get_terms（）显示插件分类法错误

Question

I have this code in wordpress plugin folder, localhost/wp-content/plugins/test/cat.php

<? 
define( "WP_INSTALLING", true );
require ('../../../wp-blog-header.php');

$categories = get_terms("ad_cat","parent=6&hide_empty=0");
print_r($categories);
?>

But, this is displaying an error as:

WP_Error Object
(
    [errors] => Array
        (
            [invalid_taxonomy] => Array
                (
                    [0] => Invalid Taxonomy
                )
        )
    [error_data] => Array
        (
        )
)

But, there isn't any error when I did the same thing in sidebar widget using PHP code plugin. Taxonomy ad_cat exists, that is created automatically using Wordpress Classifieds Theme. That works when I use taxonomy category which is default category of wordpress. But, I want it to display of ad_cat

Answer 1

Remove define( "WP_INSTALLING", true ); and that will solve the project. That worked for me.

Answer 2

Wordpress adds plugin files before any theme file added. So simply you cant get theme modified data in plugin.

So, you have to wait for theme file to be added.

Consider add_action and add_hook to hook your custom function. That will make every data available in your custom function