## Install custom exception handlers { #install-custom-exception-handlers }

You can add custom exception handlers with <a href="https://www.starlette.dev/exceptions/" class="external-link" target="_blank">the same exception utilities from Starlette</a>.

Let's say you have a custom exception `UnicornException` that you (or a library you use) might `raise`.

/// warning | 警告

如果您觉得现在还用不到以下技术细节，可以先跳过下面的内容。

///

`RequestValidationError` 是 Pydantic 的 <a href="https://docs.pydantic.dev/latest/concepts/models/#error-handling" class="external-link" target="_blank">`ValidationError`</a> 的子类。

**FastAPI** 调用的就是 `RequestValidationError` 类，因此，如果在 `response_model` 中使用 Pydantic 模型，且数据有错误时，在日志中就会看到这个错误。

但客户端或用户看不到这个错误。反之，客户端接收到的是 HTTP 状态码为 `500` 的「内部服务器错误」。

      <url>http://my.repository.com/repo/path</url>
    </mirror>
    -->
    <mirror>
      <id>maven-default-http-blocker</id>
      <mirrorOf>external:http:*</mirrorOf>
      <name>Pseudo repository to mirror external repositories initially using HTTP.</name>
      <url>http://0.0.0.0/</url>
      <blocked>true</blocked>
    </mirror>
  </mirrors>

  <!-- repositories

* 文件 `app/routers/items.py` 位于 `app/routers/` 包中，因此它是一个子模块：`app.routers.items`。
* 同样适用于 `app/routers/users.py`，它是另一个子模块：`app.routers.users`。
* 还有一个子目录 `app/internal/` 包含另一个 `__init__.py` 文件，因此它是又一个「Python 子包」：`app.internal`。
* `app/internal/admin.py` 是另一个子模块：`app.internal.admin`。

<img src="https://fastapi.tiangolo.com/img/tutorial/bigger-applications/package.drawio.svg">

带有注释的同一文件结构：

```
.

This was changed in version 0.110.0 to fix unhandled memory consumption from forwarded exceptions without a handler (internal server errors), and to make it consistent with the behavior of regular Python code.

@REM enable echoing by setting MAVEN_BATCH_ECHO to 'on'
@if "%MAVEN_BATCH_ECHO%"=="on" echo %MAVEN_BATCH_ECHO%

@REM Clear/define a variable for any options to be inserted via script
@REM We want to avoid trying to parse the external MAVEN_OPTS variable
SET INTERNAL_MAVEN_OPTS=

@REM Execute a user defined script before this one
if not "%MAVEN_SKIP_RC%"=="" goto skipRc
if exist "%PROGRAMDATA%\mavenrc.cmd" call "%PROGRAMDATA%\mavenrc.cmd" %*

## `Union`または`anyOf`

レスポンスを２つの型の`Union`として宣言することができます。

OpenAPIでは`anyOf`で定義されます。

そのためには、標準的なPythonの型ヒント<a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>を使用します:

{* ../../docs_src/extra_models/tutorial003.py hl[1,14,15,18,19,20,33] *}

## モデルのリスト

同じように、オブジェクトのリストのレスポンスを宣言することができます。

Esse é o benefício dos padrões...

///

## Veja em ação { #see-it-in-action }

Abra o docs interativo: <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

### Autentique-se { #authenticate }

Clique no botão "Authorize".

Use as credenciais:

User: `johndoe`

Password: `secret`

    - [SIG Scheduling](#sig-scheduling-1)
    - [SIG Storage](#sig-storage-1)
    - [SIG vSphere](#sig-vsphere)
    - [SIG Windows](#sig-windows-1)
    - [Additional changes](#additional-changes)
  - [External Dependencies](#external-dependencies)
  - [Bug Fixes](#bug-fixes)
      - [General Fixes and Reliability](#general-fixes-and-reliability)
  - [Non-user-facing changes](#non-user-facing-changes)
- [v1.11.0-rc.3](#v1110-rc3)

    Failure in SSL library, usually a protocol error
        error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake
        failure (external/openssl/ssl/s23_clnt.c:770 0x7f2728a53ea0:0x00000000)
    at com.android.org.conscrypt.NativeCrypto.SSL_do_handshake(Native Method)
```

You can check a web server's configuration using [Qualys SSL Labs][qualys]. OkHttp's TLS