php: access public variable in a class which is defined in an other class

Question

I have a config.php:

<?php
class GConfig {
   public $DbServer = "localhost";
   public $DbName = "golee";
   public $DbUser = "golee";
   public $DbPassword = "SASASASASAS";
   public $CharSet = "UTF8";
}
?>

I have an other file called functions.php:

<?php
class DataBase {

   function opendb() {
       $node = mysqli_connect($config->DbServer, $config->DbUser, $config->DbPassword);
       mysqli_select_db($node, $config->DbName);
       mysqli_set_charset($node, "$config->CharSet");
       return $node;
   }

}
?>

These two files are included in index.php:

<?php
   include "config.php";

   $config = new GConfig;
   echo $config->DbServer;

   include "functions.php";
   $datab = new DataBase();
   $dbnode = $datab->opendb();

?>

The "echo $config->DbServer;" display the value: localhost which is OK so I can access to the variables defined in GConfig class even if I write the "echo $config->DbServer;" at the beginning of functions.php.

But I get an error "Undefined variable: config in functions.php on line 5".

I also tried to extend the GConfig class like this but doesn't work:

class DataBase extends GConfig {
       function opendb() {
           $node = mysqli_connect($config->DbServer, $config->DbUser, $config->DbPassword);
           mysqli_select_db($node, $config->DbName);
           mysqli_set_charset($node, "$config->CharSet");
           return $node;
       }

}

My question is how can I access to the variables within the DataBase class which are defined in the GConfig class? I already read many questions and answers in the similar topic but non of them described the same problem I have.

The question is not that if a variable defined in one file is available in an other file.

`$config` is a variable, `$this->config` is a class property. Make sure you understand the difference. — u_mulder, Jul 25 '17 at 07:42
In short, you can't access global variables inside a function because a function has its own "scope" of variables (i.e. list of variables it can see directly). — apokryfos, Jul 25 '17 at 07:44
`$config` is not defined as you expect in method `opendb()`. You either have to inject it into the object when instantiating it or you need to hand it over as a call argument to the method call itself. — arkascha, Jul 25 '17 at 07:44

score 1 · Answer 1 · answered Jul 25 '17 at 07:49

just create new object in functions.php file then you can access this class in your function.

<?php
class DataBase {

   function opendb() {
       $new_connect = new GConfig();
       $node = mysqli_connect($new_connect->DbServer, $new_connect->DbUser, $new_connect->DbPassword);
       mysqli_select_db($node, $new_connect->DbName);
       mysqli_set_charset($node, "$new_connect->CharSet");
       return $node;
   }

}
?>

score 0 · Accepted Answer · answered Jul 25 '17 at 07:44

you can do this by replacing $config with $this

class DataBase extends GConfig {
       function opendb() {
           $node = mysqli_connect($this->DbServer, ($this->DbUser, $this->DbPassword);
           mysqli_select_db($node, $this->DbName);
           mysqli_set_charset($node, "$this->CharSet");
           return $node;
       }

}

php: access public variable in a class which is defined in an other class

2 Answers2