PHP 7.0中扩展的Exception类中的参数错误

Question

I'm building a REST API using Slim Framework, on PHP 7.0 (Ubuntu 16.04). For proper exception handling, I extended the base \Exception class as follows :

namespace App\Exceptions;

class AppException extends \Exception
{

}

Then I use this as a base exception for all the application exceptions. For all exceptions that have a JSON response to be given to the user, I wrote another class :

namespace App\Exceptions;


use Slim\Container;
use Slim\Http\Request;
use Slim\Http\Response;

class JsonApiException extends AppException
{

    private $params = [
        "message" => "",
        "code" => 0,
        "previous" => null,
        "api" => [
            "message" => "",
            "code" => "",
            "status" => 200
        ]
    ];

    public function __construct(array $params)
    {
        $this->params = array_merge_recursive($this->params, $params);
        parent::__construct($this->params["message"], 0, $this->params["previous"]);
    }

    public function getApiMessage() {
        return $this->params["api"]["message"];
    }

    public function getApiCode() {
        return $this->params["api"]["code"];
    }

    public function getHttpStatusCode() {
        return $this->params["api"]["status"];
    }

    public function shouldBeLogged() {
        return false;
    }

    public function log(Container $container, Request $request) {
        if(!$this->shouldBeLogged()) return;
        $logger = $container->get('logger.info');
        $logger->info($this, array_merge($request->getHeaders(), [
            "method" => $_SERVER["REQUEST_METHOD"],
            "time" => $_SERVER["REQUEST_TIME"],
            "query_string" => $_SERVER["QUERY_STRING"],
            "host" => $_SERVER["HTTP_HOST"],
            "referer" => $_SERVER["HTTP_REFERER"],
            "user_agent" => $_SERVER["HTTP_USER_AGENT"],
            "ip" => $_SERVER["REMOTE_ADDR"],
            "uri" => $_SERVER["REQUEST_URI"]
        ]));
    }

    public function httpRespond(Response $response) {
        return $response->withJson([
            "error" => true,
            "errors" => [
                "server" => [[
                    "code" => $this->getApiCode(),
                    "message" => $this->getApiMessage()
                ]]
            ]
        ], $this->getHttpStatusCode());
    }

}

Then I use this as a base exception for all JSON errors. I'm using the following error to let the client know that the e-mail address it provided for registration already exists.

namespace App\Exceptions\Validation\User;

use App\Exceptions\JsonApiException;

class EmailAlreadyUsedException extends JsonApiException
{

    public function __construct()
    {
        parent::__construct([
            "message" => "The e-mail provided by the exception has already been used",
            "api" => [
                "message" => "The provided e-mail address has already been used",
                "code" => "EmailAlreadyUsed"
            ],
            "previous" => null
        ]);
    }

}

Whenever the error occurs, I add it to another custom exception to enable responding with multiple errors at once during validation :

namespace App\Exceptions;


use Slim\Http\Response;

class JsonApiMultipleException extends JsonApiException
{

    private $httpStatusCode = 200;
    private $exceptions = [];

    public function __construct($httpStatusCode = 200, \Exception $previous = null)
    {
        parent::__construct([]);
        $this->httpStatusCode = 200;
    }

    public function setHttpStatusCode(int $code) {
        $this->httpStatusCode = $code;
    }

    public function add(string $param, JsonApiException $exception) {
        if(!array_key_exists($param, $this->exceptions)) {
            $this->exceptions[$param] = [];
        }
        $this->exceptions[$param][] = $exception;
    }

    public function length() {
        $len = 0;
        foreach ($this->exceptions as $param => $exceptions) {
            $len += count($exceptions);
        }
        return $len;
    }

    public function map() {
        $mapped = [];
        foreach ($this->exceptions as $param => $exceptions) {
            $mapped[$param] = array_map(function (JsonApiException $exception) {
                return [
                    "code" => $exception->getApiCode(),
                    "message" => $exception->getApiMessage()
                ];
            }, $exceptions);
        }
        return $mapped;
    }

    public function getExceptions() {
        return $this->exceptions;
    }

    public function httpRespond(Response $response)
    {
        return $response->withJson([
            "error" => true,
            "errors" => $this->map()
        ], $this->httpStatusCode);
    }

}

But when I throw this exception during validation () :

namespace App\Validators;

use App\Exceptions\Validation\User\EmailAlreadyUsedException;
use App\Exceptions\Validation\User\InvalidEmailException;
use App\Exceptions\Validation\User\InvalidFirstNameException;
use App\Exceptions\Validation\User\InvalidLastNameException;
use App\Exceptions\Validation\User\InvalidPasswordException;
use Respect\Validation\Validator as v;

class UserValidator extends Validator
{

    //...

    private function validateEmail() {

        //Validate e-mail
        if(!v::stringType()->email()->validate($this->user->getEmail())) {
            $this->exception->add('email', new InvalidEmailException());
        }

        //Check if e-mail already used
        if(\UserQuery::create()->filterByEmail($this->user->getEmail())->count() > 0) {
            $this->exception->add('email', new EmailAlreadyUsedException());
        }
    }

    //...

}

It throws the following exception :

[Thu Jun 30 05:42:47 2016] Slim Application Error:
Type: Error
Message: Wrong parameters for App\Exceptions\Validation\User\EmailAlreadyUsedException([string $message [, long $code [, Throwable $previous = NULL]]])
File: /var/www/ElectroAbhi/app/Exceptions/JsonApiException.php
Line: 33
Trace: #0 /var/www/ElectroAbhi/app/Exceptions/JsonApiException.php(33): Exception->__construct(Array, 0, Array)
#1 /var/www/ElectroAbhi/app/Exceptions/Validation/User/EmailAlreadyUsedException.php(19): App\Exceptions\JsonApiException->__construct(Array)
#2 /var/www/ElectroAbhi/app/Validators/UserValidator.php(58): App\Exceptions\Validation\User\EmailAlreadyUsedException->__construct()
#3 /var/www/ElectroAbhi/app/Validators/UserValidator.php(32): App\Validators\UserValidator->validateEmail()
#4 /var/www/ElectroAbhi/app/Routes/API/User/Create.php(39): App\Validators\UserValidator->validate()
#5 [internal function]: App\Routes\API\User\Create->__invoke(Object(Slim\Http\Request), Object(Slim\Http\Response), Array)
#6 /var/www/ElectroAbhi/vendor/slim/slim/Slim/Handlers/Strategies/RequestResponse.php(41): call_user_func(Object(App\Routes\API\User\Create), Object(Slim\Http\Request), Object(Slim\Http\Response), Array)
#7 /var/www/ElectroAbhi/vendor/slim/slim/Slim/Route.php(325): Slim\Handlers\Strategies\RequestResponse->__invoke(Object(App\Routes\API\User\Create), Object(Slim\Http\Request), Object(Slim\Http\Response), Array)
#8 /var/www/ElectroAbhi/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(116): Slim\Route->__invoke(Object(Slim\Http\Request), Object(Slim\Http\Response))
#9 /var/www/ElectroAbhi/vendor/slim/slim/Slim/Route.php(297): Slim\Route->callMiddlewareStack(Object(Slim\Http\Request), Object(Slim\Http\Response))
#10 /var/www/ElectroAbhi/vendor/slim/slim/Slim/App.php(443): Slim\Route->run(Object(Slim\Http\Request), Object(Slim\Http\Response))
#11 /var/www/ElectroAbhi/vendor/slim/slim/Slim/MiddlewareAwareTrait.php(116): Slim\App->__invoke(Object(Slim\Http\Request), Object(Slim\Http\Response))
#12 /var/www/ElectroAbhi/vendor/slim/slim/Slim/App.php(337): Slim\App->callMiddlewareStack(Object(Slim\Http\Request), Object(Slim\Http\Response))
#13 /var/www/ElectroAbhi/vendor/slim/slim/Slim/App.php(298): Slim\App->process(Object(Slim\Http\Request), Object(Slim\Http\Response))
#14 /var/www/ElectroAbhi/public/index.php(105): Slim\App->run()
#15 {main}

I'm really confused here, how is it showing the definition as EmailAlreadyUsedException([string $message [, long $code [, Throwable $previous = NULL]]]), when I've clearly implemented the constructor in EmailAlreadyUsedException, which takes no parameters?

UPDATE

I tried to debug and find out why $this->params["message"] is an array in the constructor of JsonApiException, but now I'm even more confused :

class JsonApiException extends AppException
{

    private $params = [
        "message" => "",
        "code" => 0,
        "previous" => null,
        "api" => [
            "message" => "",
            "code" => "",
            "status" => 200
        ]
    ];

    public function __construct(array $params)
    {
        print_r($params);
        die;
        $this->params = array_merge_recursive($this->params, $params);
        parent::__construct($this->params["message"], 0, $this->params["previous"]);
    }

}

Result -> Array ()

Even though I'm passing

parent::__construct([
            "message" => "The e-mail provided by the exception has already been used",
            "api" => [
                "message" => "The provided e-mail address has already been used",
                "code" => "EmailAlreadyUsed"
            ],
            "previous" => null
        ]);

from EmailAlreadyUsedException to the constructor of JsonApiException, the $params array seems to arrive empty. Am I missing something again?

Answer 1

After long debugging sessions, the fault was not in the OOP behavior. It was in the function I was using to merge default parameters in JsonApiException. Instead of using array_merge_recursive which merges the elements of one or more arrays together so that the values of one are appended to the end of the previous one, I used array_replace_recursive.

When using array_merge_recursive, the $params property of the JsonApiException got assigned the value :

Array
(
    [message] => Array
        (
            [0] =>
            [1] => The e-mail provided by the exception has already been used
        )

    [code] => Array
        (
            [0] => 0
            [1] => 0
        )

    [api] => Array
        (
            [message] => Array
                (
                    [0] =>
                    [1] => The provided e-mail address has already been used
                )

            [code] => Array
                (
                    [0] =>
                    [1] => EmailAlreadyUsed
                )

            [status] => Array
                (
                    [0] => 200
                    [1] => 
                )

        )

)

Whereas, when using array_replace_recursive, the $params property becomes :

Array
(
    [message] => The e-mail provided by the exception has already been used
    [code] => 0
    [previous] =>
    [api] => Array
        (
            [message] => The provided e-mail address has already been used
            [code] => EmailAlreadyUsed
            [status] => 200
        )

)

Which in turn provided correct parameters to \Exception::__construct().

Just one thing is weird though, although it works, when I try to do this :

class JsonApiException extends AppException
{

    private $params = [
        "message" => "",
        "code" => 0,
        "previous" => null,
        "api" => [
            "message" => "",
            "code" => "",
            "status" => 200
        ]
    ];

    public function __construct(array $params)
    {
        print_r($params);
        die;
        $this->params = array_replace_recursive($this->params, $params);
        parent::__construct($this->params["message"], 0, $this->params["previous"]);
    }

}

I'm still getting Array (), which is weird because array_replace_recursive sets the corrects values.