Detecting post type within init action

OK, let’s get some thing staight first.

Here is list of actions run during typical request. It goes like this:

• …
• init
• …
• parse_request
• …
• parse_query
• pre_get_posts
• posts_selection
• …
• wp

As you can see, posts are selected much later after init. To be more precise, even the request is parsed after init hook. So there is no easy way to get $post in init action, I’m afraid.

If you move your code from init to wp (or later), then you can get $post from $wp_query object.

But… I’m not sure if I understand, what are you trying to achieve with this code. If you hook your AJAX action based on queried post, it won’t fire up at all, I guess. Why? AJAX call is another request (/wp-admin/admin-ajax.php) so there won’t be any $post retrieved in this request, so your action won’t get hooked, so it won’t fire up.

I’m pretty sure this is what you really want:

function enqueue_ajax_login_scripts() {
    wp_register_script('ajax-login-script', get_template_directory_uri() . '/library/js/ajax-login-script.js', array('jquery') ); 
    wp_enqueue_script('ajax-login-script');

    // check if it's single post
    if ( is_singular('post') ) {
        $loginredirect = $_SERVER['REQUEST_URI'];
    } else {
        $loginredirect="/services/clientarea";
    }

    wp_localize_script( 'ajax-login-script', 'ajax_login_object', array( 
        'ajaxurl' => admin_url( 'admin-ajax.php' ),
        'redirecturl' => $loginredirect,
        'loadingmessage' => __('Signing in, please wait...')
    ));
}
add_action('wp_enqueue_scripts', 'enqueue_ajax_login_scripts');

// it can be registered every time (it won't fire up unless there will be such AJAX request
add_action( 'wp_ajax_nopriv_ajaxlogin', 'ajax_login' );