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| author | Tom Christie | 2014-08-29 16:46:26 +0100 |
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| committer | Tom Christie | 2014-08-29 16:46:26 +0100 |
| commit | 4ac4676a40b121d27cfd1173ff548d96b8d3de2f (patch) | |
| tree | 560509db11316a36189088dd8b03df4126a696cd /rest_framework/relations.py | |
| parent | 371d30aa8737c4b3aaf28ee10cc2b77a9c4d1fd9 (diff) | |
| download | django-rest-framework-4ac4676a40b121d27cfd1173ff548d96b8d3de2f.tar.bz2 | |
First pass
Diffstat (limited to 'rest_framework/relations.py')
| -rw-r--r-- | rest_framework/relations.py | 486 |
1 files changed, 0 insertions, 486 deletions
diff --git a/rest_framework/relations.py b/rest_framework/relations.py index 56870b40..e69de29b 100644 --- a/rest_framework/relations.py +++ b/rest_framework/relations.py @@ -1,486 +0,0 @@ -""" -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.reverse import reverse -from rest_framework.compat import urlparse -from rest_framework.compat import smart_text - - -# Relational fields - -# Not actually Writable, but subclasses may need to be. -class RelatedField(WritableField): - """ - Base class for related model fields. - - This represents a relationship using the unicode representation of the target. - """ - 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) - - 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 - - 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 - - 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): - """ - Represents a relationship as a pk value. - """ - 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 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) - - # 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 = self.error_messages['does_not_exist'] % smart_text(data) - raise ValidationError(msg) - 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 - try: - # Prefer obj.serializable_value for performance reasons - pk = obj.serializable_value(self.source or field_name) - 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) - - -# 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) - - -# 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.'), - } - - def __init__(self, *args, **kwargs): - try: - self.view_name = kwargs.pop('view_name') - except KeyError: - raise ValueError("Hyperlinked field requires 'view_name' kwarg") - - self.lookup_field = kwargs.pop('lookup_field', self.lookup_field) - self.format = kwargs.pop('format', None) - - super(HyperlinkedRelatedField, self).__init__(*args, **kwargs) - - 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) - kwargs = {self.lookup_field: lookup_field} - return reverse(view_name, kwargs=kwargs, request=request, format=format) - - 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_value = view_kwargs[self.lookup_field] - filter_kwargs = {self.lookup_field: lookup_value} - 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) - - 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') - - try: - http_prefix = value.startswith(('http:', 'https:')) - except AttributeError: - msg = self.error_messages['incorrect_type'] - raise ValidationError(msg % type(value).__name__) - - if http_prefix: - # If needed convert absolute URLs to relative path - value = urlparse.urlparse(value).path - prefix = get_script_prefix() - if value.startswith(prefix): - value = '/' + value[len(prefix):] - - try: - match = resolve(value) - except Exception: - raise ValidationError(self.error_messages['no_match']) - - if match.view_name != self.view_name: - raise ValidationError(self.error_messages['incorrect_match']) - - try: - return self.get_object(queryset, 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 - - 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 - - super(HyperlinkedIdentityField, self).__init__(*args, **kwargs) - - def field_to_native(self, obj, field_name): - 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" - " context. Add `context={'request': request}` when instantiating " - "the serializer." - ) - - # By default use whatever format is given for the current context - # unless the target is a different type to the source. - # - # Eg. Consider a HyperlinkedIdentityField pointing from a json - # representation to an html property of that representation... - # - # '/snippets/1/' should link to '/snippets/1/highlight/' - # ...but... - # '/snippets/1/.json' should link to '/snippets/1/highlight/.html' - if format and self.format and self.format != format: - format = self.format - - # 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) - - 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} - - # Handle unsaved object case - if lookup_field is None: - return None - - return reverse(view_name, kwargs=kwargs, request=request, format=format) |
