Http error 404 php

<?phpif (!function_exists('http_response_code')) {
        function http_response_code($code = NULL) {

            if (

$code !== NULL) {

                switch (

$code) {
                    case 100: $text = 'Continue'; break;
                    case 101: $text = 'Switching Protocols'; break;
                    case 200: $text = 'OK'; break;
                    case 201: $text = 'Created'; break;
                    case 202: $text = 'Accepted'; break;
                    case 203: $text = 'Non-Authoritative Information'; break;
                    case 204: $text = 'No Content'; break;
                    case 205: $text = 'Reset Content'; break;
                    case 206: $text = 'Partial Content'; break;
                    case 300: $text = 'Multiple Choices'; break;
                    case 301: $text = 'Moved Permanently'; break;
                    case 302: $text = 'Moved Temporarily'; break;
                    case 303: $text = 'See Other'; break;
                    case 304: $text = 'Not Modified'; break;
                    case 305: $text = 'Use Proxy'; break;
                    case 400: $text = 'Bad Request'; break;
                    case 401: $text = 'Unauthorized'; break;
                    case 402: $text = 'Payment Required'; break;
                    case 403: $text = 'Forbidden'; break;
                    case 404: $text = 'Not Found'; break;
                    case 405: $text = 'Method Not Allowed'; break;
                    case 406: $text = 'Not Acceptable'; break;
                    case 407: $text = 'Proxy Authentication Required'; break;
                    case 408: $text = 'Request Time-out'; break;
                    case 409: $text = 'Conflict'; break;
                    case 410: $text = 'Gone'; break;
                    case 411: $text = 'Length Required'; break;
                    case 412: $text = 'Precondition Failed'; break;
                    case 413: $text = 'Request Entity Too Large'; break;
                    case 414: $text = 'Request-URI Too Large'; break;
                    case 415: $text = 'Unsupported Media Type'; break;
                    case 500: $text = 'Internal Server Error'; break;
                    case 501: $text = 'Not Implemented'; break;
                    case 502: $text = 'Bad Gateway'; break;
                    case 503: $text = 'Service Unavailable'; break;
                    case 504: $text = 'Gateway Time-out'; break;
                    case 505: $text = 'HTTP Version not supported'; break;
                    default:
                        exit('Unknown http status code "' . htmlentities($code) . '"');
                    break;
                }$protocol = (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0');header($protocol . ' ' . $code . ' ' . $text);$GLOBALS['http_response_code'] = $code;

            } else {

$code = (isset($GLOBALS['http_response_code']) ? $GLOBALS['http_response_code'] : 200);

            }

            return

$code;

        }
    }

?>

In this example I am using $GLOBALS, but you can use whatever storage mechanism you like... I don't think there is a way to return the current status code:

https://bugs.php.net/bug.php?id=52555

For reference the error codes I got from PHP's source code:

http://lxr.php.net/opengrok/xref/PHP_5_4/sapi/cgi/cgi_main.c#354

And how the current http header is sent, with the variables it uses:

http://lxr.php.net/opengrok/xref/PHP_5_4/main/SAPI.c#856

The following codes currently work as expected (with PHP running as Apache module):
200 – 208, 226
300 – 305, 307, 308
400 – 417, 422 – 424, 426, 428 – 429, 431
500 – 508, 510 – 511

Codes 0, 100, 101, and 102 will be sent as "200 OK".

Everything else will result in "500 Internal Server Error".

If you want to send responses with a freestyle status line, you need to use the `header()` function:

<?php header("HTTP/1.0 418 I'm A Teapot"); ?>

This happens when using header(0,0,420) and http_response_code(420).
Use header('HTTP/1.1 420 Enhance Your Calm') instead.

Note that the response code in the string IS interpreted and used in the access log and output via http_response_code().

<?php
$http_status_codes = array(100 => "Continue", 101 => "Switching Protocols", 102 => "Processing", 200 => "OK", 201 => "Created", 202 => "Accepted", 203 => "Non-Authoritative Information", 204 => "No Content", 205 => "Reset Content", 206 => "Partial Content", 207 => "Multi-Status", 300 => "Multiple Choices", 301 => "Moved Permanently", 302 => "Found", 303 => "See Other", 304 => "Not Modified", 305 => "Use Proxy", 306 => "(Unused)", 307 => "Temporary Redirect", 308 => "Permanent Redirect", 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 => "Request Entity Too Large", 414 => "Request-URI Too Long", 415 => "Unsupported Media Type", 416 => "Requested Range Not Satisfiable", 417 => "Expectation Failed", 418 => "I'm a teapot", 419 => "Authentication Timeout", 420 => "Enhance Your Calm", 422 => "Unprocessable Entity", 423 => "Locked", 424 => "Failed Dependency", 424 => "Method Failure", 425 => "Unordered Collection", 426 => "Upgrade Required", 428 => "Precondition Required", 429 => "Too Many Requests", 431 => "Request Header Fields Too Large", 444 => "No Response", 449 => "Retry With", 450 => "Blocked by Windows Parental Controls", 451 => "Unavailable For Legal Reasons", 494 => "Request Header Too Large", 495 => "Cert Error", 496 => "No Cert", 497 => "HTTP to HTTPS", 499 => "Client Closed Request", 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", 507 => "Insufficient Storage", 508 => "Loop Detected", 509 => "Bandwidth Limit Exceeded", 510 => "Not Extended", 511 => "Network Authentication Required", 598 => "Network read timeout error", 599 => "Network connect timeout error");
?>

Source: Wikipedia "List_of_HTTP_status_codes"

<?php
header('HTTP/1.1 401 Unauthorized');
http_response_code(403);
print(http_response_code());
?>

The raw HTTP response will be (notice the actual status code on the first line does not match the printed http_response_code in the body):

HTTP/1.1 401 Unauthorized
Date: Tue, 24 Nov 2020 13:49:08 GMT
Server: Apache
Connection: Upgrade, Keep-Alive
Keep-Alive: timeout=5, max=100
Transfer-Encoding: chunked
Content-Type: text/html; charset=UTF-8

403

I only tested it on Apache. I am not sure if this behavior is specific to Apache or common to all PHP distributions.

        const

The documentation for the header() function has the right way to implement this if you're still on < php 5.4:

<?php
header("HTTP/1.0 404 Not Found");
?>

<?php
header($_SERVER['SERVER_PROTOCOL'] . ' 507 Insufficient Storage');
?>
result: something like

HTTP/1.1 507 Insufficient Storage

In summary - The differences between "http_response_code" and "header" for setting response codes:

1. Using http_response_code will cause PHP to match and apply a Reason Phrase from a list of Reason Phrases that are hard-coded into the PHP source code.

2. Because of point 1 above, if you use http_response_code you must set a code that PHP knows about. You can't set your own custom code, however you can set a custom code (and Reason Phrase) if you use the header method.

<?php// HTTP/1.1 404 Not Found
http_response_code(404);?>

The resulting response is HTTP/1.1 404 OK

$a

<?php

header

('Temporary-Header: True', true, 404);
header_remove('Temporary-Header');?>

if (!function_exists('http_response_code')) {
    function http_response_code($code = NULL) {    
        $prev_code = (isset($GLOBALS['http_response_code']) ? $GLOBALS['http_response_code'] : 200);

        if ($code === NULL) {
            return $prev_code;
        }

        switch ($code) {
            case 100: $text = 'Continue'; break;
            case 101: $text = 'Switching Protocols'; break;
            case 200: $text = 'OK'; break;
            case 201: $text = 'Created'; break;
            case 202: $text = 'Accepted'; break;
            case 203: $text = 'Non-Authoritative Information'; break;
            case 204: $text = 'No Content'; break;
            case 205: $text = 'Reset Content'; break;
            case 206: $text = 'Partial Content'; break;
            case 300: $text = 'Multiple Choices'; break;
            case 301: $text = 'Moved Permanently'; break;
            case 302: $text = 'Moved Temporarily'; break;
            case 303: $text = 'See Other'; break;
            case 304: $text = 'Not Modified'; break;
            case 305: $text = 'Use Proxy'; break;
            case 400: $text = 'Bad Request'; break;
            case 401: $text = 'Unauthorized'; break;
            case 402: $text = 'Payment Required'; break;
            case 403: $text = 'Forbidden'; break;
            case 404: $text = 'Not Found'; break;
            case 405: $text = 'Method Not Allowed'; break;
            case 406: $text = 'Not Acceptable'; break;
            case 407: $text = 'Proxy Authentication Required'; break;
            case 408: $text = 'Request Time-out'; break;
            case 409: $text = 'Conflict'; break;
            case 410: $text = 'Gone'; break;
            case 411: $text = 'Length Required'; break;
            case 412: $text = 'Precondition Failed'; break;
            case 413: $text = 'Request Entity Too Large'; break;
            case 414: $text = 'Request-URI Too Large'; break;
            case 415: $text = 'Unsupported Media Type'; break;
            case 500: $text = 'Internal Server Error'; break;
            case 501: $text = 'Not Implemented'; break;
            case 502: $text = 'Bad Gateway'; break;
            case 503: $text = 'Service Unavailable'; break;
            case 504: $text = 'Gateway Time-out'; break;
            case 505: $text = 'HTTP Version not supported'; break;
            default:
                trigger_error('Unknown http status code ' . $code, E_USER_ERROR); // exit('Unknown http status code "' . htmlentities($code) . '"');
                return $prev_code;
        }

        $protocol = (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0');
        header($protocol . ' ' . $code . ' ' . $text);
        $GLOBALS['http_response_code'] = $code;

        // original function always returns the previous or current code
        return $prev_code;
    }
}

Test code:
<php
http_response_code(500);  // set the code
var_dump(headers_sent());  // check if headers are sent
http_response_code(200);  // avoid a default browser page

<?php

header

('Status: 404', TRUE, 404);?>

you might wanna do something like
function ehttp_response_code(int $response_code = NULL): int {
    if ($response_code === NULL) {
        return http_response_code();
    }
    if (headers_sent()) {
        throw new Exception('tried to change http response code after sending headers!');
    }
    return http_response_code($response_code);
}