PHP Require file outside of function

Question

Is there a way to include a file outside of a function and have it work?

ie. I have a file db.inc.php, this contains my db connection string:

switch (DB_TYPE) {
case MYSQL :
    try {
        $DBH = new PDO("mysql:host=" . DB_HOST . ";dbname=" . DB_NAME . "", DB_USER, DB_PASS);
        $DBH -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch(PDOException $e) {
        echo "Error in Connection" . $e -> getMessage();
    }
}

Now I have require this file my in my functions file, functions.php:

require('db.inc.php')
function add() {

        $n = $DBH -> prepare("");
        $n -> execute((array)$s);
}

so the file is added in properly, but my function cannot access the $DBH handle. Only when I include the file in my function:

function add(){
require('db.inc.php')

....etc....

}

will my function work.

As I am going to have at least 4-5 functions in many files, any possibility of just requiring it outside the function and get the function to work?

Thank and regards

what you aim for will produce a lot of duplicate code that is hard to test. just saying, it's technically possible to do what you ask for, the question is more do you really want that? — hakre
– hakre, Commented Feb 1, 2012 at 16:56

Explosion Pills · Accepted Answer · 2012-02-01 16:21:47Z

1

After including the file outside the function, you could declare the variable as global, but that's really a bad way to do things. Instead, you should have the caller of the function pass handle as an argument. Failing that, you could create a factory for the database and call it within each function.

Why do you have to call the require outside the function?

answered Feb 1, 2012 at 16:21

Explosion Pills

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1 Comment

d123 Over a year ago

yes i know globals are bad thus i have avoided using it. reason why i want it outside, is because i want to require it once only, and not for each and every one of my functions.

TerryE · Accepted Answer · 2012-02-01 16:57:02Z

Really the only alternative to globals is to use object orientated tricks and techniques. For example if you implement your functionality as a set of classes then you can always access any static public class variables, as they will be global. Another way is to use a standard PHP pattern for a single object class. This is especially relevant in your case as you seem to be wrapping the standard PDO class. In my case, I use mysqli, but the same technique applies. Any module can access the database object using AppDB::get(). Here is the preamble to my module to give you the idea (I've trimmed the doxygen documentation to keep it short):

class AppDB extends mysqli {            

    /**            
     * This class uses a standard single class object pattern.            
     */            
    private static $_instance;            
    private static $_class = __CLASS__;            
    private function __clone() {}            
    /**            
     * Initialise the blog context. This is a static method since only one AppDB instance is allowed. The            
     * $connectParams must be provided on first invocation.            
     */            
    public static function get() {            

        if ( !isset( self::$_instance) ) self::$_instance = new self::$_class ();            
        return self::$_instance;            
    }            

    /**            
     * AppDB constructor. Connect to the database and initialise the list of tables with the given prefix.            
     */            
    private function __construct() {            

        parent::init();            
        list( $host, $db, $user, $passwd, $this->tablePrefix ) = explode ( ':', SQL_CONTEXT );            

        if( !parent::real_connect($host, $user, $passwd, $db)) {            
            throw new Exception ('Connect Error (' .             
                mysqli_connect_errno() . ') ' . mysqli_connect_error() );            
        }            
        ...            
    }
    ...
}

Rick Kuipers · Accepted Answer · 2012-02-01 16:21:27Z

0

You can use the global operator:

require('db.inc.php')
function add() {
        global $DBH;
        $n = $DBH -> prepare("");
        $n -> execute((array)$s);
}

answered Feb 1, 2012 at 16:21

Rick Kuipers

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Comments

dtbarne · Accepted Answer · 2012-02-01 16:43:55Z

0

You just want to use the global keyword to bring it in the function's scope:

function add() {
    global $DBH;
    $n = $DBH -> prepare("");
    $n -> execute((array)$s);
}

See this link for more reading on variable scope.

You could also use $GLOBALS, but I'm not a fan of this approach.

Alternatively, you could pass the handle by reference when you call add():

add($DBH);

function add(&$DBH) {
    global $DBH;
    $n = $DBH -> prepare("");
    $n -> execute((array)$s);
}

edited Feb 1, 2012 at 16:43

answered Feb 1, 2012 at 16:20

dtbarne

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