)
    Widget.objects.create(name='sonic screwdriver')
    sleep(1)

    cutoff_time = datetime.now() - timedelta(seconds=5)
    for widget in Widget.objects.filter(date_created__lt=cutoff_time):
        logger.info(widget.name)


def setup():
    with open(DB_FILE, 'w'):
        pass  # wipe the database
    settings.configure(
        DEBUG=True,
        DATABASES={
            DEFAULT_DB_ALIAS: {
                'ENGINE': 'Django.db.backends.sqlite3',
                'NAME': DB_FILE}},
        LOGGING={'version': 1,
                 'disable_existing_loggers': False,
                 'formatters': {
                    'debug': {
                        'format': '[%(levelname)s]'
                                  '%(name)s.%(funcName)s(): %(message)s',
                        'datefmt': '%Y-%m-%d %H:%M:%S'}},
                 'handlers': {
                    'console': {
                        'level': 'DEBUG',
                        'class': 'logging.StreamHandler',
                        'formatter': 'debug'}},
                 'root': {
                    'handlers': ['console'],
                    'level': 'INFO'},
                 'loggers': {
                    "Django.db": {"level": "INFO"}}})
    app_config = AppConfig(NAME, sys.modules['__main__'])
    apps.populate([app_config])
    Django.setup()
    original_new_func = ModelBase.__new__

    @staticmethod
    def patched_new(cls, name, bases, attrs):
        if 'Meta' not in attrs:
            class Meta:
                app_label = NAME
            attrs['Meta'] = Meta
        return original_new_func(cls, name, bases, attrs)
    ModelBase.__new__ = patched_new


def syncdb(model):
    """ Standard syncdb expects models to be in reliable locations.

    Based on https://github.com/Django/django/blob/1.9.3
    /Django/core/management/commands/migrate.py#L285
    """
    connection = connections[DEFAULT_DB_ALIAS]
    with connection.schema_editor() as editor:
        editor.create_model(model)


main()

Cela me montre tout sauf le dernier widget:

[INFO]__main__.main(): spline
[INFO]__main__.main(): reticulator
[INFO]__main__.main(): tardis

Cela fonctionne bien, sauf si vous avez activé la prise en charge du fuseau horaire. Dans l'exemple précédent, je le fais en modifiant settings.configure(... pour qu'il ressemble à ceci:

settings.configure(
    USE_TZ=True,
    ...

Quand je fais cela, je reçois un message comme celui-ci:

RuntimeWarning: DateTimeField Widget.date_created received a naive datetime (2019-01-07 16:39:04.563563) while time zone support is active.

Pour obtenir une date tenant compte du fuseau horaire, utilisez timezone.now() fonction au lieu de datetime.now():

# Tested with Django 1.11.15 and Python 3.6.
import logging
import sys
from datetime import timedelta
from time import sleep

import Django
from Django.apps import apps
from Django.apps.config import AppConfig
from Django.conf import settings
from Django.db import connections, models, DEFAULT_DB_ALIAS
from Django.db.models.base import ModelBase
from Django.utils import timezone

NAME = 'udjango'
DB_FILE = NAME + '.db'


def main():
    setup()
    logger = logging.getLogger(__name__)

    class Widget(models.Model):
        name = models.CharField(max_length=200)
        date_created = models.DateTimeField(auto_now_add=True)

        def __str__(self):
            return self.name

    syncdb(Widget)

    Widget.objects.create(name='spline')
    sleep(1)
    Widget.objects.create(name='reticulator')
    sleep(1)
    Widget.objects.create(name='tardis')
    sleep(5)
    Widget.objects.create(name='sonic screwdriver')
    sleep(1)

    cutoff_time = timezone.now() - timedelta(seconds=5)
    for widget in Widget.objects.filter(date_created__lt=cutoff_time):
        logger.info(widget.name)


def setup():
    with open(DB_FILE, 'w'):
        pass  # wipe the database
    settings.configure(
        USE_TZ=True,
        DEBUG=True,
        DATABASES={
            DEFAULT_DB_ALIAS: {
                'ENGINE': 'Django.db.backends.sqlite3',
                'NAME': DB_FILE}},
        LOGGING={'version': 1,
                 'disable_existing_loggers': False,
                 'formatters': {
                    'debug': {
                        'format': '[%(levelname)s]'
                                  '%(name)s.%(funcName)s(): %(message)s',
                        'datefmt': '%Y-%m-%d %H:%M:%S'}},
                 'handlers': {
                    'console': {
                        'level': 'DEBUG',
                        'class': 'logging.StreamHandler',
                        'formatter': 'debug'}},
                 'root': {
                    'handlers': ['console'],
                    'level': 'INFO'},
                 'loggers': {
                    "Django.db": {"level": "INFO"}}})
    app_config = AppConfig(NAME, sys.modules['__main__'])
    apps.populate([app_config])
    Django.setup()
    original_new_func = ModelBase.__new__

    @staticmethod
    def patched_new(cls, name, bases, attrs):
        if 'Meta' not in attrs:
            class Meta:
                app_label = NAME
            attrs['Meta'] = Meta
        return original_new_func(cls, name, bases, attrs)
    ModelBase.__new__ = patched_new


def syncdb(model):
    """ Standard syncdb expects models to be in reliable locations.

    Based on https://github.com/Django/django/blob/1.9.3
    /Django/core/management/commands/migrate.py#L285
    """
    connection = connections[DEFAULT_DB_ALIAS]
    with connection.schema_editor() as editor:
        editor.create_model(model)


main()

Il est parfois arrivé que l’horloge de la base de données ne soit plus synchronisée avec celle du serveur Web. Pour éviter ce genre de problème, vous pouvez utiliser la fonction Now() pour obtenir l'heure actuelle dans la base de données.

# Tested with Django 1.11.15 and Python 3.6.
import logging
import sys
from datetime import timedelta
from time import sleep

import Django
from Django.apps import apps
from Django.apps.config import AppConfig
from Django.conf import settings
from Django.db import connections, models, DEFAULT_DB_ALIAS
from Django.db.models.base import ModelBase
from Django.db.models.functions import Now
from Django.utils import timezone

NAME = 'udjango'
DB_FILE = NAME + '.db'


def main():
    setup()
    logger = logging.getLogger(__name__)

    class Widget(models.Model):
        name = models.CharField(max_length=200)
        date_created = models.DateTimeField()

        def __str__(self):
            return self.name

    syncdb(Widget)

    Widget.objects.create(name='spline', date_created=Now())
    sleep(1)
    Widget.objects.create(name='reticulator', date_created=Now())
    sleep(1)
    Widget.objects.create(name='tardis', date_created=Now())
    sleep(5)
    Widget.objects.create(name='sonic screwdriver', date_created=Now())
    sleep(1)

    cutoff_time = Now() - timedelta(seconds=5)
    for widget in Widget.objects.filter(date_created__lt=cutoff_time):
        logger.info(widget.name)


def setup():
    with open(DB_FILE, 'w'):
        pass  # wipe the database
    settings.configure(
        USE_TZ=True,
        DEBUG=True,
        DATABASES={
            DEFAULT_DB_ALIAS: {
                'ENGINE': 'Django.db.backends.sqlite3',
                'NAME': DB_FILE}},
        LOGGING={'version': 1,
                 'disable_existing_loggers': False,
                 'formatters': {
                    'debug': {
                        'format': '[%(levelname)s]'
                                  '%(name)s.%(funcName)s(): %(message)s',
                        'datefmt': '%Y-%m-%d %H:%M:%S'}},
                 'handlers': {
                    'console': {
                        'level': 'DEBUG',
                        'class': 'logging.StreamHandler',
                        'formatter': 'debug'}},
                 'root': {
                    'handlers': ['console'],
                    'level': 'INFO'},
                 'loggers': {
                    "Django.db": {"level": "INFO"}}})
    app_config = AppConfig(NAME, sys.modules['__main__'])
    apps.populate([app_config])
    Django.setup()
    original_new_func = ModelBase.__new__

    @staticmethod
    def patched_new(cls, name, bases, attrs):
        if 'Meta' not in attrs:
            class Meta:
                app_label = NAME
            attrs['Meta'] = Meta
        return original_new_func(cls, name, bases, attrs)
    ModelBase.__new__ = patched_new


def syncdb(model):
    """ Standard syncdb expects models to be in reliable locations.

    Based on https://github.com/Django/django/blob/1.9.3
    /Django/core/management/commands/migrate.py#L285
    """
    connection = connections[DEFAULT_DB_ALIAS]
    with connection.schema_editor() as editor:
        editor.create_model(model)


main()

Je n'ai pas vu ce problème ces dernières années, donc ça ne vaut probablement pas la peine dans la plupart des cas.

0
Don Kirkby