🎉 Use function return type annotation as response_model

tiangolo · May 20, 2020 · 17e4878 · 17e4878
1 parent 601d8eb
commit 17e4878
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Showing 2 changed files with 130 additions and 1 deletion.
diff --git a/fastapi/routing.py b/fastapi/routing.py
@@ -91,6 +91,13 @@ def _prepare_response_content(
     return res
 
 
+def _get_return_annotation(func: Callable) -> Optional[Type[Any]]:
+    try:
+        return func.__annotations__["return"]
+    except (AttributeError, KeyError):
+        return None
+
+
 async def serialize_response(
     *,
     field: ModelField = None,
@@ -305,7 +312,11 @@ def __init__(
         self.unique_id = generate_operation_id_for_path(
             name=self.name, path=self.path_format, method=list(methods)[0]
         )
-        self.response_model = response_model
+        self.response_model = (
+            _get_return_annotation(endpoint)
+            if response_model is None
+            else response_model
+        )
         if self.response_model:
             assert (
                 status_code not in STATUS_CODES_WITH_NO_BODY

diff --git a/tests/test_response_model_as_return_annotation.py b/tests/test_response_model_as_return_annotation.py
@@ -0,0 +1,118 @@
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from pydantic import BaseModel
+
+
+class ModelOne(BaseModel):
+    name: str
+
+
+class ModelTwo(BaseModel):
+    surname: str
+
+
+app = FastAPI()
+
+
+@app.get("/valid1")
+def valid1() -> ModelOne:
+    pass
+
+
+@app.get("/valid2", response_model=ModelTwo)
+def valid2():
+    pass
+
+
+@app.get("/valid3", response_model=ModelTwo)
+def valid3() -> ModelOne:
+    pass
+
+
+openapi_schema = {
+    "openapi": "3.0.2",
+    "info": {"title": "FastAPI", "version": "0.1.0"},
+    "paths": {
+        "/valid1": {
+            "get": {
+                "summary": "Valid1",
+                "operationId": "valid1_valid1_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/ModelOne"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/valid2": {
+            "get": {
+                "summary": "Valid2",
+                "operationId": "valid2_valid2_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/ModelTwo"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/valid3": {
+            "get": {
+                "summary": "Valid3",
+                "operationId": "valid3_valid3_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/ModelTwo"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+    },
+    "components": {
+        "schemas": {
+            "ModelOne": {
+                "title": "ModelOne",
+                "required": ["name"],
+                "type": "object",
+                "properties": {"name": {"title": "Name", "type": "string"}},
+            },
+            "ModelTwo": {
+                "title": "ModelTwo",
+                "required": ["surname"],
+                "type": "object",
+                "properties": {"surname": {"title": "Surname", "type": "string"}},
+            },
+        }
+    },
+}
+
+client = TestClient(app)
+
+
+def test_openapi_schema():
+    response = client.get("/openapi.json")
+    assert response.status_code == 200, response.text
+    assert response.json() == openapi_schema
+
+
+def test_path_operations():
+    response = client.get("/valid1")
+    assert response.status_code == 200, response.text
+    response = client.get("/valid2")
+    assert response.status_code == 200, response.text
+    response = client.get("/valid3")
+    assert response.status_code == 200, response.text