你可以定義任意深度的巢狀模型：

{* ../../docs_src/body_nested_models/tutorial007_py310.py hl[7,12,18,21,25] *}

/// info

請注意，`Offer` 具有一個 `Item` 的列表，而每個 `Item` 又有一個可選的 `Image` 列表。

///

## 純列表的本文 { #bodies-of-pure-lists }

如果你期望的 JSON 本文頂層值是一個 JSON `array`（Python 的 `list`），可以像在 Pydantic 模型中那樣，直接在函式參數上宣告其型別：

```Python
images: list[Image]
```

如下所示：

For example, let's say you have 4 API endpoints (*path operations*):

* `/items/public/`
* `/items/private/`
* `/users/{user_id}/activate`
* `/items/pro/`

then you could add different permission requirements for each of them just with dependencies and sub-dependencies:

```mermaid
graph TB

current_user(["current_user"])
active_user(["active_user"])

		// httpclient target is part of ListenNotification
		// which doesn't need to be listed as part of the ARN list
		// This list is only meant for external targets, filter
		// this out pro-actively.
		if !strings.HasPrefix(targetID.ID, "httpclient+") {
			arns = append(arns, targetID.ToARN(region).String())
		}
	}

	return arns
}

// Loads notification policies for all buckets into EventNotifier.

/// info | Информация

Заметьте, что у объекта `Offer` есть список объектов `Item`, которые, в свою очередь, могут содержать необязательный список объектов `Image`

///

## Тела с чистыми списками элементов { #bodies-of-pure-lists }

Если верхний уровень значения тела JSON-объекта представляет собой JSON `array` (в Python — `list`), вы можете объявить тип в параметре функции, так же как в моделях Pydantic:

```Python
images: list[Image]

* `/users/{user_id}/activate`
* `/items/pro/`

那麼你就能只透過依賴與子依賴，為每個端點加入不同的權限需求：

```mermaid
graph TB

current_user(["current_user"])
active_user(["active_user"])
admin_user(["admin_user"])
paying_user(["paying_user"])

public["/items/public/"]
private["/items/private/"]
activate_user["/users/{user_id}/activate"]
pro_items["/items/pro/"]

current_user --> active_user

Wenn eine Ihrer Abhängigkeiten mehrmals für dieselbe *Pfadoperation* deklariert wird, beispielsweise wenn mehrere Abhängigkeiten eine gemeinsame Unterabhängigkeit haben, wird **FastAPI** diese Unterabhängigkeit nur einmal pro <abbr title="Request – Anfrage: Daten, die der Client zum Server sendet">Request</abbr> aufrufen.

    // Warning to maintainers: this implementation is highly optimized.
    int utf16Length = sequence.length();
    int utf8Length = utf16Length;
    int i = 0;

    // This loop optimizes for pure ASCII.
    while (i < utf16Length && sequence.charAt(i) < 0x80) {
      i++;
    }

    // This loop optimizes for chars less than 0x800.
    for (; i < utf16Length; i++) {
      char c = sequence.charAt(i);

    // Warning to maintainers: this implementation is highly optimized.
    int utf16Length = sequence.length();
    int utf8Length = utf16Length;
    int i = 0;

    // This loop optimizes for pure ASCII.
    while (i < utf16Length && sequence.charAt(i) < 0x80) {
      i++;
    }

    // This loop optimizes for chars less than 0x800.
    for (; i < utf16Length; i++) {
      char c = sequence.charAt(i);

# Transmitir dados { #stream-data }

Se você quer transmitir dados que podem ser estruturados como JSON, você deveria [Transmitir JSON Lines](../tutorial/stream-json-lines.md).

Mas se você quer transmitir dados binários puros ou strings, veja como fazer.

/// info | Informação

Adicionado no FastAPI 0.134.0.

///

## Casos de uso { #use-cases }

* `/users/{user_id}/activate`
* `/items/pro/`

そして、依存関係とサブ依存関係だけで、それぞれに異なるパーミッション要件を追加することができます:

```mermaid
graph TB

current_user(["current_user"])
active_user(["active_user"])
admin_user(["admin_user"])
paying_user(["paying_user"])

public["/items/public/"]
private["/items/private/"]
activate_user["/users/{user_id}/activate"]
pro_items["/items/pro/"]

current_user --> active_user