A blank page is shown after I add a Function

Question

I am redesigning a template. So I am trying to show a holding page till the redesign process is done.

I ever used following function for the purpose on many other projects and it's redirected to the holding.php if the user is not an Admin

add_action( 'template_redirect', function() { if( !current_user_can( 'manage_options' ) ) { include( get_template_directory() . '/holding.php' ); exit; } });

But when I try to put this code on my current redesigning project it's shows a blank page if I go to the home page or any other page. if I remove the above code from function.php the site works fine.

And I've noted that this current projects' all php file has /** * @package WordPress * @subpackage Starkers */

my theme folder contains WordPress, Starkers too I thought it's commented out. so it does nothing.

Those lines are included every files such as index.php, function.php, etc

Why it's showing a blank page if I add the redirection function as I mentioned below.?? Any help will be appreciated.

[UPDATE] when I enable the debug i got the following lines.

Notice: load_plugin_textdomain was called with an argument that is deprecated since version 2.7 with no alternative available. in /home/supgower/public_html/wp-includes/functions.php on line 3008

Notice: date_default_timezone_set() [function.date-default-timezone-set]: Timezone ID 'UTC-1' is invalid in /home/supgower/public_html/wp-content/plugins/event-calendar/tz.php on line 27

Notice: date_default_timezone_set() [function.date-default-timezone-set]: Timezone ID 'UTC-1' is invalid in /home/supgower/public_html/wp-content/plugins/event-calendar/tz.php on line 27

Notice: wp_enqueue_script was called incorrectly. Scripts and styles should not be registered or enqueued until the wp_enqueue_scripts, admin_enqueue_scripts, or login_enqueue_scripts hooks. Please see Debugging in WordPress for more information. (This message was added in version 3.3.) in /home/supgower/public_html/wp-includes/functions.php on line 3049

Notice: wp_enqueue_style was called incorrectly. Scripts and styles should not be registered or enqueued until the wp_enqueue_scripts, admin_enqueue_scripts, or login_enqueue_scripts hooks. Please see Debugging in WordPress for more information. (This message was added in version 3.3.) in /home/supgower/public_html/wp-includes/functions.php on line 3049

Answer 1

Have you tried this:

<?php
add_action( 'template_redirect', 'wp138320_template_redirect' );

function wp138320_template_redirect()
{
    if ( ! current_user_can( 'manage_options' ) )
    {
        include( get_template_directory() . '/holding.php' );
        exit;
    }
}
?>

I'm currently working on a site that has issues with hooking into actions/filters like that too, changing it to something like the code above did the trick in that install.

---- edit: Using the hook @Pieter mentions:

<?php
add_filter( 'template_include', 'wp138320_template_include' );

function wp138320_template_include( $template )
{
    if ( ! current_user_can( 'manage_options' ) )
    {
        if ( '' != locate_template( 'holding.php' ) )
            return 'holding.php'; // holding.php should be in the root of your theme's folder
    }

    return $template;
}
?>