### 提供 `root_path` { #providing-the-root-path }

为此，你可以像下面这样使用命令行选项 `--root-path`：

<div class="termy">

```console
$ fastapi run main.py --forwarded-allow-ips="*" --root-path /api/v1

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

如果你使用 Hypercorn，它也有 `--root-path` 选项。

/// note | 技术细节

## Importer `Header` { #import-header }

Commencez par importer `Header` :

{* ../../docs_src/header_params/tutorial001_an_py310.py hl[3] *}

## Déclarer des paramètres `Header` { #declare-header-parameters }

Déclarez ensuite les paramètres d'en-tête en utilisant la même structure qu'avec `Path`, `Query` et `Cookie`.

   
   *Please let us know if this helps.*
   
windows_comment: >
   From the stack trace it looks like you are hitting windows path length limit.
      * Try to disable path length limit on Windows 10.
        * Refer [disable path length limit instructions guide.](https://mspoweruser.com/ntfs-260-character-windows-10/)
   

     */
    @Nonnull
    default SettingsBuilderResult build(
            @Nonnull Session session,
            @Nonnull Path installationSettingsPath,
            @Nonnull Path projectSettingsPath,
            @Nonnull Path userSettingsPath) {
        return build(
                SettingsBuilderRequest.build(session, installationSettingsPath, projectSettingsPath, userSettingsPath));
    }

* Toma cada **request** que llega a tu aplicación.
* Puede entonces hacer algo a esa **request** o ejecutar cualquier código necesario.
* Luego pasa la **request** para que sea procesada por el resto de la aplicación (por alguna *path operation*).

    void testValidSmbPaths(String path) {
        assertDoesNotThrow(() -> InputValidator.validateSmbPath(path));
    }

    @ParameterizedTest
    @DisplayName("Test invalid path characters")
    @ValueSource(strings = { "file:name.txt", "file<name>.txt", "file|name.txt", "file*name.txt", "file?name.txt", "file\"name.txt" })
    void testInvalidPathCharacters(String path) {

			if v.obscured {
				tf, err := obscuretestdata.DecodeToTempFile(path)
				if err != nil {
					t.Fatalf("obscuredtestdata.DecodeToTempFile(%s): %v", path, err)
				}
				path = tf
			}

			f, err := os.Open(path)
			if err != nil {
				t.Fatalf("unexpected error: %v", err)
			}
			defer f.Close()

			var fr io.Reader = f

### Bereitstellung des `root_path` { #providing-the-root-path }

Um dies zu erreichen, können Sie die Kommandozeilenoption `--root-path` wie folgt verwenden:

<div class="termy">

```console
$ fastapi run main.py --forwarded-allow-ips="*" --root-path /api/v1

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)

Imaginemos que quieres obtener la dirección IP/host del cliente dentro de tu *path operation function*.

Para eso necesitas acceder al request directamente.

{* ../../docs_src/using_request_directly/tutorial001_py310.py hl[1,7:8] *}

Al declarar un parámetro de *path operation function* con el tipo siendo `Request`, **FastAPI** sabrá pasar el `Request` en ese parámetro.

/// tip | Consejo

def get_parameterless_sub_dependant(*, depends: params.Depends, path: str) -> Dependant:
    assert callable(depends.dependency), (
        "A parameter-less dependency must have a callable dependency"
    )
    own_oauth_scopes: list[str] = []
    if isinstance(depends, params.Security) and depends.scopes:
        own_oauth_scopes.extend(depends.scopes)
    return get_dependant(
        path=path,
        call=depends.dependency,