from functools import lru_cache

from fastapi import Depends, FastAPI

from .config import Settings

app = FastAPI()


@lru_cache
def get_settings():
    return Settings()


@app.get("/info")
async def info(settings: Settings = Depends(get_settings)):
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

from typing import Annotated

from fastapi import Depends, FastAPI

from .config import Settings

app = FastAPI()


@lru_cache
def get_settings():
    return Settings()


@app.get("/info")
async def info(settings: Annotated[Settings, Depends(get_settings)]):
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

from fastapi.testclient import TestClient

from .config import Settings
from .main import app, get_settings

client = TestClient(app)


def get_settings_override():
    return Settings(admin_email="******@****.***")


app.dependency_overrides[get_settings] = get_settings_override


def test_app():
    response = client.get("/info")
    data = response.json()
    assert data == {
        "app_name": "Awesome API",

🚥 🔗 🔢 💖:

```Python
def get_settings():
    return Settings()
```

👥 🔜 ✍ 👈 🎚 🔠 📨, & 👥 🔜 👂 `.env` 📁 🔠 📨. 👶 👶

✋️ 👥 ⚙️ `@lru_cache` 👨‍🎨 🔛 🔝, `Settings` 🎚 🔜 ✍ 🕴 🕐, 🥇 🕰 ⚫️ 🤙. 👶 👶

```Python hl_lines="1  10"
{!../../docs_src/settings/app03/main.py!}
```

///

```Python hl_lines="1  10"
{!> ../../docs_src/settings/app03/main.py!}
```

////

Dessa forma, todas as chamadas da função `get_settings()` nas dependências das próximas requisições, em vez de executar o código interno de `get_settings()` e instanciar um novo objeto `Settings`, irão retornar o mesmo objeto que foi retornado na primeira chamada, de novo e de novo.

#### Detalhes Técnicos de `lru_cache`

///

```Python hl_lines="1  10"
{!> ../../docs_src/settings/app03/main.py!}
```

////

Then for any subsequent call of `get_settings()` in the dependencies for the next requests, instead of executing the internal code of `get_settings()` and creating a new `Settings` object, it will return the same object that was returned on the first call, again and again.

#### `lru_cache` Technical Details

/// tip

如果可能，请尽量使用 `Annotated` 版本。

///

```Python hl_lines="1  10"
{!> ../../docs_src/settings/app03/main.py!}
```

////

然后，在下一次请求的依赖项中对 `get_settings()` 进行任何后续调用时，它不会执行 `get_settings()` 的内部代码并创建新的 `Settings` 对象，而是返回在第一次调用时返回的相同对象，一次又一次。

#### `lru_cache` 技术细节

`@lru_cache` 修改了它所装饰的函数，以返回第一次返回的相同值，而不是再次计算它，每次都执行函数的代码。

因此，下面的函数将对每个参数组合执行一次。然后，每个参数组合返回的值将在使用完全相同的参数组合调用函数时再次使用。

          + "enim, at feugiat leo magna nec libero. Mauris quis odio eget nisl rutrum cursus nec "
          + "eget augue. Sed nec arcu sem. In hac habitasse platea dictumst.";

  static final ImmutableMap<String, String> TEST_STRINGS =
      ImmutableMap.<String, String>builder()
          .put("empty", "")
          .put("1 char", "0")
          .put("1 word", "hello")
          .put("2 words", "hello world")

  static TestSuite tests(String name, ByteSinkFactory factory) {
    TestSuite suite = new TestSuite(name);
    for (Entry<String, String> entry : TEST_STRINGS.entrySet()) {
      String desc = entry.getKey();
      TestSuite stringSuite = suiteForString(name, factory, entry.getValue(), desc);
      suite.addTest(stringSuite);
    }
    return suite;
  }

  static TestSuite tests(String name, ByteSinkFactory factory) {
    TestSuite suite = new TestSuite(name);
    for (Entry<String, String> entry : TEST_STRINGS.entrySet()) {
      String desc = entry.getKey();
      TestSuite stringSuite = suiteForString(name, factory, entry.getValue(), desc);
      suite.addTest(stringSuite);
    }
    return suite;
  }