django-rest-framework/rest_framework/fields.py
Ludwig Kraatz bf77a92c66 Namespace for views specified in Serializers attr possible
added _default_view_namespace attr of serializers, and view_namespace
as hyperlinked fields init attr
2012-11-08 16:27:38 +01:00

918 lines
30 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, 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
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, 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, 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:
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")
super(ModelField, self).__init__(*args, **kwargs)
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 serializier 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, 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, 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.view_namespace = kwargs.pop('view_namespace',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)
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):
if self.view_namespace:
view_name = "%(namespace)s:%(view)s" % {
'view':self.view_name,
'namespace':self.view_namespace
}
else:
view_name = self.view_name
request = self.context.get('request', None)
format = self.format or self.context.get('format', None)
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(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(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.view_namespace = kwargs.pop('view_namespace', 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_namespace = self.view_namespace or self.parent.opts.view_namespace
view_name = self.view_name or self.parent.opts.view_name
if view_namespace:
view_name = "%(namespace)s:%(view)s" % {
'view':view_name,
'namespace':view_namespace
}
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(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(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 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 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)