Scope Problem (I think.)

[JackMagic]

I am having a problem with the code below. I create an instance of the class 'user' in another script, passing a string. The class successfully calls function 'user1' and then proceeds to do as it says. But, then going back to the other script it says that the variable 'table' is not set. I debugged by testing to see if it would print out, and it prints out in the function 'user1', but not from any global perspective. As strange as that is, if I then use the 'setTable', and then proceed to call 'getTable' in the other script, it works just fine. Why doesn't the constructor approach work while the 'setTable' does?

See code below:

<?php

class user {

var $table;
var $userid;

function user() {
	global $table;
	session_start();
	$args_count = func_num_args();
	if ($args_count > 0) {
		$name = "user".$args_count;
		$args = func_get_args();
		call_user_func_array(array(get_class($this), $name), $args);
	}
}

function user1($table_name) {
	$this->table = $table_name; 
}

function user2($table_name, $id) {
	$this->table = $table_name;
	$this->userid = $id; 
}

function setTable($table_name) {
	$this->table = $table_name; 
}

function getTable() {
	return $this->table; 
}	

function setUserid($id) {
	$this->userid = $id; 
}

function getUserid() {
	return $this->userid; 
}

function checkLogin() {
	global $_SESSION;
	if ($_SESSION['userid']) {
		$this->userid = $_SESSION['userid'];
		return true;
	}
	else return false;
}

function isUser($username) {
	$database = new database;
	$result = mysql_query("SELECT * FROM ".$this->table." WHERE username=".$database->quote($username));
	if (mysql_num_rows($result) == 0) return false;
	else return true;
}

function login($username, $password) {
	global $_SESSION;
	$database = new database;
	$result = mysql_query("SELECT * FROM ".$this->table." WHERE username=".$database->quote($username)." AND password='".md5($password)."'");
	if (mysql_num_rows($result) != 1) return false;
	else {
		$info = mysql_fetch_array($result);
		$_SESSION['userid'] = $info['id'];
		$this->userid = $info['id'];
		$_SESSION['username'] = $info['username'];
		return $info;
	}	
}

function getUserarray() {
	$args_count = func_num_args();
	if ($args_count > 0) {
		$name = "getUserarray".$args_count; 
		$args = func_get_args();
		call_user_func_array(array(get_class($this), $name), $args);
	}
}

function getUserarray1($id) {
	$database = new database;
	$this->userid = $id;
	$result = mysql_query("SELECT * FROM ".$this->table." WHERE id='$id'");
	return mysql_fetch_array($result);
}

function getUserarray2($username, $password) {
	$database = new database;
	$result = mysql_query("SELECT * FROM ".$this->table." WHERE username=".$database->quote($username)." AND password='".md5($password)."'");
	$info = mysql_fetch_array($result);
	$this->userid = $info['id'];
	return $info;
}
} 

?>

[NogDog]

I think you might be confusing the global $table with the class variable $table. A short example:

<?php
class Foo
{
   var $bar;
   function Foo()
   {
      global $bar;
      $this->bar = "Hello";
      printf("<p>%s, %s.</p>", $this->bar, $bar);
   }
}
$bar = "World";
$test = new Foo(); // outputs "Hello, World."
//

What I think you might be intending is:

//
	function user() {
		global $table;
		$this->table = $table;
		session_start();
		$args_count = func_num_args();
		if ($args_count > 0) {
			$name = "user".$args_count;
			$args = func_get_args();
			call_user_func_array(array(get_class($this), $name), $args);
		}
	}

However, I'd probably prefer to see the value for table passed as an argument to the constructor, rather than messing with variables:

//
	function user($table) {
		$this->table = $table;
		session_start();
		$args_count = func_num_args();
		if ($args_count > 0) {
			$name = "user".$args_count;
			$args = func_get_args();
			call_user_func_array(array(get_class($this), $name), $args);
		}
	}

Then you could just instantiate it as:

$test = new user($table);

[JackMagic]

I don't think that's my issue. The values are passed through a constructor. The code in the constructor is to call a function based on the number of arguments. You can remove the "global $table;" line as it has no bearing on the issue. The script uses the constructor to, in this case, call "user1()" and set the table name. So, locally, in the function user1(), it sets it, but then it doesn't outside of the function. What puzzles me is that I can call setTable() after creating the instance of the class, and it works just as it should, updating the class variable $table. So, the issue may very well be scope, but my problem is why user1() doesn't work but setTable() does when it's the exact same code.

So the following doesn't do anything:

<?php
require "../include/include_all.inc.php";

$user = new user("test1");
print "Table: ".$user->getTable()."<br><br>";
?>

It just prints out:
Table:

But then, on top of that, after creating the instance of the class, I can call user1 again, even though I know it was called by the constructor, and it works just as setTable() does:

<?php
require "../include/include_all.inc.php";

$user = new user("test1");
$user->user1("test2");
print "Table: ".$user->getTable()."<br><br>";
?>

Which outputs:
Table: test2

So, I guess the question in the end is why can't it set the class variable $table when the constructor calls user1() even though it can do it outside of the constructor?

[NogDog]

Perhaps:

call_user_func_array(array($this, $name), $args);

?

[JackMagic]

No, class_name() has to be there because call_user_func_array() requires the class, and then the name of the function, and then arguments. It makes it to the function just fine.

Could I perhaps set up FTP access to somewhere so you can see what it is doing?

[NogDog]

OK, I pared things down to just the issue at hand, and it seemed to work fine for me (PHP 5):

<?php
class user {

   var $table;
   var $userid;

   function user() {
      $args_count = func_num_args();
      if ($args_count > 0) {
         $name = "user".$args_count;
         $args = func_get_args();
         call_user_func_array(array(get_class($this), $name), $args);
      }
   }

   function user1($table_name) {
      $this->table = $table_name; 
   }

   function user2($table_name, $id) {
      $this->table = $table_name;
      $this->userid = $id; 
   }

   function getTable() {
      return $this->table; 
   }

   function getUserid() {
      return $this->userid; 
   }
}
$test1 = new user('foo');
printf("<p>Table: %s", $test1->getTable());
$test2 = new user('foo', 'bar');
printf("<p>Table: %s, User: %s", $test2->getTable(), $test2->getUserid());
?>

Output:

Table: foo

Table: foo, User: bar

(I also tried it using just call_user_func_array(array($this, $name), $args);, and it worked identically, just FYI.)

So as far as I can tell, that aspect of your code should be working fine, unless you can see anything I did differently than you did?

[JackMagic]

I just copied and pasted your code, but nothing... Do you think it's an issue in the version of PHP? I am not using PHP 5...

[NogDog]

JackMagic wrote:

I just copied and pasted your code, but nothing... Do you think it's an issue in the version of PHP? I am not using PHP 5...

Looks like it. 🙁 I just tried it on a PHP4 host and it didn't work (and didn't throw any errors, either).

All I can suggest at this point is the way I probably would have done it:

class user {

   var $table;
   var $userid;

   function user($table = NULL, $userid = NULL) {
      $this->table = $table;
      $this->userid = $userid;
   }

   // ...etc....
}

[JackMagic]

Thanks. Ironically enough, that makes just as much sense because Table is always needed to be set while id is only sometimes. I contacted my server admin and he said that the script has some remnants of PHP 5 features, but I looked up functions and such and they are all supported in PHP 4, so I am not quite sure what the issue is...