from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[Union[str, None], Query(min_length=3)]):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

    client = TestClient(mod.app)
    client.headers.clear()
    return client


def test_get_item(client: TestClient):
    response = client.get("/items/next")
    assert response.status_code == 200
    assert response.json() == {
        "name": "Island In The Moon",
        "price": 12.99,
        "description": "A place to be playin' and havin' fun",

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[
        str | None, Query(min_length=3, max_length=50, regex="^fixedquery$")
    ] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[str | None, Query(title="Query string", min_length=3)] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

    response = client.get("/items/")
    assert response.status_code == 200
    assert response.json() == {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}


def test_query_params_str_validations_q_fixedquery(client: TestClient):
    response = client.get("/items/", params={"q": "fixedquery"})
    assert response.status_code == 200
    assert response.json() == {
        "items": [{"item_id": "Foo"}, {"item_id": "Bar"}],

    response = client.post("/usersx/rick")
    assert response.status_code == 404, response.text


def test_websocket():
    with client.websocket_connect("/items/portal-gun") as websocket:
        data = websocket.receive_json()
        assert data == {"item_id": "portal-gun", "path": "/items/{item_id}"}


def test_websocket_invalid_path_doesnt_match():
    with pytest.raises(WebSocketDisconnect):

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[
        Union[str, None], Query(min_length=3, max_length=50, pattern="^fixedquery$")
    ] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

Der Wert des Pfad-Parameters `item_id` wird Ihrer Funktion als das Argument `item_id` übergeben.

Wenn Sie dieses Beispiel ausführen und auf <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a> gehen, sehen Sie als <abbr title="Response – Antwort: Daten, die der Server zum anfragenden Client zurücksendet">Response</abbr>:

```JSON
{"item_id":"foo"}
```

                                "application/json": {
                                    "schema": {
                                        "items": {"$ref": "#/components/schemas/Item"},
                                        "type": "array",
                                        "title": "Response Read Items Items  Get",
                                    }
                                }
                            },
                        }

                    "properties": {
                        "files": {
                            "title": "Files",
                            "type": "array",
                            "items": {"type": "string", "format": "binary"},
                            "description": "Multiple files as bytes",
                        }
                    },
                },