django-rest-framework/rest_framework/fields.py
Stephan Groß 6ba4df8a27 Merge remote-tracking branch 'upstream/master' into regex_field
Conflicts:
	docs/topics/release-notes.md
2012-11-21 11:56:34 +01:00

1076 lines
36 KiB
Python

import copy
import datetime
import inspect
import re
import warnings
from io import BytesIO
from django.core import validators
from django.core.exceptions import ObjectDoesNotExist, ValidationError
from django.core.urlresolvers import resolve, get_script_prefix
from django.conf import settings
from django.forms import widgets
from django.forms.models import ModelChoiceIterator
from django.utils.encoding import is_protected_type, smart_unicode
from django.utils.translation import ugettext_lazy as _
from rest_framework.reverse import reverse
from rest_framework.compat import parse_date, parse_datetime
from rest_framework.compat import timezone
from urlparse import urlparse
def is_simple_callable(obj):
"""
True if the object is a callable that takes no arguments.
"""
return (
(inspect.isfunction(obj) and not inspect.getargspec(obj)[0]) or
(inspect.ismethod(obj) and len(inspect.getargspec(obj)[0]) <= 1)
)
class Field(object):
creation_counter = 0
empty = ''
type_name = None
_use_files = None
def __init__(self, source=None):
self.parent = None
self.creation_counter = Field.creation_counter
Field.creation_counter += 1
self.source = source
def initialize(self, parent, field_name):
"""
Called to set up a field prior to field_to_native or field_from_native.
parent - The parent serializer.
model_field - The model field this field corresponds to, if one exists.
"""
self.parent = parent
self.root = parent.root or parent
self.context = self.root.context
def field_from_native(self, data, files, field_name, into):
"""
Given a dictionary and a field name, updates the dictionary `into`,
with the field and it's deserialized value.
"""
return
def field_to_native(self, obj, field_name):
"""
Given and object and a field name, returns the value that should be
serialized for that field.
"""
if obj is None:
return self.empty
if self.source == '*':
return self.to_native(obj)
if self.source:
value = obj
for component in self.source.split('.'):
value = getattr(value, component)
if is_simple_callable(value):
value = value()
else:
value = getattr(obj, field_name)
return self.to_native(value)
def to_native(self, value):
"""
Converts the field's value into it's simple representation.
"""
if is_simple_callable(value):
value = value()
if is_protected_type(value):
return value
elif hasattr(value, '__iter__') and not isinstance(value, (dict, basestring)):
return [self.to_native(item) for item in value]
elif isinstance(value, dict):
return dict(map(self.to_native, (k, v)) for k, v in value.items())
return smart_unicode(value)
def attributes(self):
"""
Returns a dictionary of attributes to be used when serializing to xml.
"""
if self.type_name:
return {'type': self.type_name}
return {}
class WritableField(Field):
"""
Base for read/write fields.
"""
default_validators = []
default_error_messages = {
'required': _('This field is required.'),
'invalid': _('Invalid value.'),
}
widget = widgets.TextInput
default = None
def __init__(self, source=None, read_only=False, required=None,
validators=[], error_messages=None, widget=None,
default=None, blank=None):
super(WritableField, self).__init__(source=source)
self.read_only = read_only
if required is None:
self.required = not(read_only)
else:
assert not read_only, "Cannot set required=True and read_only=True"
self.required = required
messages = {}
for c in reversed(self.__class__.__mro__):
messages.update(getattr(c, 'default_error_messages', {}))
messages.update(error_messages or {})
self.error_messages = messages
self.validators = self.default_validators + validators
self.default = default if default is not None else self.default
self.blank = blank
# Widgets are ony used for HTML forms.
widget = widget or self.widget
if isinstance(widget, type):
widget = widget()
self.widget = widget
def validate(self, value):
if value in validators.EMPTY_VALUES and self.required:
raise ValidationError(self.error_messages['required'])
def run_validators(self, value):
if value in validators.EMPTY_VALUES:
return
errors = []
for v in self.validators:
try:
v(value)
except ValidationError as e:
if hasattr(e, 'code') and e.code in self.error_messages:
message = self.error_messages[e.code]
if e.params:
message = message % e.params
errors.append(message)
else:
errors.extend(e.messages)
if errors:
raise ValidationError(errors)
def field_from_native(self, data, files, field_name, into):
"""
Given a dictionary and a field name, updates the dictionary `into`,
with the field and it's deserialized value.
"""
if self.read_only:
return
try:
if self._use_files:
native = files[field_name]
else:
native = data[field_name]
except KeyError:
if self.default is not None:
native = self.default
else:
if self.required:
raise ValidationError(self.error_messages['required'])
return
value = self.from_native(native)
if self.source == '*':
if value:
into.update(value)
else:
self.validate(value)
self.run_validators(value)
into[self.source or field_name] = value
def from_native(self, value):
"""
Reverts a simple representation back to the field's value.
"""
return value
class ModelField(WritableField):
"""
A generic field that can be used against an arbitrary model field.
"""
def __init__(self, *args, **kwargs):
try:
self.model_field = kwargs.pop('model_field')
except:
raise ValueError("ModelField requires 'model_field' kwarg")
self.min_length = kwargs.pop('min_length',
getattr(self.model_field, 'min_length', None))
self.max_length = kwargs.pop('max_length',
getattr(self.model_field, 'max_length', None))
super(ModelField, self).__init__(*args, **kwargs)
if self.min_length is not None:
self.validators.append(validators.MinLengthValidator(self.min_length))
if self.max_length is not None:
self.validators.append(validators.MaxLengthValidator(self.max_length))
def from_native(self, value):
rel = getattr(self.model_field, "rel", None)
if rel is not None:
return rel.to._meta.get_field(rel.field_name).to_python(value)
else:
return self.model_field.to_python(value)
def field_to_native(self, obj, field_name):
value = self.model_field._get_val_from_obj(obj)
if is_protected_type(value):
return value
return self.model_field.value_to_string(obj)
def attributes(self):
return {
"type": self.model_field.get_internal_type()
}
##### Relational fields #####
# Not actually Writable, but subclasses may need to be.
class RelatedField(WritableField):
"""
Base class for related model fields.
If not overridden, this represents a to-one relationship, using the unicode
representation of the target.
"""
widget = widgets.Select
cache_choices = False
empty_label = None
default_read_only = True # TODO: Remove this
def __init__(self, *args, **kwargs):
self.queryset = kwargs.pop('queryset', None)
super(RelatedField, self).__init__(*args, **kwargs)
self.read_only = kwargs.pop('read_only', self.default_read_only)
def initialize(self, parent, field_name):
super(RelatedField, self).initialize(parent, field_name)
if self.queryset is None and not self.read_only:
try:
manager = getattr(self.parent.opts.model, self.source or field_name)
if hasattr(manager, 'related'): # Forward
self.queryset = manager.related.model._default_manager.all()
else: # Reverse
self.queryset = manager.field.rel.to._default_manager.all()
except:
raise
msg = ('Serializer related fields must include a `queryset`' +
' argument or set `read_only=True')
raise Exception(msg)
### We need this stuff to make form choices work...
# def __deepcopy__(self, memo):
# result = super(RelatedField, self).__deepcopy__(memo)
# result.queryset = result.queryset
# return result
def prepare_value(self, obj):
return self.to_native(obj)
def label_from_instance(self, obj):
"""
Return a readable representation for use with eg. select widgets.
"""
desc = smart_unicode(obj)
ident = smart_unicode(self.to_native(obj))
if desc == ident:
return desc
return "%s - %s" % (desc, ident)
def _get_queryset(self):
return self._queryset
def _set_queryset(self, queryset):
self._queryset = queryset
self.widget.choices = self.choices
queryset = property(_get_queryset, _set_queryset)
def _get_choices(self):
# If self._choices is set, then somebody must have manually set
# the property self.choices. In this case, just return self._choices.
if hasattr(self, '_choices'):
return self._choices
# Otherwise, execute the QuerySet in self.queryset to determine the
# choices dynamically. Return a fresh ModelChoiceIterator that has not been
# consumed. Note that we're instantiating a new ModelChoiceIterator *each*
# time _get_choices() is called (and, thus, each time self.choices is
# accessed) so that we can ensure the QuerySet has not been consumed. This
# construct might look complicated but it allows for lazy evaluation of
# the queryset.
return ModelChoiceIterator(self)
def _set_choices(self, value):
# Setting choices also sets the choices on the widget.
# choices can be any iterable, but we call list() on it because
# it will be consumed more than once.
self._choices = self.widget.choices = list(value)
choices = property(_get_choices, _set_choices)
### Regular serializer stuff...
def field_to_native(self, obj, field_name):
value = getattr(obj, self.source or field_name)
return self.to_native(value)
def field_from_native(self, data, files, field_name, into):
if self.read_only:
return
value = data.get(field_name)
into[(self.source or field_name)] = self.from_native(value)
class ManyRelatedMixin(object):
"""
Mixin to convert a related field to a many related field.
"""
widget = widgets.SelectMultiple
def field_to_native(self, obj, field_name):
value = getattr(obj, self.source or field_name)
return [self.to_native(item) for item in value.all()]
def field_from_native(self, data, files, field_name, into):
if self.read_only:
return
try:
# Form data
value = data.getlist(self.source or field_name)
except:
# Non-form data
value = data.get(self.source or field_name)
else:
if value == ['']:
value = []
into[field_name] = [self.from_native(item) for item in value]
class ManyRelatedField(ManyRelatedMixin, RelatedField):
"""
Base class for related model managers.
If not overridden, this represents a to-many relationship, using the unicode
representations of the target, and is read-only.
"""
pass
### PrimaryKey relationships
class PrimaryKeyRelatedField(RelatedField):
"""
Represents a to-one relationship as a pk value.
"""
default_read_only = False
# TODO: Remove these field hacks...
def prepare_value(self, obj):
return self.to_native(obj.pk)
def label_from_instance(self, obj):
"""
Return a readable representation for use with eg. select widgets.
"""
desc = smart_unicode(obj)
ident = smart_unicode(self.to_native(obj.pk))
if desc == ident:
return desc
return "%s - %s" % (desc, ident)
# TODO: Possibly change this to just take `obj`, through prob less performant
def to_native(self, pk):
return pk
def from_native(self, data):
if self.queryset is None:
raise Exception('Writable related fields must include a `queryset` argument')
try:
return self.queryset.get(pk=data)
except ObjectDoesNotExist:
msg = "Invalid pk '%s' - object does not exist." % smart_unicode(data)
raise ValidationError(msg)
def field_to_native(self, obj, field_name):
try:
# Prefer obj.serializable_value for performance reasons
pk = obj.serializable_value(self.source or field_name)
except AttributeError:
# RelatedObject (reverse relationship)
obj = getattr(obj, self.source or field_name)
return self.to_native(obj.pk)
# Forward relationship
return self.to_native(pk)
class ManyPrimaryKeyRelatedField(ManyRelatedField):
"""
Represents a to-many relationship as a pk value.
"""
default_read_only = False
def prepare_value(self, obj):
return self.to_native(obj.pk)
def label_from_instance(self, obj):
"""
Return a readable representation for use with eg. select widgets.
"""
desc = smart_unicode(obj)
ident = smart_unicode(self.to_native(obj.pk))
if desc == ident:
return desc
return "%s - %s" % (desc, ident)
def to_native(self, pk):
return pk
def field_to_native(self, obj, field_name):
try:
# Prefer obj.serializable_value for performance reasons
queryset = obj.serializable_value(self.source or field_name)
except AttributeError:
# RelatedManager (reverse relationship)
queryset = getattr(obj, self.source or field_name)
return [self.to_native(item.pk) for item in queryset.all()]
# Forward relationship
return [self.to_native(item.pk) for item in queryset.all()]
def from_native(self, data):
if self.queryset is None:
raise Exception('Writable related fields must include a `queryset` argument')
try:
return self.queryset.get(pk=data)
except ObjectDoesNotExist:
msg = "Invalid pk '%s' - object does not exist." % smart_unicode(data)
raise ValidationError(msg)
### Slug relationships
class SlugRelatedField(RelatedField):
default_read_only = False
def __init__(self, *args, **kwargs):
self.slug_field = kwargs.pop('slug_field', None)
assert self.slug_field, 'slug_field is required'
super(SlugRelatedField, self).__init__(*args, **kwargs)
def to_native(self, obj):
return getattr(obj, self.slug_field)
def from_native(self, data):
if self.queryset is None:
raise Exception('Writable related fields must include a `queryset` argument')
try:
return self.queryset.get(**{self.slug_field: data})
except ObjectDoesNotExist:
raise ValidationError('Object with %s=%s does not exist.' %
(self.slug_field, unicode(data)))
class ManySlugRelatedField(ManyRelatedMixin, SlugRelatedField):
pass
### Hyperlinked relationships
class HyperlinkedRelatedField(RelatedField):
"""
Represents a to-one relationship, using hyperlinking.
"""
pk_url_kwarg = 'pk'
slug_field = 'slug'
slug_url_kwarg = None # Defaults to same as `slug_field` unless overridden
default_read_only = False
def __init__(self, *args, **kwargs):
try:
self.view_name = kwargs.pop('view_name')
except:
raise ValueError("Hyperlinked field requires 'view_name' kwarg")
self.slug_field = kwargs.pop('slug_field', self.slug_field)
default_slug_kwarg = self.slug_url_kwarg or self.slug_field
self.pk_url_kwarg = kwargs.pop('pk_url_kwarg', self.pk_url_kwarg)
self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', default_slug_kwarg)
self.format = kwargs.pop('format', None)
super(HyperlinkedRelatedField, self).__init__(*args, **kwargs)
def get_slug_field(self):
"""
Get the name of a slug field to be used to look up by slug.
"""
return self.slug_field
def to_native(self, obj):
view_name = self.view_name
request = self.context.get('request', None)
format = self.format or self.context.get('format', None)
pk = getattr(obj, 'pk', None)
if pk is None:
return
kwargs = {self.pk_url_kwarg: pk}
try:
return reverse(view_name, kwargs=kwargs, request=request, format=format)
except:
pass
slug = getattr(obj, self.slug_field, None)
if not slug:
raise ValidationError('Could not resolve URL for field using view name "%s"' % view_name)
kwargs = {self.slug_url_kwarg: slug}
try:
return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
except:
pass
kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
try:
return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
except:
pass
raise ValidationError('Could not resolve URL for field using view name "%s"', view_name)
def from_native(self, value):
# Convert URL -> model instance pk
# TODO: Use values_list
if self.queryset is None:
raise Exception('Writable related fields must include a `queryset` argument')
if value.startswith('http:') or value.startswith('https:'):
# If needed convert absolute URLs to relative path
value = urlparse(value).path
prefix = get_script_prefix()
if value.startswith(prefix):
value = '/' + value[len(prefix):]
try:
match = resolve(value)
except:
raise ValidationError('Invalid hyperlink - No URL match')
if match.url_name != self.view_name:
raise ValidationError('Invalid hyperlink - Incorrect URL match')
pk = match.kwargs.get(self.pk_url_kwarg, None)
slug = match.kwargs.get(self.slug_url_kwarg, None)
# Try explicit primary key.
if pk is not None:
queryset = self.queryset.filter(pk=pk)
# Next, try looking up by slug.
elif slug is not None:
slug_field = self.get_slug_field()
queryset = self.queryset.filter(**{slug_field: slug})
# If none of those are defined, it's an error.
else:
raise ValidationError('Invalid hyperlink')
try:
obj = queryset.get()
except ObjectDoesNotExist:
raise ValidationError('Invalid hyperlink - object does not exist.')
return obj
class ManyHyperlinkedRelatedField(ManyRelatedMixin, HyperlinkedRelatedField):
"""
Represents a to-many relationship, using hyperlinking.
"""
pass
class HyperlinkedIdentityField(Field):
"""
Represents the instance, or a property on the instance, using hyperlinking.
"""
pk_url_kwarg = 'pk'
slug_field = 'slug'
slug_url_kwarg = None # Defaults to same as `slug_field` unless overridden
def __init__(self, *args, **kwargs):
# TODO: Make view_name mandatory, and have the
# HyperlinkedModelSerializer set it on-the-fly
self.view_name = kwargs.pop('view_name', None)
self.format = kwargs.pop('format', None)
self.slug_field = kwargs.pop('slug_field', self.slug_field)
default_slug_kwarg = self.slug_url_kwarg or self.slug_field
self.pk_url_kwarg = kwargs.pop('pk_url_kwarg', self.pk_url_kwarg)
self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', default_slug_kwarg)
super(HyperlinkedIdentityField, self).__init__(*args, **kwargs)
def field_to_native(self, obj, field_name):
request = self.context.get('request', None)
format = self.format or self.context.get('format', None)
view_name = self.view_name or self.parent.opts.view_name
kwargs = {self.pk_url_kwarg: obj.pk}
try:
return reverse(view_name, kwargs=kwargs, request=request, format=format)
except:
pass
slug = getattr(obj, self.slug_field, None)
if not slug:
raise ValidationError('Could not resolve URL for field using view name "%s"' % view_name)
kwargs = {self.slug_url_kwarg: slug}
try:
return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
except:
pass
kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
try:
return reverse(self.view_name, kwargs=kwargs, request=request, format=format)
except:
pass
raise ValidationError('Could not resolve URL for field using view name "%s"', view_name)
##### Typed Fields #####
class BooleanField(WritableField):
type_name = 'BooleanField'
widget = widgets.CheckboxInput
default_error_messages = {
'invalid': _(u"'%s' value must be either True or False."),
}
empty = False
# Note: we set default to `False` in order to fill in missing value not
# supplied by html form. TODO: Fix so that only html form input gets
# this behavior.
default = False
def from_native(self, value):
if value in ('t', 'True', '1'):
return True
if value in ('f', 'False', '0'):
return False
return bool(value)
class CharField(WritableField):
type_name = 'CharField'
def __init__(self, max_length=None, min_length=None, *args, **kwargs):
self.max_length, self.min_length = max_length, min_length
super(CharField, self).__init__(*args, **kwargs)
if min_length is not None:
self.validators.append(validators.MinLengthValidator(min_length))
if max_length is not None:
self.validators.append(validators.MaxLengthValidator(max_length))
def validate(self, value):
"""
Validates that the value is supplied (if required).
"""
# if empty string and allow blank
if self.blank and not value:
return
else:
super(CharField, self).validate(value)
def from_native(self, value):
if isinstance(value, basestring) or value is None:
return value
return smart_unicode(value)
class URLField(CharField):
type_name = 'URLField'
def __init__(self, **kwargs):
kwargs['max_length'] = kwargs.get('max_length', 200)
kwargs['validators'] = [validators.URLValidator()]
super(URLField, self).__init__(**kwargs)
class SlugField(CharField):
type_name = 'SlugField'
def __init__(self, *args, **kwargs):
kwargs['max_length'] = kwargs.get('max_length', 50)
super(SlugField, self).__init__(*args, **kwargs)
class ChoiceField(WritableField):
type_name = 'ChoiceField'
widget = widgets.Select
default_error_messages = {
'invalid_choice': _('Select a valid choice. %(value)s is not one of the available choices.'),
}
def __init__(self, choices=(), *args, **kwargs):
super(ChoiceField, self).__init__(*args, **kwargs)
self.choices = choices
def _get_choices(self):
return self._choices
def _set_choices(self, value):
# Setting choices also sets the choices on the widget.
# choices can be any iterable, but we call list() on it because
# it will be consumed more than once.
self._choices = self.widget.choices = list(value)
choices = property(_get_choices, _set_choices)
def validate(self, value):
"""
Validates that the input is in self.choices.
"""
super(ChoiceField, self).validate(value)
if value and not self.valid_value(value):
raise ValidationError(self.error_messages['invalid_choice'] % {'value': value})
def valid_value(self, value):
"""
Check to see if the provided value is a valid choice.
"""
for k, v in self.choices:
if isinstance(v, (list, tuple)):
# This is an optgroup, so look inside the group for options
for k2, v2 in v:
if value == smart_unicode(k2):
return True
else:
if value == smart_unicode(k):
return True
return False
class EmailField(CharField):
type_name = 'EmailField'
default_error_messages = {
'invalid': _('Enter a valid e-mail address.'),
}
default_validators = [validators.validate_email]
def from_native(self, value):
ret = super(EmailField, self).from_native(value)
if ret is None:
return None
return ret.strip()
def __deepcopy__(self, memo):
result = copy.copy(self)
memo[id(self)] = result
#result.widget = copy.deepcopy(self.widget, memo)
result.validators = self.validators[:]
return result
class RegexField(CharField):
type_name = 'RegexField'
def __init__(self, regex, max_length=None, min_length=None, *args, **kwargs):
super(RegexField, self).__init__(max_length, min_length, *args, **kwargs)
self.regex = regex
def _get_regex(self):
return self._regex
def _set_regex(self, regex):
if isinstance(regex, basestring):
regex = re.compile(regex)
self._regex = regex
if hasattr(self, '_regex_validator') and self._regex_validator in self.validators:
self.validators.remove(self._regex_validator)
self._regex_validator = validators.RegexValidator(regex=regex)
self.validators.append(self._regex_validator)
regex = property(_get_regex, _set_regex)
def __deepcopy__(self, memo):
result = copy.copy(self)
memo[id(self)] = result
result.validators = self.validators[:]
return result
class DateField(WritableField):
type_name = 'DateField'
default_error_messages = {
'invalid': _(u"'%s' value has an invalid date format. It must be "
u"in YYYY-MM-DD format."),
'invalid_date': _(u"'%s' value has the correct format (YYYY-MM-DD) "
u"but it is an invalid date."),
}
empty = None
def from_native(self, value):
if value in validators.EMPTY_VALUES:
return None
if isinstance(value, datetime.datetime):
if timezone and settings.USE_TZ and timezone.is_aware(value):
# Convert aware datetimes to the default time zone
# before casting them to dates (#17742).
default_timezone = timezone.get_default_timezone()
value = timezone.make_naive(value, default_timezone)
return value.date()
if isinstance(value, datetime.date):
return value
try:
parsed = parse_date(value)
if parsed is not None:
return parsed
except ValueError:
msg = self.error_messages['invalid_date'] % value
raise ValidationError(msg)
msg = self.error_messages['invalid'] % value
raise ValidationError(msg)
class DateTimeField(WritableField):
type_name = 'DateTimeField'
default_error_messages = {
'invalid': _(u"'%s' value has an invalid format. It must be in "
u"YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format."),
'invalid_date': _(u"'%s' value has the correct format "
u"(YYYY-MM-DD) but it is an invalid date."),
'invalid_datetime': _(u"'%s' value has the correct format "
u"(YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ]) "
u"but it is an invalid date/time."),
}
empty = None
def from_native(self, value):
if value in validators.EMPTY_VALUES:
return None
if isinstance(value, datetime.datetime):
return value
if isinstance(value, datetime.date):
value = datetime.datetime(value.year, value.month, value.day)
if settings.USE_TZ:
# For backwards compatibility, interpret naive datetimes in
# local time. This won't work during DST change, but we can't
# do much about it, so we let the exceptions percolate up the
# call stack.
warnings.warn(u"DateTimeField received a naive datetime (%s)"
u" while time zone support is active." % value,
RuntimeWarning)
default_timezone = timezone.get_default_timezone()
value = timezone.make_aware(value, default_timezone)
return value
try:
parsed = parse_datetime(value)
if parsed is not None:
return parsed
except ValueError:
msg = self.error_messages['invalid_datetime'] % value
raise ValidationError(msg)
try:
parsed = parse_date(value)
if parsed is not None:
return datetime.datetime(parsed.year, parsed.month, parsed.day)
except ValueError:
msg = self.error_messages['invalid_date'] % value
raise ValidationError(msg)
msg = self.error_messages['invalid'] % value
raise ValidationError(msg)
class IntegerField(WritableField):
type_name = 'IntegerField'
default_error_messages = {
'invalid': _('Enter a whole number.'),
'max_value': _('Ensure this value is less than or equal to %(limit_value)s.'),
'min_value': _('Ensure this value is greater than or equal to %(limit_value)s.'),
}
def __init__(self, max_value=None, min_value=None, *args, **kwargs):
self.max_value, self.min_value = max_value, min_value
super(IntegerField, self).__init__(*args, **kwargs)
if max_value is not None:
self.validators.append(validators.MaxValueValidator(max_value))
if min_value is not None:
self.validators.append(validators.MinValueValidator(min_value))
def from_native(self, value):
if value in validators.EMPTY_VALUES:
return None
try:
value = int(str(value))
except (ValueError, TypeError):
raise ValidationError(self.error_messages['invalid'])
return value
class FloatField(WritableField):
type_name = 'FloatField'
default_error_messages = {
'invalid': _("'%s' value must be a float."),
}
def from_native(self, value):
if value in validators.EMPTY_VALUES:
return None
try:
return float(value)
except (TypeError, ValueError):
msg = self.error_messages['invalid'] % value
raise ValidationError(msg)
class FileField(WritableField):
_use_files = True
type_name = 'FileField'
widget = widgets.FileInput
default_error_messages = {
'invalid': _("No file was submitted. Check the encoding type on the form."),
'missing': _("No file was submitted."),
'empty': _("The submitted file is empty."),
'max_length': _('Ensure this filename has at most %(max)d characters (it has %(length)d).'),
'contradiction': _('Please either submit a file or check the clear checkbox, not both.')
}
def __init__(self, *args, **kwargs):
self.max_length = kwargs.pop('max_length', None)
self.allow_empty_file = kwargs.pop('allow_empty_file', False)
super(FileField, self).__init__(*args, **kwargs)
def from_native(self, data):
if data in validators.EMPTY_VALUES:
return None
# UploadedFile objects should have name and size attributes.
try:
file_name = data.name
file_size = data.size
except AttributeError:
raise ValidationError(self.error_messages['invalid'])
if self.max_length is not None and len(file_name) > self.max_length:
error_values = {'max': self.max_length, 'length': len(file_name)}
raise ValidationError(self.error_messages['max_length'] % error_values)
if not file_name:
raise ValidationError(self.error_messages['invalid'])
if not self.allow_empty_file and not file_size:
raise ValidationError(self.error_messages['empty'])
return data
def to_native(self, value):
return value.name
class ImageField(FileField):
_use_files = True
default_error_messages = {
'invalid_image': _("Upload a valid image. The file you uploaded was either not an image or a corrupted image."),
}
def from_native(self, data):
"""
Checks that the file-upload field data contains a valid image (GIF, JPG,
PNG, possibly others -- whatever the Python Imaging Library supports).
"""
f = super(ImageField, self).from_native(data)
if f is None:
return None
# Try to import PIL in either of the two ways it can end up installed.
try:
from PIL import Image
except ImportError:
import Image
# We need to get a file object for PIL. We might have a path or we might
# have to read the data into memory.
if hasattr(data, 'temporary_file_path'):
file = data.temporary_file_path()
else:
if hasattr(data, 'read'):
file = BytesIO(data.read())
else:
file = BytesIO(data['content'])
try:
# load() could spot a truncated JPEG, but it loads the entire
# image in memory, which is a DoS vector. See #3848 and #18520.
# verify() must be called immediately after the constructor.
Image.open(file).verify()
except ImportError:
# Under PyPy, it is possible to import PIL. However, the underlying
# _imaging C module isn't available, so an ImportError will be
# raised. Catch and re-raise.
raise
except Exception: # Python Imaging Library doesn't recognize it as an image
raise ValidationError(self.error_messages['invalid_image'])
if hasattr(f, 'seek') and callable(f.seek):
f.seek(0)
return f
class SerializerMethodField(Field):
"""
A field that gets its value by calling a method on the serializer it's attached to.
"""
def __init__(self, method_name):
self.method_name = method_name
super(SerializerMethodField, self).__init__()
def field_to_native(self, obj, field_name):
value = getattr(self.parent, self.method_name)(obj)
return self.to_native(value)