# 事件：启动 - 关闭

**FastAPI** 支持定义在应用启动前，或应用关闭后执行的事件处理器（函数）。

事件函数既可以声明为异步函数（`async def`），也可以声明为普通函数（`def`）。

/// warning | "警告"

**FastAPI** 只执行主应用中的事件处理器，不执行[子应用 - 挂载](sub-applications.md){.internal-link target=_blank}中的事件处理器。

///

## `startup` 事件

使用 `startup` 事件声明 `app` 启动前运行的函数：

```Python hl_lines="8"
{!../../docs_src/events/tutorial001.py!}
```

本例中，`startup` 事件处理器函数为项目数据库（只是**字典**）提供了一些初始值。

 * override one or more methods to modify the behavior of the backing map as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class forwards calls to <i>only some</i> {@code
 * default} methods. Specifically, it forwards calls only for methods that existed <a

  public static void flush(Flushable flushable, boolean swallowIOException) throws IOException {
    try {
      flushable.flush();
    } catch (IOException e) {
      if (swallowIOException) {
        logger.log(Level.WARNING, "IOException thrown while flushing Flushable.", e);
      } else {
        throw e;
      }
    }
  }

  /**
   * Equivalent to calling {@code flush(flushable, true)}, but with no {@code IOException} in the

# WARNING: DO NOT EDIT, THIS FILE IS PROBABLY A COPY
#
# The original version of this file is located in the https://github.com/istio/common-files repo.
# If you're looking at this file in a different repo and want to make a change, please go to the
# common-files repo, make the change there and check it in. Then come back to this repo and run
# "make update-common".

run:
  # Timeout for analysis, e.g. 30s, 5m.
  # Default: 1m
  timeout: 20m
  build-tags:

 * as desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator
 * pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingBlockingQueue}.

  virtual ~AbstractContext() {}

 public:
  AbstractContextKind getKind() const { return kind_; }

  // Release any underlying resources, including the interface object.
  //
  // WARNING: The destructor of this class is marked as protected to disallow
  // clients from directly destroying this object since it may manage its own
  // lifetime through ref counting. Thus clients MUST call Release() in order to

# WARNING: DO NOT EDIT, THIS FILE IS PROBABLY A COPY
#
# The original version of this file is located in the https://github.com/istio/common-files repo.
# If you're looking at this file in a different repo and want to make a change, please go to the
# common-files repo, make the change there and check it in. Then come back to this repo and run
# "make update-common".

# Copyright Istio Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");

しかし、新しいitemも許可したいです。itemが存在しない場合は、それらを作成して201 "Created"を返します。

これを達成するには、 `JSONResponse` をインポートし、 `status_code` を設定して直接内容を返します。

```Python hl_lines="4  25"
{!../../docs_src/additional_status_codes/tutorial001.py!}
```

/// warning | "注意"

上記の例のように `Response` を明示的に返す場合、それは直接返されます。

モデルなどはシリアライズされません。

必要なデータが含まれていることや、値が有効なJSONであること (`JSONResponse` を使う場合) を確認してください。

///

/// note | "技術詳細"

}

func (i warningMsg) pretty(msg string, args ...interface{}) {
	if msg == "" {
		fmt.Fprintln(Output, args...)
	} else {
		fmt.Fprintf(Output, `WARN: `+msg, args...)
	}
}

// Warning :
func Warning(msg string, data ...interface{}) {
	if DisableLog {
		return
	}
	consoleLog(warningMessage, msg, data...)

			// If they don't, the user will be warned and be presented with the command to label their namespace as ambient if they
			// choose to do so.
			//
			// NOTE: This is a warning and not an error because the user may not intend to label their namespace as ambient.
			//
			// e.g. Users are handling ambient redirection per workload rather than at the namespace level.