from __future__ import unicode_literals
import collections
import copy
import datetime
import decimal
import inspect
import re
import uuid
from django.conf import settings
from django.core.exceptions import ValidationError as DjangoValidationError
from django.core.exceptions import ObjectDoesNotExist
from django.core.validators import RegexValidator, ip_address_validators
from django.forms import ImageField as DjangoImageField
from django.utils import six, timezone
from django.utils.dateparse import parse_date, parse_datetime, parse_time
from django.utils.encoding import is_protected_type, smart_text
from django.utils.ipv6 import clean_ipv6_address
from django.utils.translation import ugettext_lazy as _
from rest_framework import ISO_8601
from rest_framework.compat import (
EmailValidator, MaxLengthValidator, MaxValueValidator, MinLengthValidator,
MinValueValidator, OrderedDict, URLValidator, duration_string,
parse_duration, unicode_repr, unicode_to_repr
)
from rest_framework.exceptions import ValidationError
from rest_framework.settings import api_settings
from rest_framework.utils import html, humanize_datetime, representation
class empty:
"""
This class is used to represent no data being provided for a given input
or output value.
It is required because `None` may be a valid input or output value.
"""
pass
def is_simple_callable(obj):
"""
True if the object is a callable that takes no arguments.
"""
function = inspect.isfunction(obj)
method = inspect.ismethod(obj)
if not (function or method):
return False
args, _, _, defaults = inspect.getargspec(obj)
len_args = len(args) if function else len(args) - 1
len_defaults = len(defaults) if defaults else 0
return len_args <= len_defaults
def get_attribute(instance, attrs):
"""
Similar to Python's built in `getattr(instance, attr)`,
but takes a list of nested attributes, instead of a single attribute.
Also accepts either attribute lookup on objects or dictionary lookups.
"""
for attr in attrs:
if instance is None:
# Break out early if we get `None` at any point in a nested lookup.
return None
try:
if isinstance(instance, collections.Mapping):
instance = instance[attr]
else:
instance = getattr(instance, attr)
except ObjectDoesNotExist:
return None
if is_simple_callable(instance):
try:
instance = instance()
except (AttributeError, KeyError) as exc:
# If we raised an Attribute or KeyError here it'd get treated
# as an omitted field in `Field.get_attribute()`. Instead we
# raise a ValueError to ensure the exception is not masked.
raise ValueError('Exception raised in callable attribute "{0}"; original exception was: {1}'.format(attr, exc))
return instance
def set_value(dictionary, keys, value):
"""
Similar to Python's built in `dictionary[key] = value`,
but takes a list of nested keys instead of a single key.
set_value({'a': 1}, [], {'b': 2}) -> {'a': 1, 'b': 2}
set_value({'a': 1}, ['x'], 2) -> {'a': 1, 'x': 2}
set_value({'a': 1}, ['x', 'y'], 2) -> {'a': 1, 'x': {'y': 2}}
"""
if not keys:
dictionary.update(value)
return
for key in keys[:-1]:
if key not in dictionary:
dictionary[key] = {}
dictionary = dictionary[key]
dictionary[keys[-1]] = value
class CreateOnlyDefault(object):
"""
This class may be used to provide default values that are only used
for create operations, but that do not return any value for update
operations.
"""
def __init__(self, default):
self.default = default
def set_context(self, serializer_field):
self.is_update = serializer_field.parent.instance is not None
if callable(self.default) and hasattr(self.default, 'set_context') and not self.is_update:
self.default.set_context(serializer_field)
def __call__(self):
if self.is_update:
raise SkipField()
if callable(self.default):
return self.default()
return self.default
def __repr__(self):
return unicode_to_repr(
'%s(%s)' % (self.__class__.__name__, unicode_repr(self.default))
)
class CurrentUserDefault(object):
def set_context(self, serializer_field):
self.user = serializer_field.context['request'].user
def __call__(self):
return self.user
def __repr__(self):
return unicode_to_repr('%s()' % self.__class__.__name__)
class SkipField(Exception):
pass
NOT_READ_ONLY_WRITE_ONLY = 'May not set both `read_only` and `write_only`'
NOT_READ_ONLY_REQUIRED = 'May not set both `read_only` and `required`'
NOT_REQUIRED_DEFAULT = 'May not set both `required` and `default`'
USE_READONLYFIELD = 'Field(read_only=True) should be ReadOnlyField'
MISSING_ERROR_MESSAGE = (
'ValidationError raised by `{class_name}`, but error key `{key}` does '
'not exist in the `error_messages` dictionary.'
)
class Field(object):
_creation_counter = 0
default_error_messages = {
'required': _('This field is required.'),
'null': _('This field may not be null.')
}
default_validators = []
default_empty_html = empty
initial = None
def __init__(self, read_only=False, write_only=False,
required=None, default=empty, initial=empty, source=None,
label=None, help_text=None, style=None,
error_messages=None, validators=None, allow_null=False):
self._creation_counter = Field._creation_counter
Field._creation_counter += 1
# If `required` is unset, then use `True` unless a default is provided.
if required is None:
required = default is empty and not read_only
# Some combinations of keyword arguments do not make sense.
assert not (read_only and write_only), NOT_READ_ONLY_WRITE_ONLY
assert not (read_only and required), NOT_READ_ONLY_REQUIRED
assert not (required and default is not empty), NOT_REQUIRED_DEFAULT
assert not (read_only and self.__class__ == Field), USE_READONLYFIELD
self.read_only = read_only
self.write_only = write_only
self.required = required
self.default = default
self.source = source
self.initial = self.initial if (initial is empty) else initial
self.label = label
self.help_text = help_text
self.style = {} if style is None else style
self.allow_null = allow_null
if self.default_empty_html is not empty:
if not required:
self.default_empty_html = empty
elif default is not empty:
self.default_empty_html = default
if validators is not None:
self.validators = validators[:]
# These are set up by `.bind()` when the field is added to a serializer.
self.field_name = None
self.parent = None
# Collect default error message from self and parent classes
messages = {}
for cls in reversed(self.__class__.__mro__):
messages.update(getattr(cls, 'default_error_messages', {}))
messages.update(error_messages or {})
self.error_messages = messages
def bind(self, field_name, parent):
"""
Initializes the field name and parent for the field instance.
Called when a field is added to the parent serializer instance.
"""
# In order to enforce a consistent style, we error if a redundant
# 'source' argument has been used. For example:
# my_field = serializer.CharField(source='my_field')
assert self.source != field_name, (
"It is redundant to specify `source='%s'` on field '%s' in "
"serializer '%s', because it is the same as the field name. "
"Remove the `source` keyword argument." %
(field_name, self.__class__.__name__, parent.__class__.__name__)
)
self.field_name = field_name
self.parent = parent
# `self.label` should default to being based on the field name.
if self.label is None:
self.label = field_name.replace('_', ' ').capitalize()
# self.source should default to being the same as the field name.
if self.source is None:
self.source = field_name
# self.source_attrs is a list of attributes that need to be looked up
# when serializing the instance, or populating the validated data.
if self.source == '*':
self.source_attrs = []
else:
self.source_attrs = self.source.split('.')
# .validators is a lazily loaded property, that gets its default
# value from `get_validators`.
@property
def validators(self):
if not hasattr(self, '_validators'):
self._validators = self.get_validators()
return self._validators
@validators.setter
def validators(self, validators):
self._validators = validators
def get_validators(self):
return self.default_validators[:]
def get_initial(self):
"""
Return a value to use when the field is being returned as a primitive
value, without any object instance.
"""
return self.initial
def get_value(self, dictionary):
"""
Given the *incoming* primitive data, return the value for this field
that should be validated and transformed to a native value.
"""
if html.is_html_input(dictionary):
# HTML forms will represent empty fields as '', and cannot
# represent None or False values directly.
if self.field_name not in dictionary:
if getattr(self.root, 'partial', False):
return empty
return self.default_empty_html
ret = dictionary[self.field_name]
if ret == '' and self.allow_null:
# If the field is blank, and null is a valid value then
# determine if we should use null instead.
return '' if getattr(self, 'allow_blank', False) else None
return ret
return dictionary.get(self.field_name, empty)
def get_attribute(self, instance):
"""
Given the *outgoing* object instance, return the primitive value
that should be used for this field.
"""
try:
return get_attribute(instance, self.source_attrs)
except (KeyError, AttributeError) as exc:
if not self.required and self.default is empty:
raise SkipField()
msg = (
'Got {exc_type} when attempting to get a value for field '
'`{field}` on serializer `{serializer}`.\nThe serializer '
'field might be named incorrectly and not match '
'any attribute or key on the `{instance}` instance.\n'
'Original exception text was: {exc}.'.format(
exc_type=type(exc).__name__,
field=self.field_name,
serializer=self.parent.__class__.__name__,
instance=instance.__class__.__name__,
exc=exc
)
)
raise type(exc)(msg)
def get_default(self):
"""
Return the default value to use when validating data if no input
is provided for this field.
If a default has not been set for this field then this will simply
return `empty`, indicating that no value should be set in the
validated data for this field.
"""
if self.default is empty:
raise SkipField()
if callable(self.default):
if hasattr(self.default, 'set_context'):
self.default.set_context(self)
return self.default()
return self.default
def validate_empty_values(self, data):
"""
Validate empty values, and either:
* Raise `ValidationError`, indicating invalid data.
* Raise `SkipField`, indicating that the field should be ignored.
* Return (True, data), indicating an empty value that should be
returned without any further validation being applied.
* Return (False, data), indicating a non-empty value, that should
have validation applied as normal.
"""
if self.read_only:
return (True, self.get_default())
if data is empty:
if getattr(self.root, 'partial', False):
raise SkipField()
if self.required:
self.fail('required')
return (True, self.get_default())
if data is None:
if not self.allow_null:
self.fail('null')
return (True, None)
return (False, data)
def run_validation(self, data=empty):
"""
Validate a simple representation and return the internal value.
The provided data may be `empty` if no representation was included
in the input.
May raise `SkipField` if the field should not be included in the
validated data.
"""
(is_empty_value, data) = self.validate_empty_values(data)
if is_empty_value:
return data
value = self.to_internal_value(data)
self.run_validators(value)
return value
def run_validators(self, value):
"""
Test the given value against all the validators on the field,
and either raise a `ValidationError` or simply return.
"""
errors = []
for validator in self.validators:
if hasattr(validator, 'set_context'):
validator.set_context(self)
try:
validator(value)
except ValidationError as exc:
# If the validation error contains a mapping of fields to
# errors then simply raise it immediately rather than
# attempting to accumulate a list of errors.
if isinstance(exc.detail, dict):
raise
errors.extend(exc.detail)
except DjangoValidationError as exc:
errors.extend(exc.messages)
if errors:
raise ValidationError(errors)
def to_internal_value(self, data):
"""
Transform the *incoming* primitive data into a native value.
"""
raise NotImplementedError(
'{cls}.to_internal_value() must be implemented.'.format(
cls=self.__class__.__name__
)
)
def to_representation(self, value):
"""
Transform the *outgoing* native value into primitive data.
"""
raise NotImplementedError(
'{cls}.to_representation() must be implemented for field '
'{field_name}. If you do not need to support write operations '
'you probably want to subclass `ReadOnlyField` instead.'.format(
cls=self.__class__.__name__,
field_name=self.field_name,
)
)
def fail(self, key, **kwargs):
"""
A helper method that simply raises a validation error.
"""
try:
msg = self.error_messages[key]
except KeyError:
class_name = self.__class__.__name__
msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
raise AssertionError(msg)
message_string = msg.format(**kwargs)
raise ValidationError(message_string)
@property
def root(self):
"""
Returns the top-level serializer for this field.
"""
root = self
while root.parent is not None:
root = root.parent
return root
@property
def context(self):
"""
Returns the context as passed to the root serializer on initialization.
"""
return getattr(self.root, '_context', {})
def __new__(cls, *args, **kwargs):
"""
When a field is instantiated, we store the arguments that were used,
so that we can present a helpful representation of the object.
"""
instance = super(Field, cls).__new__(cls)
instance._args = args
instance._kwargs = kwargs
return instance
def __deepcopy__(self, memo):
"""
When cloning fields we instantiate using the arguments it was
originally created with, rather than copying the complete state.
"""
args = copy.deepcopy(self._args)
kwargs = dict(self._kwargs)
# Bit ugly, but we need to special case 'validators' as Django's
# RegexValidator does not support deepcopy.
# We treat validator callables as immutable objects.
# See https://github.com/tomchristie/django-rest-framework/issues/1954
validators = kwargs.pop('validators', None)
kwargs = copy.deepcopy(kwargs)
if validators is not None:
kwargs['validators'] = validators
return self.__class__(*args, **kwargs)
def __repr__(self):
"""
Fields are represented using their initial calling arguments.
This allows us to create descriptive representations for serializer
instances that show all the declared fields on the serializer.
"""
return unicode_to_repr(representation.field_repr(self))
# Boolean types...
class BooleanField(Field):
default_error_messages = {
'invalid': _('"{input}" is not a valid boolean.')
}
default_empty_html = False
initial = False
TRUE_VALUES = set(('t', 'T', 'true', 'True', 'TRUE', '1', 1, True))
FALSE_VALUES = set(('f', 'F', 'false', 'False', 'FALSE', '0', 0, 0.0, False))
def __init__(self, **kwargs):
assert 'allow_null' not in kwargs, '`allow_null` is not a valid option. Use `NullBooleanField` instead.'
super(BooleanField, self).__init__(**kwargs)
def to_internal_value(self, data):
if data in self.TRUE_VALUES:
return True
elif data in self.FALSE_VALUES:
return False
self.fail('invalid', input=data)
def to_representation(self, value):
if value in self.TRUE_VALUES:
return True
elif value in self.FALSE_VALUES:
return False
return bool(value)
class NullBooleanField(Field):
default_error_messages = {
'invalid': _('"{input}" is not a valid boolean.')
}
initial = None
TRUE_VALUES = set(('t', 'T', 'true', 'True', 'TRUE', '1', 1, True))
FALSE_VALUES = set(('f', 'F', 'false', 'False', 'FALSE', '0', 0, 0.0, False))
NULL_VALUES = set(('n', 'N', 'null', 'Null', 'NULL', '', None))
def __init__(self, **kwargs):
assert 'allow_null' not in kwargs, '`allow_null` is not a valid option.'
kwargs['allow_null'] = True
super(NullBooleanField, self).__init__(**kwargs)
def to_internal_value(self, data):
if data in self.TRUE_VALUES:
return True
elif data in self.FALSE_VALUES:
return False
elif data in self.NULL_VALUES:
return None
self.fail('invalid', input=data)
def to_representation(self, value):
if value in self.NULL_VALUES:
return None
if value in self.TRUE_VALUES:
return True
elif value in self.FALSE_VALUES:
return False
return bool(value)
# String types...
class CharField(Field):
default_error_messages = {
'blank': _('This field may not be blank.'),
'max_length': _('Ensure this field has no more than {max_length} characters.'),
'min_length': _('Ensure this field has at least {min_length} characters.')
}
initial = ''
def __init__(self, **kwargs):
self.allow_blank = kwargs.pop('allow_blank', False)
self.trim_whitespace = kwargs.pop('trim_whitespace', True)
self.max_length = kwargs.pop('max_length', None)
self.min_length = kwargs.pop('min_length', None)
super(CharField, self).__init__(**kwargs)
if self.max_length is not None:
message = self.error_messages['max_length'].format(max_length=self.max_length)
self.validators.append(MaxLengthValidator(self.max_length, message=message))
if self.min_length is not None:
message = self.error_messages['min_length'].format(min_length=self.min_length)
self.validators.append(MinLengthValidator(self.min_length, message=message))
def run_validation(self, data=empty):
# Test for the empty string here so that it does not get validated,
# and so that subclasses do not need to handle it explicitly
# inside the `to_internal_value()` method.
if data == '' or (self.trim_whitespace and six.text_type(data).strip() == ''):
if not self.allow_blank:
self.fail('blank')
return ''
return super(CharField, self).run_validation(data)
def to_internal_value(self, data):
value = six.text_type(data)
return value.strip() if self.trim_whitespace else value
def to_representation(self, value):
return six.text_type(value)
class EmailField(CharField):
default_error_messages = {
'invalid': _('Enter a valid email address.')
}
def __init__(self, **kwargs):
super(EmailField, self).__init__(**kwargs)
validator = EmailValidator(message=self.error_messages['invalid'])
self.validators.append(validator)
class RegexField(CharField):
default_error_messages = {
'invalid': _('This value does not match the required pattern.')
}
def __init__(self, regex, **kwargs):
super(RegexField, self).__init__(**kwargs)
validator = RegexValidator(regex, message=self.error_messages['invalid'])
self.validators.append(validator)
class SlugField(CharField):
default_error_messages = {
'invalid': _('Enter a valid "slug" consisting of letters, numbers, underscores or hyphens.')
}
def __init__(self, **kwargs):
super(SlugField, self).__init__(**kwargs)
slug_regex = re.compile(r'^[-a-zA-Z0-9_]+$')
validator = RegexValidator(slug_regex, message=self.error_messages['invalid'])
self.validators.append(validator)
class URLField(CharField):
default_error_messages = {
'invalid': _('Enter a valid URL.')
}
def __init__(self, **kwargs):
super(URLField, self).__init__(**kwargs)
validator = URLValidator(message=self.error_messages['invalid'])
self.validators.append(validator)
class UUIDField(Field):
valid_formats = ('hex_verbose', 'hex', 'int', 'urn')
default_error_messages = {
'invalid': _('"{value}" is not a valid UUID.'),
}
def __init__(self, **kwargs):
self.uuid_format = kwargs.pop('format', 'hex_verbose')
if self.uuid_format not in self.valid_formats:
raise ValueError(
'Invalid format for uuid representation. '
'Must be one of "{0}"'.format('", "'.join(self.valid_formats))
)
super(UUIDField, self).__init__(**kwargs)
def to_internal_value(self, data):
if not isinstance(data, uuid.UUID):
try:
if isinstance(data, six.integer_types):
return uuid.UUID(int=data)
else:
return uuid.UUID(hex=data)
except (ValueError, TypeError):
self.fail('invalid', value=data)
return data
def to_representation(self, value):
if self.uuid_format == 'hex_verbose':
return str(value)
else:
return getattr(value, self.uuid_format)
class IPAddressField(CharField):
"""Support both IPAddressField and GenericIPAddressField"""
default_error_messages = {
'invalid': _('Enter a valid IPv4 or IPv6 address.'),
}
def __init__(self, protocol='both', **kwargs):
self.protocol = protocol.lower()
self.unpack_ipv4 = (self.protocol == 'both')
super(IPAddressField, self).__init__(**kwargs)
validators, error_message = ip_address_validators(protocol, self.unpack_ipv4)
self.validators.extend(validators)
def to_internal_value(self, data):
if data and ':' in data:
try:
if self.protocol in ('both', 'ipv6'):
return clean_ipv6_address(data, self.unpack_ipv4)
except DjangoValidationError:
self.fail('invalid', value=data)
return super(IPAddressField, self).to_internal_value(data)
# Number types...
class IntegerField(Field):
default_error_messages = {
'invalid': _('A valid integer is required.'),
'max_value': _('Ensure this value is less than or equal to {max_value}.'),
'min_value': _('Ensure this value is greater than or equal to {min_value}.'),
'max_string_length': _('String value too large.')
}
MAX_STRING_LENGTH = 1000 # Guard against malicious string inputs.
re_decimal = re.compile(r'\.0*\s*$') # allow e.g. '1.0' as an int, but not '1.2'
def __init__(self, **kwargs):
self.max_value = kwargs.pop('max_value', None)
self.min_value = kwargs.pop('min_value', None)
super(IntegerField, self).__init__(**kwargs)
if self.max_value is not None:
message = self.error_messages['max_value'].format(max_value=self.max_value)
self.validators.append(MaxValueValidator(self.max_value, message=message))
if self.min_value is not None:
message = self.error_messages['min_value'].format(min_value=self.min_value)
self.validators.append(MinValueValidator(self.min_value, message=message))
def to_internal_value(self, data):
if isinstance(data, six.text_type) and len(data) > self.MAX_STRING_LENGTH:
self.fail('max_string_length')
try:
data = int(self.re_decimal.sub('', str(data)))
except (ValueError, TypeError):
self.fail('invalid')
return data
def to_representation(self, value):
return int(value)
class FloatField(Field):
default_error_messages = {
'invalid': _('A valid number is required.'),
'max_value': _('Ensure this value is less than or equal to {max_value}.'),
'min_value': _('Ensure this value is greater than or equal to {min_value}.'),
'max_string_length': _('String value too large.')
}
MAX_STRING_LENGTH = 1000 # Guard against malicious string inputs.
def __init__(self, **kwargs):
self.max_value = kwargs.pop('max_value', None)
self.min_value = kwargs.pop('min_value', None)
super(FloatField, self).__init__(**kwargs)
if self.max_value is not None:
message = self.error_messages['max_value'].format(max_value=self.max_value)
self.validators.append(MaxValueValidator(self.max_value, message=message))
if self.min_value is not None:
message = self.error_messages['min_value'].format(min_value=self.min_value)
self.validators.append(MinValueValidator(self.min_value, message=message))
def to_internal_value(self, data):
if isinstance(data, six.text_type) and len(data) > self.MAX_STRING_LENGTH:
self.fail('max_string_length')
try:
return float(data)
except (TypeError, ValueError):
self.fail('invalid')
def to_representation(self, value):
return float(value)
class DecimalField(Field):
default_error_messages = {
'invalid': _('A valid number is required.'),
'max_value': _('Ensure this value is less than or equal to {max_value}.'),
'min_value': _('Ensure this value is greater than or equal to {min_value}.'),
'max_digits': _('Ensure that there are no more than {max_digits} digits in total.'),
'max_decimal_places': _('Ensure that there are no more than {max_decimal_places} decimal places.'),
'max_whole_digits': _('Ensure that there are no more than {max_whole_digits} digits before the decimal point.'),
'max_string_length': _('String value too large.')
}
MAX_STRING_LENGTH = 1000 # Guard against malicious string inputs.
coerce_to_string = api_settings.COERCE_DECIMAL_TO_STRING
def __init__(self, max_digits, decimal_places, coerce_to_string=None, max_value=None, min_value=None, **kwargs):
self.max_digits = max_digits
self.decimal_places = decimal_places
self.coerce_to_string = coerce_to_string if (coerce_to_string is not None) else self.coerce_to_string
self.max_value = max_value
self.min_value = min_value
super(DecimalField, self).__init__(**kwargs)
if self.max_value is not None:
message = self.error_messages['max_value'].format(max_value=self.max_value)
self.validators.append(MaxValueValidator(self.max_value, message=message))
if self.min_value is not None:
message = self.error_messages['min_value'].format(min_value=self.min_value)
self.validators.append(MinValueValidator(self.min_value, message=message))
def to_internal_value(self, data):
"""
Validate that the input is a decimal number and return a Decimal
instance.
"""
data = smart_text(data).strip()
if len(data) > self.MAX_STRING_LENGTH:
self.fail('max_string_length')
try:
value = decimal.Decimal(data)
except decimal.DecimalException:
self.fail('invalid')
# Check for NaN. It is the only value that isn't equal to itself,
# so we can use this to identify NaN values.
if value != value:
self.fail('invalid')
# Check for infinity and negative infinity.
if value in (decimal.Decimal('Inf'), decimal.Decimal('-Inf')):
self.fail('invalid')
return self.validate_precision(value)
def validate_precision(self, value):
"""
Ensure that there are no more than max_digits in the number, and no
more than decimal_places digits after the decimal point.
Override this method to disable the precision validation for input
values or to enhance it in any way you need to.
"""
sign, digittuple, exponent = value.as_tuple()
decimals = exponent * decimal.Decimal(-1) if exponent < 0 else 0
# digittuple doesn't include any leading zeros.
digits = len(digittuple)
if decimals > digits:
# We have leading zeros up to or past the decimal point. Count
# everything past the decimal point as a digit. We do not count
# 0 before the decimal point as a digit since that would mean
# we would not allow max_digits = decimal_places.
digits = decimals
whole_digits = digits - decimals
if self.max_digits is not None and digits > self.max_digits:
self.fail('max_digits', max_digits=self.max_digits)
if self.decimal_places is not None and decimals > self.decimal_places:
self.fail('max_decimal_places', max_decimal_places=self.decimal_places)
if self.max_digits is not None and self.decimal_places is not None and whole_digits > (self.max_digits - self.decimal_places):
self.fail('max_whole_digits', max_whole_digits=self.max_digits - self.decimal_places)
return value
def to_representation(self, value):
if not isinstance(value, decimal.Decimal):
value = decimal.Decimal(six.text_type(value).strip())
quantized = self.quantize(value)
if not self.coerce_to_string:
return quantized
return '{0:f}'.format(quantized)
def quantize(self, value):
"""
Quantize the decimal value to the configured precision.
"""
context = decimal.getcontext().copy()
context.prec = self.max_digits
return value.quantize(
decimal.Decimal('.1') ** self.decimal_places,
context=context)
# Date & time fields...
class DateTimeField(Field):
default_error_messages = {
'invalid': _('Datetime has wrong format. Use one of these formats instead: {format}.'),
'date': _('Expected a datetime but got a date.'),
}
format = api_settings.DATETIME_FORMAT
input_formats = api_settings.DATETIME_INPUT_FORMATS
default_timezone = timezone.get_default_timezone() if settings.USE_TZ else None
datetime_parser = datetime.datetime.strptime
def __init__(self, format=empty, input_formats=None, default_timezone=None, *args, **kwargs):
self.format = format if format is not empty else self.format
self.input_formats = input_formats if input_formats is not None else self.input_formats
self.default_timezone = default_timezone if default_timezone is not None else self.default_timezone
super(DateTimeField, self).__init__(*args, **kwargs)
def enforce_timezone(self, value):
"""
When `self.default_timezone` is `None`, always return naive datetimes.
When `self.default_timezone` is not `None`, always return aware datetimes.
"""
if (self.default_timezone is not None) and not timezone.is_aware(value):
return timezone.make_aware(value, self.default_timezone)
elif (self.default_timezone is None) and timezone.is_aware(value):
return timezone.make_naive(value, timezone.UTC())
return value
def to_internal_value(self, value):
if isinstance(value, datetime.date) and not isinstance(value, datetime.datetime):
self.fail('date')
if isinstance(value, datetime.datetime):
return self.enforce_timezone(value)
for format in self.input_formats:
if format.lower() == ISO_8601:
try:
parsed = parse_datetime(value)
except (ValueError, TypeError):
pass
else:
if parsed is not None:
return self.enforce_timezone(parsed)
else:
try:
parsed = self.datetime_parser(value, format)
except (ValueError, TypeError):
pass
else:
return self.enforce_timezone(parsed)
humanized_format = humanize_datetime.datetime_formats(self.input_formats)
self.fail('invalid', format=humanized_format)
def to_representation(self, value):
if self.format is None:
return value
if self.format.lower() == ISO_8601:
value = value.isoformat()
if value.endswith('+00:00'):
value = value[:-6] + 'Z'
return value
return value.strftime(self.format)
class DateField(Field):
default_error_messages = {
'invalid': _('Date has wrong format. Use one of these formats instead: {format}.'),
'datetime': _('Expected a date but got a datetime.'),
}
format = api_settings.DATE_FORMAT
input_formats = api_settings.DATE_INPUT_FORMATS
datetime_parser = datetime.datetime.strptime
def __init__(self, format=empty, input_formats=None, *args, **kwargs):
self.format = format if format is not empty else self.format
self.input_formats = input_formats if input_formats is not None else self.input_formats
super(DateField, self).__init__(*args, **kwargs)
def to_internal_value(self, value):
if isinstance(value, datetime.datetime):
self.fail('datetime')
if isinstance(value, datetime.date):
return value
for format in self.input_formats:
if format.lower() == ISO_8601:
try:
parsed = parse_date(value)
except (ValueError, TypeError):
pass
else:
if parsed is not None:
return parsed
else:
try:
parsed = self.datetime_parser(value, format)
except (ValueError, TypeError):
pass
else:
return parsed.date()
humanized_format = humanize_datetime.date_formats(self.input_formats)
self.fail('invalid', format=humanized_format)
def to_representation(self, value):
if not value:
return None
if self.format is None:
return value
# Applying a `DateField` to a datetime value is almost always
# not a sensible thing to do, as it means naively dropping
# any explicit or implicit timezone info.
assert not isinstance(value, datetime.datetime), (
'Expected a `date`, but got a `datetime`. Refusing to coerce, '
'as this may mean losing timezone information. Use a custom '
'read-only field and deal with timezone issues explicitly.'
)
if self.format.lower() == ISO_8601:
if (isinstance(value, str)):
value = datetime.datetime.strptime(value, '%Y-%m-%d').date()
return value.isoformat()
return value.strftime(self.format)
class TimeField(Field):
default_error_messages = {
'invalid': _('Time has wrong format. Use one of these formats instead: {format}.'),
}
format = api_settings.TIME_FORMAT
input_formats = api_settings.TIME_INPUT_FORMATS
datetime_parser = datetime.datetime.strptime
def __init__(self, format=empty, input_formats=None, *args, **kwargs):
self.format = format if format is not empty else self.format
self.input_formats = input_formats if input_formats is not None else self.input_formats
super(TimeField, self).__init__(*args, **kwargs)
def to_internal_value(self, value):
if isinstance(value, datetime.time):
return value
for format in self.input_formats:
if format.lower() == ISO_8601:
try:
parsed = parse_time(value)
except (ValueError, TypeError):
pass
else:
if parsed is not None:
return parsed
else:
try:
parsed = self.datetime_parser(value, format)
except (ValueError, TypeError):
pass
else:
return parsed.time()
humanized_format = humanize_datetime.time_formats(self.input_formats)
self.fail('invalid', format=humanized_format)
def to_representation(self, value):
if self.format is None:
return value
# Applying a `TimeField` to a datetime value is almost always
# not a sensible thing to do, as it means naively dropping
# any explicit or implicit timezone info.
assert not isinstance(value, datetime.datetime), (
'Expected a `time`, but got a `datetime`. Refusing to coerce, '
'as this may mean losing timezone information. Use a custom '
'read-only field and deal with timezone issues explicitly.'
)
if self.format.lower() == ISO_8601:
return value.isoformat()
return value.strftime(self.format)
class DurationField(Field):
default_error_messages = {
'invalid': _('Duration has wrong format. Use one of these formats instead: {format}.'),
}
def __init__(self, *args, **kwargs):
if parse_duration is None:
raise NotImplementedError(
'DurationField not supported for django versions prior to 1.8')
return super(DurationField, self).__init__(*args, **kwargs)
def to_internal_value(self, value):
if isinstance(value, datetime.timedelta):
return value
parsed = parse_duration(value)
if parsed is not None:
return parsed
self.fail('invalid', format='[DD] [HH:[MM:]]ss[.uuuuuu]')
def to_representation(self, value):
return duration_string(value)
# Choice types...
class ChoiceField(Field):
default_error_messages = {
'invalid_choice': _('"{input}" is not a valid choice.')
}
def __init__(self, choices, **kwargs):
# Allow either single or paired choices style:
# choices = [1, 2, 3]
# choices = [(1, 'First'), (2, 'Second'), (3, 'Third')]
pairs = [
isinstance(item, (list, tuple)) and len(item) == 2
for item in choices
]
if all(pairs):
self.choices = OrderedDict([(key, display_value) for key, display_value in choices])
else:
self.choices = OrderedDict([(item, item) for item in choices])
# Map the string representation of choices to the underlying value.
# Allows us to deal with eg. integer choices while supporting either
# integer or string input, but still get the correct datatype out.
self.choice_strings_to_values = dict([
(six.text_type(key), key) for key in self.choices.keys()
])
self.allow_blank = kwargs.pop('allow_blank', False)
super(ChoiceField, self).__init__(**kwargs)
def to_internal_value(self, data):
if data == '' and self.allow_blank:
return ''
try:
return self.choice_strings_to_values[six.text_type(data)]
except KeyError:
self.fail('invalid_choice', input=data)
def to_representation(self, value):
if value in ('', None):
return value
return self.choice_strings_to_values.get(six.text_type(value), value)
class MultipleChoiceField(ChoiceField):
default_error_messages = {
'invalid_choice': _('"{input}" is not a valid choice.'),
'not_a_list': _('Expected a list of items but got type "{input_type}".')
}
default_empty_html = []
def get_value(self, dictionary):
# We override the default field access in order to support
# lists in HTML forms.
if html.is_html_input(dictionary):
ret = dictionary.getlist(self.field_name)
if getattr(self.root, 'partial', False) and not ret:
ret = empty
return ret
return dictionary.get(self.field_name, empty)
def to_internal_value(self, data):
if isinstance(data, type('')) or not hasattr(data, '__iter__'):
self.fail('not_a_list', input_type=type(data).__name__)
return set([
super(MultipleChoiceField, self).to_internal_value(item)
for item in data
])
def to_representation(self, value):
return set([
self.choice_strings_to_values.get(six.text_type(item), item) for item in value
])
# File types...
class FileField(Field):
default_error_messages = {
'required': _('No file was submitted.'),
'invalid': _('The submitted data was not a file. Check the encoding type on the form.'),
'no_name': _('No filename could be determined.'),
'empty': _('The submitted file is empty.'),
'max_length': _('Ensure this filename has at most {max_length} characters (it has {length}).'),
}
use_url = api_settings.UPLOADED_FILES_USE_URL
def __init__(self, *args, **kwargs):
self.max_length = kwargs.pop('max_length', None)
self.allow_empty_file = kwargs.pop('allow_empty_file', False)
self.use_url = kwargs.pop('use_url', self.use_url)
super(FileField, self).__init__(*args, **kwargs)
def to_internal_value(self, data):
try:
# `UploadedFile` objects should have name and size attributes.
file_name = data.name
file_size = data.size
except AttributeError:
self.fail('invalid')
if not file_name:
self.fail('no_name')
if not self.allow_empty_file and not file_size:
self.fail('empty')
if self.max_length and len(file_name) > self.max_length:
self.fail('max_length', max_length=self.max_length, length=len(file_name))
return data
def to_representation(self, value):
if not value:
return None
if self.use_url:
if not getattr(value, 'url', None):
# If the file has not been saved it may not have a URL.
return None
url = value.url
request = self.context.get('request', None)
if request is not None:
return request.build_absolute_uri(url)
return url
return value.name
class ImageField(FileField):
default_error_messages = {
'invalid_image': _(
'Upload a valid image. The file you uploaded was either not an image or a corrupted image.'
),
}
def __init__(self, *args, **kwargs):
self._DjangoImageField = kwargs.pop('_DjangoImageField', DjangoImageField)
super(ImageField, self).__init__(*args, **kwargs)
def to_internal_value(self, data):
# Image validation is a bit grungy, so we'll just outright
# defer to Django's implementation so we don't need to
# consider it, or treat PIL as a test dependency.
file_object = super(ImageField, self).to_internal_value(data)
django_field = self._DjangoImageField()
django_field.error_messages = self.error_messages
django_field.to_python(file_object)
return file_object
# Composite field types...
class _UnvalidatedField(Field):
def __init__(self, *args, **kwargs):
super(_UnvalidatedField, self).__init__(*args, **kwargs)
self.allow_blank = True
self.allow_null = True
def to_internal_value(self, data):
return data
def to_representation(self, value):
return value
class ListField(Field):
child = _UnvalidatedField()
initial = []
default_error_messages = {
'not_a_list': _('Expected a list of items but got type "{input_type}".')
}
def __init__(self, *args, **kwargs):
self.child = kwargs.pop('child', copy.deepcopy(self.child))
assert not inspect.isclass(self.child), '`child` has not been instantiated.'
super(ListField, self).__init__(*args, **kwargs)
self.child.bind(field_name='', parent=self)
def get_value(self, dictionary):
# We override the default field access in order to support
# lists in HTML forms.
if html.is_html_input(dictionary):
return html.parse_html_list(dictionary, prefix=self.field_name)
return dictionary.get(self.field_name, empty)
def to_internal_value(self, data):
"""
List of dicts of native values <- List of dicts of primitive datatypes.
"""
if html.is_html_input(data):
data = html.parse_html_list(data)
if isinstance(data, type('')) or not hasattr(data, '__iter__'):
self.fail('not_a_list', input_type=type(data).__name__)
return [self.child.run_validation(item) for item in data]
def to_representation(self, data):
"""
List of object instances -> List of dicts of primitive datatypes.
"""
return [self.child.to_representation(item) for item in data]
class DictField(Field):
child = _UnvalidatedField()
initial = {}
default_error_messages = {
'not_a_dict': _('Expected a dictionary of items but got type "{input_type}".')
}
def __init__(self, *args, **kwargs):
self.child = kwargs.pop('child', copy.deepcopy(self.child))
assert not inspect.isclass(self.child), '`child` has not been instantiated.'
super(DictField, self).__init__(*args, **kwargs)
self.child.bind(field_name='', parent=self)
def get_value(self, dictionary):
# We override the default field access in order to support
# dictionaries in HTML forms.
if html.is_html_input(dictionary):
return html.parse_html_dict(dictionary, prefix=self.field_name)
return dictionary.get(self.field_name, empty)
def to_internal_value(self, data):
"""
Dicts of native values <- Dicts of primitive datatypes.
"""
if html.is_html_input(data):
data = html.parse_html_dict(data)
if not isinstance(data, dict):
self.fail('not_a_dict', input_type=type(data).__name__)
return dict([
(six.text_type(key), self.child.run_validation(value))
for key, value in data.items()
])
def to_representation(self, value):
"""
List of object instances -> List of dicts of primitive datatypes.
"""
return dict([
(six.text_type(key), self.child.to_representation(val))
for key, val in value.items()
])
# Miscellaneous field types...
class ReadOnlyField(Field):
"""
A read-only field that simply returns the field value.
If the field is a method with no parameters, the method will be called
and it's return value used as the representation.
For example, the following would call `get_expiry_date()` on the object:
class ExampleSerializer(self):
expiry_date = ReadOnlyField(source='get_expiry_date')
"""
def __init__(self, **kwargs):
kwargs['read_only'] = True
super(ReadOnlyField, self).__init__(**kwargs)
def to_representation(self, value):
return value
class HiddenField(Field):
"""
A hidden field does not take input from the user, or present any output,
but it does populate a field in `validated_data`, based on its default
value. This is particularly useful when we have a `unique_for_date`
constraint on a pair of fields, as we need some way to include the date in
the validated data.
"""
def __init__(self, **kwargs):
assert 'default' in kwargs, 'default is a required argument.'
kwargs['write_only'] = True
super(HiddenField, self).__init__(**kwargs)
def get_value(self, dictionary):
# We always use the default value for `HiddenField`.
# User input is never provided or accepted.
return empty
def to_internal_value(self, data):
return data
class SerializerMethodField(Field):
"""
A read-only field that get its representation from calling a method on the
parent serializer class. The method called will be of the form
"get_{field_name}", and should take a single argument, which is the
object being serialized.
For example:
class ExampleSerializer(self):
extra_info = SerializerMethodField()
def get_extra_info(self, obj):
return ... # Calculate some data to return.
"""
def __init__(self, method_name=None, **kwargs):
self.method_name = method_name
kwargs['source'] = '*'
kwargs['read_only'] = True
super(SerializerMethodField, self).__init__(**kwargs)
def bind(self, field_name, parent):
# In order to enforce a consistent style, we error if a redundant
# 'method_name' argument has been used. For example:
# my_field = serializer.CharField(source='my_field')
default_method_name = 'get_{field_name}'.format(field_name=field_name)
assert self.method_name != default_method_name, (
"It is redundant to specify `%s` on SerializerMethodField '%s' in "
"serializer '%s', because it is the same as the default method name. "
"Remove the `method_name` argument." %
(self.method_name, field_name, parent.__class__.__name__)
)
# The method name should default to `get_{field_name}`.
if self.method_name is None:
self.method_name = default_method_name
super(SerializerMethodField, self).bind(field_name, parent)
def to_representation(self, value):
method = getattr(self.parent, self.method_name)
return method(value)
class ModelField(Field):
"""
A generic field that can be used against an arbitrary model field.
This is used by `ModelSerializer` when dealing with custom model fields,
that do not have a serializer field to be mapped to.
"""
default_error_messages = {
'max_length': _('Ensure this field has no more than {max_length} characters.'),
}
def __init__(self, model_field, **kwargs):
self.model_field = model_field
# The `max_length` option is supported by Django's base `Field` class,
# so we'd better support it here.
max_length = kwargs.pop('max_length', None)
super(ModelField, self).__init__(**kwargs)
if max_length is not None:
message = self.error_messages['max_length'].format(max_length=max_length)
self.validators.append(MaxLengthValidator(max_length, message=message))
def to_internal_value(self, data):
rel = getattr(self.model_field, 'rel', None)
if rel is not None:
return rel.to._meta.get_field(rel.field_name).to_python(data)
return self.model_field.to_python(data)
def get_attribute(self, obj):
# We pass the object instance onto `to_representation`,
# not just the field attribute.
return obj
def to_representation(self, obj):
value = self.model_field._get_val_from_obj(obj)
if is_protected_type(value):
return value
return self.model_field.value_to_string(obj)