Extending Exception: avoiding code duplication

Question

I'm implementing a REST API in PHP 7.1. It is designed to throw Exceptions to print non-200 responses.

I decided to go with the following:

abstract class APIException extends \Exception
{
    public function __construct($message, $code, Exception $previous = null) {
        parent::__construct($message, $code, $previous);
    }

    public function parseException() {
        return ResponseParser::parseResponse($this->message, $this->code);
    }
}

And then I extended the BaseException with my various personal exceptions, like IncorrectMethodException here.

class IncorrectMethodException extends APIException
{
    public function __construct(String $expectedMethod, Exception $previous = null) {
        parent::__construct("Incorrect method, $expectedMethod expected", 405, $previous);
    }
}

Here is the code to my ResponseParser class:

class ResponseParser
{
    /**
     * @param $data
     * @param int $status
     * @return string
     */
    public static function parseResponse($data, $status = 200)
    {
        header("Access-Control-Allow-Origin: *");
        header("Access-Control-Allow-Methods: *");
        header("Content-Type: application/json");
        header("HTTP/1.1 " . $status . " " . self::_requestStatus($status));
        return json_encode($data);
    }

    /**
     * @param $code
     * @return string status code
     */
    private static function _requestStatus($code)
    {
        $status = array(
            200 => 'OK',
            400 => 'Bad Request',
            401 => 'Unauthorized',
            404 => 'Not Found',
            405 => 'Method Not Allowed',
            500 => 'Internal Server Error',
        );
        return ($status[$code]) ? $status[$code] : $status[500];
    }
}

Is this a correct way to avoid code duplication here?

Answer 1

Naming:

• ResponseParser doesn't actually parse a response. Parsing a response would mean taking some response object and extracting data from it. This class does the opposite - given some data, it generates HTTP response.

Separation of concerns:

• Exception classes are aware of how to output themselves as HTTP response. Would be better to structure things the other way around: passing the exception object to ResponseParser that generates the HTTP response.

Side-effects:

• parseResponse() outputs HTTP headers and returns JSON. It's confusing when function has a return value and it also generates some output. I would it to expect to also output the JSON as the response, or returning both headers data and JSON without causing any side-effects.