`Header`は`Path`や`Query`、`Cookie`の「姉妹」クラスです。また、同じ共通の`Param`クラスを継承しています。

しかし、`fastapi`から`Query`や`Path`、`Header`などをインポートする場合、それらは実際には特殊なクラスを返す関数であることを覚えておいてください。

///

/// info | "情報"

ヘッダーを宣言するには、`Header`を使う必要があります。なぜなら、そうしないと、パラメータがクエリのパラメータとして解釈されてしまうからです。

///

## 自動変換

`Header`は`Path`や`Query`、`Cookie`が提供する機能に加え、少しだけ追加の機能を持っています。

ほとんどの標準ヘッダーは、「マイナス記号」（`-`）としても知られる「ハイフン」で区切られています。

しかし、`user-agent`のような変数はPythonでは無効です。

                  'JUnit-based XML file inside a specified directory.')

  parser.add_argument('build_log',
                      help='Path to a build log.')
  parser.add_argument('--xml-out-path',
                      required=False,
                      help='Path to which to output '
                           'the JUnit-based XML with ResultStore links.')
  parser.add_argument('--print',

    $env:PATH = [Environment]::GetEnvironmentVariable('PATH', 'Machine') + ';C:\tools\msys64;C:\tools\msys64\usr\bin\'; \
    [Environment]::SetEnvironmentVariable('PATH', $env:PATH, 'Machine');

# Disable signature checking on pacman because we cannot initialize the keyring.
RUN Add-Content -Path C:\tools\msys64\etc\pacman.d\mirrorlist.mingw32 -Value 'SigLevel = Never'

		<property name="name">"msofficeThumbnailGenerator"</property>
		<property name="commandList">
			["${path}/generate-thumbnail",
			"msoffice",
			"${url}",
			"${outputFile}"]
		</property>
		<property name="generatorList">
			["${path}/generate-thumbnail"]
		</property>
		<postConstruct name="addCondition">
			<arg>"mimetype"</arg>

All the same process that applied for path parameters also applies for query parameters:

* Editor support (obviously)
* Data <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>
* Data validation
* Automatic documentation

## Defaults

As query parameters are not a fixed part of a path, they can be optional and can have default values.

import (
	"bufio"
	"errors"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"

	"github.com/prometheus/procfs/blockdevice"
	"golang.org/x/sys/unix"
)

// GetInfo returns total and free bytes available in a directory, e.g. `/`.
func GetInfo(path string, firstTime bool) (info Info, err error) {
	s := syscall.Statfs_t{}
	err = syscall.Statfs(path, &s)
	if err != nil {
		return Info{}, err
	}

@needs_py39
def test_post_file(tmp_path: Path, client: TestClient):
    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")

    with path.open("rb") as file:
        response = client.post("/files/", files={"file": file})
    assert response.status_code == 200, response.text
    assert response.json() == {"file_size": 14}


@needs_py39
def test_post_upload_file(tmp_path: Path, client: TestClient):

    route: APIRoute = request.scope["route"]
    return {"user_id": user_id, "path": route.path}


@app.websocket("/items/{item_id}")
async def websocket_item(item_id: str, websocket: WebSocket):
    route: APIWebSocketRoute = websocket.scope["route"]
    await websocket.accept()
    await websocket.send_json({"item_id": item_id, "path": route.path})


client = TestClient(app)


def test_get():

            continue
        lang = match.group(1)
        path = match.group(2)
        if path.endswith("index.md"):
            path = path.replace("index.md", "")
        else:
            path = path.replace(".md", "/")
        if lang == "en":
            link = f"{deploy_url}/{path}"
        else:
            link = f"{deploy_url}/{lang}/{path}"
        lang_links.setdefault(lang, []).append(link)

    placeholder_a = Default("a")
    placeholder_b = Default("")
    assert placeholder_a
    assert not placeholder_b


def test_upload_file_is_closed(tmp_path: Path):
    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")
    app = FastAPI()

    testing_file_store: List[UploadFile] = []

    @app.post("/uploadfile/")
    def create_upload_file(file: UploadFile):