✅ Update response_model_by_alias (#1642)

* Make openapi models honor response_model_by_alias

* Add test for response_model_by_alias working with openapi models

* ⏪ Revert changes

* ✅ Update and extend tests for response_model_by_alias

* ⏪ Revert test name change

* 📌 Pin Pytest and Pytest-Cov

Co-authored-by: Martin Zaťko <martin.zatko@kiwi.com>

fastapi/routing.py

@@ -52,7 +52,6 @@ except ImportError:  # pragma: nocover
 def _prepare_response_content(
     res: Any,
     *,
-    by_alias: bool = True,
     exclude_unset: bool,
     exclude_defaults: bool = False,
     exclude_none: bool = False,
@@ -60,14 +59,14 @@ def _prepare_response_content(
     if isinstance(res, BaseModel):
         if PYDANTIC_1:
             return res.dict(
-                by_alias=by_alias,
+                by_alias=True,
                 exclude_unset=exclude_unset,
                 exclude_defaults=exclude_defaults,
                 exclude_none=exclude_none,
             )
         else:
             return res.dict(
-                by_alias=by_alias, skip_defaults=exclude_unset,
+                by_alias=True, skip_defaults=exclude_unset,
             )  # pragma: nocover
     elif isinstance(res, list):
         return [
@@ -108,7 +107,6 @@ async def serialize_response(
         errors = []
         response_content = _prepare_response_content(
             response_content,
-            by_alias=by_alias,
             exclude_unset=exclude_unset,
             exclude_defaults=exclude_defaults,
             exclude_none=exclude_none,

pyproject.toml

@@ -43,8 +43,8 @@ Documentation = "https://fastapi.tiangolo.com/"
 
 [tool.flit.metadata.requires-extra]
 test = [
-    "pytest >=5.4.3",
+    "pytest==5.4.3",
-    "pytest-cov",
+    "pytest-cov==2.10.0",
     "mypy",
     "black",
     "isort",

tests/test_duplicate_models_openapi.py

@@ -1,23 +1,82 @@
 from fastapi import FastAPI
+from fastapi.testclient import TestClient
 from pydantic import BaseModel
 
+app = FastAPI()
 
-def test_get_openapi():
-    app = FastAPI()
 
-    class Model(BaseModel):
+class Model(BaseModel):
     pass
 
-    class Model2(BaseModel):
+
+class Model2(BaseModel):
     a: Model
 
-    class Model3(BaseModel):
+
+class Model3(BaseModel):
     c: Model
     d: Model2
 
-    @app.get("/", response_model=Model3)
-    def f():
-        pass  # pragma: no cover
 
-    openapi = app.openapi()
+@app.get("/", response_model=Model3)
-    assert isinstance(openapi, dict)
+def f():
+    return {"c": {}, "d": {"a": {}}}
+
+
+openapi_schema = {
+    "openapi": "3.0.2",
+    "info": {"title": "FastAPI", "version": "0.1.0"},
+    "paths": {
+        "/": {
+            "get": {
+                "summary": "F",
+                "operationId": "f__get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/Model3"}
+                            }
+                        },
+                    }
+                },
+            }
+        }
+    },
+    "components": {
+        "schemas": {
+            "Model": {"title": "Model", "type": "object", "properties": {}},
+            "Model2": {
+                "title": "Model2",
+                "required": ["a"],
+                "type": "object",
+                "properties": {"a": {"$ref": "#/components/schemas/Model"}},
+            },
+            "Model3": {
+                "title": "Model3",
+                "required": ["c", "d"],
+                "type": "object",
+                "properties": {
+                    "c": {"$ref": "#/components/schemas/Model"},
+                    "d": {"$ref": "#/components/schemas/Model2"},
+                },
+            },
+        }
+    },
+}
+
+
+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_get_api_route():
+    response = client.get("/")
+    assert response.status_code == 200, response.text
+    assert response.json() == {"c": {}, "d": {"a": {}}}

tests/test_response_by_alias.py

@@ -0,0 +1,323 @@
+from typing import List
+
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from pydantic import BaseModel, Field
+
+app = FastAPI()
+
+
+class Model(BaseModel):
+    name: str = Field(alias="alias")
+
+
+class ModelNoAlias(BaseModel):
+    name: str
+
+    class Config:
+        schema_extra = {
+            "description": (
+                "response_model_by_alias=False is basically a quick hack, to support "
+                "proper OpenAPI use another model with the correct field names"
+            )
+        }
+
+
+@app.get("/dict", response_model=Model, response_model_by_alias=False)
+def read_dict():
+    return {"alias": "Foo"}
+
+
+@app.get("/model", response_model=Model, response_model_by_alias=False)
+def read_model():
+    return Model(alias="Foo")
+
+
+@app.get("/list", response_model=List[Model], response_model_by_alias=False)
+def read_list():
+    return [{"alias": "Foo"}, {"alias": "Bar"}]
+
+
+@app.get("/by-alias/dict", response_model=Model)
+def by_alias_dict():
+    return {"alias": "Foo"}
+
+
+@app.get("/by-alias/model", response_model=Model)
+def by_alias_model():
+    return Model(alias="Foo")
+
+
+@app.get("/by-alias/list", response_model=List[Model])
+def by_alias_list():
+    return [{"alias": "Foo"}, {"alias": "Bar"}]
+
+
+@app.get("/no-alias/dict", response_model=ModelNoAlias)
+def by_alias_dict():
+    return {"name": "Foo"}
+
+
+@app.get("/no-alias/model", response_model=ModelNoAlias)
+def by_alias_model():
+    return ModelNoAlias(name="Foo")
+
+
+@app.get("/no-alias/list", response_model=List[ModelNoAlias])
+def by_alias_list():
+    return [{"name": "Foo"}, {"name": "Bar"}]
+
+
+openapi_schema = {
+    "openapi": "3.0.2",
+    "info": {"title": "FastAPI", "version": "0.1.0"},
+    "paths": {
+        "/dict": {
+            "get": {
+                "summary": "Read Dict",
+                "operationId": "read_dict_dict_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/Model"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/model": {
+            "get": {
+                "summary": "Read Model",
+                "operationId": "read_model_model_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/Model"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/list": {
+            "get": {
+                "summary": "Read List",
+                "operationId": "read_list_list_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "title": "Response Read List List Get",
+                                    "type": "array",
+                                    "items": {"$ref": "#/components/schemas/Model"},
+                                }
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/by-alias/dict": {
+            "get": {
+                "summary": "By Alias Dict",
+                "operationId": "by_alias_dict_by_alias_dict_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/Model"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/by-alias/model": {
+            "get": {
+                "summary": "By Alias Model",
+                "operationId": "by_alias_model_by_alias_model_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/Model"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/by-alias/list": {
+            "get": {
+                "summary": "By Alias List",
+                "operationId": "by_alias_list_by_alias_list_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "title": "Response By Alias List By Alias List Get",
+                                    "type": "array",
+                                    "items": {"$ref": "#/components/schemas/Model"},
+                                }
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/no-alias/dict": {
+            "get": {
+                "summary": "By Alias Dict",
+                "operationId": "by_alias_dict_no_alias_dict_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/ModelNoAlias"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/no-alias/model": {
+            "get": {
+                "summary": "By Alias Model",
+                "operationId": "by_alias_model_no_alias_model_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {"$ref": "#/components/schemas/ModelNoAlias"}
+                            }
+                        },
+                    }
+                },
+            }
+        },
+        "/no-alias/list": {
+            "get": {
+                "summary": "By Alias List",
+                "operationId": "by_alias_list_no_alias_list_get",
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "title": "Response By Alias List No Alias List Get",
+                                    "type": "array",
+                                    "items": {
+                                        "$ref": "#/components/schemas/ModelNoAlias"
+                                    },
+                                }
+                            }
+                        },
+                    }
+                },
+            }
+        },
+    },
+    "components": {
+        "schemas": {
+            "Model": {
+                "title": "Model",
+                "required": ["alias"],
+                "type": "object",
+                "properties": {"alias": {"title": "Alias", "type": "string"}},
+            },
+            "ModelNoAlias": {
+                "title": "ModelNoAlias",
+                "required": ["name"],
+                "type": "object",
+                "properties": {"name": {"title": "Name", "type": "string"}},
+                "description": "response_model_by_alias=False is basically a quick hack, to support proper OpenAPI use another model with the correct field names",
+            },
+        }
+    },
+}
+
+
+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_read_dict():
+    response = client.get("/dict")
+    assert response.status_code == 200, response.text
+    assert response.json() == {"name": "Foo"}
+
+
+def test_read_model():
+    response = client.get("/model")
+    assert response.status_code == 200, response.text
+    assert response.json() == {"name": "Foo"}
+
+
+def test_read_list():
+    response = client.get("/list")
+    assert response.status_code == 200, response.text
+    assert response.json() == [
+        {"name": "Foo"},
+        {"name": "Bar"},
+    ]
+
+
+def test_read_dict_by_alias():
+    response = client.get("/by-alias/dict")
+    assert response.status_code == 200, response.text
+    assert response.json() == {"alias": "Foo"}
+
+
+def test_read_model_by_alias():
+    response = client.get("/by-alias/model")
+    assert response.status_code == 200, response.text
+    assert response.json() == {"alias": "Foo"}
+
+
+def test_read_list_by_alias():
+    response = client.get("/by-alias/list")
+    assert response.status_code == 200, response.text
+    assert response.json() == [
+        {"alias": "Foo"},
+        {"alias": "Bar"},
+    ]
+
+
+def test_read_dict_no_alias():
+    response = client.get("/no-alias/dict")
+    assert response.status_code == 200, response.text
+    assert response.json() == {"name": "Foo"}
+
+
+def test_read_model_no_alias():
+    response = client.get("/no-alias/model")
+    assert response.status_code == 200, response.text
+    assert response.json() == {"name": "Foo"}
+
+
+def test_read_list_no_alias():
+    response = client.get("/no-alias/list")
+    assert response.status_code == 200, response.text
+    assert response.json() == [
+        {"name": "Foo"},
+        {"name": "Bar"},
+    ]