WordPress中文文档：activate_plugin()函数

功能

尝试在“沙箱”中激活插件，并在激活成功后进行重定向。

格式

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

描述

当一个函数已经被激活时，该函数不会再次尝试激活该插件。

该函数的工作原理是，在引入插件文件之前就将重定向的结果设置为错误，如果插件启动失败，这个错误的结果就不会被启动成功的信号覆盖。同时，如果插件启动失败，插件的设置不会被更新，也不会调用插件激活钩子。

需要注意的是，该函数不会阻止插件文件产生的错误报告，该函数也不能在任何地方用于复制“沙箱”环境，因为该函数只通过重定向来工作。

该函数会捕捉插件产生的所有错误报告或其他输出信息，以确保在重定向成功执行时更新默认的为“错误”的重定向状态。

参数

$plugin
(string) (必须参数) 插件文件所在位置的相对路径。

$redirect
(string) (可选参数) 重定向所指向的 URL.
默认值：''

$network_wide
(bool) (可选参数) 是否对网络中的所有站点启用插件，或只对当前站点启用插件。该参数只适用于多站点模式下。
默认值：false

$silent
(bool) (可选参数) 是否阻止唤起激活钩子。
默认值：false

返回值

(null|WP_Error) 若执行成功则返回 `Null`, 若执行的插件文件无效则返回 `WP_Error`.

源码

代码所在文件：

wp-admin/includes/plugin.php

相关代码片段：

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, true )
    ) {
        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();

        // Load the plugin to test whether it throws any errors.
        plugin_sandbox_scrape( $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 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 $network_wide Whether to enable the plugin for all sites in the network
             *                           or just the current site. Multisite only. Default false.
             */
            do_action( "activate_{$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 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;
}