php版本更新后的codeigniter问题

Question

我正在使用Framework 3创建一个员工信息系统，在此之前，它在PHP版本5上运行良好，但是在我升级到PHP版本7.3之后，该问题出现了，如果通过URL访问它只会显示一个空白页面。 / p>

我已经搜索了多个参考文献，但没有找到解决方案，登录会话中还会出现其他问题，如果我使用用户登录，则页面无法响应管理仪表板。

这是我在index.php中的代码

<?php
require 'config.php';

switch (ENVIRONMENT)
{
    case 'development':
        error_reporting(-1);
        ini_set('display_errors', 1);
    break;

    case 'testing':
    case 'production':
        ini_set('display_errors', 0);
        if (version_compare(PHP_VERSION, '5.3', '>='))
        {
            error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED & ~E_STRICT & ~E_USER_NOTICE & ~E_USER_DEPRECATED);
        }
        else
        {
            error_reporting(E_ALL & ~E_NOTICE & ~E_STRICT & ~E_USER_NOTICE);
        }
    break;

    default:
        header('HTTP/1.1 503 Service Unavailable.', TRUE, 503);
        echo 'The application environment is not set correctly.';
        exit(1); // EXIT_ERROR
}

    $system_path = CI_SYSTEM_DIR;

    $application_folder = CI_APPLICATION_DIR;

    $view_folder = '';

    // Set the current directory correctly for CLI requests
    if (defined('STDIN'))
    {
        chdir(dirname(__FILE__));
    }

    if (($_temp = realpath($system_path)) !== FALSE)
    {
        $system_path = $_temp.'/';
    }
    else
    {
        // Ensure there's a trailing slash
        $system_path = rtrim($system_path, '/').'/';
    }

    // Is the system path correct?
    if ( ! is_dir($system_path))
    {
        header('HTTP/1.1 503 Service Unavailable.', TRUE, 503);
        echo 'Your system folder path does not appear to be set correctly. Please open the following file and correct this: '.pathinfo(__FILE__, PATHINFO_BASENAME);
        exit(3); // EXIT_CONFIG
    }



    define('SELF', pathinfo(__FILE__, PATHINFO_BASENAME));

    // Path to the system folder
    define('BASEPATH', str_replace('\\', '/', $system_path));

    // Path to the front controller (this file)
    define('FCPATH', dirname(__FILE__).'/');

    // Name of the "system folder"
    define('SYSDIR', trim(strrchr(trim(BASEPATH, '/'), '/'), '/'));

    // The path to the "application" folder
    if (is_dir($application_folder))
    {
        if (($_temp = realpath($application_folder)) !== FALSE)
        {
            $application_folder = $_temp;
        }

        define('APPPATH', $application_folder.DIRECTORY_SEPARATOR);
    }
    else
    {
        if ( ! is_dir(BASEPATH.$application_folder.DIRECTORY_SEPARATOR))
        {
            header('HTTP/1.1 503 Service Unavailable.', TRUE, 503);
            echo 'Your application folder path does not appear to be set correctly. Please open the following file and correct this: '.SELF;
            exit(3); // EXIT_CONFIG
        }

        define('APPPATH', BASEPATH.$application_folder.DIRECTORY_SEPARATOR);
    }

    // The path to the "views" folder
    if ( ! is_dir($view_folder))
    {
        if ( ! empty($view_folder) && is_dir(APPPATH.$view_folder.DIRECTORY_SEPARATOR))
        {
            $view_folder = APPPATH.$view_folder;
        }
        elseif ( ! is_dir(APPPATH.'views'.DIRECTORY_SEPARATOR))
        {
            header('HTTP/1.1 503 Service Unavailable.', TRUE, 503);
            echo 'Your view folder path does not appear to be set correctly. Please open the following file and correct this: '.SELF;
            exit(3); // EXIT_CONFIG
        }
        else
        {
            $view_folder = APPPATH.'views';
        }
    }

    if (($_temp = realpath($view_folder)) !== FALSE)
    {
        $view_folder = $_temp.DIRECTORY_SEPARATOR;
    }
    else
    {
        $view_folder = rtrim($view_folder, '/\\').DIRECTORY_SEPARATOR;
    }

    define('VIEWPATH', $view_folder);

require_once BASEPATH.'core/CodeIgniter.php';