undefined function error when calling it in another directory

Question

I have another directory(admin) there i have an index file which require blog file and i got an error its say's Call to undefined function Blog\\DB\\connect() but what really confuse me is that it never gives me an error when i require it in the root directory files( index or single ) it runs very fine.

admin/index.php code:

<?php 
require '../blog.php';

view('admin/create');
?> 

blog.php code:

    require 'functions.php';
    require 'config/config.php';
    require 'db.php';

     use Blog\DB;
 $conn = DB\connect($config['DB_USERNAME'],$config['DB_PASSWORD'],$config['DATABASE']);
 if (!$conn) die('Could not Connect');

I have spent 2 days finding the reason for this error if anyone can enlighten that would be great.

Answer 1

You need to select the correct directory. If you're not in the directory right below where the file is, you need to go up another level

require '../../blog.php';

Or, you can specify the path starting from DOCUMENT_ROOT, so that you never have to calculate how many levels to go up:

require $_SERVER['DOCUMENT_ROOT'].'/path/to/blog.php'

Answer 2

That's because require uses the calling scripts folder (which is admin/ ). Change your require in blog.php to:

require dirname(__FILE__) . '/functions.php';
require dirname(__FILE__) . '/config/config.php';
require dirname(__FILE__) . '/db.php';

Using $_SERVER['DOCUMENT_ROOT'] only works it the script is called through a web server and not from CLI.