板邓：【WordPress文件解读】wp-load.php

wp-load.php文件思路

wp-load.php文件主要加载重点配置wp-config.php文件。如果根目录不存在该配置文件，则WordPress会加载setup-config.php文件自动跳转到安装页面，安装WordPress

文件涉及的PHP函数解析

defined（）函数判断常量是否存在；

error_reporting（）规定不同的错误级别报告

<?php
 // 关闭错误报告
 error_reporting(0);

 // 报告 runtime 错误
 error_reporting(E_ERROR | E_WARNING | E_PARSE);

 // 报告所有错误
 error_reporting(E_ALL);

 // 等同 error_reporting(E_ALL);
 ini_set("error_reporting", E_ALL);

 // 报告 E_NOTICE 之外的所有错误
 error_reporting(E_ALL & ~E_NOTICE);
?> 

file_exists() 函数检查文件或目录是否存在,如果指定的文件或目录存在则返回 true，否则返回 false。

dirname( __FILE__ ) 函数返回路径中的目录部分。

require_once()  PHP 会检查文件是否已经被包含过，如果是则不会再次包含。

strpos() 函数查找字符串在另一字符串中第一次出现的位置。

sprintf() 函数把格式化的字符串写入变量中。

源代码：

<?php
/**
 * Bootstrap file for setting the ABSPATH constant
 * and loading the wp-config.php file. The wp-config.php
 * file will then load the wp-settings.php file, which
 * will then set up the WordPress environment.
 *
 * If the wp-config.php file is not found then an error
 * will be displayed asking the visitor to set up the
 * wp-config.php file.
 *
 * Will also search for wp-config.php in WordPress' parent
 * directory to allow the WordPress directory to remain
 * untouched.
 *
 * @package WordPress
 */

/** Define ABSPATH as this file's directory */
if ( ! defined( 'ABSPATH' ) ) {
    define( 'ABSPATH', dirname( __FILE__ ) . '/' );
}

error_reporting( E_CORE_ERROR | E_CORE_WARNING | E_COMPILE_ERROR | E_ERROR | E_WARNING | E_PARSE | E_USER_ERROR | E_USER_WARNING | E_RECOVERABLE_ERROR );

/*
 * If wp-config.php exists in the WordPress root, or if it exists in the root and wp-settings.php
 * doesn't, load wp-config.php. The secondary check for wp-settings.php has the added benefit
 * of avoiding cases where the current directory is a nested installation, e.g. / is WordPress(a)
 * and /blog/ is WordPress(b).
 *
 * If neither set of conditions is true, initiate loading the setup process.
 */
if ( file_exists( ABSPATH . 'wp-config.php') ) {

    /** The config file resides in ABSPATH */
    require_once( ABSPATH . 'wp-config.php' );

} elseif ( @file_exists( dirname( ABSPATH ) . '/wp-config.php' ) && ! @file_exists( dirname( ABSPATH ) . '/wp-settings.php' ) ) {

    /** The config file resides one level above ABSPATH but is not part of another install */
    require_once( dirname( ABSPATH ) . '/wp-config.php' );

} else {

    // A config file doesn't exist

    define( 'WPINC', 'wp-includes' );
    require_once( ABSPATH . WPINC . '/load.php' );

    // Standardize $_SERVER variables across setups.
    wp_fix_server_vars();

    require_once( ABSPATH . WPINC . '/functions.php' );

    $path = wp_guess_url() . '/wp-admin/setup-config.php';

    /*
     * We're going to redirect to setup-config.php. While this shouldn't result
     * in an infinite loop, that's a silly thing to assume, don't you think? If
     * we're traveling in circles, our last-ditch effort is "Need more help?"
     */
    if ( false === strpos( $_SERVER['REQUEST_URI'], 'setup-config' ) ) {
        header( 'Location: ' . $path );
        exit;
    }

    define( 'WP_CONTENT_DIR', ABSPATH . 'wp-content' );
    require_once( ABSPATH . WPINC . '/version.php' );

    wp_check_php_mysql_versions();
    wp_load_translations_early();

    // Die with an error message
    $die  = sprintf(
        /* translators: %s: wp-config.php */
        __( "There doesn't seem to be a %s file. I need this before we can get started." ),
        '<code>wp-config.php</code>'
    ) . '</p>';
    $die .= '<p>' . sprintf(
        /* translators: %s: Codex URL */
        __( "Need more help? <a href='%s'>We got it</a>." ),
        __( 'https://codex.wordpress.org/Editing_wp-config.php' )
    ) . '</p>';
    $die .= '<p>' . sprintf(
        /* translators: %s: wp-config.php */
        __( "You can create a %s file through a web interface, but this doesn't work for all server setups. The safest way is to manually create the file." ),
        '<code>wp-config.php</code>'
    ) . '</p>';
    $die .= '<p><a href="' . $path . '" class="button button-large">' . __( "Create a Configuration File" ) . '</a>';

    wp_die( $die, __( 'WordPress &rsaquo; Error' ) );
}