* **`400`** und darüber stehen für „Client error“-Responses („Client-Fehler“). Auch diese verwenden Sie am häufigsten.
    * Ein Beispiel ist `404`, für eine „Not Found“-Response („Nicht gefunden“).
    * Für allgemeine Fehler beim Client können Sie einfach `400` verwenden.

* **`4XX`** – статус-коды, сообщающие о клиентской ошибке. Это ещё одна наиболее часто используемая категория.
    * Пример – код `404` для статуса "Not Found".
    * Для общих ошибок со стороны клиента можно просто использовать код `400`.

## [Responses](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-response/)

The response answers the request with a code (like 200 for success or 404 for not found), headers, and its own optional body.

## Rewriting Requests

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This input was created by taking the instruction productions in
// the old assembler's (6a's) grammar and hand-writing complete
// instructions for each rule, to guarantee we cover the same space.

#include "../../../../../runtime/textflag.h"

TEXT	foo(SB), DUPOK|NOSPLIT, $0

	for j := 0; j < 16; j++ {
		newFormat := format.Clone()
		newFormat.Erasure.This = format.Erasure.Sets[0][j]
		formats[j] = newFormat
	}

	// empty format to indicate disk not found, but this
	// empty should return false.
	formats[0] = nil

	if ok := formatErasureV3ThisEmpty(formats); ok {
		t.Fatalf("expected value false, got %t", ok)
	}

	formats[2].Erasure.This = ""

        final File parentFile = outputFile.getParentFile();
        if (!parentFile.exists()) {
            parentFile.mkdirs();
        }
        if (!parentFile.isDirectory()) {
            logger.warn("Not found: {}", parentFile.getAbsolutePath());
            return false;
        }

        return process(thumbnailId, responseData -> {
            if (!isImageMimeType(responseData)) {

	config.SetRegion(region)
	if err = config.Validate(region, globalEventNotifier.targetList); err != nil {
		arnErr, ok := err.(*event.ErrARNNotFound)
		if ok {
			for i, queue := range config.QueueList {
				// Remove ARN not found queues, because we previously allowed
				// adding unexpected entries into the config.
				//
				// With newer config disallowing changing / turning off
				// notification targets without removing ARN in notification

  static final int DEFAULT_SIZE = 3;

  /**
   * Minimum size of the hash table of a compact hash-based collection. Because small hash tables
   * use a byte[], any smaller size uses the same amount of memory due to object padding.
   */
  private static final int MIN_HASH_TABLE_SIZE = 4;

  private static final int BYTE_MAX_SIZE = 1 << Byte.SIZE; // 2^8 = 256

```JSON
{
  "item": "The Foo Wrestlers"
}
```

しかし、クライアントが`http://example.com/items/bar`（存在しない`item_id` `"bar"`）をリクエストした場合、HTTPステータスコード404（"not found"エラー）と以下のJSONレスポンスが返されます:

```JSON
{
  "detail": "Item not found"
}
```

/// tip | "豆知識"

`HTTPException`を発生させる際には、`str`だけでなく、JSONに変換できる任意の値を`detail`パラメータとして渡すことができます。

`dist`や`list`などを渡すことができます。

                            ioff += maxChunkSize;
                        }

                        if ( dfd == null || !dfd.isValid() ) {
                            // don't reopen the file for every round if it's not necessary, keep the lock
                            dfd = openCopyTargetFile(dest, src.getAttributes(), !write);
                        }