Django Documentation, Release 1.5.12
override
( timezone)
This is a Python context manager that sets the
current time zone
on entry with
activate()
, and restores the
previously active time zone on exit. If the timezone argument is None, the
current time zone
is unset on entry with
deactivate()
instead.
localtime
( value , timezone=None)
Converts an aware datetime to a different time zone, by default the
current time zone
.
This function doesn’t work on naive datetimes; use
make_aware()
instead.
now
()
Returns an aware or naive datetime that represents the current point in time when
USE_TZ
is True or
False respectively.
is_aware
( value)
Returns True if value is aware, False if it is naive. This function assumes that value is a datetime
.
is_naive
( value)
Returns True if value is naive, False if it is aware. This function assumes that value is a datetime
.
make_aware
( value , timezone)
Returns an aware datetime that represents the same point in time as value in timezone, value being a naive datetime .
This function can raise an exception if value doesn’t exist or is ambiguous because of DST transitions.
make_naive
( value , timezone)
Returns an naive datetime that represents in timezone the same point in time as value, value being an aware datetime
django.utils.tzinfo
class FixedOffset
Fixed offset in minutes east from UTC.
class LocalTimezone
Proxy timezone information from time module.
Validators
Writing validators
A validator is a callable that takes a value and raises a
ValidationError
if it doesn’t meet some criteria. Validators can be useful for re-using validation logic between different types of fields.
For example, here’s a validator that only allows even numbers:
from
django.core.exceptions
import
ValidationError
def validate_even
(value):
if
value % 2
!=
0 :
raise
ValidationError( u'%s is not an even number'
%
value)
You can add this to a model field via the field’s
validators
argument:
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from
django.db
import
models
class MyModel
(models.Model): even_field = models.IntegerField(validators=[validate_even])
Because values are converted to Python before validators are run, you can even use the same validator with forms:
from
django
import
forms
class MyForm
(forms.Form): even_field = forms.IntegerField(validators=[validate_even])
How validators are run
See the
form validation
for more information on how validators are run in forms, and
Validating objects
for how they’re run in models. Note that validators will not be run automatically when you save a model, but if you are using a
ModelForm
, it will run your validators on any fields that are included in your form. See the ModelForm documentation
for information on how model validation interacts with forms.
Built-in validators
The
django.core.validators
module contains a collection of callable validators for use with model and form fields. They’re used internally but are available for use with your own fields, too. They can be used in addition to, or in lieu of custom field.clean() methods.
RegexValidator
class RegexValidator(
[ regex=None , message=None, code=None
]
)
Parameters
• regex – If not None, overrides
regex
. Can be a regular expression string or a pre-
compiled regular expression.
• message – If not None, overrides
message
.
• code – If not None, overrides
code
.
regex
The regular expression pattern to search for the provided value, or a pre-compiled regular expression.
Raises a
ValidationError
with
message
and
code
if no match is found. By default, matches any string (including an empty string).
message
The error message used by
ValidationError
if validation fails. Defaults to "Enter a valid value" .
code
The error code used by
ValidationError
if validation fails. Defaults to "invalid".
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URLValidator
class URLValidator
A
RegexValidator
that ensures a value looks like a URL, and raises an error code of 'invalid' if it doesn’t.
validate_email validate_email
A
RegexValidator
instance that ensures a value looks like an email address.
validate_slug validate_slug
A
RegexValidator
instance that ensures a value consists of only letters, numbers, underscores or hyphens.
validate_ipv4_address validate_ipv4_address
A
RegexValidator
instance that ensures a value looks like an IPv4 address.
validate_ipv6_address validate_ipv6_address
Uses django.utils.ipv6 to check the validity of an IPv6 address.
validate_ipv46_address validate_ipv46_address
Uses both validate_ipv4_address and validate_ipv6_address to ensure a value is either a valid
IPv4 or IPv6 address.
validate_comma_separated_integer_list validate_comma_separated_integer_list
A
RegexValidator
instance that ensures a value is a comma-separated list of integers.
MaxValueValidator
class MaxValueValidator(max_value)
Raises a
ValidationError
with a code of 'max_value' if value is greater than max_value.
MinValueValidator
class MinValueValidator(min_value)
Raises a
ValidationError
with a code of 'min_value' if value is less than min_value.
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