✨ Add support for function return type annotations to declare the response_model (#1436)

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

docs_src/response_model/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import List, Union
+from typing import Any, List, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -15,5 +15,13 @@ class Item(BaseModel):
 
 
 @app.post("/items/", response_model=Item)
-async def create_item(item: Item):
+async def create_item(item: Item) -> Any:
     return item
+
+
+@app.get("/items/", response_model=List[Item])
+async def read_items() -> Any:
+    return [
+        {"name": "Portal Gun", "price": 42.0},
+        {"name": "Plumbus", "price": 32.0},
+    ]

docs_src/response_model/tutorial001_01.py

@@ -0,0 +1,27 @@
+from typing import List, Union
+
+from fastapi import FastAPI
+from pydantic import BaseModel
+
+app = FastAPI()
+
+
+class Item(BaseModel):
+    name: str
+    description: Union[str, None] = None
+    price: float
+    tax: Union[float, None] = None
+    tags: List[str] = []
+
+
+@app.post("/items/")
+async def create_item(item: Item) -> Item:
+    return item
+
+
+@app.get("/items/")
+async def read_items() -> List[Item]:
+    return [
+        Item(name="Portal Gun", price=42.0),
+        Item(name="Plumbus", price=32.0),
+    ]

docs_src/response_model/tutorial001_01_py310.py

@@ -0,0 +1,25 @@
+from fastapi import FastAPI
+from pydantic import BaseModel
+
+app = FastAPI()
+
+
+class Item(BaseModel):
+    name: str
+    description: str | None = None
+    price: float
+    tax: float | None = None
+    tags: list[str] = []
+
+
+@app.post("/items/")
+async def create_item(item: Item) -> Item:
+    return item
+
+
+@app.get("/items/")
+async def read_items() -> list[Item]:
+    return [
+        Item(name="Portal Gun", price=42.0),
+        Item(name="Plumbus", price=32.0),
+    ]

docs_src/response_model/tutorial001_01_py39.py

@@ -0,0 +1,27 @@
+from typing import Union
+
+from fastapi import FastAPI
+from pydantic import BaseModel
+
+app = FastAPI()
+
+
+class Item(BaseModel):
+    name: str
+    description: Union[str, None] = None
+    price: float
+    tax: Union[float, None] = None
+    tags: list[str] = []
+
+
+@app.post("/items/")
+async def create_item(item: Item) -> Item:
+    return item
+
+
+@app.get("/items/")
+async def read_items() -> list[Item]:
+    return [
+        Item(name="Portal Gun", price=42.0),
+        Item(name="Plumbus", price=32.0),
+    ]

docs_src/response_model/tutorial001_py310.py

@@ -1,3 +1,5 @@
+from typing import Any
+
 from fastapi import FastAPI
 from pydantic import BaseModel
 
@@ -13,5 +15,13 @@ class Item(BaseModel):
 
 
 @app.post("/items/", response_model=Item)
-async def create_item(item: Item):
+async def create_item(item: Item) -> Any:
     return item
+
+
+@app.get("/items/", response_model=list[Item])
+async def read_items() -> Any:
+    return [
+        {"name": "Portal Gun", "price": 42.0},
+        {"name": "Plumbus", "price": 32.0},
+    ]

docs_src/response_model/tutorial001_py39.py

@@ -1,4 +1,4 @@
-from typing import Union
+from typing import Any, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -15,5 +15,13 @@ class Item(BaseModel):
 
 
 @app.post("/items/", response_model=Item)
-async def create_item(item: Item):
+async def create_item(item: Item) -> Any:
     return item
+
+
+@app.get("/items/", response_model=list[Item])
+async def read_items() -> Any:
+    return [
+        {"name": "Portal Gun", "price": 42.0},
+        {"name": "Plumbus", "price": 32.0},
+    ]

docs_src/response_model/tutorial002.py

@@ -14,6 +14,6 @@ class UserIn(BaseModel):
 
 
 # Don't do this in production!
-@app.post("/user/", response_model=UserIn)
-async def create_user(user: UserIn):
+@app.post("/user/")
+async def create_user(user: UserIn) -> UserIn:
     return user

docs_src/response_model/tutorial002_py310.py

@@ -12,6 +12,6 @@ class UserIn(BaseModel):
 
 
 # Don't do this in production!
-@app.post("/user/", response_model=UserIn)
-async def create_user(user: UserIn):
+@app.post("/user/")
+async def create_user(user: UserIn) -> UserIn:
     return user

docs_src/response_model/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Union
+from typing import Any, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
@@ -20,5 +20,5 @@ class UserOut(BaseModel):
 
 
 @app.post("/user/", response_model=UserOut)
-async def create_user(user: UserIn):
+async def create_user(user: UserIn) -> Any:
     return user

docs_src/response_model/tutorial003_01.py

@@ -0,0 +1,21 @@
+from typing import Union
+
+from fastapi import FastAPI
+from pydantic import BaseModel, EmailStr
+
+app = FastAPI()
+
+
+class BaseUser(BaseModel):
+    username: str
+    email: EmailStr
+    full_name: Union[str, None] = None
+
+
+class UserIn(BaseUser):
+    password: str
+
+
+@app.post("/user/")
+async def create_user(user: UserIn) -> BaseUser:
+    return user

docs_src/response_model/tutorial003_01_py310.py

@@ -0,0 +1,19 @@
+from fastapi import FastAPI
+from pydantic import BaseModel, EmailStr
+
+app = FastAPI()
+
+
+class BaseUser(BaseModel):
+    username: str
+    email: EmailStr
+    full_name: str | None = None
+
+
+class UserIn(BaseUser):
+    password: str
+
+
+@app.post("/user/")
+async def create_user(user: UserIn) -> BaseUser:
+    return user

docs_src/response_model/tutorial003_py310.py

@@ -1,3 +1,5 @@
+from typing import Any
+
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
 
@@ -18,5 +20,5 @@ class UserOut(BaseModel):
 
 
 @app.post("/user/", response_model=UserOut)
-async def create_user(user: UserIn):
+async def create_user(user: UserIn) -> Any:
     return user