assert response.json() == {"detail": "Invalid X-Token header"}


def test_read_nonexistent_item():
    response = client.get("/items/baz", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 404
    assert response.json() == {"detail": "Item not found"}


def test_create_item():
    response = client.post(
        "/items/",
        headers={"X-Token": "coneofsilence"},

    assert response.json() == {"detail": "Invalid X-Token header"}


def test_read_nonexistent_item():
    response = client.get("/items/baz", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 404
    assert response.json() == {"detail": "Item not found"}


def test_create_item():
    response = client.post(
        "/items/",
        headers={"X-Token": "coneofsilence"},

        tf_device.return %5 : tensor<i1>
      }, {
        %5 = "tf.opC"(%1#0) : (tensor<i1>) -> tensor<i32>
        tf_device.return %5 : tensor<i32>
      }) {} : () -> (tensor<i1>, tensor<i32>)
      tf_executor.yield %4#0, %4#1 : tensor<i1>, tensor<i32>
    }
    tf_executor.fetch %3#0, %3#1 : tensor<i1>, tensor<i32>
  }
  func.return
}

// CHECK:      [[INPUT_A:%.+]], {{%.+}} = tf_executor.island {

    public static final int BAD_REQUEST_STATUS_CODE = 400;

    public static final int FORBIDDEN_STATUS_CODE = 403;

    public static final int NOT_FOUND_STATUS_CODE = 404;

    public static final int SERVER_ERROR_STATUS_CODE = 500;

    public static final String NO_TRANSFORMER = "NONE";

    public static final String FALSE = "false";

Die Statuscodes im 400er-Bereich bedeuten hingegen, dass es einen Fehler gab.

Erinnern Sie sich an all diese **404 Not Found** Fehler (und Witze)?

## `HTTPException` verwenden

Um HTTP-Responses mit Fehlern zum Client zurückzugeben, verwenden Sie `HTTPException`.

### `HTTPException` importieren

```Python hl_lines="1"

	}

	switch extractBits(isar0, 32, 35) {
	case 1:
		ARM64.HasSHA3 = true
	}

	switch extractBits(isar0, 36, 39) {
	case 1:
		ARM64.HasSM3 = true
	}

	switch extractBits(isar0, 40, 43) {
	case 1:
		ARM64.HasSM4 = true
	}

	switch extractBits(isar0, 44, 47) {
	case 1:
		ARM64.HasASIMDDP = true
	}

	// ID_AA64ISAR1_EL1
	switch extractBits(isar1, 0, 3) {
	case 1:

需要向客户端返回错误提示的场景主要如下：

- 客户端没有执行操作的权限
- 客户端没有访问资源的权限
- 客户端要访问的项目不存在
- 等等 ...

遇到这些情况时，通常要返回 **4XX**（400 至 499）**HTTP 状态码**。

**4XX** 状态码与表示请求成功的 **2XX**（200 至 299） HTTP 状态码类似。

只不过，**4XX** 状态码表示客户端发生的错误。

大家都知道**「404 Not Found」**错误，还有调侃这个错误的笑话吧？

## 使用 `HTTPException`

向客户端返回 HTTP 错误响应，可以使用 `HTTPException`。

### 导入 `HTTPException`

```Python hl_lines="1"
{!../../../docs_src/handling_errors/tutorial001.py!}

```

// It checks if the request have been made before the server has installed all known HTTP paths.
// In that case it returns a 503 response otherwise it returns a 404.
//
// Note that we don't want to add additional checks to the readyz path as it might prevent fixing bricked clusters.

* **`300`** & 🔛 "❎". 📨 ⏮️ 👫 👔 📟 5️⃣📆 ⚖️ 5️⃣📆 🚫 ✔️ 💪, 🌖 `304`, "🚫 🔀", ❔ 🔜 🚫 ✔️ 1️⃣.
* **`400`** & 🔛 "👩‍💻 ❌" 📨. 👫 🥈 🆎 👆 🔜 🎲 ⚙️ 🏆.
    * 🖼 `404`, "🚫 🔎" 📨.
    * 💊 ❌ ⚪️➡️ 👩‍💻, 👆 💪 ⚙️ `400`.
* `500` & 🔛 💽 ❌. 👆 🌖 🙅 ⚙️ 👫 🔗. 🕐❔ 🕳 🚶 ❌ 🍕 👆 🈸 📟, ⚖️ 💽, ⚫️ 🔜 🔁 📨 1️⃣ 👫 👔 📟.

!!! tip

	StatusUnauthorized                 = 401 // RFC 9110, 15.5.2
	StatusPaymentRequired              = 402 // RFC 9110, 15.5.3
	StatusForbidden                    = 403 // RFC 9110, 15.5.4
	StatusNotFound                     = 404 // RFC 9110, 15.5.5
	StatusMethodNotAllowed             = 405 // RFC 9110, 15.5.6
	StatusNotAcceptable                = 406 // RFC 9110, 15.5.7
	StatusProxyAuthRequired            = 407 // RFC 9110, 15.5.8