///

## Writing templates

Then you can write a template at `templates/item.html` with, for example:

```jinja hl_lines="7"
{!../../docs_src/templates/templates/item.html!}
```

### Template Context Values

In the HTML that contains:

{% raw %}

```jinja
Item ID: {{ id }}
```

{% endraw %}

...it will show the `id` taken from the "context" `dict` you passed:

///

## 编写模板

编写模板 `templates/item.html`，代码如下：

```jinja hl_lines="7"
{!../../docs_src/templates/templates/item.html!}
```

### 模板上下文

在包含如下语句的html中:

{% raw %}

```jinja
Item ID: {{ id }}
```

{% endraw %}

...这将显示你从"context"字典传递的 `id`:

```Python
{"id": id}
```

例如。当ID为 `42`时, 会渲染成:

```html
Item ID: 42
```

### 模板 `url_for` 参数

from fastapi import FastAPI, Path
from typing_extensions import Annotated

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    item_id: Annotated[int, Path(title="The ID of the item to get", ge=1)], q: str
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

这将或多或少会成为一种“神奇”属性，其中表示该表与其他相关的表中的值。

```Python hl_lines="2  15  26"
{!../../docs_src/sql_databases/sql_app/models.py!}
```

当访问 user 中的属性`items`时，如 中`my_user.items`，它将有一个`Item`SQLAlchemy 模型列表（来自`items`表），这些模型具有指向`users`表中此记录的外键。

当您访问`my_user.items`时，SQLAlchemy 实际上会从`items`表中的获取一批记录并在此处填充进去。

同样，当访问 Item中的属性`owner`时，它将包含表中的`User`SQLAlchemy 模型`users`。使用`owner_id`属性/列及其外键来了解要从`users`表中获取哪条记录。

## 创建 Pydantic 模型

from fastapi import FastAPI, Path
from typing_extensions import Annotated

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    item_id: Annotated[int, Path(title="The ID of the item to get", gt=0, le=1000)],
    q: str,
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

  private void testItems() {
    for (Object item : Iterables.concat(equalityGroups)) {
      assertTrue(item + " must not be Object#equals to null", !item.equals(null));
      assertTrue(
          item + " must not be Object#equals to an arbitrary object of another class",
          !item.equals(NotAnInstance.EQUAL_TO_NOTHING));
      assertTrue(item + " must be Object#equals to itself", item.equals(item));
      assertEquals(

from typing import Annotated

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    *,
    item_id: Annotated[int, Path(title="The ID of the item to get", ge=0, le=1000)],
    q: str,
    size: Annotated[float, Query(gt=0, lt=10.5)],
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})
    if size:
        results.update({"size": size})

Imaginez que vous vouliez que votre paramètre se nomme `item-query`.

Comme dans la requête :

```
http://127.0.0.1:8000/items/?item-query=foobaritems
```

Mais `item-query` n'est pas un nom de variable valide en Python.

Le nom le plus proche serait `item_query`.

Mais vous avez vraiment envie que ce soit exactement `item-query`...

  // Items in this list are combined using a logical OR operation. If this field is
  // empty or missing, this rule matches all destinations (traffic not restricted by
  // destination). If this field is present and contains at least one item, this rule
  // allows traffic only if the traffic matches at least one item in the to list.
  // +optional
  repeated NetworkPolicyPeer to = 2;

## FastAPI App with Tags

In many cases your FastAPI app will be bigger, and you will probably use tags to separate different groups of *path operations*.

For example, you could have a section for **items** and another section for **users**, and they could be separated by tags:

//// tab | Python 3.9+

```Python hl_lines="21  26  34"
{!> ../../docs_src/generate_clients/tutorial002_py39.py!}
```

////