activate_plugin( string $plugin, string $redirect = ”, bool $network_wide = false, bool $silent = false )

尝试激活插件，并在成功时重定向。
Attempts activation of plugin in a “sandbox” and redirects on success.

目录锚点：#说明#参数#返回#源码#笔记

说明（Description）

已激活的插件将不会再次尝试激活。

其工作方式是在尝试包含插件文件之前将重定向设置为错误。如果插件失败，则重定向将不会被成功消息覆盖。此外，选项将不会更新，激活挂钩也不会在插件错误时调用。

如果发现任何错误或输出了文本，则将捕获它以确保成功重定向将更新错误重定向。

参数（Parameters）

返回（Return）

（null|WP_Error）成功时为空，无效文件时为WP_Error。

源码（Source）

function activate_plugin( $plugin, $redirect = '', $network_wide = false, $silent = false ) {
    $plugin = plugin_basename( trim( $plugin ) );
 
    if ( is_multisite() && ( $network_wide || is_network_only_plugin( $plugin ) ) ) {
        $network_wide        = true;
        $current             = get_site_option( 'active_sitewide_plugins', array() );
        $_GET['networkwide'] = 1; // Back compat for plugins looking for this value.
    } else {
        $current = get_option( 'active_plugins', array() );
    }
 
    $valid = validate_plugin( $plugin );
    if ( is_wp_error( $valid ) ) {
        return $valid;
    }
 
    $requirements = validate_plugin_requirements( $plugin );
    if ( is_wp_error( $requirements ) ) {
        return $requirements;
    }
 
    if ( ( $network_wide && ! isset( $current[ $plugin ] ) ) || ( ! $network_wide && ! in_array( $plugin, $current ) ) ) {
        if ( ! empty( $redirect ) ) {
            // We'll override this later if the plugin can be included without fatal error.
            wp_redirect( add_query_arg( '_error_nonce', wp_create_nonce( 'plugin-activation-error_' . $plugin ), $redirect ) );
        }
 
        ob_start();
        wp_register_plugin_realpath( WP_PLUGIN_DIR . '/' . $plugin );
        $_wp_plugin_file = $plugin;
        if ( ! defined( 'WP_SANDBOX_SCRAPING' ) ) {
            define( 'WP_SANDBOX_SCRAPING', true );
        }
        include_once WP_PLUGIN_DIR . '/' . $plugin;
        $plugin = $_wp_plugin_file; // Avoid stomping of the $plugin variable in a plugin.
 
        if ( ! $silent ) {
            /**
             * Fires before a plugin is activated.
             *
             * If a plugin is silently activated (such as during an update),
             * this hook does not fire.
             *
             * @since 2.9.0
             *
             * @param string $plugin       Path to the plugin file relative to the plugins directory.
             * @param bool   $network_wide Whether to enable the plugin for all sites in the network
             *                             or just the current site. Multisite only. Default is false.
             */
            do_action( 'activate_plugin', $plugin, $network_wide );
 
            /**
             * Fires as a specific plugin is being activated.
             *
             * This hook is the "activation" hook used internally by register_activation_hook().
             * The dynamic portion of the hook name, `$plugin`, refers to the plugin basename.
             *
             * If a plugin is silently activated (such as during an update), this hook does not fire.
             *
             * @since 2.0.0
             *
             * @param bool $network_wide Whether to enable the plugin for all sites in the network
             *                           or just the current site. Multisite only. Default is false.
             */
            do_action( "activate_{$plugin}", $network_wide );
        }
 
        if ( $network_wide ) {
            $current            = get_site_option( 'active_sitewide_plugins', array() );
            $current[ $plugin ] = time();
            update_site_option( 'active_sitewide_plugins', $current );
        } else {
            $current   = get_option( 'active_plugins', array() );
            $current[] = $plugin;
            sort( $current );
            update_option( 'active_plugins', $current );
        }
 
        if ( ! $silent ) {
            /**
             * Fires after a plugin has been activated.
             *
             * If a plugin is silently activated (such as during an update),
             * this hook does not fire.
             *
             * @since 2.9.0
             *
             * @param string $plugin       Path to the plugin file relative to the plugins directory.
             * @param bool   $network_wide Whether to enable the plugin for all sites in the network
             *                             or just the current site. Multisite only. Default is false.
             */
            do_action( 'activated_plugin', $plugin, $network_wide );
        }
 
        if ( ob_get_length() > 0 ) {
            $output = ob_get_clean();
            return new WP_Error( 'unexpected_output', __( 'The plugin generated unexpected output.' ), $output );
        }
        ob_end_clean();
    }
 
    return null;
}

笔记（Notes）

基本示例

// 尝试激活插件，并在失败时返回WP_Error
$result = activate_plugin( 'wp2-dir/wp2-file.php' );
if ( is_wp_error( $result ) ) {
    // 出错...
}