<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]
<span style="color: green;">INFO</span>:     Started server process [28722]

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]
<span style="color: green;">INFO</span>:     Started server process [28722]

```

これを`main.py`にコピーします。

ライブサーバーを実行します:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]
<span style="color: green;">INFO</span>:     Started server process [28722]

Now, run the `fastapi` command with your file:

<div class="termy">

```console
$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

And open the docs at <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

from pydantic import BaseModel

app = FastAPI()


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


@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}


@app.put("/items/{item_id}")

from typing import Optional

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: bool = Optional[None]


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


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


@app.put("/items/{item_id}")

///

用下面的命令运行该示例：

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

## 查看文档

打开 API 文档： <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs。</a>

界面如下图所示：

, 🔢 🔛 ⚫️ 🔜 🛠️ 🕐 🔠 🌀 ❌. & ⤴️ 💲 📨 🔠 👈 🌀 ❌ 🔜 ⚙️ 🔄 & 🔄 🕐❔ 🔢 🤙 ⏮️ ⚫️❔ 🎏 🌀 ❌.

🖼, 🚥 👆 ✔️ 🔢:

```Python
@lru_cache
def say_hi(name: str, salutation: str = "Ms."):
    return f"Hello {salutation} {name}"
```

👆 📋 💪 🛠️ 💖 👉:

```mermaid
sequenceDiagram

participant code as Code
participant function as say_hi()

from pydantic import BaseModel

app = FastAPI()


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


@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}


@app.put("/items/{item_id}")

	LUI	$524287, X15				// b7f7ff7f

	SLL	X6, X5, X7				// b3936200
	SLL	X5, X6					// 33135300
	SLL	$1, X5, X6				// 13931200
	SLL	$1, X5					// 93921200
	SRL	X6, X5, X7				// b3d36200
	SRL	X5, X6					// 33535300
	SRL	$1, X5, X6				// 13d31200
	SRL	$1, X5					// 93d21200

	SUB	X6, X5, X7				// b3836240
	SUB	X5, X6					// 33035340
	SUB	$-2047, X5, X6				// 1383f27f
	SUB	$2048, X5, X6				// 13830280