简单检查is_ssl() 应该这样做：

add_action( \'plugins_loaded\', \'wpse_2718_force_ssl\' );

function wpse_2718_force_ssl()
{
    if ( is_ssl() )
        return;

    wp_redirect(
        \'https://\' . $_SERVER[\'HTTP_HOST\'] . $_SERVER[\'REQUEST_URI\'] 
    );
    exit;
}

RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

将此规则添加到的顶部。htaccess：

# BEGIN Force SSL
# This should be the first rule before other rules
<IfModule mod_rewrite.c>
    RewriteEngine On

    RewriteCond %{HTTPS} !=on
    RewriteRule ^/?(.*) https://%{SERVER_NAME}/$1 [R,L]
</IfModule>
# END Force SSL

我用过Really Simple SSL 对于我所有的客户网站，它工作得非常好。如果您不想修改代码，只需安装此插件并对其进行配置即可。