395 lines
17 KiB
Python
395 lines
17 KiB
Python
import inspect
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import logging
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from rest_framework import serializers
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from .. import openapi
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from ..utils import force_real_str, get_field_default, is_list_view
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#: Sentinel value that inspectors must return to signal that they do not know how to handle an object
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NotHandled = object()
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logger = logging.getLogger(__name__)
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class BaseInspector(object):
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def __init__(self, view, path, method, components, request):
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"""
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:param view: the view associated with this endpoint
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:param str path: the path component of the operation URL
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:param str method: the http method of the operation
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:param openapi.ReferenceResolver components: referenceable components
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:param Request request: the request made against the schema view; can be None
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"""
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self.view = view
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self.path = path
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self.method = method
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self.components = components
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self.request = request
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def process_result(self, result, method_name, obj, **kwargs):
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"""After an inspector handles an object (i.e. returns a value other than :data:`.NotHandled`), all inspectors
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that were probed get the chance to alter the result, in reverse order. The inspector that handled the object
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is the first to receive a ``process_result`` call with the object it just returned.
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This behaviour is similar to the Django request/response middleware processing.
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If this inspector has no post-processing to do, it should just ``return result`` (the default implementation).
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:param result: the return value of the winning inspector, or ``None`` if no inspector handled the object
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:param str method_name: name of the method that was called on the inspector
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:param obj: first argument passed to inspector method
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:param kwargs: additional arguments passed to inspector method
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:return:
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"""
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return result
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def probe_inspectors(self, inspectors, method_name, obj, initkwargs=None, **kwargs):
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"""Probe a list of inspectors with a given object. The first inspector in the list to return a value that
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is not :data:`.NotHandled` wins.
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:param list[type[BaseInspector]] inspectors: list of inspectors to probe
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:param str method_name: name of the target method on the inspector
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:param obj: first argument to inspector method
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:param dict initkwargs: extra kwargs for instantiating inspector class
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:param kwargs: additional arguments to inspector method
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:return: the return value of the winning inspector, or ``None`` if no inspector handled the object
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"""
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initkwargs = initkwargs or {}
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tried_inspectors = []
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for inspector in inspectors:
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assert inspect.isclass(inspector), "inspector must be a class, not an object"
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assert issubclass(inspector, BaseInspector), "inspectors must subclass BaseInspector"
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inspector = inspector(self.view, self.path, self.method, self.components, self.request, **initkwargs)
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tried_inspectors.append(inspector)
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method = getattr(inspector, method_name, None)
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if method is None:
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continue
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result = method(obj, **kwargs)
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if result is not NotHandled:
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break
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else: # pragma: no cover
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logger.warning("%s ignored because no inspector in %s handled it (operation: %s)",
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obj, inspectors, method_name)
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result = None
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for inspector in reversed(tried_inspectors):
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result = inspector.process_result(result, method_name, obj, **kwargs)
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return result
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class PaginatorInspector(BaseInspector):
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"""Base inspector for paginators.
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Responisble for determining extra query parameters and response structure added by given paginators.
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"""
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def get_paginator_parameters(self, paginator):
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"""Get the pagination parameters for a single paginator **instance**.
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Should return :data:`.NotHandled` if this inspector does not know how to handle the given `paginator`.
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:param BasePagination paginator: the paginator
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:rtype: list[openapi.Parameter]
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"""
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return NotHandled
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def get_paginated_response(self, paginator, response_schema):
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"""Add appropriate paging fields to a response :class:`.Schema`.
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Should return :data:`.NotHandled` if this inspector does not know how to handle the given `paginator`.
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:param BasePagination paginator: the paginator
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:param openapi.Schema response_schema: the response schema that must be paged.
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:rtype: openapi.Schema
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"""
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return NotHandled
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class FilterInspector(BaseInspector):
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"""Base inspector for filter backends.
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Responsible for determining extra query parameters added by given filter backends.
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"""
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def get_filter_parameters(self, filter_backend):
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"""Get the filter parameters for a single filter backend **instance**.
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Should return :data:`.NotHandled` if this inspector does not know how to handle the given `filter_backend`.
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:param BaseFilterBackend filter_backend: the filter backend
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:rtype: list[openapi.Parameter]
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"""
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return NotHandled
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class FieldInspector(BaseInspector):
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"""Base inspector for serializers and serializer fields. """
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def __init__(self, view, path, method, components, request, field_inspectors):
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super(FieldInspector, self).__init__(view, path, method, components, request)
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self.field_inspectors = field_inspectors
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def add_manual_fields(self, serializer_or_field, schema):
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"""Set fields from the ``swagger_schem_fields`` attribute on the Meta class. This method is called
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only for serializers or fields that are converted into ``openapi.Schema`` objects.
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:param serializer_or_field: serializer or field instance
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:param openapi.Schema schema: the schema object to be modified in-place
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"""
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meta = getattr(serializer_or_field, 'Meta', None)
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swagger_schema_fields = getattr(meta, 'swagger_schema_fields', {})
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if swagger_schema_fields:
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for attr, val in swagger_schema_fields.items():
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setattr(schema, attr, val)
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def field_to_swagger_object(self, field, swagger_object_type, use_references, **kwargs):
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"""Convert a drf Serializer or Field instance into a Swagger object.
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Should return :data:`.NotHandled` if this inspector does not know how to handle the given `field`.
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:param rest_framework.serializers.Field field: the source field
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:param type[openapi.SwaggerDict] swagger_object_type: should be one of Schema, Parameter, Items
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:param bool use_references: if False, forces all objects to be declared inline
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instead of by referencing other components
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:param kwargs: extra attributes for constructing the object;
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if swagger_object_type is Parameter, ``name`` and ``in_`` should be provided
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:return: the swagger object
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:rtype: openapi.Parameter,openapi.Items,openapi.Schema,openapi.SchemaRef
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"""
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return NotHandled
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def probe_field_inspectors(self, field, swagger_object_type, use_references, **kwargs):
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"""Helper method for recursively probing `field_inspectors` to handle a given field.
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All arguments are the same as :meth:`.field_to_swagger_object`.
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:rtype: openapi.Parameter,openapi.Items,openapi.Schema,openapi.SchemaRef
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"""
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return self.probe_inspectors(
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self.field_inspectors, 'field_to_swagger_object', field, {'field_inspectors': self.field_inspectors},
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swagger_object_type=swagger_object_type, use_references=use_references, **kwargs
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)
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def _get_partial_types(self, field, swagger_object_type, use_references, **kwargs):
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"""Helper method to extract generic information from a field and return a partial constructor for the
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appropriate openapi object.
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All arguments are the same as :meth:`.field_to_swagger_object`.
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The return value is a tuple consisting of:
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* a function for constructing objects of `swagger_object_type`; its prototype is: ::
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def SwaggerType(existing_object=None, **instance_kwargs):
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This function creates an instance of `swagger_object_type`, passing the following attributes to its init,
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in order of precedence:
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- arguments specified by the ``kwargs`` parameter of :meth:`._get_partial_types`
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- ``instance_kwargs`` passed to the constructor function
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- ``title``, ``description``, ``required`` and ``default`` inferred from the field,
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where appropriate
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If ``existing_object`` is not ``None``, it is updated instead of creating a new object.
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* a type that should be used for child objects if `field` is of an array type. This can currently have two
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values:
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- :class:`.Schema` if `swagger_object_type` is :class:`.Schema`
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- :class:`.Items` if `swagger_object_type` is :class:`.Parameter` or :class:`.Items`
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:rtype: tuple[callable,(type[openapi.Schema],type[openapi.Items])]
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"""
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assert swagger_object_type in (openapi.Schema, openapi.Parameter, openapi.Items)
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assert not isinstance(field, openapi.SwaggerDict), "passed field is already a SwaggerDict object"
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title = force_real_str(field.label) if field.label else None
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title = title if swagger_object_type == openapi.Schema else None # only Schema has title
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description = force_real_str(field.help_text) if field.help_text else None
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description = description if swagger_object_type != openapi.Items else None # Items has no description either
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def SwaggerType(existing_object=None, **instance_kwargs):
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if 'required' not in instance_kwargs and swagger_object_type == openapi.Parameter:
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instance_kwargs['required'] = field.required
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if 'default' not in instance_kwargs and swagger_object_type != openapi.Items:
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default = get_field_default(field)
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if default not in (None, serializers.empty):
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instance_kwargs['default'] = default
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if instance_kwargs.get('type', None) != openapi.TYPE_ARRAY:
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instance_kwargs.setdefault('title', title)
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if description is not None:
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instance_kwargs.setdefault('description', description)
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instance_kwargs.update(kwargs)
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if existing_object is not None:
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assert isinstance(existing_object, swagger_object_type)
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for key, val in sorted(instance_kwargs.items()):
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setattr(existing_object, key, val)
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result = existing_object
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else:
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result = swagger_object_type(**instance_kwargs)
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# Provide an option to add manual paremeters to a schema
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# for example, to add examples
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if swagger_object_type == openapi.Schema:
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self.add_manual_fields(field, result)
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return result
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# arrays in Schema have Schema elements, arrays in Parameter and Items have Items elements
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child_swagger_type = openapi.Schema if swagger_object_type == openapi.Schema else openapi.Items
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return SwaggerType, child_swagger_type
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class SerializerInspector(FieldInspector):
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def get_schema(self, serializer):
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"""Convert a DRF Serializer instance to an :class:`.openapi.Schema`.
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Should return :data:`.NotHandled` if this inspector does not know how to handle the given `serializer`.
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:param serializers.BaseSerializer serializer: the ``Serializer`` instance
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:rtype: openapi.Schema
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"""
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return NotHandled
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def get_request_parameters(self, serializer, in_):
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"""Convert a DRF serializer into a list of :class:`.Parameter`\\ s.
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Should return :data:`.NotHandled` if this inspector does not know how to handle the given `serializer`.
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:param serializers.BaseSerializer serializer: the ``Serializer`` instance
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:param str in_: the location of the parameters, one of the `openapi.IN_*` constants
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:rtype: list[openapi.Parameter]
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"""
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return NotHandled
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class ViewInspector(BaseInspector):
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body_methods = ('PUT', 'PATCH', 'POST', 'DELETE') #: methods that are allowed to have a request body
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#: methods that are assumed to require a request body determined by the view's ``serializer_class``
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implicit_body_methods = ('PUT', 'PATCH', 'POST')
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# real values set in __init__ to prevent import errors
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field_inspectors = [] #:
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filter_inspectors = [] #:
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paginator_inspectors = [] #:
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def __init__(self, view, path, method, components, request, overrides):
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"""
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Inspector class responsible for providing :class:`.Operation` definitions given a view, path and method.
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:param dict overrides: manual overrides as passed to :func:`@swagger_auto_schema <.swagger_auto_schema>`
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"""
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super(ViewInspector, self).__init__(view, path, method, components, request)
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self.overrides = overrides
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self._prepend_inspector_overrides('field_inspectors')
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self._prepend_inspector_overrides('filter_inspectors')
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self._prepend_inspector_overrides('paginator_inspectors')
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def _prepend_inspector_overrides(self, inspectors):
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extra_inspectors = self.overrides.get(inspectors, None)
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if extra_inspectors:
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default_inspectors = [insp for insp in getattr(self, inspectors) if insp not in extra_inspectors]
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setattr(self, inspectors, extra_inspectors + default_inspectors)
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def get_operation(self, operation_keys):
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"""Get an :class:`.Operation` for the given API endpoint (path, method).
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This includes query, body parameters and response schemas.
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:param tuple[str] operation_keys: an array of keys describing the hierarchical layout of this view in the API;
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e.g. ``('snippets', 'list')``, ``('snippets', 'retrieve')``, etc.
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:rtype: openapi.Operation
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"""
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raise NotImplementedError("ViewInspector must implement get_operation()!")
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# methods below provided as default implementations for probing inspectors
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def should_filter(self):
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"""Determine whether filter backend parameters should be included for this request.
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:rtype: bool
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"""
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if not getattr(self.view, 'filter_backends', None):
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return False
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if self.method.lower() not in ["get", "delete"]:
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return False
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return is_list_view(self.path, self.method, self.view)
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def get_filter_parameters(self):
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"""Return the parameters added to the view by its filter backends.
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:rtype: list[openapi.Parameter]
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"""
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if not self.should_filter():
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return []
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fields = []
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for filter_backend in self.view.filter_backends:
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fields += self.probe_inspectors(self.filter_inspectors, 'get_filter_parameters', filter_backend()) or []
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return fields
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def should_page(self):
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"""Determine whether paging parameters and structure should be added to this operation's request and response.
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:rtype: bool
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"""
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if not getattr(self.view, 'paginator', None):
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return False
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if self.method.lower() != 'get':
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return False
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return is_list_view(self.path, self.method, self.view)
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def get_pagination_parameters(self):
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"""Return the parameters added to the view by its paginator.
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:rtype: list[openapi.Parameter]
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"""
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if not self.should_page():
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return []
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return self.probe_inspectors(self.paginator_inspectors, 'get_paginator_parameters', self.view.paginator) or []
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def serializer_to_schema(self, serializer):
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"""Convert a serializer to an OpenAPI :class:`.Schema`.
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:param serializers.BaseSerializer serializer: the ``Serializer`` instance
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:returns: the converted :class:`.Schema`, or ``None`` in case of an unknown serializer
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:rtype: openapi.Schema,openapi.SchemaRef
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"""
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return self.probe_inspectors(
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self.field_inspectors, 'get_schema', serializer, {'field_inspectors': self.field_inspectors}
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)
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def serializer_to_parameters(self, serializer, in_):
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"""Convert a serializer to a possibly empty list of :class:`.Parameter`\\ s.
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:param serializers.BaseSerializer serializer: the ``Serializer`` instance
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:param str in_: the location of the parameters, one of the `openapi.IN_*` constants
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:rtype: list[openapi.Parameter]
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"""
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return self.probe_inspectors(
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self.field_inspectors, 'get_request_parameters', serializer, {'field_inspectors': self.field_inspectors},
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in_=in_
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) or []
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def get_paginated_response(self, response_schema):
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"""Add appropriate paging fields to a response :class:`.Schema`.
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:param openapi.Schema response_schema: the response schema that must be paged.
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:returns: the paginated response class:`.Schema`, or ``None`` in case of an unknown pagination scheme
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:rtype: openapi.Schema
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"""
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return self.probe_inspectors(self.paginator_inspectors, 'get_paginated_response',
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self.view.paginator, response_schema=response_schema)
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