# 模板

**FastAPI** 支持多种模板引擎。

Flask 等工具使用的 Jinja2 是最用的模板引擎。

在 Starlette 的支持下，**FastAPI** 应用可以直接使用工具轻易地配置 Jinja2。

## 安装依赖项

安装 `jinja2`：

<div class="termy">

```console
$ pip install jinja2

---> 100%
```

</div>

## 使用 `Jinja2Templates`

* 导入 `Jinja2Templates`
* 创建可复用的 `templates` 对象
* 在返回模板的*路径操作*中声明 `Request` 参数

from typing import Union

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None


class User(BaseModel):
    username: str
    full_name: Union[str, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,

* <a href="https://github.com/tiangolo/full-stack" class="external-link" target="_blank">https://github.com/tiangolo/full-stack</a>
* <a href="https://github.com/tiangolo/full-stack-flask-couchbase" class="external-link" target="_blank">https://github.com/tiangolo/full-stack-flask-couchbase</a>

 * TODO: this is session scoped as SPI can contribute.
 */
@Named
@Singleton
public class DefaultLifecycleRegistry implements LifecycleRegistry {

    private static final String MAVEN_PLUGINS = "org.apache.maven.plugins:";

    public static final String DEFAULT_LIFECYCLE_MODELID = "org.apache.maven:maven-core:"
            + DefaultLifecycleRegistry.class.getPackage().getImplementationVersion()
            + ":default-lifecycle-bindings";

{* ../../docs_src/cookie_params/tutorial001_an_py310.py hl[9] *}

/// note | Detalhes Técnicos

`Cookie` é uma classe "irmã" de `Path` e `Query`. Ela também herda da mesma classe em comum `Param`.

Mas lembre-se que quando você importa `Query`, `Path`, `Cookie` e outras de `fastapi`, elas são na verdade funções que retornam classes especiais.

///

        ("/callable-dependency-class", "callable-dependency-class"),
        ("/callable-gen-dependency-class", "callable-gen-dependency-class"),
        ("/async-callable-dependency-class", "async-callable-dependency-class"),
        ("/async-callable-gen-dependency-class", "async-callable-gen-dependency-class"),
    ],
)
def test_class_dependency(route, value):

    ) -> Mapping[str, Any]:
        from ._compat.v2 import with_info_plain_validator_function

        return with_info_plain_validator_function(cls._validate)


class DefaultPlaceholder:
    """
    You shouldn't use this class directly.

    It's used internally to recognize when a default value has been overwritten, even
    if the overridden default value was truthy.
    """

const val MASTER_CHECK_CONFIGURATION = "Gradle_Master_Check"
const val MAX_PROJECT_NUMBER_IN_BUCKET = 11

/**
 * Process test-class-data.json and generates test-buckets.json
 *
 * Usage: `mvn compile exec:java@update-test-buckets -DinputTestClassDataJson=/path/to/test-class-data.json`.
 * You can get the JSON file as an artifacts of the "autoUpdateTestSplitJsonOnGradleMaster" pipeline in TeamCity.
 */
fun main() {

from typing import Union

from fastapi import FastAPI, status
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: set[str] = set()


@app.post("/items/", response_model=Item, status_code=status.HTTP_201_CREATED)
async def create_item(item: Item):

     * @returns {string} - String of attributes.
     */
    _attributes(line) {
        let attrs = '';
        for (let prop in line) {
            // Custom add class
            if (prop === 'class') {
                attrs += ` class=${line[prop]} `
                continue
            }
            if (prop === 'type') {
                attrs += `${this.pfx}="${line[prop]}" `