headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the `X-` prefix</a>.

But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your CORS configurations (read more in [CORS (Cross-Origin Resource Sharing)](../tutorial/cors.md){.internal-link target=_blank}), using the parameter `expose_headers` documented in <a href="https://www.starlette.dev/middleware/#corsmiddleware"...

Qualquer função que possa ser utilizada com:

* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager" class="external-link" target="_blank">`@contextlib.contextmanager`</a> ou
* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.asynccontextmanager" class="external-link" target="_blank">`@contextlib.asynccontextmanager`</a>

pode ser utilizada como uma dependência do **FastAPI**.

Any function that is valid to use with:

* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager" class="external-link" target="_blank">`@contextlib.contextmanager`</a> or
* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.asynccontextmanager" class="external-link" target="_blank">`@contextlib.asynccontextmanager`</a>

would be valid to use as a **FastAPI** dependency.

### Install `pydantic-settings` { #install-pydantic-settings }

First, make sure you create your [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install the `pydantic-settings` package:

<div class="termy">

```console

하지만 똑같은 편집기 지원을 <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">PyCharm</a>에서 받을 수 있거나, 대부분의 다른 편집기에서도 받을 수 있습니다:

<img src="/img/tutorial/body/image05.png">

/// tip | 팁

Et les sections suivantes supposent que vous l'avez lu et que vous en connaissez les idées principales.

## Cours TestDriven.io

     * @return session
     */
    SmbSession getSmbSession(CIFSContext ctx);

    /**
     * Gets or creates an SMB session for the specified target.
     *
     * @param tf the CIFS context
     * @param targetHost the target host name
     * @param targetDomain the target domain
     * @return session
     */
    SmbSession getSmbSession(CIFSContext tf, String targetHost, String targetDomain);

    /**

## Example { #example }

For a simple example, let's consider a file structure similar to the one described in [Bigger Applications](../tutorial/bigger-applications.md){.internal-link target=_blank} and [Testing](../tutorial/testing.md){.internal-link target=_blank}:

```
.
├── app
│   ├── __init__.py

    int tmp = 0;
    for (int i = 0; i < reps; i++) {
      StringWriter target = new StringWriter(2 * n);
      OutputStream encodingStream = encoding.encoding.encodingStream(target);
      encodingStream.write(encodingInputs[i & INPUTS_MASK]);
      encodingStream.close();
      tmp += target.getBuffer().length();
    }
    return tmp;
  }

  @Benchmark

* 可获取上传文件的元数据；
* 自带 <a href="https://docs.python.org/zh-cn/3/glossary.html#term-file-like-object" class="external-link" target="_blank">file-like</a> `async` 接口；
* 暴露的 Python <a href="https://docs.python.org/zh-cn/3/library/tempfile.html#tempfile.SpooledTemporaryFile" class="external-link" target="_blank">`SpooledTemporaryFile`</a> 对象，可直接传递给其他预期「file-like」对象的库。

### `UploadFile`

`UploadFile` 的属性如下：