Django rest framework recursive support (#110)

* add get_serializer_ref_name utility function
* implement RecursiveFieldInspector
* add option to allow non-existing reference in SchemaRef
* add examples and README
* Update changelog and docs

src/drf_yasg/app_settings.py

@@ -6,12 +6,13 @@ SWAGGER_DEFAULTS = {
 
     'DEFAULT_FIELD_INSPECTORS': [
         'drf_yasg.inspectors.CamelCaseJSONFilter',
+        'drf_yasg.inspectors.RecursiveFieldInspector',
         'drf_yasg.inspectors.ReferencingSerializerInspector',
-        'drf_yasg.inspectors.RelatedFieldInspector',
         'drf_yasg.inspectors.ChoiceFieldInspector',
         'drf_yasg.inspectors.FileFieldInspector',
         'drf_yasg.inspectors.DictFieldInspector',
         'drf_yasg.inspectors.HiddenFieldInspector',
+        'drf_yasg.inspectors.RelatedFieldInspector',
         'drf_yasg.inspectors.SimpleFieldInspector',
         'drf_yasg.inspectors.StringDefaultFieldInspector',
     ],

src/drf_yasg/inspectors/__init__.py

@@ -4,8 +4,8 @@ from .base import (
 )
 from .field import (
     CamelCaseJSONFilter, ChoiceFieldInspector, DictFieldInspector, FileFieldInspector, HiddenFieldInspector,
-    InlineSerializerInspector, ReferencingSerializerInspector, RelatedFieldInspector, SimpleFieldInspector,
-    StringDefaultFieldInspector
+    InlineSerializerInspector, RecursiveFieldInspector, ReferencingSerializerInspector, RelatedFieldInspector,
+    SimpleFieldInspector, StringDefaultFieldInspector
 )
 from .query import CoreAPICompatInspector, DjangoRestResponsePagination
 from .view import SwaggerAutoSchema
@@ -23,9 +23,9 @@ __all__ = [
     'CoreAPICompatInspector', 'DjangoRestResponsePagination',
 
     # field inspectors
-    'InlineSerializerInspector', 'ReferencingSerializerInspector', 'RelatedFieldInspector', 'SimpleFieldInspector',
-    'FileFieldInspector', 'ChoiceFieldInspector', 'DictFieldInspector', 'StringDefaultFieldInspector',
-    'CamelCaseJSONFilter', 'HiddenFieldInspector',
+    'InlineSerializerInspector', 'RecursiveFieldInspector', 'ReferencingSerializerInspector', 'RelatedFieldInspector',
+    'SimpleFieldInspector', 'FileFieldInspector', 'ChoiceFieldInspector', 'DictFieldInspector',
+    'StringDefaultFieldInspector', 'CamelCaseJSONFilter', 'HiddenFieldInspector',
 
     # view inspectors
     'SwaggerAutoSchema',

src/drf_yasg/inspectors/field.py

@@ -10,7 +10,7 @@ from rest_framework.settings import api_settings as rest_framework_settings
 
 from .. import openapi
 from ..errors import SwaggerGenerationError
-from ..utils import decimal_as_float, filter_none
+from ..utils import decimal_as_float, filter_none, get_serializer_ref_name
 from .base import FieldInspector, NotHandled, SerializerInspector
 
 logger = logging.getLogger(__name__)
@@ -55,23 +55,12 @@ class InlineSerializerInspector(SerializerInspector):
             if swagger_object_type != openapi.Schema:
                 raise SwaggerGenerationError("cannot instantiate nested serializer as " + swagger_object_type.__name__)
 
-            serializer = field
-            serializer_meta = getattr(serializer, 'Meta', None)
-            serializer_name = type(serializer).__name__
-            if hasattr(serializer_meta, 'ref_name'):
-                ref_name = serializer_meta.ref_name
-            elif serializer_name == 'NestedSerializer' and isinstance(serializer, serializers.ModelSerializer):
-                logger.debug("Forcing inline output for ModelSerializer named 'NestedSerializer': " + str(serializer))
-                ref_name = None
-            else:
-                ref_name = serializer_name
-                if ref_name.endswith('Serializer'):
-                    ref_name = ref_name[:-len('Serializer')]
+            ref_name = get_serializer_ref_name(field)
 
             def make_schema_definition():
                 properties = OrderedDict()
                 required = []
-                for property_name, child in serializer.fields.items():
+                for property_name, child in field.fields.items():
                     property_name = self.get_property_name(property_name)
                     prop_kwargs = {
                         'read_only': child.read_only or None
@@ -531,3 +520,24 @@ else:
                 return camelize_schema(result, self.components)
 
             return result
+
+try:
+    from rest_framework_recursive.fields import RecursiveField
+except ImportError:
+    class RecursiveFieldInspector(FieldInspector):
+        """Provides conversion for RecursiveField (https://github.com/heywbj/django-rest-framework-recursive)"""
+        pass
+else:
+    class RecursiveFieldInspector(FieldInspector):
+        """Provides conversion for RecursiveField (https://github.com/heywbj/django-rest-framework-recursive)"""
+        def field_to_swagger_object(self, field, swagger_object_type, use_references, **kwargs):
+            if isinstance(field, RecursiveField) and swagger_object_type == openapi.Schema:
+                assert use_references is True, "Can not create schema for RecursiveField when use_references is False"
+
+                ref_name = get_serializer_ref_name(field.proxied)
+                assert ref_name is not None, "Can not create RecursiveField schema for inline ModelSerializer"
+
+                return openapi.SchemaRef(self.components.with_scope(openapi.SCHEMA_DEFINITIONS), ref_name,
+                                         ignore_unresolved=True)
+
+            return NotHandled

src/drf_yasg/openapi.py

@@ -466,7 +466,7 @@ class Schema(SwaggerDict):
 class _Ref(SwaggerDict):
     ref_name_re = re.compile(r"#/(?P<scope>.+)/(?P<name>[^/]+)$")
 
-    def __init__(self, resolver, name, scope, expected_type):
+    def __init__(self, resolver, name, scope, expected_type, ignore_unresolved=False):
         """Base class for all reference types. A reference object has only one property, ``$ref``, which must be a JSON
         reference to a valid object in the specification, e.g. ``#/definitions/Article`` to refer to an article model.
 
@@ -474,13 +474,15 @@ class _Ref(SwaggerDict):
         :param str name: referenced object name, e.g. "Article"
         :param str scope: reference scope, e.g. "definitions"
         :param type[.SwaggerDict] expected_type: the expected type that will be asserted on the object found in resolver
+        :param bool ignore_unresolved: allow the reference to be not defined in resolver
         """
         super(_Ref, self).__init__()
         assert not type(self) == _Ref, "do not instantiate _Ref directly"
         ref_name = "#/{scope}/{name}".format(scope=scope, name=name)
-        obj = resolver.get(name, scope)
-        assert isinstance(obj, expected_type), ref_name + " is a {actual}, not a {expected}" \
-            .format(actual=type(obj).__name__, expected=expected_type.__name__)
+        if not ignore_unresolved:
+            obj = resolver.get(name, scope)
+            assert isinstance(obj, expected_type), ref_name + " is a {actual}, not a {expected}" \
+                .format(actual=type(obj).__name__, expected=expected_type.__name__)
         self.ref = ref_name
 
     def resolve(self, resolver):
@@ -502,14 +504,15 @@ class _Ref(SwaggerDict):
 
 
 class SchemaRef(_Ref):
-    def __init__(self, resolver, schema_name):
+    def __init__(self, resolver, schema_name, ignore_unresolved=False):
         """Adds a reference to a named Schema defined in the ``#/definitions/`` object.
 
         :param .ReferenceResolver resolver: component resolver which must contain the definition
         :param str schema_name: schema name
+        :param bool ignore_unresolved: allow the reference to be not defined in resolver
         """
         assert SCHEMA_DEFINITIONS in resolver.scopes
-        super(SchemaRef, self).__init__(resolver, schema_name, SCHEMA_DEFINITIONS, Schema)
+        super(SchemaRef, self).__init__(resolver, schema_name, SCHEMA_DEFINITIONS, Schema, ignore_unresolved)
 
 
 Schema.OR_REF = (Schema, SchemaRef)

src/drf_yasg/utils.py

@@ -295,3 +295,25 @@ def decimal_as_float(field):
     if isinstance(field, serializers.DecimalField) or isinstance(field, models.DecimalField):
         return not getattr(field, 'coerce_to_string', rest_framework_settings.COERCE_DECIMAL_TO_STRING)
     return False
+
+
+def get_serializer_ref_name(serializer):
+    """
+    Get serializer's ref_name (or None for ModelSerializer if it is named 'NestedSerializer')
+
+    :param serializer: Serializer instance
+    :return: Serializer's ref_name or None for inline serializer
+    :rtype: str or None
+    """
+    serializer_meta = getattr(serializer, 'Meta', None)
+    serializer_name = type(serializer).__name__
+    if hasattr(serializer_meta, 'ref_name'):
+        ref_name = serializer_meta.ref_name
+    elif serializer_name == 'NestedSerializer' and isinstance(serializer, serializers.ModelSerializer):
+        logger.debug("Forcing inline output for ModelSerializer named 'NestedSerializer': " + str(serializer))
+        ref_name = None
+    else:
+        ref_name = serializer_name
+        if ref_name.endswith('Serializer'):
+            ref_name = ref_name[:-len('Serializer')]
+    return ref_name