Handling read_only/write_only fields on OpenAPI

https://pulp.plan.io/issues/5622
closes #5622

CHANGES/5622.bugfix

@@ -0,0 +1 @@
+Handling `read_only` and `write_only` fields on OpenAPISchema.

pulpcore/app/openapigenerator.py

@@ -7,7 +7,42 @@
 from drf_yasg.generators import OpenAPISchemaGenerator
 from drf_yasg.inspectors import SwaggerAutoSchema
 from drf_yasg.openapi import Parameter
-from drf_yasg.utils import filter_none, force_real_str
+from drf_yasg.utils import filter_none, force_real_str, no_body
+
+
+class ReadOnly:
+    """
+    Read only objects from schema.
+    Patch: https://github.com/axnsan12/drf-yasg/issues/70#issuecomment-485050813
+    """
+
+    def __init__(self, serializer):
+        """
+        Get the read_only fields.
+        """
+
+        new_fields = OrderedDict()
+        for field_name, field in serializer.get_fields().items():
+            if not field.write_only:
+                new_fields[field_name] = field
+        serializer.fields = new_fields
+
+
+class WriteOnly:
+    """
+    Write only objects from schema.
+    Patch: https://github.com/axnsan12/drf-yasg/issues/70#issuecomment-485050813
+    """
+
+    def __init__(self, serializer):
+        """
+        Get the write_only fields.
+        """
+        new_fields = OrderedDict()
+        for field_name, field in serializer.get_fields().items():
+            if not field.read_only:
+                new_fields[field_name] = field
+        serializer.fields = new_fields
 
 
 class Paths(openapi.SwaggerDict):
@@ -373,3 +408,36 @@ def get_tags(self, operation_keys):
             tags = [' '.join(operation_keys[:-1])]
 
         return tags
+
+    def get_view_serializer(self):
+        """
+        Return the view's serializer without read_only fields.
+        Patch: https://github.com/axnsan12/drf-yasg/issues/70#issuecomment-485050813
+        """
+
+        return self._convert_serializer(WriteOnly)
+
+    def get_default_response_serializer(self):
+        """
+        Return the default response serializer for this endpoint without write_only fields.
+        Patch: https://github.com/axnsan12/drf-yasg/issues/70#issuecomment-485050813
+        """
+
+        body_override = self._get_request_body_override()
+        if body_override and body_override is not no_body:
+            return body_override
+
+        return self._convert_serializer(ReadOnly)
+
+    def _convert_serializer(self, new_class):
+        """
+        Creates a new serializer without read_only/write_only fields.
+        Patch: https://github.com/axnsan12/drf-yasg/issues/70#issuecomment-485050813
+        """
+
+        serializer = super().get_view_serializer()
+        if not serializer:
+            return serializer
+
+        new_class(serializer)
+        return serializer