PHP error: Message: Cannot modify header information - headers already sent by (output started at

Question

Our web hosting company has upgraded the server from php 5.5 to 5.6. then I am getting this PHP error: Message: Cannot modify header information - headers already sent by (output started at /home/xxxxx/public_html/orders/xxxxxx/system/core/Exceptions.php:185) Filename: core/Common.php Line Number: 438 404 Page Not Found The page you requested was not found.

Exceptions.php

        // For safety reasons we do not show the full file path
        if (FALSE !== strpos($filepath, '/'))
        {
            $x = explode('/', $filepath);
            $filepath = $x[count($x)-2].'/'.end($x);
        }

        if (ob_get_level() > $this->ob_level + 1)
        {
            ob_end_flush();
        }
        ob_start();
        include(APPPATH.'errors/error_php.php');
        $buffer = ob_get_contents();
        ob_end_clean();
        echo $buffer;
    }


}
// END Exceptions Class

Common.php

    function set_status_header($code = 200, $text = '')
    {
        $stati = array(
                            200 => 'OK',
                            201 => 'Created',
                            202 => 'Accepted',
                            203 => 'Non-Authoritative Information',
                            204 => 'No Content',
                            205 => 'Reset Content',
                            206 => 'Partial Content',

                            300 => 'Multiple Choices',
                            301 => 'Moved Permanently',
                            302 => 'Found',
                            304 => 'Not Modified',
                            305 => 'Use Proxy',
                            307 => 'Temporary Redirect',

                            400 => 'Bad Request',
                            401 => 'Unauthorized',
                            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',

                            500 => 'Internal Server Error',
                            501 => 'Not Implemented',
                            502 => 'Bad Gateway',
                            503 => 'Service Unavailable',
                            504 => 'Gateway Timeout',
                            505 => 'HTTP Version Not Supported'
                        );

        if ($code == '' OR ! is_numeric($code))
        {
            show_error('Status codes must be numeric', 500);
        }

        if (isset($stati[$code]) AND $text == '')
        {
            $text = $stati[$code];
        }

        if ($text == '')
        {
            show_error('No status text available.  Please check your status code number or supply your own message text.', 500);
        }

        $server_protocol = (isset($_SERVER['SERVER_PROTOCOL'])) ? $_SERVER['SERVER_PROTOCOL'] : FALSE;

        if (substr(php_sapi_name(), 0, 3) == 'cgi')
        {
            header("Status: {$code} {$text}", TRUE);
        }
        elseif ($server_protocol == 'HTTP/1.1' OR $server_protocol == 'HTTP/1.0')
        {
            header($server_protocol." {$code} {$text}", TRUE, $code);
        }
        else
        {
            header("HTTP/1.1 {$code} {$text}", TRUE, $code);
        }
    }
}

Lumis · Answer 1 · 2019-10-31T16:21:40.433

This is the matter of order of things: no HTML, including spaces, should be outputted before the invoke of the header() function.

The error does happen when PHP is upgraded to a later version.

In my case the page was a submit form which contained PHP code to process and save the data as well. But, when processing data, some of the form HTML code was unnecessarily outputted before this line

header('Location: ' . $_POST['referer']); exit;

hence this error. So I moved ALL formatting HTML code after the PHP data processing block that contained the header jump above and solved this problem.

PHP error: Message: Cannot modify header information - headers already sent by (output started at

1 Answers1