diff options
Diffstat (limited to 'rest_framework/relations.py')
| -rw-r--r-- | rest_framework/relations.py | 761 |
1 files changed, 261 insertions, 500 deletions
diff --git a/rest_framework/relations.py b/rest_framework/relations.py index 1acbdce2..79c8057b 100644 --- a/rest_framework/relations.py +++ b/rest_framework/relations.py @@ -1,356 +1,183 @@ -""" -Serializer fields that deal with relationships. - -These fields allow you to specify the style that should be used to represent -model relationships, including hyperlinks, primary keys, or slugs. -""" -from __future__ import unicode_literals -from django.core.exceptions import ObjectDoesNotExist, ValidationError -from django.core.urlresolvers import resolve, get_script_prefix, NoReverseMatch -from django import forms -from django.db.models.fields import BLANK_CHOICE_DASH -from django.forms import widgets -from django.forms.models import ModelChoiceIterator -from django.utils.translation import ugettext_lazy as _ -from rest_framework.fields import Field, WritableField, get_component, is_simple_callable +from rest_framework.compat import smart_text, urlparse +from rest_framework.fields import get_attribute, empty, Field from rest_framework.reverse import reverse -from rest_framework.compat import urlparse -from rest_framework.compat import smart_text -import warnings - +from rest_framework.utils import html +from django.core.exceptions import ObjectDoesNotExist, ImproperlyConfigured +from django.core.urlresolvers import resolve, get_script_prefix, NoReverseMatch, Resolver404 +from django.db.models.query import QuerySet +from django.utils import six +from django.utils.translation import ugettext_lazy as _ -# Relational fields -# Not actually Writable, but subclasses may need to be. -class RelatedField(WritableField): +class PKOnlyObject(object): """ - Base class for related model fields. - - This represents a relationship using the unicode representation of the target. + This is a mock object, used for when we only need the pk of the object + instance, but still want to return an object with a .pk attribute, + in order to keep the same interface as a regular model instance. """ - widget = widgets.Select - many_widget = widgets.SelectMultiple - form_field_class = forms.ChoiceField - many_form_field_class = forms.MultipleChoiceField - null_values = (None, '', 'None') - - cache_choices = False - empty_label = None - read_only = True - many = False - - def __init__(self, *args, **kwargs): - queryset = kwargs.pop('queryset', None) - self.many = kwargs.pop('many', self.many) - if self.many: - self.widget = self.many_widget - self.form_field_class = self.many_form_field_class - - kwargs['read_only'] = kwargs.pop('read_only', self.read_only) - super(RelatedField, self).__init__(*args, **kwargs) - - if not self.required: - # Accessed in ModelChoiceIterator django/forms/models.py:1034 - # If set adds empty choice. - self.empty_label = BLANK_CHOICE_DASH[0][1] - - self.queryset = queryset - - def initialize(self, parent, field_name): - super(RelatedField, self).initialize(parent, field_name) - if self.queryset is None and not self.read_only: - 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() - - # We need this stuff to make form choices work... - - 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_text(obj) - ident = smart_text(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) - - # Default value handling - - def get_default_value(self): - default = super(RelatedField, self).get_default_value() - if self.many and default is None: - return [] - return default - - # Regular serializer stuff... - - def field_to_native(self, obj, field_name): - try: - if self.source == '*': - return self.to_native(obj) + def __init__(self, pk): + self.pk = pk - source = self.source or field_name - value = obj - for component in source.split('.'): - if value is None: - break - value = get_component(value, component) - except ObjectDoesNotExist: - return None - - if value is None: - return None +# We assume that 'validators' are intended for the child serializer, +# rather than the parent serializer. +MANY_RELATION_KWARGS = ( + 'read_only', 'write_only', 'required', 'default', 'initial', 'source', + 'label', 'help_text', 'style', 'error_messages' +) - if self.many: - if is_simple_callable(getattr(value, 'all', None)): - return [self.to_native(item) for item in value.all()] - else: - # Also support non-queryset iterables. - # This allows us to also support plain lists of related items. - return [self.to_native(item) for item in value] - return self.to_native(value) - def field_from_native(self, data, files, field_name, into): - if self.read_only: - return +class RelatedField(Field): + def __init__(self, **kwargs): + self.queryset = kwargs.pop('queryset', None) + assert self.queryset is not None or kwargs.get('read_only', None), ( + 'Relational field must provide a `queryset` argument, ' + 'or set read_only=`True`.' + ) + assert not (self.queryset is not None and kwargs.get('read_only', None)), ( + 'Relational fields should not provide a `queryset` argument, ' + 'when setting read_only=`True`.' + ) + super(RelatedField, self).__init__(**kwargs) + + def __new__(cls, *args, **kwargs): + # We override this method in order to automagically create + # `ManyRelatedField` classes instead when `many=True` is set. + if kwargs.pop('many', False): + return cls.many_init(*args, **kwargs) + return super(RelatedField, cls).__new__(cls, *args, **kwargs) + + @classmethod + def many_init(cls, *args, **kwargs): + list_kwargs = {'child_relation': cls(*args, **kwargs)} + for key in kwargs.keys(): + if key in MANY_RELATION_KWARGS: + list_kwargs[key] = kwargs[key] + return ManyRelatedField(**list_kwargs) + + def run_validation(self, data=empty): + # We force empty strings to None values for relational fields. + if data == '': + data = None + return super(RelatedField, self).run_validation(data) + + def get_queryset(self): + queryset = self.queryset + if isinstance(queryset, QuerySet): + # Ensure queryset is re-evaluated whenever used. + queryset = queryset.all() + return queryset + + def get_iterable(self, instance, source_attrs): + relationship = get_attribute(instance, source_attrs) + return relationship.all() if (hasattr(relationship, 'all')) else relationship + + @property + def choices(self): + return dict([ + ( + str(self.to_representation(item)), + str(item) + ) + for item in self.queryset.all() + ]) - try: - if self.many: - try: - # Form data - value = data.getlist(field_name) - if value == [''] or value == []: - raise KeyError - except AttributeError: - # Non-form data - value = data[field_name] - else: - value = data[field_name] - except KeyError: - if self.partial: - return - value = self.get_default_value() - - if value in self.null_values: - if self.required: - raise ValidationError(self.error_messages['required']) - into[(self.source or field_name)] = None - elif self.many: - into[(self.source or field_name)] = [self.from_native(item) for item in value] - else: - into[(self.source or field_name)] = self.from_native(value) - - -# PrimaryKey relationships -class PrimaryKeyRelatedField(RelatedField): +class StringRelatedField(RelatedField): """ - Represents a relationship as a pk value. + A read only field that represents its targets using their + plain string representation. """ - read_only = False - - default_error_messages = { - 'does_not_exist': _("Invalid pk '%s' - object does not exist."), - 'incorrect_type': _('Incorrect type. Expected pk value, received %s.'), - } - # TODO: Remove these field hacks... - def prepare_value(self, obj): - return self.to_native(obj.pk) + def __init__(self, **kwargs): + kwargs['read_only'] = True + super(StringRelatedField, self).__init__(**kwargs) - def label_from_instance(self, obj): - """ - Return a readable representation for use with eg. select widgets. - """ - desc = smart_text(obj) - ident = smart_text(self.to_native(obj.pk)) - if desc == ident: - return desc - return "%s - %s" % (desc, ident) + def to_representation(self, value): + return six.text_type(value) - # 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') +class PrimaryKeyRelatedField(RelatedField): + default_error_messages = { + 'required': 'This field is required.', + 'does_not_exist': "Invalid pk '{pk_value}' - object does not exist.", + 'incorrect_type': 'Incorrect type. Expected pk value, received {data_type}.', + } + def to_internal_value(self, data): try: - return self.queryset.get(pk=data) + return self.get_queryset().get(pk=data) except ObjectDoesNotExist: - msg = self.error_messages['does_not_exist'] % smart_text(data) - raise ValidationError(msg) + self.fail('does_not_exist', pk_value=data) except (TypeError, ValueError): - received = type(data).__name__ - msg = self.error_messages['incorrect_type'] % received - raise ValidationError(msg) - - def field_to_native(self, obj, field_name): - if self.many: - # To-many relationship - - queryset = None - if not self.source: - # Prefer obj.serializable_value for performance reasons - try: - queryset = obj.serializable_value(field_name) - except AttributeError: - pass - if queryset is None: - # RelatedManager (reverse relationship) - source = self.source or field_name - queryset = obj - for component in source.split('.'): - if queryset is None: - return [] - queryset = get_component(queryset, component) - - # Forward relationship - if is_simple_callable(getattr(queryset, 'all', None)): - return [self.to_native(item.pk) for item in queryset.all()] - else: - # Also support non-queryset iterables. - # This allows us to also support plain lists of related items. - return [self.to_native(item.pk) for item in queryset] - - # To-one relationship + self.fail('incorrect_type', data_type=type(data).__name__) + + def get_attribute(self, instance): + # We customize `get_attribute` here for performance reasons. + # For relationships the instance will already have the pk of + # the related object. We return this directly instead of returning the + # object itself, which would require a database lookup. try: - # Prefer obj.serializable_value for performance reasons - pk = obj.serializable_value(self.source or field_name) + instance = get_attribute(instance, self.source_attrs[:-1]) + return PKOnlyObject(pk=instance.serializable_value(self.source_attrs[-1])) except AttributeError: - # RelatedObject (reverse relationship) - try: - pk = getattr(obj, self.source or field_name).pk - except (ObjectDoesNotExist, AttributeError): - return None - - # Forward relationship - return self.to_native(pk) + return get_attribute(instance, self.source_attrs) + def get_iterable(self, instance, source_attrs): + # For consistency with `get_attribute` we're using `serializable_value()` + # here. Typically there won't be any difference, but some custom field + # types might return a non-primative value for the pk otherwise. + # + # We could try to get smart with `values_list('pk', flat=True)`, which + # would be better in some case, but would actually end up with *more* + # queries if the developer is using `prefetch_related` across the + # relationship. + relationship = super(PrimaryKeyRelatedField, self).get_iterable(instance, source_attrs) + return [ + PKOnlyObject(pk=item.serializable_value('pk')) + for item in relationship + ] -# Slug relationships - -class SlugRelatedField(RelatedField): - """ - Represents a relationship using a unique field on the target. - """ - read_only = False - - default_error_messages = { - 'does_not_exist': _("Object with %s=%s does not exist."), - 'invalid': _('Invalid value.'), - } - - 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(self.error_messages['does_not_exist'] % - (self.slug_field, smart_text(data))) - except (TypeError, ValueError): - msg = self.error_messages['invalid'] - raise ValidationError(msg) - + def to_representation(self, value): + return value.pk -# Hyperlinked relationships class HyperlinkedRelatedField(RelatedField): - """ - Represents a relationship using hyperlinking. - """ - read_only = False lookup_field = 'pk' default_error_messages = { - 'no_match': _('Invalid hyperlink - No URL match'), - 'incorrect_match': _('Invalid hyperlink - Incorrect URL match'), - 'configuration_error': _('Invalid hyperlink due to configuration error'), - 'does_not_exist': _("Invalid hyperlink - object does not exist."), - 'incorrect_type': _('Incorrect type. Expected url string, received %s.'), + 'required': 'This field is required.', + 'no_match': 'Invalid hyperlink - No URL match', + 'incorrect_match': 'Invalid hyperlink - Incorrect URL match.', + 'does_not_exist': 'Invalid hyperlink - Object does not exist.', + 'incorrect_type': 'Incorrect type. Expected URL string, received {data_type}.', } - # These are all deprecated - pk_url_kwarg = 'pk' - slug_field = 'slug' - slug_url_kwarg = None # Defaults to same as `slug_field` unless overridden - - def __init__(self, *args, **kwargs): - try: - self.view_name = kwargs.pop('view_name') - except KeyError: - raise ValueError("Hyperlinked field requires 'view_name' kwarg") - + def __init__(self, view_name=None, **kwargs): + assert view_name is not None, 'The `view_name` argument is required.' + self.view_name = view_name self.lookup_field = kwargs.pop('lookup_field', self.lookup_field) + self.lookup_url_kwarg = kwargs.pop('lookup_url_kwarg', self.lookup_field) self.format = kwargs.pop('format', None) - # These are deprecated - if 'pk_url_kwarg' in kwargs: - msg = 'pk_url_kwarg is deprecated. Use lookup_field instead.' - warnings.warn(msg, DeprecationWarning, stacklevel=2) - if 'slug_url_kwarg' in kwargs: - msg = 'slug_url_kwarg is deprecated. Use lookup_field instead.' - warnings.warn(msg, DeprecationWarning, stacklevel=2) - if 'slug_field' in kwargs: - msg = 'slug_field is deprecated. Use lookup_field instead.' - warnings.warn(msg, DeprecationWarning, stacklevel=2) + # We include these simply for dependency injection in tests. + # We can't add them as class attributes or they would expect an + # implicit `self` argument to be passed. + self.reverse = reverse + self.resolve = resolve + + super(HyperlinkedRelatedField, self).__init__(**kwargs) - self.pk_url_kwarg = kwargs.pop('pk_url_kwarg', self.pk_url_kwarg) - self.slug_field = kwargs.pop('slug_field', self.slug_field) - default_slug_kwarg = self.slug_url_kwarg or self.slug_field - self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', default_slug_kwarg) + def get_object(self, view_name, view_args, view_kwargs): + """ + Return the object corresponding to a matched URL. - super(HyperlinkedRelatedField, self).__init__(*args, **kwargs) + Takes the matched URL conf arguments, and should return an + object instance, or raise an `ObjectDoesNotExist` exception. + """ + lookup_value = view_kwargs[self.lookup_url_kwarg] + lookup_kwargs = {self.lookup_field: lookup_value} + return self.get_queryset().get(**lookup_kwargs) def get_url(self, obj, view_name, request, format): """ @@ -359,176 +186,48 @@ class HyperlinkedRelatedField(RelatedField): May raise a `NoReverseMatch` if the `view_name` and `lookup_field` attributes are not configured to correctly match the URL conf. """ - lookup_field = getattr(obj, self.lookup_field) - kwargs = {self.lookup_field: lookup_field} - try: - return reverse(view_name, kwargs=kwargs, request=request, format=format) - except NoReverseMatch: - pass - - if self.pk_url_kwarg != 'pk': - # Only try pk if it has been explicitly set. - # Otherwise, the default `lookup_field = 'pk'` has us covered. - pk = obj.pk - kwargs = {self.pk_url_kwarg: pk} - try: - return reverse(view_name, kwargs=kwargs, request=request, format=format) - except NoReverseMatch: - pass - - slug = getattr(obj, self.slug_field, None) - if slug is not None: - # Only try slug if it corresponds to an attribute on the object. - kwargs = {self.slug_url_kwarg: slug} - try: - ret = reverse(view_name, kwargs=kwargs, request=request, format=format) - if self.slug_field == 'slug' and self.slug_url_kwarg == 'slug': - # If the lookup succeeds using the default slug params, - # then `slug_field` is being used implicitly, and we - # we need to warn about the pending deprecation. - msg = 'Implicit slug field hyperlinked fields are deprecated.' \ - 'You should set `lookup_field=slug` on the HyperlinkedRelatedField.' - warnings.warn(msg, DeprecationWarning, stacklevel=2) - return ret - except NoReverseMatch: - pass - - raise NoReverseMatch() - - def get_object(self, queryset, view_name, view_args, view_kwargs): - """ - Return the object corresponding to a matched URL. - - Takes the matched URL conf arguments, and the queryset, and should - return an object instance, or raise an `ObjectDoesNotExist` exception. - """ - lookup = view_kwargs.get(self.lookup_field, None) - pk = view_kwargs.get(self.pk_url_kwarg, None) - slug = view_kwargs.get(self.slug_url_kwarg, None) - - if lookup is not None: - filter_kwargs = {self.lookup_field: lookup} - elif pk is not None: - filter_kwargs = {'pk': pk} - elif slug is not None: - filter_kwargs = {self.slug_field: slug} - else: - raise ObjectDoesNotExist() - - return queryset.get(**filter_kwargs) - - 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) - - assert request is not None, ( - "`HyperlinkedRelatedField` requires the request in the serializer " - "context. Add `context={'request': request}` when instantiating " - "the serializer." - ) - - # If the object has not yet been saved then we cannot hyperlink to it. - if getattr(obj, 'pk', None) is None: - return - - # Return the hyperlink, or error if incorrectly configured. - try: - return self.get_url(obj, view_name, request, format) - except NoReverseMatch: - msg = ( - 'Could not resolve URL for hyperlinked relationship using ' - 'view name "%s". You may have failed to include the related ' - 'model in your API, or incorrectly configured the ' - '`lookup_field` attribute on this field.' - ) - raise Exception(msg % view_name) + # Unsaved objects will not yet have a valid URL. + if obj.pk is None: + return None - def from_native(self, value): - # Convert URL -> model instance pk - # TODO: Use values_list - queryset = self.queryset - if queryset is None: - raise Exception('Writable related fields must include a `queryset` argument') + lookup_value = getattr(obj, self.lookup_field) + kwargs = {self.lookup_url_kwarg: lookup_value} + return self.reverse(view_name, kwargs=kwargs, request=request, format=format) + def to_internal_value(self, data): try: - http_prefix = value.startswith(('http:', 'https:')) + http_prefix = data.startswith(('http:', 'https:')) except AttributeError: - msg = self.error_messages['incorrect_type'] - raise ValidationError(msg % type(value).__name__) + self.fail('incorrect_type', data_type=type(data).__name__) if http_prefix: # If needed convert absolute URLs to relative path - value = urlparse.urlparse(value).path + data = urlparse.urlparse(data).path prefix = get_script_prefix() - if value.startswith(prefix): - value = '/' + value[len(prefix):] + if data.startswith(prefix): + data = '/' + data[len(prefix):] try: - match = resolve(value) - except Exception: - raise ValidationError(self.error_messages['no_match']) + match = self.resolve(data) + except Resolver404: + self.fail('no_match') if match.view_name != self.view_name: - raise ValidationError(self.error_messages['incorrect_match']) + self.fail('incorrect_match') try: - return self.get_object(queryset, match.view_name, - match.args, match.kwargs) + return self.get_object(match.view_name, match.args, match.kwargs) except (ObjectDoesNotExist, TypeError, ValueError): - raise ValidationError(self.error_messages['does_not_exist']) - - -class HyperlinkedIdentityField(Field): - """ - Represents the instance, or a property on the instance, using hyperlinking. - """ - lookup_field = 'pk' - read_only = True + self.fail('does_not_exist') - # These are all deprecated - pk_url_kwarg = 'pk' - slug_field = 'slug' - slug_url_kwarg = None # Defaults to same as `slug_field` unless overridden - - def __init__(self, *args, **kwargs): - try: - self.view_name = kwargs.pop('view_name') - except KeyError: - msg = "HyperlinkedIdentityField requires 'view_name' argument" - raise ValueError(msg) - - self.format = kwargs.pop('format', None) - lookup_field = kwargs.pop('lookup_field', None) - self.lookup_field = lookup_field or self.lookup_field - - # These are deprecated - if 'pk_url_kwarg' in kwargs: - msg = 'pk_url_kwarg is deprecated. Use lookup_field instead.' - warnings.warn(msg, DeprecationWarning, stacklevel=2) - if 'slug_url_kwarg' in kwargs: - msg = 'slug_url_kwarg is deprecated. Use lookup_field instead.' - warnings.warn(msg, DeprecationWarning, stacklevel=2) - if 'slug_field' in kwargs: - msg = 'slug_field is deprecated. Use lookup_field instead.' - warnings.warn(msg, DeprecationWarning, stacklevel=2) - - 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): + def to_representation(self, value): request = self.context.get('request', None) format = self.context.get('format', None) - view_name = self.view_name assert request is not None, ( - "`HyperlinkedIdentityField` requires the request in the serializer" + "`%s` requires the request in the serializer" " context. Add `context={'request': request}` when instantiating " - "the serializer." + "the serializer." % self.__class__.__name__ ) # By default use whatever format is given for the current context @@ -545,7 +244,7 @@ class HyperlinkedIdentityField(Field): # Return the hyperlink, or error if incorrectly configured. try: - return self.get_url(obj, view_name, request, format) + return self.get_url(value, self.view_name, request, format) except NoReverseMatch: msg = ( 'Could not resolve URL for hyperlinked relationship using ' @@ -553,43 +252,105 @@ class HyperlinkedIdentityField(Field): 'model in your API, or incorrectly configured the ' '`lookup_field` attribute on this field.' ) - raise Exception(msg % view_name) + raise ImproperlyConfigured(msg % self.view_name) - def get_url(self, obj, view_name, request, format): - """ - Given an object, return the URL that hyperlinks to the object. - May raise a `NoReverseMatch` if the `view_name` and `lookup_field` - attributes are not configured to correctly match the URL conf. - """ - lookup_field = getattr(obj, self.lookup_field, None) - kwargs = {self.lookup_field: lookup_field} +class HyperlinkedIdentityField(HyperlinkedRelatedField): + """ + A read-only field that represents the identity URL for an object, itself. + + This is in contrast to `HyperlinkedRelatedField` which represents the + URL of relationships to other objects. + """ + + def __init__(self, view_name=None, **kwargs): + assert view_name is not None, 'The `view_name` argument is required.' + kwargs['read_only'] = True + kwargs['source'] = '*' + super(HyperlinkedIdentityField, self).__init__(view_name, **kwargs) - # Handle unsaved object case - if lookup_field is None: - return None +class SlugRelatedField(RelatedField): + """ + A read-write field the represents the target of the relationship + by a unique 'slug' attribute. + """ + + default_error_messages = { + 'does_not_exist': _("Object with {slug_name}={value} does not exist."), + 'invalid': _('Invalid value.'), + } + + def __init__(self, slug_field=None, **kwargs): + assert slug_field is not None, 'The `slug_field` argument is required.' + self.slug_field = slug_field + super(SlugRelatedField, self).__init__(**kwargs) + + def to_internal_value(self, data): try: - return reverse(view_name, kwargs=kwargs, request=request, format=format) - except NoReverseMatch: - pass - - if self.pk_url_kwarg != 'pk': - # Only try pk lookup if it has been explicitly set. - # Otherwise, the default `lookup_field = 'pk'` has us covered. - kwargs = {self.pk_url_kwarg: obj.pk} - try: - return reverse(view_name, kwargs=kwargs, request=request, format=format) - except NoReverseMatch: - pass - - slug = getattr(obj, self.slug_field, None) - if slug: - # Only use slug lookup if a slug field exists on the model - kwargs = {self.slug_url_kwarg: slug} - try: - return reverse(view_name, kwargs=kwargs, request=request, format=format) - except NoReverseMatch: - pass - - raise NoReverseMatch() + return self.get_queryset().get(**{self.slug_field: data}) + except ObjectDoesNotExist: + self.fail('does_not_exist', slug_name=self.slug_field, value=smart_text(data)) + except (TypeError, ValueError): + self.fail('invalid') + + def to_representation(self, obj): + return getattr(obj, self.slug_field) + + +class ManyRelatedField(Field): + """ + Relationships with `many=True` transparently get coerced into instead being + a ManyRelatedField with a child relationship. + + The `ManyRelatedField` class is responsible for handling iterating through + the values and passing each one to the child relationship. + + You shouldn't need to be using this class directly yourself. + """ + initial = [] + default_empty_html = [] + + def __init__(self, child_relation=None, *args, **kwargs): + self.child_relation = child_relation + assert child_relation is not None, '`child_relation` is a required argument.' + super(ManyRelatedField, self).__init__(*args, **kwargs) + self.child_relation.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 dictionary.getlist(self.field_name) + return dictionary.get(self.field_name, empty) + + def to_internal_value(self, data): + return [ + self.child_relation.to_internal_value(item) + for item in data + ] + + def get_attribute(self, instance): + return self.child_relation.get_iterable(instance, self.source_attrs) + + def to_representation(self, iterable): + return [ + self.child_relation.to_representation(value) + for value in iterable + ] + + @property + def choices(self): + queryset = self.child_relation.queryset + iterable = queryset.all() if (hasattr(queryset, 'all')) else queryset + items_and_representations = [ + (item, self.child_relation.to_representation(item)) + for item in iterable + ] + return dict([ + ( + str(item_representation), + str(item) + ' - ' + str(item_representation) + ) + for item, item_representation in items_and_representations + ]) |