* @param extension the file extension to look up (without the dot)
     * @param def the default MIME type to return if no mapping is found
     * @return the MIME type for the extension, or the specified default if not found
     * @throws IOException if there is an error processing the MIME mappings
     */
    public String getMimeType(final String extension, final String def) throws IOException {
        int state, t, x, i, off;
        byte ch;

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Tàbí lò <code>async def</code>...</summary>

Tí kóòdù rẹ̀ bá ń lò `async` / `await`, lò `async def`:

```Python hl_lines="9  14"

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>همچنین می‌توانید از <code>async def</code>... نیز استفاده کنید</summary>

    assertThat(response1.body.source().readUtf8(3)).isEqualTo("ABC")
    assertThat(response2.body.source().readUtf8(3)).isEqualTo("GHI")
    assertThat(response1.body.source().readUtf8(3)).isEqualTo("DEF")
    assertThat(response2.body.source().readUtf8(3)).isEqualTo("JKL")
    val c0e0 = server.takeRequest()
    assertThat(c0e0.connectionIndex).isEqualTo(0)
    assertThat(c0e0.exchangeIndex).isEqualTo(0)

👆 💪 🎲 🚶 👉 🍕.

///

📤 🎛 🌌 🔬 👉 ⚛ 🛠️ ⏮️ *🕴* & ⏮️ *🤫*.

👆 💪 🔬 🎉 🐕‍🦺 (🔢) 👈 💪 🛠️ ⏭ 🈸 ▶️ 🆙, ⚖️ 🕐❔ 🈸 🤫 🔽.

👫 🔢 💪 📣 ⏮️ `async def` ⚖️ 😐 `def`.

### `startup` 🎉

🚮 🔢 👈 🔜 🏃 ⏭ 🈸 ▶️, 📣 ⚫️ ⏮️ 🎉 `"startup"`:

{* ../../docs_src/events/tutorial001.py hl[8] *}

👉 💼, `startup` 🎉 🐕‍🦺 🔢 🔜 🔢 🏬 "💽" ( `dict`) ⏮️ 💲.

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>O usa <code>async def</code>...</summary>

Si tu código usa `async` / `await`, usa `async def`:

```Python hl_lines="9  14"

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Of maak gebruik van <code>async def</code>...</summary>

Als je code gebruik maakt van `async` / `await`, gebruik dan `async def`:

```Python hl_lines="9  14"

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Ou use <code>async def</code>...</summary>

Se seu código utiliza `async` / `await`, use `async def`:

```Python hl_lines="9  14"

Diese Funktionen können mit `async def` oder normalem `def` deklariert werden.

### `startup`-Event

Um eine Funktion hinzuzufügen, die vor dem Start der Anwendung ausgeführt werden soll, deklarieren Sie diese mit dem Event `startup`:

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>或可以使用 <code>async def</code>...</summary>

如果你的程式使用 `async` / `await`，請使用 `async def`：

```Python hl_lines="9  14"
from typing import Union