from typing import Annotated, Union

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None


@app.put("/items/{item_id}")
async def update_item(
    item_id: int,
    item: Annotated[
        Item,
        Body(
            examples=[
                {

from fastapi.testclient import TestClient

from ..utils import needs_pydanticv2


@needs_pydanticv2
def test_recursive():
    from .app_pv2 import app

    client = TestClient(app)
    response = client.get("/items/recursive")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "sub_items": [{"name": "subitem", "sub_items": []}],
        "name": "item",
    }

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.dependencies.tutorial008d_an_py39 import app

    client = TestClient(app)
    return client


@needs_py39
def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")
    assert response.status_code == 404, response.text

```

/// note | "Technical Details"

You could also use `from starlette.requests import Request` and `from starlette.responses import JSONResponse`.

**FastAPI** provides the same `starlette.responses` as `fastapi.responses` just as a convenience for you, the developer. But most of the available responses come directly from Starlette. The same with `Request`.

///

## Override the default exception handlers

from typing import Any, 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/", response_model=Item)
async def create_item(item: Item) -> Any:
    return item


@app.get("/items/", response_model=list[Item])

 * is returned by upstream, or after the upstream source has been exhausted.
 *
 * As bytes are returned from upstream they are written to a local file. Downstream sources read
 * from this file as necessary.
 *
 * This class also keeps a small buffer of bytes recently read from upstream. This is intended to
 * save a small amount of file I/O and data copying.
 */
class Relay private constructor(
  /**

import pytest
from fastapi.exceptions import FastAPIError
from fastapi.testclient import TestClient


@pytest.fixture(name="client")
def get_client():
    from docs_src.dependencies.tutorial008c_an import app

    client = TestClient(app)
    return client


def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")
    assert response.status_code == 404, response.text

from functools import lru_cache
from typing import Annotated

from fastapi import Depends, FastAPI

from .config import Settings

app = FastAPI()


@lru_cache
def get_settings():
    return Settings()


@app.get("/info")
async def info(settings: Annotated[Settings, Depends(get_settings)]):
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,

from fastapi.responses import PlainTextResponse
from fastapi.testclient import TestClient

from docs_src.advanced_middleware.tutorial003 import app


@app.get("/large")
async def large():
    return PlainTextResponse("x" * 4000, status_code=200)


client = TestClient(app)


def test_middleware():
    response = client.get("/large", headers={"accept-encoding": "gzip"})
    assert response.status_code == 200, response.text

from typing import Union

from fastapi import Body, FastAPI
from pydantic import BaseModel, Field

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = Field(
        default=None, title="The description of the item", max_length=300
    )
    price: float = Field(gt=0, description="The price must be greater than zero")
    tax: Union[float, None] = None


@app.put("/items/{item_id}")