PDO request within a class - php

Question

Here is my class :
class ProfileLink {
function profileLink(PDO $pdo, $string, $i=0)
{
if ($i!=0) {
$link = $string . '-' . $i;
} else {
$link = $string;
}
$req = $pdo->prepare('SELECT link FROM users WHERE link = ?');
$req->execute(array($link));
$nb = $req->rowCount();
$req->closeCursor();
if ($nb > 0) {
$i++;
return profileLink($pdo, $string, $i);
} else {
return $link;
}
}
}
When I call the profileLink function from the class, it doesn't work, but if I call it outside the class, everything is ok. It might be a problem with the PDO, what do you think ?
require_once ('lib/profileLink.class.php');
$profileLink = new ProfileLink();
$link = $profileLink->profileLink($pdo, $string);

Answer 1

I would store the instance of PDO as a class property so that it can be easily accessed within the class. Note that my example uses slightly different syntax (modern PHP).
class ProfileLink {
protected $pdo;
public function __construct(PDO $pdo) {
$this->pdo = $pdo;
}
public function profileLink($string, $i=0)
{
if ($i!=0) {
$link = $string . '-' . $i;
} else {
$link = $string;
}
$req = $this->pdo->prepare('SELECT link FROM users WHERE link = ?');
$req->execute(array($link));
$nb = $req->rowCount();
$req->closeCursor();
if ($nb > 0) {
$i++;
return profileLink($string, $i);
} else {
return $link;
}
}
}
$profileLink = new ProfileLink($pdo);

Answer 2

2 Things:
here
return profileLink($pdo, $string, $i);
you are missing a $this, because it's no regular function but a class method:
return $this->profileLink($pdo, $string, $i);
And second, your method has the same name as the class (except of the first capital letter), and thus seems to be interpreted as constructor. I have just tested this:
class Test {
function test() {
echo "test";
}
}
$t = new Test();
And it outputs "test".
So you should rename your method to getLink or something similar.