开始的开始。

知识点:

错误提示

ini_set('display_errors', 1);

设置指定配置选项的值。这个选项会在脚本运行时保持新的值,并在脚本结束时恢复。

int error_reporting ([ int $level ] )

error_reporting() 函数能够在运行时设置 error_reporting 指令。 PHP 有诸多错误级别,使用该函数可以设置在脚本运行时的级别。 如果没有设置可选参数 level, error_reporting() 仅会返回当前的错误报告级别。

这里有两种错误相关的函数:

ini_set('display_errors', 0);
error_reporting(E_ALL & ~E_NOTICE & ~E_STRICT & ~E_USER_NOTICE);

他们的区别是:

display_errors 是开启php错误提示,而且是所有错误提示, 开启错误提示,是为了方便调试修改,只有两种状态量:On & Off
error_reporting 可以选择性的关闭或者说忽略某些不想要的错误提示。

关于 error_reporting 可选参数介绍

文件/文件夹操作

string realpath ( string $path ) 

获取 文件(或文件夹)绝对路径

realpath() 扩展所有的符号连接并且处理输入的 path 中的 ‘/./‘, ‘/../‘ 以及多余的 ‘/‘ 并返回规范化后的绝对路径名。返回的路径中没有符号连接,’/./‘ 或 ‘/../‘ 成分。 失败时返回 FALSE,比如说文件不存在的话。

string dirname ( string $path )

给出一个包含有指向一个文件的全路径的字符串,本函数返回去掉文件名后的目录名。

EG:

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<?php
echo "1) " . dirname("/etc/passwd") . PHP_EOL; // 1) /etc
echo "2) " . dirname("/etc/") . PHP_EOL; // 2) / (or \ on Windows)
echo "3) " . dirname("."); // 3) .
?>
mixed pathinfo ( string $path [, int $options = PATHINFO_DIRNAME | PATHINFO_BASENAME | PATHINFO_EXTENSION | PATHINFO_FILENAME ] )

pathinfo() 返回一个关联数组包含有 path 的信息。返回关联数组还是字符串取决于 options。

eg:

print_r(pathinfo('/a/b/c.s'));

结果:

Array ( [dirname] => /a/b [basename] => c.s [extension] => s [filename] => c )

字符串操作

string strrchr ( string $haystack , mixed $needle )

该函数返回 haystack 字符串中的一部分,这部分以 needle 的最后出现位置开始,直到 haystack 末尾。

EG:

源码中利用此函数来获取 system folder的名字:

define('SYSDIR', trim(strrchr(trim(BASEPATH, '/'), '/'), '/'));

mixed version_compare ( string $version1 , string $version2 [, string $operator ] )

默认情况下,在第一个版本低于第二个时,version_compare() 返回 -1;如果两者相等,返回 0;第二个版本更低时则返回 1。

当使用了可选参数 operator 时,如果关系是操作符所指定的那个,函数将返回 TRUE,否则返回 FALSE。


int error_reporting ([ int $level ] )

源码分析:

<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, 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. (http://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT    MIT License
 * @link    http://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');

定义了常量ENVIRONMENT,不同的级别显示不同的错误。

/*
 *---------------------------------------------------------------
 * 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 FOLDER NAME
 *---------------------------------------------------------------
 *
 * This variable must contain the name of your "system" folder.
 * Include the path if the folder is not in the same directory
 * as this file.
 */
    $system_path = 'system';

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

/*
 *---------------------------------------------------------------
 * VIEW FOLDER NAME
 *---------------------------------------------------------------
 *
 * If you want to move the view folder out of the application
 * folder set the path to the folder here. The folder can be renamed
 * and relocated anywhere on your server. If blank, it will default
 * to the standard location inside your application folder. If you
 * do move this, use the full server path to this folder.
 *
 * 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" folder.  Leave blank
    // if your controller is not in a sub-folder within the "controllers" folder
    // $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.'/';
    }
    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
    }

/*
 * -------------------------------------------------------------------
 *  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 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);

定义了一系列常量如application、view 的路径等。
用到的函数:pathinfo、realpath、strrchr、dirname、is_dir、chdir、rtrim等

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