OO PHP Problem Please Offer Advice!!

[shodow]

I am trying to develop a PHP application. And I am having a problem with php classes.

What I have is a proceedural php file calling a php class and creating an instance of that class. Internally to that class there is a call to a simple database class which handles simple database functionality (saves me having to type it out over and over again).

The problem occurs when I try to call another php class file from the proceedural php file. When I do this I get a blank page as output, I get html and body tags but that's all. I've tried putting echo and print statements in both classes and the proceedural php file but these dont output.

When I comment out the call to the second class I get output again. I can't figure this out!!

Has anyone ever had this problem and if they have how did you get around it?

Any help will be much appreciated

Thanks

[Shrike]

Check that there is nothing in the 2nd class that can cause the parser to stop, e.g. conditional exit()'s etc.

It's hard to say w/out seeing some code.

[shodow]

There are no exits in the second class. Thats what I find so strange. Here is the code :

Flat file:
<?php

require_once ("../../smarty/Smarty.class.php");
require_once ("../../classes/class.categories.php");
require_once ("../../classes/class.modifiedcategory.php");
require_once ("../../config/config.php");

$smarty = new Smarty;
$categories_obj = new categories;
//$modifiedcategory_obj = new modifiedcategory;

print_r($_POST);

if ($_POST[Action] == "Save") 
{
	if (!$_POST[IsDisplay]) { $IsDisplay = "N"; } else { $IsDisplay = "Y"; }
    if (!$_POST[IsTopLevel]) { $IsTopLevel = "N"; } else { $IsTopLevel = "Y"; }
    if (!$_POST[SpecialCase]) { $SpecialCase = "N"; } else { $SpecialCase = "Y"; }

	$categories_obj->saveCategory($parentID, $name, $userID, $display, $topLevel, $specialCase, $specialDescription);
}
elseif ($_POST[Action] == "Update") 
{
	if (!$_POST[IsDisplay]) { $IsDisplay = "N"; } else { $IsDisplay = "Y"; }
    if (!$_POST[IsTopLevel]) { $IsTopLevel = "N"; } else { $IsTopLevel = "Y"; }
    if (!$_POST[SpecialCase]) { $SpecialCase = "N"; } else { $SpecialCase = "Y"; }

	$categories_obj->updateCategory($_POST[CategoryId], $_POST[CategoryName], $IsDisplay, $IsTopLevel, $SpecialCase, $_POST[SpecialDescription]);

	//if ($categories_obj->updateCategory($_POST[CategoryId], $_POST[CategoryName], $IsDisplay, $IsTopLevel, $SpecialCase, $_POST[SpecialDescription]))
		//$modifiedcategory_obj->saveModifiedCategory($_POST[CategoryId], $_POST[CategoryName], $IsDisplay, $IsTopLevel, $SpecialCase, $_POST[SpecialDescription])
}

...

$smarty->display('categories.tpl');

?>

Categories Class:

<?php
include_once ("class.mysqldb.php");

class categories
{
// Object Attributes
var $CategoryID;
var $ParentID;
var $lvalue;
var $rvalue;
var $Name;
var $UserID;
var $DateCreated;
var $HierarchyID;
var $Display;
var $TopLevel;
var $SpecialCase;
var $SpecialDescription;
var $db;

// Object Constructor
function categories()
{
	$this->init();
}

// Object Methods	
function init()
{
	$this->CategoryID = "";
	$this->ParentID = "";
	$this->lvalue = "";
	$this->rvalue = "";
	$this->Name = "";
	$this->UserID = "";
	$this->DateCreated = "";
	$this->HierarchyID = "";
	$this->Display = "";
	$this->TopLevel = "";
	$this->SpecialCase = "";
	$this->SpecialDescription = "";		
	$this->db = new mysqldb;		
}

function saveCategory($parentID, $name, $userID, $display, $topLevel, $specialCase, $specialDescription)
{
	// check to see if the category already exists
	if (!$this->alreadyExists($name, $parentID)) 
	{ 
		// to save a new node in the table we first have to get the left and right values of the parent node
		$sql = "SELECT lvalue, rvalue FROM Categories WHERE CategoryID = $parentID";
		$this->db->query($sql);
		$row = $this->db->getRows();
		$lft = $row[lvalue];
		$rgt = $row[rvalue];

		// Update the rvalue value of all nodes to the right of the inserted node
		$sql = "UPDATE Categories SET rvalue = rvalue + 2 WHERE rvalue >= '$rgt'";	
		$this->db->query($sql);

		// Update the lvalue value of all nodes to the right of the inserted node
		$sql = "UPDATE Categories SET lvalue = lvalue + 2 WHERE lvalue > '$rgt'";
		$this->db->query($sql);

		// default level for a new Category is level 1 as level 0 of the tree is the root with a value of "Gotcha"
		// Now we can insert the new node using the right value and right value + 1
		$sql = "INSERT INTO Categories VALUES(NULL, $parentID, $rgt, $rgt+1, '$name', $userID, now(), '$display', '$topLevel', '$specialCase', '$specialDescription')";
		$this->db->query($sql);
		if ($this->db->getaffectedrows())
		{														 
			$verifyinsert = 1;
		}
		else
		{
			echo "class.categories.php - function SaveCategory() : Problem inserting new node.<br />";	
		}
	} 
	else
	{
		$verifyinsert = 2;		
	}
	return $verifyinsert;
}

function updateCategory($categoryID, $name, $display, $topLevel, $specialCase, $specialDescription)
{

	// update the entry in the Categories Table
	$sql = "Update Categories set Name = '$name', Display = '$display', TopLevel = '$topLevel', SpecialCase = '$specialCase', SpecialDescription = '$specialDescription'  where CategoryID = '$categoryID'";
	echo $sql."<br />";
	$this->db->query($sql);
	if ($this->db->getaffectedrows())
	{
		return 1;
	}
	else
		return -1;			
}

// Other Object Functions set and get etc

}

database class:

<?php

class mysqldb
{
// Object Attributes
var $dbhost;
var $db;
var $dbuser;
var $dbpassword;
var $sql;
var $numberrows;
var $affectedrows;
var $dbopenstatus;
var $dbconnection;
var $result;

// Object Constructor
function mysqldb()
{
	$this->init();
}

function init() 
{    				
	$this->setdbhost(DBSERVER);
	$this->setdb(DBNAME);
	$this->setdbuser(DBUSERNAME);
	$this->setdbpassword(DBPASSWORD);
	$this->setdbconnection(false);    

	$this->opendbconnection();
}

// Object Methods	
function opendbconnection() 
{
	$link = mysql_connect($this->getdbhost(), $this->getdbuser(), $this->getdbpassword());

	if ($link) 
	{
		mysql_select_db($this->getdb());
		$this->setdbconnection($link);
	} 
	else 
	{
		$this->setdbconnection($link);
		return false;
	}
	return true;
}

function closedbconnection() 
{
	if ($this->dbconnection = $TRUE) 
	{
		mysql_close($this->dbconnection);
	}
}

function query($sql) 
{       
	if ($this->getdbconnection()) 
	{
		$this->opendbconnection();
	}

	//echo $sql."<br />";

	$this->qry = mysql_query($sql);
	if (!$this->qry) 
	{
		die("Invalid query: " . mysql_error());
		return false;
	} 
	else 
	{			
		if (preg_match("/\bselect\b/i", $sql))
			$this->setnumberrows(mysql_num_rows($this->qry));
		elseif (preg_match("/\binsert\b/i", $sql) || preg_match("/\bupdate\b/i", $sql) || preg_match("/\bdelete\b/i", $sql))
			$this->setaffectedrows(mysql_affected_rows());
		else
		{
			echo("[Error:] Querrying Database<br />");
			return false;
		}
	}
}	

// get and set functions, etc

}

Modified Category Class:

<?php
include_once ("class.mysqldb.php");

class modifiedcategory
{
// Object Attributes
var $ModifiedID;
var $CategoryID;
var $Modification;
var $UserID;
var $Date;

// Object Constructor
function modifiedcategory()
{
	$this->init();
}

// Object Methods	
function init()
{
	$this->ModifiedID = "";
	$this->CategoryID = "";
	$this->Modification = "";
	$this->UserID = "";
	$this->Date = ""; 
	$this->db = new mysqldb;
}

function saveModifiedCategory($categoryID, $name, $display, $topLevel, $specialCase, $specialDescription)
{
	$tempName = null;
	$tempDisplay = null;
	$tempTopLevel = null;
	$tempSpecialCase = null;
	$tempSpecialDescription = null;
	$mod = null;

	$sql = "SELECT Name, Display, TopLevel, SpecialCase, SpecialDescription FROM Categories WHERE CategoryID = $CategoryId";	
	$this->db->query($sql);

	while ($row = $this->db->getRows();)
	{
		$tempName = $row[Name];
		$tempDisplay = $row[Display];
		$tempTopLevel = $row[TopLevel];
		$tempSpecialCase = $row[SpecialCase];
		$tempSpecialDescription = $row[SpecialDescription];
 	}

	if ($tempName != $CategoryName)
		$mod .= "Changed Name to : ".$CategoryName." from ".$tempName.".";
	if ($tempDisplay != $IsDisplay)
		$mod .= "Changed Display to : ".$IsDisplay." from ".$tempDisplay.".";
	if ($tempTopLevel != $IsTopLevel)
		$mod .= "Changed TopLevel to : ".$IsTopLevel." from ".$tempTopLevel.".";
	if ($tempSpecialCase != $SpecialCase)
		$mod .= "Changed SpecialCase to : ".$SpecialCase." from ".$tempSpecialCase.".";
	if ($tempSpecialDescription != $SpecialDescription)
		$mod .= "Changed SpecialDescription to : ".$SpecialDescription." from ".$tempSpecialDescription.".";

	echo $mod."<br />";
	//mysql_query ("INSERT INTO ModifiedCategory VALUES (Null, '$CategoryId', '$mod', '$USER_ID', now())")
}

// etc etc
}

if I uncomment in the flat file at the line :

$modifiedcategory_obj = new modifiedcategory;

Thats when I get the blank output

Hope this helps

[Shrike]

And how about in the 4 included classes?

[shodow]

Sorry about that Had to go and get something half way through the post.

I Haven't really looked at the code from the Smarty Template Engine - sorry!

I've included my three classes above

[shodow]

Thanks Shrike, I found the problem, there was a few syntax errors which I did not pick up on.

Thanks for your help