- 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`

{* ../../docs_src/handling_errors/tutorial001.py hl[1] *}

### 触发 `HTTPException`

// Copyright 2016 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.

package tar

import (
	"bytes"
	"fmt"
	"strconv"
	"strings"
	"time"
)

// hasNUL reports whether the NUL character exists within s.
func hasNUL(s string) bool {
	return strings.Contains(s, "\x00")
}

// isASCII reports whether the input is an ASCII C-style string.

Right before deciding to build **FastAPI** I found **APIStar** server. It had almost everything I was looking for and had a great design.

It was one of the first implementations of a framework using Python type hints to declare parameters and requests that I ever saw (before NestJS and Molten). I found it more or less at the same time as Hug. But APIStar used the OpenAPI standard.

	expects := []User{
		{Name: "distinct", Age: 20},
		{Name: "distinct", Age: 18},
		{Name: "distinct-2", Age: 18},
		{Name: "distinct-3", Age: 18},
	}

	if len(results) != 4 {
		t.Fatalf("invalid results length found, expects: %v, got %v", len(expects), len(results))
	}

	for idx, expect := range expects {
		AssertObjEqual(t, results[idx], expect, "Name", "Age")
	}

	var count int64

#!/usr/bin/env bash
# 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.

# When run as (for example)
#
#	GOOS=linux GOARCH=ppc64 bootstrap.bash
#
# this script cross-compiles a toolchain for that GOOS/GOARCH
# combination, leaving the resulting tree in ../../go-${GOOS}-${GOARCH}-bootstrap.
# That tree can be copied to a machine of the given target type

// 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 file encapsulates some of the odd characteristics of the
// 64-bit PowerPC (PPC64) instruction set, to minimize its interaction
// with the core of the assembler.

package arch

import (
	"cmd/internal/obj"
	"cmd/internal/obj/ppc64"
)

func jumpPPC64(word string) bool {

fun Test.filterEnvironmentVariables(inheritDevelocityAccessToken: Boolean) {
    environment = makePropagatedEnvironment()
    environment.forEach { (key, _) ->
        require(credentialsKeywords.none { key.contains(it, true) }) { "Found sensitive data in filtered environment variables: $key" }
    }

    if (inheritDevelocityAccessToken) {
        System.getenv("DEVELOCITY_ACCESS_KEY")?.let {
            environment["DEVELOCITY_ACCESS_KEY"] = it

    // UTF-32LE.
    "fffe0000".decodeHex(),
    // UTF-16LE.
    "fffe".decodeHex(),
    // UTF-32BE.
    "0000feff".decodeHex(),
  )

/**
 * Returns an array containing only elements found in this array and also in [other]. The returned
 * elements are in the same order as in this.
 */
internal fun Array<String>.intersect(
  other: Array<String>,
  comparator: Comparator<in String>,
): Array<String> {

	}

	return nil
}

// Exists - checks whether target by target ID exists or not.
func (list *TargetList) Exists(id TargetID) bool {
	list.RLock()
	defer list.RUnlock()

	_, found := list.targets[id]
	return found
}

// TargetIDResult returns result of Remove/Send operation, sets err if
// any for the associated TargetID
type TargetIDResult struct {
	// ID where the remove or send were initiated.

        // Find and load the root POM
        Path rootPomPath = startDirectory.resolve(POM_XML);
        if (!Files.exists(rootPomPath)) {
            throw new IOException("No pom.xml found in directory: " + startDirectory);
        }

        Document rootPom = loadPom(rootPomPath);
        pomMap.put(rootPomPath, rootPom);

        // Recursively discover modules