from typing import Annotated

from fastapi import Depends


async def dependency_a():
    dep_a = generate_dep_a()
    try:
        yield dep_a
    finally:
        dep_a.close()


async def dependency_b(dep_a: Annotated[DepA, Depends(dependency_a)]):
    dep_b = generate_dep_b()
    try:
        yield dep_b
    finally:
        dep_b.close(dep_a)


async def dependency_c(dep_b: Annotated[DepB, Depends(dependency_b)]):

inner_strict = APIRouter(prefix="/strict", strict_content_type=True)
inner_default = APIRouter(prefix="/default")


@inner_strict.post("/items/")
async def inner_strict_post(data: dict):
    return data


@inner_default.post("/items/")
async def inner_default_post(data: dict):
    return data


outer_router.include_router(inner_strict)
outer_router.include_router(inner_default)

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/", tags=["items"])
async def read_items():
    return [{"name": "Foo", "price": 42}]


@app.get("/users/", tags=["users"])
async def read_users():
    return [{"username": "johndoe"}]


@app.get("/elements/", tags=["items"], deprecated=True)
async def read_elements():

from fastapi import Depends, FastAPI

app = FastAPI()


async def common_parameters(q: str | None = None, skip: int = 0, limit: int = 100):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/items/")
async def read_items(commons: Annotated[dict, Depends(common_parameters)]):
    return commons


@app.get("/users/")
async def read_users(commons: Annotated[dict, Depends(common_parameters)]):

                throw new RuntimeException(e);
            }
        }

        @Override
        public boolean isAsync() {
            return async;
        }

        public void setAsync(boolean async) {
            this.async = async;
        }

        @Override
        public boolean isRetainPayload() {
            return retainPayload;
        }

### Lifespan 函式 { #lifespan-function }

首先要注意的是，我們定義了一個帶有 `yield` 的 async 函式。這和帶有 `yield` 的依賴（Dependencies）非常相似。

{* ../../docs_src/events/tutorial003_py310.py hl[14:19] *}

函式在 `yield` 之前的部分，會在應用啟動前先執行。

`yield` 之後的部分，會在應用結束後再執行。

### 非同步內容管理器（Async Context Manager） { #async-context-manager }

你會看到這個函式被 `@asynccontextmanager` 裝飾。

它會把函式轉換成所謂的「**非同步內容管理器（async context manager）**」。

from fastapi.testclient import TestClient

app = FastAPI()


async def response_status_setter(response: Response):
    response.status_code = 201


async def parent_dep(result=Depends(response_status_setter)):
    return result


@app.get("/", dependencies=[Depends(parent_dep)])
async def get_main():
    return {"msg": "Hello World"}


client = TestClient(app)

package cmd

//go:generate msgp -file=$GOFILE -unexported

import (
	"context"
	"fmt"
	"strconv"
	"sync"
	"sync/atomic"
	"time"

	"github.com/minio/minio/internal/dsync"
)

// Reject new lock requests immediately when this many are queued
// for the local lock mutex.
// We do not block unlocking or maintenance, but they add to the count.

### Arquivos e async { #files-and-async }

Na maioria dos casos, objetos semelhantes a arquivo não são compatíveis com async e await por padrão.

Por exemplo, eles não têm `await file.read()`, nem `async for chunk in file`.

    name: str
    owner: UserDB


class PetOut(BaseModel):
    name: str
    owner: User


@app.post("/users/", response_model=User)
async def create_user(user: UserCreate):
    return user


@app.get("/pets/{pet_id}", response_model=PetOut)
async def read_pet(pet_id: int):
    user = UserDB(
        email="******@****.***",
        hashed_password="secrethashed",
    )