Variable scope in PHP class

Question

my problem is very straightforward but I can't resolve it.

In my index.php I'am including two PHP files.

    require_once("/lib/config.php");
    require_once("/lib/connect.php");

In config file I declare variable #config

$config = array(  
    "db" => array(  
        "www_db" => array(  
            "username" => "user1",  
            "password" => "pass1",  
            "conn_string" => "blabla"
        )  
    ),  
    "paths" => array("images" => $_SERVER["DOCUMENT_ROOT"] . "/images")  
);

In connect.php I have a singleton class Connection.

    class Connection
    {

private static $instance = NULL;

public static function getInstance()
{
    if (!self::$instance)
        self::$instance = new Connection();
    return self::$instance;
}


private $conn;

// Create connection to Oracle
public function getConnection() 
{
    //if (INCLUDE_CHECK == true)
//  {
        $conn = oci_connect($this -> $config["db"]["www_db"]["username"], 
                            $this -> $config["db"]["www_db"]["password"], 
                            $this -> $config["db"]["www_db"]["conn_string"]);

My problem is that my Connection class doesn't see $config variable declared in config.php. I have also tried to declare $config as global. I am getting error " Undefined variable: config..." "... in connect.php". Please help.

If you include a file with variables, you can't use $this because it refers to properties of the current object. — JorgeeFG
– JorgeeFG, Commented May 12, 2013 at 15:48

sh03 · Accepted Answer · 2013-05-12 15:52:30Z

3

You can't see the variable inside a class as it is declared outside. Pass it to the class, use Dependency Injection (either setter or constructor injection) and then $config will be available in your connection class.

edited May 12, 2013 at 15:52

sh03

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answered May 12, 2013 at 15:47

Shaun Hare

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1 Comment

Steve L Over a year ago

Hi Shaun, yes, that would work except the methods that need the DB info are all static (essentially alternate constructors) I could pass in the DB info as an arg to these, but in the interest of simplicity, I used the global keyword to pull them in from global scope. (See Chen's answer below). Thanks though!

casraf · Accepted Answer · 2013-08-29 07:05:57Z

2

You have to use the global keyword to specify when you want to include global variables. For instance, this is how it works:

$config = array ('one' => 'two');

class Foo {
    public function bar() {
        print_r($config); // NULL
        global $config;
        print_r($config); // Array ( 'one' => 'ywo' )
    }
}

edited Aug 29, 2013 at 7:05

answered May 12, 2013 at 15:48

casraf

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1 Comment

Steve L Over a year ago

Thanks Chen! This is how I solved it because I'm using these inside static methods so the constructor injection and setter ways are not useful to me.

Mr. B. · Accepted Answer · 2013-05-12 15:49:26Z

0

I recommend adding a new setter-method to your Connection.class, like:

public function set_config($config = array()) {
    if (empty($config)) return false;

    $this->_username = $config["username"];
    $this->_password = $config["password"];
    // ... 
}

Then you're able to use the data in other methods like:

oci_connection($this->_username, $this->_password);

Otherwise you set the $config global:

global $config;

answered May 12, 2013 at 15:49

Mr. B.

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4 Comments

Mr. B. Over a year ago

@Havelock You're right, but I guess Exception-Handling is another chapter - I try to keep the example-code as simple as possible. :-)

Igor Over a year ago

Like I wrote, I use statement global $config but still doesn't see $config variable.

Mr. B. Over a year ago

did you try the setter-method?

Mr. B. Over a year ago

@Igor Please post the solution, if it's possible. It could help anyone else who has the same problem. Thank you!

Igor · Accepted Answer · 2013-05-13 05:26:10Z

0

I solve it like this:

private $username = "usr1";
private $password = "pass1";
private $conn_string = "connection_string";

private $conn;

// Create connection to Oracle
public function getConnection() 
{
    $conn = oci_connect($this -> username, 
                        $this -> password, 
                        $this -> conn_string);
    if (!$conn) {
       $m = oci_error();
       echo $m['message'], "\n";
       exit;
    }
    else
    {
        return $conn;
    }
}

answered May 13, 2013 at 5:26

Igor

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