ci 定义的各种常量 在 index.php 和 config 目录里面

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author EllisLab Dev Team
 * @copyright  Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright  Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT MIT License
 * @link   https://codeigniter.com
 * @since  Version 1.0.0
 * @filesource
 */

/*
 *---------------------------------------------------------------
 * APPLICATION ENVIRONMENT
 *---------------------------------------------------------------
 *
 * You can load different configurations depending on your
 * current environment. Setting the environment also influences
 * things like logging and error reporting.
 *
 * This can be set to anything, but default usage is:
 *
 *     development
 *     testing
 *     production
 *
 * NOTE: If you change these, also change the error_reporting() code below
 */
   define('ENVIRONMENT', isset($_SERVER['CI_ENV']) ? $_SERVER['CI_ENV'] : 'development');
// define('ENVIRONMENT','production');

/*
 *---------------------------------------------------------------
 * ERROR REPORTING
 *---------------------------------------------------------------
 *
 * Different environments will require different levels of error reporting.
 * By default development will show errors but testing and live will hide them.
 */
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 DIRECTORY NAME
 *---------------------------------------------------------------
 *
 * This variable must contain the name of your "system" directory.
 * Set the path if it is not in the same directory as this file.
 */
   $system_path = 'system';

/*
 *---------------------------------------------------------------
 * APPLICATION DIRECTORY NAME
 *---------------------------------------------------------------
 *
 * If you want this front controller to use a different "application"
 * directory than the default one you can set its name here. The directory
 * can also be renamed or relocated anywhere on your server. If you do,
 * use an absolute (full) server path.
 * For more info please see the user guide:
 *
 * https://codeigniter.com/user_guide/general/managing_apps.html
 *
 * NO TRAILING SLASH!
 */
   $application_folder = 'application';

/*
 *---------------------------------------------------------------
 * VIEW DIRECTORY NAME
 *---------------------------------------------------------------
 *
 * If you want to move the view directory out of the application
 * directory, set the path to it here. The directory can be renamed
 * and relocated anywhere on your server. If blank, it will default
 * to the standard location inside your application directory.
 * If you do move this, use an absolute (full) server path.
 *
 * NO TRAILING SLASH!
 */
   $view_folder = '';


/*
 * --------------------------------------------------------------------
 * DEFAULT CONTROLLER
 * --------------------------------------------------------------------
 *
 * Normally you will set your default controller in the routes.php file.
 * You can, however, force a custom routing by hard-coding a
 * specific controller class/function here. For most applications, you
 * WILL NOT set your routing here, but it's an option for those
 * special instances where you might want to override the standard
 * routing in a specific front controller that shares a common CI installation.
 *
 * IMPORTANT: If you set the routing here, NO OTHER controller will be
 * callable. In essence, this preference limits your application to ONE
 * specific controller. Leave the function name blank if you need
 * to call functions dynamically via the URI.
 *
 * Un-comment the $routing array below to use this feature
 */
   // The directory name, relative to the "controllers" directory.  Leave blank
   // if your controller is not in a sub-directory within the "controllers" one
   // $routing['directory'] = '';

   // The controller class file name.  Example:  mycontroller
   // $routing['controller'] = '';

   // The controller function you wish to be called.
   // $routing['function']    = '';


/*
 * -------------------------------------------------------------------
 *  CUSTOM CONFIG VALUES
 * -------------------------------------------------------------------
 *
 * The $assign_to_config array below will be passed dynamically to the
 * config class when initialized. This allows you to set custom config
 * items or override any default config values found in the config.php file.
 * This can be handy as it permits you to share one application between
 * multiple front controller files, with each file containing different
 * config values.
 *
 * Un-comment the $assign_to_config array below to use this feature
 */
   // $assign_to_config['name_of_config_item'] = 'value of config item';



// --------------------------------------------------------------------
// END OF USER CONFIGURABLE SETTINGS.  DO NOT EDIT BELOW THIS LINE
// --------------------------------------------------------------------

/*
 * ---------------------------------------------------------------
 *  Resolve the system path for increased reliability
 * ---------------------------------------------------------------
 */

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

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

   // 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
   }

/*
 * -------------------------------------------------------------------
 *  Now that we know the path, set the main path constants
 * -------------------------------------------------------------------
 */
   // The name of THIS file
   define('SELF', pathinfo(__FILE__, PATHINFO_BASENAME));

   // Path to the system directory
   define('BASEPATH', $system_path);

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

   // Name of the "system" directory
   define('SYSDIR', basename(BASEPATH));

   // The path to the "application" directory
   if (is_dir($application_folder))
   {
      if (($_temp = realpath($application_folder)) !== FALSE)
      {
         $application_folder = $_temp;
      }
      else
      {
         $application_folder = strtr(
            rtrim($application_folder, '/\\'),
            '/\\',
            DIRECTORY_SEPARATOR.DIRECTORY_SEPARATOR
         );
      }
   }
   elseif (is_dir(BASEPATH.$application_folder.DIRECTORY_SEPARATOR))
   {
      $application_folder = BASEPATH.strtr(
         trim($application_folder, '/\\'),
         '/\\',
         DIRECTORY_SEPARATOR.DIRECTORY_SEPARATOR
      );
   }
   else
   {
      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', $application_folder.DIRECTORY_SEPARATOR);

   // The path to the "views" directory
   if ( ! isset($view_folder[0]) && is_dir(APPPATH.'views'.DIRECTORY_SEPARATOR))
   {
      $view_folder = APPPATH.'views';
   }
   elseif (is_dir($view_folder))
   {
      if (($_temp = realpath($view_folder)) !== FALSE)
      {
         $view_folder = $_temp;
      }
      else
      {
         $view_folder = strtr(
            rtrim($view_folder, '/\\'),
            '/\\',
            DIRECTORY_SEPARATOR.DIRECTORY_SEPARATOR
         );
      }
   }
   elseif (is_dir(APPPATH.$view_folder.DIRECTORY_SEPARATOR))
   {
      $view_folder = APPPATH.strtr(
         trim($view_folder, '/\\'),
         '/\\',
         DIRECTORY_SEPARATOR.DIRECTORY_SEPARATOR
      );
   }
   else
   {
      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
   }

   define('VIEWPATH', $view_folder.DIRECTORY_SEPARATOR);

/*
 * --------------------------------------------------------------------
 * LOAD THE BOOTSTRAP FILE
 * --------------------------------------------------------------------
 *
 * And away we go...
 */
require_once BASEPATH.'core/CodeIgniter.php';