👉 🐍 🔢.

⚫️ 🔜 🤙 **FastAPI** 🕐❔ ⚫️ 📨 📨 📛 "`/`" ⚙️ `GET` 🛠️.

👉 💼, ⚫️ `async` 🔢.

---

👆 💪 🔬 ⚫️ 😐 🔢 ↩️ `async def`:

{* ../../docs_src/first_steps/tutorial003.py hl[7] *}

/// note

🚥 👆 🚫 💭 🔺, ✅ [🔁: *"🏃 ❓"*](../async.md#_2){.internal-link target=_blank}.

///

### 🔁 5️⃣: 📨 🎚

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"bytes"
	"context"
	"maps"
	"sync"

	"github.com/minio/minio-go/v7"
	"github.com/minio/minio-go/v7/pkg/tags"
	"github.com/minio/minio/internal/crypto"
	"github.com/minio/minio/internal/hash"
	xhttp "github.com/minio/minio/internal/http"

ut[type=file].valid{color:#468847;background:0 0;-webkit-box-shadow:none;box-shadow:none}.form-error{display:block;color:#b94a48;margin-top:5px;margin-bottom:10px;line-height:140%}span.help{color:#999;font-size:90%}input.async-validation,input.validating-server-side,select.async-validation,select.validating-server-side{opacity:.5;background-image:url(data:image/gif;base64,R0lGODlhEAAQAPQAAP///wAAAPDw8IqKiuDg4EZGRnp6egAAAFhYWCQkJKysrL6+vhQUFJycnAQEBDY2NmhoaAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"bytes"
	"context"
	"errors"
	"hash"
	"io"
	"sync"

	xhttp "github.com/minio/minio/internal/http"
	"github.com/minio/minio/internal/ioutil"
	"github.com/minio/minio/internal/ringbuffer"
)

// Calculates bitrot in chunks and writes the hash into the stream.

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

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

	"github.com/rcrowley/go-metrics"
)

//go:generate msgp -file $GOFILE

const (
	// beta is the weight used to calculate exponential moving average

**FastAPI** は、`BackgroundTasks` 型のオブジェクトを作成し、そのパラメーターに渡します。

## タスク関数の作成

バックグラウンドタスクとして実行される関数を作成します。

これは、パラメーターを受け取ることができる単なる標準的な関数です。

これは `async def` または通常の `def` 関数であり、**FastAPI** はこれを正しく処理します。

ここで、タスク関数はファイル書き込みを実行します (メール送信のシミュレーション)。

また、書き込み操作では `async` と `await` を使用しないため、通常の `def` で関数を定義します。

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## バックグラウンドタスクの追加

Ici, c'est une fonction asynchrone (définie avec `async def`).

---

Vous pourriez aussi la définir comme une fonction classique plutôt qu'avec `async def` :

{* ../../docs_src/first_steps/tutorial003.py hl[7] *}

/// note

Si vous ne connaissez pas la différence, allez voir la section [Concurrence : *"Vous êtes pressés ?"*](../async.md#vous-etes-presses){.internal-link target=_blank}.

///

package stmt_store

import (
	"context"
	"database/sql"
	"math"
	"sync"
	"time"

	"gorm.io/gorm/internal/lru"
)

type Stmt struct {
	*sql.Stmt
	Transaction bool
	prepared    chan struct{}
	prepareErr  error
}

func (stmt *Stmt) Error() error {
	return stmt.prepareErr
}

func (stmt *Stmt) Close() error {
	<-stmt.prepared

	if stmt.Stmt != nil {
		return stmt.Stmt.Close()
	}
	return nil

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

If your code uses `async` / `await`, use `async def`:

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

from fastapi import FastAPI

app = FastAPI()


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


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

    // ThreadLocal is not available to GWT, so we always reuse the same
    // instance.  It is always safe to return the same instance because
    // javascript is single-threaded, and only used by blocks that doesn't
    // involve async callbacks.
    return CHAR_BUFFER;
  }

  private Platform() {}