[Resolved] [Resolved] Calling class in function - Scope problem

[Herk]

How can I call a function, inside of a class from within another function outside the class. The only way I seem to be able to get into the right scope is to call my object as a global in the outside function.

Making my object global seems like a bad idea. Is it? How else can I call objects functions from within another function?

Here is a snippet:

$db = new Sql_db($dbname, $dbserver, $dbusername, $dbpassword);
$db->connect();

function authenticate($usernamefunction, $passwordfunction) {
  global $userdata;
  global $username_in_db;
  global $db;
  $usernamefunction = strtolower($usernamefunction);
  $query = "SELECT * FROM users WHERE username =\"".$usernamefunction."\"";
  $result = $db->do_query($query);

Without global $db; in there I get the error: "Fatal error: Call to a member function on a non-object in /home/virtual/site3/fst/var/www/html/resources/integral.php on line 220"

Is it ok for that object instance to be global? Thank you kindly.

Herk

[ZibingsCoder]

Some people will tell you that having global variables isn't desirable, and others will tell you that it is the only way to go. Personally, I just try and use them as efficiently as possible. It's ok to use a few global variables, just...don't get carried away. 😉

[Herk]

Thank you for your reply.

I guess it boils down to: Should I just reinstanciate inside of each function or make the instance global. The global would be much much easier and quite a bit more efficient I believe.

I just hope I am not causing any security issues or any other problems by taking the easier, seemingly more sensible, route.

Is anybody aware of any disadvantages of globalizing database abstraction objects?

Herk

[laserlight]

I would advise against using global variables since you're trying to use OOP.

One way out would be to have $db be a member variable in your class, and pass it by reference in instantiation.

Is anybody aware of any disadvantages of globalizing database abstraction objects?

Yes, your class may be less usable under certain circumstances.

[Herk]

One way out would be to have $db be a member variable in your class, and pass it by reference in instantiation.

Mmm. Feeling newbhood falling in one me. 🙂 Please explain how to do this, and thank you very much for the incite.

Herk

[laserlight]

heh, I think I misread your question, and so using global variables is a can-do.
I'm looking more along the lines of authenticate() being part of another class.

Still, if you're looking for something like the alternative I mentioned, it would be:

    function authenticate(&$db, $usernamefunction, $passwordfunction) {
      global $userdata;
      global $username_in_db;
      global $db;
      $usernamefunction = strtolower($usernamefunction);
      $query = "SELECT * FROM users WHERE username =\"".$usernamefunction."\"";
      $result = $db->do_query($query);

and then

$db = new Sql_db($dbname, $dbserver, $dbusername, $dbpassword);
$db->connect();
authenticate($db, $foo, $bar);

[Herk]

I think I've mislead you, but you've still been quite helpful.

Now I just have to figure out what

&$db

is. Then I might be set.

Anyway, the function authenticate is not part of a class. I just use an instance $db in it.

Herk

[laserlight]

Read up on references in PHP.