django-rest-framework/rest_framework/fields.py
2012-10-15 09:14:01 +02:00

588 lines
19 KiB
Python

import copy
import datetime
import inspect
import warnings
from django.core import validators
from django.core.exceptions import ObjectDoesNotExist, ValidationError
from django.core.urlresolvers import resolve
from django.conf import settings
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
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
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):
"""
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 corrosponds to, if one exists.
"""
self.parent = parent
self.root = parent.root or parent
self.context = self.root.context
def field_from_native(self, data, 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)
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]
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.'),
}
def __init__(self, source=None, readonly=False, required=None,
validators=[], error_messages=None):
super(WritableField, self).__init__(source=source)
self.readonly = readonly
if required is None:
self.required = not(readonly)
else:
assert not readonly, "Cannot set required=True and readonly=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
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, field_name, into):
"""
Given a dictionary and a field name, updates the dictionary `into`,
with the field and it's deserialized value.
"""
if self.readonly:
return
try:
native = data[field_name]
except KeyError:
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 arbirtrary model field.
"""
def __init__(self, *args, **kwargs):
try:
self.model_field = kwargs.pop('model_field')
except:
raise ValueError("ModelField requires 'model_field' kwarg")
super(ModelField, self).__init__(*args, **kwargs)
def from_native(self, value):
try:
rel = self.model_field.rel
except:
return self.model_field.to_python(value)
return rel.to._meta.get_field(rel.field_name).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 #####
class RelatedField(WritableField):
"""
Base class for related model fields.
"""
def __init__(self, *args, **kwargs):
self.queryset = kwargs.pop('queryset', None)
super(RelatedField, self).__init__(*args, **kwargs)
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, field_name, into):
value = data.get(field_name)
into[(self.source or field_name) + '_id'] = self.from_native(value)
class ManyRelatedMixin(object):
"""
Mixin to convert a related field to a many related field.
"""
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, field_name, into):
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.
"""
pass
### PrimaryKey relationships
class PrimaryKeyRelatedField(RelatedField):
"""
Serializes a related field or related object to a pk value.
"""
def to_native(self, pk):
return pk
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):
"""
Serializes a to-many related field or related manager to a pk value.
"""
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()]
### Hyperlinked relationships
class HyperlinkedRelatedField(RelatedField):
pk_url_kwarg = 'pk'
slug_url_kwarg = 'slug'
slug_field = 'slug'
def __init__(self, *args, **kwargs):
try:
self.view_name = kwargs.pop('view_name')
except:
raise ValueError("Hyperlinked field requires 'view_name' kwarg")
super(HyperlinkedRelatedField, self).__init__(*args, **kwargs)
def to_native(self, obj):
view_name = self.view_name
request = self.context.get('request', None)
kwargs = {self.pk_url_kwarg: obj.pk}
try:
return reverse(view_name, kwargs=kwargs, request=request)
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)
except:
pass
kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
try:
return reverse(self.view_name, kwargs=kwargs, request=request)
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
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:
return 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.pk
class ManyHyperlinkedRelatedField(ManyRelatedMixin, HyperlinkedRelatedField):
pass
class HyperlinkedIdentityField(Field):
"""
A field that represents the model's identity using a hyperlink.
"""
def __init__(self, *args, **kwargs):
# TODO: Make this mandatory, and have the HyperlinkedModelSerializer
# set it on-the-fly
self.view_name = kwargs.pop('view_name', None)
super(HyperlinkedIdentityField, self).__init__(*args, **kwargs)
def field_to_native(self, obj, field_name):
request = self.context.get('request', None)
view_name = self.view_name or self.parent.opts.view_name
view_kwargs = {'pk': obj.pk}
return reverse(view_name, kwargs=view_kwargs, request=request)
##### Typed Fields #####
class BooleanField(WritableField):
type_name = 'BooleanField'
default_error_messages = {
'invalid': _(u"'%s' value must be either True or False."),
}
def from_native(self, value):
if value in (True, False):
# if value is 1 or 0 than it's equal to True or False, but we want
# to return a true bool for semantic reasons.
return bool(value)
if value in ('t', 'True', '1'):
return True
if value in ('f', 'False', '0'):
return False
raise ValidationError(self.error_messages['invalid'] % value)
class TextField(WritableField):
type_name = 'TextField'
def from_native(self, value):
if isinstance(value, basestring) or value is None:
return value
return smart_unicode(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 from_native(self, value):
if isinstance(value, basestring) or value is None:
return value
return smart_unicode(value)
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):
return super(EmailField, self).from_native(value).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 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 is None:
return value
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 is None:
return value
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 is None:
return value
try:
return float(value)
except (TypeError, ValueError):
msg = self.error_messages['invalid'] % value
raise ValidationError(msg)