Additional Responses implementation

fastapi/openapi/models.py

@@ -1,9 +1,10 @@
 import logging
 from enum import Enum
-from typing import Any, Dict, List, Optional, Union
+from typing import Any, Dict, List, Optional, Union, Type, ClassVar, Callable
 
 from pydantic import BaseModel, Schema as PSchema
 from pydantic.types import UrlStr
+from pydantic.fields import Field
 
 try:
     import email_validator
@@ -343,6 +344,35 @@ class Tag(BaseModel):
     externalDocs: Optional[ExternalDocumentation] = None
 
 
+class BaseAdditionalResponse(BaseModel):
+    description: str
+    content_type: str = None
+
+
+class AdditionalResponse(BaseAdditionalResponse):
+    status_code: int = PSchema(
+        ...,
+        ge=100,
+        le=540,
+        title='Status Code',
+        description='HTTP status code',
+    )
+    # NOTE: waiting for pydantic to allow `typing.Type[BasicModel]` type
+    # so, going for `Any` and extra validation on
+    # routing methods
+    models: Optional[List[Any]] = PSchema(
+        [],
+        title='Additional Response Models',
+    )
+
+
+class AdditionalResponseDescription(BaseAdditionalResponse):
+    schema_field: Optional[Field] = None
+
+    class Config:
+        arbitrary_types_allowed = True
+
+
 class OpenAPI(BaseModel):
     openapi: str
     info: Info

fastapi/openapi/utils.py

@@ -205,6 +205,26 @@ def get_openapi_path(
                         }
                     },
                 }
+            for add_response_code, add_response in route.additional_responses.items():
+                add_response_schema = {}
+                if (add_response.content_type or route.content_type.media_type
+                    ) == 'application/json' and add_response.schema_field is not None:
+                    add_response_schema, _ = field_schema(
+                        add_response.schema_field,
+                        model_name_map=model_name_map,
+                        ref_prefix=REF_PREFIX,
+                    )
+                add_content = {
+                    add_response.content_type or
+                    route.content_type.media_type: {
+                        "schema": add_response_schema,
+                    },
+                }
+                operation["responses"][str(add_response_code)] = \
+                    {
+                        "description": add_response.description,
+                        "content": add_content,
+                    }
             path[method.lower()] = operation
     return path, security_schemes, definitions