how to throw exception that returns 400 HTTP response code

I have some Codeigniter 4 projects where I extend the base controller with my own base controller. I have a function in this base controller that I call from my various autorouted controller methods if I want to be sure the request is a POST request. Sadly, this results in a 500 error code. I'd like to throw an exception to halt further code execution but I want to return 400 to indicate the error is on the client end. Here's the function in my base controller:

PHP Code:

/**
     * If the page request method is not POST, show an error and die
     */
    protected function post_or_error() {
        if (!$this->request->is('post')) {
            // TODO send 400 BAD REQUEST
            throw new \Exception('BAD REQUEST');
        }
    } 


From some autorouted controller method, I can use it like so:

PHP Code:

    public function form_handler() {
        $this->post_or_error();
        // BLAH BLAH
    } 


The CI4 docs hint this is possible using HTTPExceptionInterface but don't provide any detail at all about how that might be done.

What is considered best practice in this case?

Implement an Exception class that implements HTTPExceptionInterface, and set the error code 400.
And throw it.

I think this is not good, but try:

PHP Code:

throw new class ('BAD REQUEST', 400) extends \Exception implements \CodeIgniter\Exceptions\HTTPExceptionInterface {}; 


ci-phpunit-test | CodeIgniter Testing Guide | CodeIgniter 3 to 4 Upgrade Helper

Implement an Exception class that implements HTTPExceptionInterface, and set the error code 400.
And throw it.

I think this is not good, but try:

PHP Code:

throw new class ('BAD REQUEST', 400) extends \Exception implements \CodeIgniter\Exceptions\HTTPExceptionInterface {}; 


Hmmm thank you for the suggestion. That looks pretty clever but doesn't really look ideal. Perhaps I shouldn't be throwing an exception? I like throwing an exception because I get the debug/trace information when environment is "development" and it responds with a generic WOOPS message when environment is "production." Perhaps there's some way to utilize the Response class? It already has statusCodes defined for all the usual HTTP codes.

I made my own exception class as you suggested. Sadly, I can't just retrieve the standard phrase for each error code from the Response class because that array, while static, is protected. I sorta borrowed from PageNotFoundException:

PHP Code:

<?php
/**
 * CI4 lacks a generic exception to easily throw an exception for the usual HTTP response codes
 * so I cooked up this custom exception class which lets you just specify empty string and
 * the response code and it'll look up the standard phrase for that HTTP code. 
 */

namespace App\Exceptions;

use CodeIgniter\Exceptions\HTTPExceptionInterface;

class HTTPGenericException extends \OutOfBoundsException implements HTTPExceptionInterface
{
    
    protected static $statusCodes = [
            // 1xx: Informational
            100 => 'Continue',
            101 => 'Switching Protocols',
            102 => 'Processing', // http://www.iana.org/go/rfc2518
            103 => 'Early Hints', // http://www.ietf.org/rfc/rfc8297.txt
            // 2xx: Success
            200 => 'OK',
            201 => 'Created',
            202 => 'Accepted',
            203 => 'Non-Authoritative Information', // 1.1
            204 => 'No Content',
            205 => 'Reset Content',
            206 => 'Partial Content',
            207 => 'Multi-Status', // http://www.iana.org/go/rfc4918
            208 => 'Already Reported', // http://www.iana.org/go/rfc5842
            226 => 'IM Used', // 1.1; http://www.ietf.org/rfc/rfc3229.txt
            // 3xx: Redirection
            300 => 'Multiple Choices',
            301 => 'Moved Permanently',
            302 => 'Found', // Formerly 'Moved Temporarily'
            303 => 'See Other', // 1.1
            304 => 'Not Modified',
            305 => 'Use Proxy', // 1.1
            306 => 'Switch Proxy', // No longer used
            307 => 'Temporary Redirect', // 1.1
            308 => 'Permanent Redirect', // 1.1; Experimental; http://www.ietf.org/rfc/rfc7238.txt
            // 4xx: Client error
            400 => 'Bad Request',
            401 => 'Unauthorized',
            402 => 'Payment Required',
            403 => 'Forbidden',
            404 => 'Not Found',
            405 => 'Method Not Allowed',
            406 => 'Not Acceptable',
            407 => 'Proxy Authentication Required',
            408 => 'Request Timeout',
            409 => 'Conflict',
            410 => 'Gone',
            411 => 'Length Required',
            412 => 'Precondition Failed',
            413 => 'Content Too Large', // https://www.iana.org/assignments/http-status-codes/http-status-codes.xml
            414 => 'URI Too Long', // https://www.iana.org/assignments/http-status-codes/http-status-codes.xml
            415 => 'Unsupported Media Type',
            416 => 'Requested Range Not Satisfiable',
            417 => 'Expectation Failed',
            418 => "I'm a teapot", // April's Fools joke; http://www.ietf.org/rfc/rfc2324.txt
            // 419 (Authentication Timeout) is a non-standard status code with unknown origin
            421 => 'Misdirected Request', // http://www.iana.org/go/rfc7540 Section 9.1.2
            422 => 'Unprocessable Content', // https://www.iana.org/assignments/http-status-codes/http-status-codes.xml
            423 => 'Locked', // http://www.iana.org/go/rfc4918
            424 => 'Failed Dependency', // http://www.iana.org/go/rfc4918
            425 => 'Too Early', // https://datatracker.ietf.org/doc/draft-ietf-httpbis-replay/
            426 => 'Upgrade Required',
            428 => 'Precondition Required', // 1.1; http://www.ietf.org/rfc/rfc6585.txt
            429 => 'Too Many Requests', // 1.1; http://www.ietf.org/rfc/rfc6585.txt
            431 => 'Request Header Fields Too Large', // 1.1; http://www.ietf.org/rfc/rfc6585.txt
            451 => 'Unavailable For Legal Reasons', // http://tools.ietf.org/html/rfc7725
            499 => 'Client Closed Request', // http://lxr.nginx.org/source/src/http/ngx_http_request.h#0133
            // 5xx: Server error
            500 => 'Internal Server Error',
            501 => 'Not Implemented',
            502 => 'Bad Gateway',
            503 => 'Service Unavailable',
            504 => 'Gateway Timeout',
            505 => 'HTTP Version Not Supported',
            506 => 'Variant Also Negotiates', // 1.1; http://www.ietf.org/rfc/rfc2295.txt
            507 => 'Insufficient Storage', // http://www.iana.org/go/rfc4918
            508 => 'Loop Detected', // http://www.iana.org/go/rfc5842
            510 => 'Not Extended', // http://www.ietf.org/rfc/rfc2774.txt
            511 => 'Network Authentication Required', // http://www.ietf.org/rfc/rfc6585.txt
            599 => 'Network Connect Timeout Error', // https://httpstatuses.com/599
    ];
    
    
    /**
     * Customized constructor fetches generic message and, like DebugTraceableTrait, 
     * Tweaks the exception's constructor to assign the file/line to where
     * it is actually raised rather than were it is instantiated.
     */
    public function __construct(string $message = '', int $code = 0, ?Throwable $previous = null)
    {
    
        if (!$message) {
            $message = array_key_exists($code, self::$statusCodes) ? self::$statusCodes[$code] : 'Error';
        }
        
        parent::__construct($message, $code, $previous);
        
        $trace = $this->getTrace()[0];
        
        if (isset($trace['class']) && $trace['class'] === static::class) {
            [
            'line' => $this->line,
            'file' => $this->file,
            ] = $trace;
        }
    }
} 


Hi, guys,

I'm using exceptions to define a filter that uses IP restriction on my routes.

I use this method and I get the file error_403.php :

PHP Code:

throw new class ('BAD REQUEST', 403) extends \Exception implements \CodeIgniter\Exceptions\HTTPExceptionInterface {};  


but with an entry 200

and if I use :

PHP Code:

throw new \Exception('BAD REQUEST', 403); 


I get a 500 header but no 403.