* Use o `templates` que você criou para renderizar e retornar uma `TemplateResponse`, passe o nome do template, o objeto `request` e um dicionário "context" com pares chave-valor a serem usados dentro do template do Jinja2.

{* ../../docs_src/templates/tutorial001_py39.py hl[4,11,15:18] *}

/// note | Nota

Antes do FastAPI 0.108.0, Starlette 0.29.0, `name` era o primeiro parâmetro.

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

    (I hope that this workaround does not cause its own problems in the future.)
-->
<super-source path="super"/>

<inherits name="com.google.common.annotations.Annotations" />

## Parâmetros opcionais { #optional-parameters }

Da mesma forma, você pode declarar parâmetros de consulta opcionais, definindo o valor padrão para `None`:

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

Nesse caso, o parâmetro da função `q` será opcional, e `None` será o padrão.

/// check | Verifique

<img src="https://fastapi.tiangolo.com/img/tutorial/response-model/image02.png">

## 响应模型编码参数

你的响应模型可以具有默认值，例如：

{* ../../docs_src/response_model/tutorial004.py hl[11,13:14] *}

* `description: Union[str, None] = None` 具有默认值 `None`。
* `tax: float = 10.5` 具有默认值 `10.5`.
* `tags: List[str] = []` 具有一个空列表作为默认值： `[]`.

但如果它们并没有存储实际的值，你可能想从结果中忽略它们的默认值。

举个例子，当你在 NoSQL 数据库中保存了具有许多可选属性的模型，但你又不想发送充满默认值的很长的 JSON 响应。

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

    (I hope that this workaround does not cause its own problems in the future.)
-->
<super-source path="super"/>

<inherits name="com.google.common.annotations.Annotations" />

        return flags;
    }

    /**
     * Gets the new node address.
     *
     * @return the new node address
     */
    public String getNewNodeAddress() {
        return newNodeAddress;
    }

    /**
     * Sets the new node address.
     *
     * @param newNodeAddress the new node address
     */
    public void setNewNodeAddress(String newNodeAddress) {

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

    (I hope that this workaround does not cause its own problems in the future.)
-->
<super-source path="super"/>

<inherits name="com.google.common.annotations.Annotations" />

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

```Python
contents = myfile.file.read()
```

/// note | `async` Technical Details

When you use the `async` methods, **FastAPI** runs the file methods in a threadpool and awaits for them.

///

/// note | Starlette Technical Details

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//