Learning OOP - Need pointer in the right direction.

[iPixel]

So i've been wanting to expand my php horizons if you will and finally break of my fear of OOP.

Here's a simple connection script i built, however i'm kind of stuck on a part of it.

 

user passes username/password.

 

i instantiate the mysqlcon class and call the connect function.

the connect function attempts a connection to the database.

if successful, pass on the username and password to the authenticator class.

call the authenticate function.

select user based on username/passwrod criteria.

if found return "Confirmed" otherwise "Denied"

 

here's my issue, i'm assuming that my

return $this->ok

variable is returned back to the mysqlcon class. however how can i return that variable once more back outside of the object class so that i can continue with my script assuming authentication was confirmed.

 

Here's my code... thanks for the help!

 

<?php
## OOP PRACTICE ##

class mysqlcon
{
	function connect($user,$pass)
		{
			//Note: Connect to the database
			$db = mysql_connect("localhost", "usr","psw") or die(mysql_error()); 
			if(mysql_select_db("database",$db) or die(mysql_error()))
				{
					$auth = new authenticator();
					$auth->authenticate($user,$pass);
				}

		}
}

class authenticator
{
	var $ok = "Confirmed";
	var $ex = "Denied";
	function authenticate($user,$pass)
		{
			//Note: User user and pass variables to check for user in table
			$qry = "SELECT * FROM users WHERE username = '$user' AND password = '$pass'";
			$sql = mysql_query($qry) or die(mysql_error());
			$cnt = mysql_num_rows($sql);
			if($cnt > 0)
				{
					return $this->ok;
				}
			else
				{
					return $this->ex;
				}
		}
}



$con = new mysqlcon();
$con->connect($_POST['username'],$_POST['password']);

?>

 

PS: the classes are in class.php and the instantiation are in index.php. I just placed them together for easy of viewing.

[iPixel]

I got it working, but any criticism or enhancements to my code would be most appreciated.

 

<?php
## OOP PRACTICE ##

class mysqlcon
{
	function connect($user,$pass)
		{
			//Note: Connect to the database
			$db = mysql_connect("localhost", "usr","psw") or die(mysql_error()); 
			if(mysql_select_db("monet3",$db) or die(mysql_error()))
				{
					$auth = new authenticator();
					return $auth->authenticate($user,$pass);

				}

		}
}

class authenticator
{
	var $ok = "Confirmed";
	var $ex = "Denied";
	function authenticate($user,$pass)
		{
			//Note: Use the user and pass variables to check for user in table
			$qry = "SELECT * FROM users WHERE username = '$user' AND password = '$pass'";
			$sql = mysql_query($qry) or die(mysql_error());
			$cnt = mysql_num_rows($sql);
			if($cnt > 0)
				{
					return $this->ok;
				}
			else
				{
					return $this->ex;
				}
		}
}



$con = new mysqlcon();
if($con->connect("$_POST['username']","$_POST['password']") == "Confirmed")
{
	echo "User Authenticated!";
}

?>

[KevinM1]

I think you have the relationship backwards.  Your authenticator should use/contain your db object, not the other way around.  Why?  Because a db object shouldn't care about authentication.  It has a singular purpose - execute db queries and return their results and other metadata about the queries (like number of rows affected).  The authenticator should handle the higher level stuff.

 

I'd also make your authenticate method a pure boolean.  Get rid of $ex/$ok - they're superfluous - and simply return true or false.  Rename your method to isAuthenticated, and you can do something like:

 

if($auth->isAuthenticated($user, $pass))
{
   echo "Welcome!";
}
else
{
   // handle it
}

 

Better yet, if you don't need the authenticator to maintain state, turn the function static and call it like:

 

if(Authenticator::isAuthenticated($user, $pass))
{
   // etc.
}

 

For more of a general idea of how to determine good code, Google the following:

 

Separation of Concerns

Single Responsibility Principle

DRY - Don't Repeat Yourself

Tell, Don't Ask

[iPixel]

Great, thanks for the input i'll definately look into all of it!.

[iPixel]

Could you elaborate a little on how you would go about making the function static?

is it as simple as doing

static function()

or is there more to it that i should know about.

[KevinM1]

Could you elaborate a little on how you would go about making the function static?

is it as simple as doing

static function()

or is there more to it that i should know about.

 

http://www.php.net/manual/en/language.oop5.static.php