错误和错误响应

在dingo Api 中，不需要手动的指定错误，只需要抛出一个继承Symfony\Component\HttpKernel\Exception\HttpException
的异常，API会自动处理这个响应。

异常	状态码
Symfony\Component\HttpKernel\Exception\BadRequestHttpException	400
Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException	401
Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException	403
Symfony\Component\HttpKernel\Exception\NotFoundHttpException	404
Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException	405
Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException	406
Symfony\Component\HttpKernel\Exception\ConflictHttpException	409
Symfony\Component\HttpKernel\Exception\GoneHttpException	410
Symfony\Component\HttpKernel\Exception\LengthRequiredHttpException	411
Symfony\Component\HttpKernel\Exception\PreconditionFailedHttpException	412
Symfony\Component\HttpKernel\Exception\UnsupportedMediaTypeHttpException	415
Symfony\Component\HttpKernel\Exception\PreconditionRequiredHttpException	428
Symfony\Component\HttpKernel\Exception\TooManyRequestsHttpException	429
Symfony\Component\HttpKernel\Exception\HttpException	500
Symfony\Component\HttpKernel\Exception\ServiceUnavailableHttpException	503

列子：

$api->version('v1', function ($api) {
    $api->put('user/{id}', function ($id) {
        $user = User::find($id);

        if ($user->updated_at > app('request')->get('last_updated')) {
            throw new Symfony\Component\HttpKernel\Exception\ConflictHttpException('User was updated prior to your request.');
        }

        // No error, we can continue to update the user as per usual.
    });
});

当程序出现上面的异常，会自动捕捉到这个异常并转化成json，同时http响应吗也会自动变成这个异常的status_code以相对应

{
    "message": "User was updated prior to your request.",
    "status_code": 409
}

资源异常

下面列表中是常见的资源异常，resource exceptions, 他们返回的状态吗全部是422

Dingo\Api\Exception\DeleteResourceFailedException
Dingo\Api\Exception\ResourceException
Dingo\Api\Exception\StoreResourceFailedException
Dingo\Api\Exception\UpdateResourceFailedException

这些异常特殊之处在于你可以将创建、更新或者删除资源时遇到的验证错误传递到这些异常中。
下面我们就来看一个创建新用户验证失败抛出StoreResourceFailedException异常的例子：

$api->version('v1', function ($api) {
    $api->post('users', function () {
        $rules = [
            'username' => ['required', 'alpha'],
            'password' => ['required', 'min:7']
        ];

        $payload = app('request')->only('username', 'password');

        $validator = app('validator')->make($payload, $rules);

        if ($validator->fails()) {
            throw new Dingo\Api\Exception\StoreResourceFailedException('Could not create new user.', $validator->errors());
        }

        // Create user as per usual.
    });
});

Dingo 会自动捕捉这个异常并且将其转成Json格式，同时HTTP Status也会变成status_code,

{
  "message": "Could not create new user.",
  "errors": {
    "username": [
      "The username field is required."
    ],
    "password": [
      "The password field is required."
    ]
  },
  "status_code": 422
}

用户自定义的HTTP异常

创建自己的HTTP 异常，需要继承Symfony\Component\HttpKernel\Exception\HttpException或者是实现Symfony\Component\HttpKernel\Exception\HttpExceptionInterface接口

自定义异常响应

app('Dingo\Api\Exception\Handler')->register(function (Symfony\Component\HttpKernel\Exception\UnauthorizedHttpException $exception) {
    return Response::make(['error' => 'Hey, what do you think you are doing!?'], 401);
}); ????????????

如果你使用表单请求，那么需要继承API表单请求基类或者实现自己的类。API请求基类会检查输入请求是否是请求API，如果是的话当验证失败会抛出Dingo\Api\Exception\ValidationHttpException异常。这个异常会被Dingo API渲染并返回错误响应。
如果你想要实现自己的表单请求，则必须重载failedValidation和failedAuthorization方法，这些方法必须抛出上述其中一种异常而不是Laravel抛出的HTTP异常。