Instead of that, by being an "asynchronous" system, once finished, the task can wait in line a little bit (some microseconds) for the computer / program to finish whatever it went to do, and then come back to take the results and continue working with them.

如果你已经安装 Typer CLI ，则可以使用以下命令安装自动补全功能：

<div class="termy">

```console
$ typer --install-completion

zsh completion installed in /home/user/.bashrc.
Completion will take effect once you restart the terminal.
```

</div>

### 文档架构

文档使用 <a href="https://www.mkdocs.org/" class="external-link" target="_blank">MkDocs</a> 生成。

在 `./scripts/docs.py` 中还有额外工具 / 脚本来处理翻译。

<a href="https://www.codacy.com/?utm_source=github&utm_medium=sponsors&utm_id=pioneers" target="_blank" title="Take code reviews from hours to minutes"><img src="https://fastapi.tiangolo.com/img/sponsors/codacy.png"></a>

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```json
{"message": "Hello World"}
```

...this response will return:

```json
{
  "message": "Hello World"
}
```

Of course, you will probably find much better ways to take advantage of this than formatting JSON. 😉

## Default response class

When creating a **FastAPI** class instance or an `APIRouter` you can specify which response class to use by default.

                    for param in parameters
                    if param.get("required")
                }
                # Make sure required definitions of the same parameter take precedence
                # over non-required definitions
                all_parameters.update(required_parameters)
                operation["parameters"] = list(all_parameters.values())

    rect rgba(0, 255, 255, .1)
        code ->> function: say_hi(name="Camila")
        function ->> code: return stored result
    end
```

In the case of our dependency `get_settings()`, the function doesn't even take any arguments, so it always returns the same value.

That way, it behaves almost as if it was just a global variable. But as it uses a dependency function, then we can override it easily for testing.

You will see the JSON response as:

```JSON
{"item_id": 5, "q": "somequery"}
```

You already created an API that:

* Receives HTTP requests in the _paths_ `/` and `/items/{item_id}`.
* Both _paths_ take `GET` operations (also known as HTTP _methods_).
* The _path_ `/items/{item_id}` has a _path parameter_ `item_id` that should be an `int`.
* The _path_ `/items/{item_id}` has an optional `str` _query parameter_ `q`.

Downloading and installing the package dependencies **could take minutes**, but using the **cache** would **take seconds** at most.

And as you would be building the container image again and again during development to check that your code changes are working, there's a lot of accumulated time this would save.