`Header` ist eine Schwesterklasse von `Path`, `Query` und `Cookie`. Sie erbt von derselben gemeinsamen `Param`-Elternklasse.

Aber erinnern Sie sich, dass, wenn Sie `Query`, `Path`,  `Header` und andere von `fastapi` importieren, diese tatsächlich Funktionen sind, welche spezielle Klassen zurückgeben.

///

/// info

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

In diesem Fall wird der Funktionsparameter `q` optional, und standardmäßig `None` sein.

/// check

Beachten Sie auch, dass **FastAPI** intelligent genug ist, um zu erkennen, dass `item_id` ein Pfad-Parameter ist und `q` keiner, daher muss letzteres ein Query-Parameter sein.

///

## Query-Parameter Typkonvertierung

# Развёртывание

Развернуть приложение **FastAPI** довольно просто.

## Да что такое это ваше - "развёртывание"?!

Термин **развёртывание** (приложения) означает выполнение необходимых шагов, чтобы сделать приложение **доступным для пользователей**.

from pathlib import Path

from fastapi.testclient import TestClient

from docs_src.custom_response import tutorial008
from docs_src.custom_response.tutorial008 import app

client = TestClient(app)


def test_get(tmp_path: Path):
    file_path: Path = tmp_path / "large-video-file.mp4"
    tutorial008.some_file_path = str(file_path)
    test_content = b"Fake video bytes"
    file_path.write_bytes(test_content)
    response = client.get("/")

from fastapi.testclient import TestClient
from pytest import MonkeyPatch

from ...utils import needs_pydanticv1


@needs_pydanticv1
def test_settings(monkeypatch: MonkeyPatch):
    monkeypatch.setenv("ADMIN_EMAIL", "******@****.***")
    from docs_src.settings.tutorial001_pv1 import app

    client = TestClient(app)
    response = client.get("/info")
    assert response.status_code == 200, response.text
    assert response.json() == {

from fastapi import Depends
from typing_extensions import Annotated


async def dependency_a():
    dep_a = generate_dep_a()
    try:
        yield dep_a
    finally:
        dep_a.close()


async def dependency_b(dep_a: Annotated[DepA, Depends(dependency_a)]):
    dep_b = generate_dep_b()
    try:
        yield dep_b
    finally:
        dep_b.close(dep_a)

from fastapi.testclient import TestClient
from pytest import MonkeyPatch

from ...utils import needs_pydanticv2


@needs_pydanticv2
def test_settings(monkeypatch: MonkeyPatch):
    monkeypatch.setenv("ADMIN_EMAIL", "******@****.***")
    from docs_src.settings.tutorial001 import app

    client = TestClient(app)
    response = client.get("/info")
    assert response.status_code == 200, response.text
    assert response.json() == {

from fastapi.testclient import TestClient

from docs_src.advanced_middleware.tutorial002 import app


def test_middleware():
    client = TestClient(app, base_url="http://example.com")
    response = client.get("/")
    assert response.status_code == 200, response.text
    client = TestClient(app, base_url="http://subdomain.example.com")
    response = client.get("/")
    assert response.status_code == 200, response.text

from fastapi.testclient import TestClient

from docs_src.custom_request_and_route.tutorial003 import app

client = TestClient(app)


def test_get():
    response = client.get("/")
    assert response.json() == {"message": "Not timed"}
    assert "X-Response-Time" not in response.headers


def test_get_timed():
    response = client.get("/timed")
    assert response.json() == {"message": "It's the time of my life"}

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",
    }