metadata.py

fromcollectionsimportOrderedDict

fromdjango.db.models.fieldsimportrelated
fromdjango.utils.encodingimportforce_text
fromrest_frameworkimportserializers
fromrest_framework.metadataimportSimpleMetadata
fromrest_framework.settingsimportapi_settings
fromrest_framework.utils.field_mappingimportClassLookupDict

fromrest_framework_json_api.utilsimportget_related_resource_type


classJSONAPIMetadata(SimpleMetadata):
"""
 This is the JSON:API metadata implementation.
 It returns an ad-hoc set of information about the view.
 There are not any formalized standards for `OPTIONS` responses
 for us to base this on.
 """
type_lookup=ClassLookupDict({
serializers.Field: 'GenericField',
serializers.RelatedField: 'Relationship',
serializers.BooleanField: 'Boolean',
serializers.NullBooleanField: 'Boolean',
serializers.CharField: 'String',
serializers.URLField: 'URL',
serializers.EmailField: 'Email',
serializers.RegexField: 'Regex',
serializers.SlugField: 'Slug',
serializers.IntegerField: 'Integer',
serializers.FloatField: 'Float',
serializers.DecimalField: 'Decimal',
serializers.DateField: 'Date',
serializers.DateTimeField: 'DateTime',
serializers.TimeField: 'Time',
serializers.ChoiceField: 'Choice',
serializers.MultipleChoiceField: 'MultipleChoice',
serializers.FileField: 'File',
serializers.ImageField: 'Image',
serializers.ListField: 'List',
serializers.DictField: 'Dict',
serializers.Serializer: 'Serializer',
 })

try:
relation_type_lookup=ClassLookupDict({
related.ManyToManyDescriptor: 'ManyToMany',
related.ReverseManyToOneDescriptor: 'OneToMany',
related.ForwardManyToOneDescriptor: 'ManyToOne',
 })
exceptAttributeError:
relation_type_lookup=ClassLookupDict({
related.ManyRelatedObjectsDescriptor: 'ManyToMany',
related.ReverseManyRelatedObjectsDescriptor: 'ManyToMany',
related.ForeignRelatedObjectsDescriptor: 'OneToMany',
related.ReverseSingleRelatedObjectDescriptor: 'ManyToOne',
 })

defdetermine_metadata(self, request, view):
metadata=OrderedDict()
metadata['name'] =view.get_view_name()
metadata['description'] =view.get_view_description()
metadata['renders'] = [renderer.media_typeforrendererinview.renderer_classes]
metadata['parses'] = [parser.media_typeforparserinview.parser_classes]
metadata['allowed_methods'] =view.allowed_methods
ifhasattr(view, 'get_serializer'):
actions=self.determine_actions(request, view)
ifactions:
metadata['actions'] =actions
returnmetadata

defget_serializer_info(self, serializer):
"""
 Given an instance of a serializer, return a dictionary of metadata
 about its fields.
 """
ifhasattr(serializer, 'child'):
# If this is a `ListSerializer` then we want to examine the
# underlying child serializer instance instead.
serializer=serializer.child

# Remove the URL field if present
serializer.fields.pop(api_settings.URL_FIELD_NAME, None)

returnOrderedDict(
 [(field_name, self.get_field_info(field)) forfield_name, fieldinserializer.fields.items()]
 )

defget_field_info(self, field):
"""
 Given an instance of a serializer field, return a dictionary
 of metadata about it.
 """
field_info=OrderedDict()
serializer=field.parent

ifisinstance(field, serializers.ManyRelatedField):
field_info['type'] =self.type_lookup[field.child_relation]
else:
field_info['type'] =self.type_lookup[field]

try:
serializer_model=getattr(serializer.Meta, 'model')
field_info['relationship_type'] =self.relation_type_lookup[getattr(serializer_model, field.field_name)]
exceptKeyError:
pass
exceptAttributeError:
pass
else:
field_info['relationship_resource'] =get_related_resource_type(field)

field_info['required'] =getattr(field, 'required', False)

attrs= [
'read_only', 'write_only', 'label', 'help_text',
'min_length', 'max_length',
'min_value', 'max_value', 'initial'
 ]

forattrinattrs:
value=getattr(field, attr, None)
ifvalueisnotNoneandvalue!='':
field_info[attr] =force_text(value, strings_only=True)

ifgetattr(field, 'child', None):
field_info['child'] =self.get_field_info(field.child)
elifgetattr(field, 'fields', None):
field_info['children'] =self.get_serializer_info(field)

if (notfield_info.get('read_only')
andhasattr(field, 'choices')
andnotfield_info.get('relationship_resource')):
field_info['choices'] = [
 {
'value': choice_value,
'display_name': force_text(choice_name, strings_only=True)
 }
forchoice_value, choice_nameinfield.choices.items()
 ]

ifhasattr(serializer, 'included_serializers') and'relationship_resource'infield_info:
field_info['allows_include'] =field.field_nameinserializer.included_serializers

returnfield_info