* Setting `status_code` to `204`, `304`, or any code below `200` (1xx) will remove the body from the response.
    * This fixes an error in Uvicorn that otherwise would be thrown: `RuntimeError: Response content longer than Content-Length`.
    * This removes `fastapi.openapi.constants.STATUS_CODES_WITH_NO_BODY`, it is replaced by a function in utils.

### Translations

I have been avoiding the creation of a new framework for several years. First I tried to solve all the features covered by **FastAPI** using many different frameworks, plug-ins, and tools.

But at some point, there was no other option than creating something that provided all these features, taking the best ideas from previous tools, and combining them in the best way possible, using language features that weren't even available before (Python 3.6+ type hints).

When you run `fastapi dev`, it will run on development mode.

By default, it will have **auto-reload** enabled, so it will automatically reload the server when you make changes to your code. This is resource intensive and could be less stable than without it, you should only use it for development.

By default it will listen on the IP address `127.0.0.1`, which is the IP for your machine to communicate with itself alone (`localhost`).

## `fastapi run`

# Extra Models

Continuing with the previous example, it will be common to have more than one related model.

This is especially the case for user models, because:

* The **input model** needs to be able to have a password.
* The **output model** should not have a password.
* The **database model** would probably need to have a hashed password.

!!! danger
    Never store user's plaintext passwords. Always store a "secure hash" that you can then verify.

使用 `Query` 和 `Path`（以及你将在后面看到的其他类）可以声明字符串约束，但也可以声明数值约束。

像下面这样，添加 `ge=1` 后，`item_id` 将必须是一个大于（`g`reater than）或等于（`e`qual）`1` 的整数。

```Python hl_lines="8"
{!../../../docs_src/path_params_numeric_validations/tutorial004.py!}
```

## 数值校验：大于和小于等于

同样的规则适用于：

* `gt`：大于（`g`reater `t`han）
* `le`：小于等于（`l`ess than or `e`qual）

```Python hl_lines="9"
{!../../../docs_src/path_params_numeric_validations/tutorial005.py!}

```

### Declare a `list` with a type parameter

To declare types that have type parameters (internal types), like `list`, `dict`, `tuple`:

* If you are in a Python version lower than 3.9, import their equivalent version from the `typing` module
* Pass the internal type(s) as "type parameters" using square brackets: `[` and `]`

In Python 3.9 it would be:

```Python
my_list: list[str]
```

Because `Annotated` can have more than one metadata annotation, you could now even use the same function with other tools, like <a href="https://typer.tiangolo.com/" class="external-link" target="_blank">Typer</a>. 🚀

## Add more validations

* After being able to understand the question, you can give them a possible **answer**.

* In many cases, it's better to understand their **underlying problem or use case**, because there might be a better way to solve it than what they are trying to do.

### Ask to close

If they reply, there's a high chance you would have solved their problem, congrats, **you're a hero**! 🦸

* Now, if that solved their problem, you can ask them to:

<div style="text-align: right; margin-right: 10%;">Kabir Khan - <strong>Microsoft</strong> <a href="https://github.com/tiangolo/fastapi/pull/26" target="_blank"><small>(ref)</small></a></div>

---

"*Estou extremamente entusiasmado com o **FastAPI**. É tão divertido!*"

<div style="text-align: right; margin-right: 10%;">Kabir Khan - <strong>Microsoft</strong> <a href="https://github.com/tiangolo/fastapi/pull/26" target="_blank"><small>(ref)</small></a></div>

---