from fastapi import FastAPI

app = FastAPI(swagger_ui_parameters={"syntaxHighlight.theme": "obsidian"})


@app.get("/users/{username}")
async def read_user(username: str):

* 用正确的参数调用依赖项函数（「可依赖项」）
* 获取函数返回的结果
* 把函数返回的结果赋值给*路径操作函数*的参数

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

这样，只编写一次代码，**FastAPI** 就可以为多个*路径操作*共享这段代码 。

/// check | "检查"

注意，无需创建专门的类，并将之传递给 **FastAPI** 以进行「注册」或执行类似的操作。

from fastapi import FastAPI

app = FastAPI()


@app.get("/users/me")
async def read_user_me():
    return {"user_id": "the current user"}


@app.get("/users/{user_id}")
async def read_user(user_id: str):

from fastapi import APIRouter, FastAPI
from fastapi.testclient import TestClient

app = FastAPI()

router = APIRouter()


@router.get("/users/{id}")
def read_user(segment: str, id: str):
    return {"segment": segment, "id": id}


app.include_router(router, prefix="/{segment}")


client = TestClient(app)


def test_get():
    response = client.get("/seg/users/foo")

        openapi_url=app.openapi_url,
        title=app.title + " - ReDoc",
        redoc_js_url="https://unpkg.com/redoc@next/bundles/redoc.standalone.js",
    )


@app.get("/users/{username}")
async def read_user(username: str):

from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    },
    auto_error=False,
)


class User(BaseModel):
    username: str

from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    }
)


class User(BaseModel):
    username: str


# Here we use string annotations to test them

from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    },
    description="OAuth2 security scheme",
    auto_error=False,
)


class User(BaseModel):
    username: str

* 🤚 🏁 ⚪️➡️ 👆 🔢.
* 🛠️ 👈 🏁 🔢 👆 *➡ 🛠️ 🔢*.

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

👉 🌌 👆 ✍ 🔗 📟 🕐 & **FastAPI** ✊ 💅 🤙 ⚫️ 👆 *➡ 🛠️*.

/// check

👀 👈 👆 🚫 ✔️ ✍ 🎁 🎓 & 🚶‍♀️ ⚫️ 👱 **FastAPI** "®" ⚫️ ⚖️ 🕳 🎏.

    return get_redoc_html(
        openapi_url=app.openapi_url,
        title=app.title + " - ReDoc",
        redoc_js_url="/static/redoc.standalone.js",
    )


@app.get("/users/{username}")
async def read_user(username: str):