Adrian Callaghan`s Blog » Work

session_start hangs when it used to work

Adrian — Tue, 13 Dec 2011 09:48:35 +0000

I had a problem with my zend application hanging with a white screen for no reason.
I narrowed it down to when

1	$adminSession = new Zend_Session_Namespace('Admin');

was executed, this is just a session? so debugging further, confirmed that session_start() hangs when it used to work.

There are lots of explanations for this, but before you start modifying ini settings, just try this

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session_write_close();
session_start();
die(print_r($_SESSION,true));

I found this resolved the problem completely.
I then just removed this debug-code and went back to developing my zend app.

database class php

Adrian — Mon, 08 Aug 2011 17:05:05 +0000

Updated the database class

Usage:

 
// min instantiation
$dataBase = new DB('hostname','username','password','database');
 
// max instantiation
$dataBase = new DB('hostname','username','password','database',DEBUG_LEVEL,array('admin@domain.com','admin@domain2.com));

Class:

 
class DB{
 
	/* 
	 * DESCRIPTION:		Object class, Handles all database requests and returns content accordingly
	 * WRITER:			Adrian Callaghan 12,08,08      
	 * UPDATED: 		Adrian Callaghan 08,08,11
	 * 
	 * 
	 * errLvl 
	 * 		(0), none, 
	 * 		(1) show a user error, 
	 * 		(2) (1) + mysql error
	 * 		(3) (2) + show a full error (mysql errors), 
	 * 		(4) (3) + plus debugging 
	*/
 
 
	private $host, $usr, $pwd, $errLvl, $mySqlHost, $dataBase, $emailAddresses;
 
 
	public function __construct($host, $usr, $pwd, $db, $errLvl=0, $adminEmails=array()) {
 
		/*
		 * Sets up a new connection
		 */
 
		// MIN required
		$this->setHost($host);
		$this->setUsr($usr);
		$this->setPwd($pwd);
 
		$this->setErrLvl($errLvl); // sets defualt RTE
		$this->setEmailErrsTo($adminEmails);
 
		// connect
		$this->connect();
		$this->setDb($db);
 
		}
 	public function __destruct(){
 		/*
 		 * Close the connection
 		 */
 		$this->disconnect();
 	}
	protected function setHost($host='localhost'){
		/*
		 * Sets the hostname
		 */
		$this->host = $host;
	}	
 	protected function setUsr($usr=''){
		/*
		 * Sets the username
		 */
 		$this->usr = $usr;
	}	
	protected function setPwd($pwd=''){
		/*
		 * Sets the password
		 */
		$this->pwd = $pwd;
	}	
	protected function setErrLvl($errLvl=0){
		/*
		 * Sets the error reporting level
		 */
		$this->errLvl = $errLvl;
	}	
	protected function connect(){
		/*
		 * Connect to server
		 */
		$this->mySqlHost = @mysql_connect($this->host, $this->usr, $this->pwd);
		if (!$this->mySqlHost) {
			$this->error('Cannot connect to server',mysql_error());
		}	
 
	}
	protected function disconnect() {
		/*
		 * closes current connection
		 */ 
		@mysql_close($this->mySqlHost);
	}
	public function setDb($db){
		/*
		 * Set the database
		 */
		$this->dataBase = @mysql_select_db($db,$this->mySqlHost);
		if (!$this->dataBase) {
			$this->error('Cannot select database',mysql_error());
		}
	}
	public function setEmailErrsTo($email = array()){
 
		// ensure it is an array
		$email = !is_array($email) ? array($email) : $email;
 
		// if empty return
		if (empty($email)){
			return;
		}
 
		// assign the email addresses
		$this->emailAddresses = $email;
	}
 
 
 
 
	function getQuery($SQL){
		// executes a query
		$result = @mysql_query($SQL);
		if (!$result) {
			$this->error('Invalid query',mysql_error(),$SQL);
			}
		// create a 2D array of results
		$return = array();
		while ($row = mysql_fetch_assoc($result)) $return[] = $row;
		return $return;
		}
 
 
 
 
	function setQuery($SQL){
		// executes a query without returning any results, used for insert, create etc, returns the ID of the last auto-increment
		$result = @mysql_query($SQL);
		if (!$result) {
			$this->error('Invalid query',mysql_error(),$SQL);
			}
		$return = mysql_insert_id();
		return $return;
		}
 
 
 
 
	public function error($message, $mysqlErr='', $SQL=''){
 
		/*
		 * Handles errors
		 * 
		 */
 
		switch ($this->errLvl){
 
			case 0: break;
			case 1:	$mysqlErr=''; // kill the mysql output
			case 2:	$SQL=''; // kill the sql output
			case 3: 
			case 4: 
				echo "$message
";
				if ($mysqlErr!=='') {
					echo "Mysql: $mysqlErr
";
				}
				if ($SQL!=='') {
					echo "Whole query: $SQL
";
				}			
 
		}
 
 		$email = $this->generateEmail(array('Error'=>$message,'Mysql'=>$mysqlErr,'Sql'=>$SQL,'Err Level'=>$this->errLvl));
 
 		// three is for debugging
 		if ($this->errLvl>3){
			echo $email;
		}
 
		if (!empty($this->emailAddresses)){
 
			$sent = $this->sendEmails($email);
 
 			if ($sent) echo 'The administrator has been notified
';
			else {
				echo 'Please notify the administrator';
				echo count($this->emailAddresses)>1 ? "'s " : " ";
				echo implode(' or ',$this->emailAddresses);
				echo '
';
			}
 
		}
 
		exit();
	}	
	private function generateEmail($err=array()){
 
		$fields = array(
			'Server name'=>$_SERVER['SERVER_NAME'],
			'Query'=>$_SERVER['SCRIPT_FILENAME'].'?'.$_SERVER['QUERY_STRING'],
			'Ip'=>$_SERVER['REMOTE_ADDR'].':'.$_SERVER['REMOTE_PORT'],
			'@'=>date("D dS M,Y h:i a")
		);	
 
		$rtn = '';foreach(array_merge($fields,$err)AS$title=>$value){$rtn.="";}return$rtn.'
		    
			$title $value
		
		 
';
 
	}
	public function sendEmails($reciptents=array()){
 
		// email message
		$Name = $_SERVER['SERVER_NAME']; //senders name 
		$email = "noreply@".$_SERVER['SERVER_NAME']; //senders e-mail adress 
 
		$subject = $_SERVER['SERVER_NAME']." Error"; //subject 
 
		$header = 'MIME-Version: 1.0' . "\r\n";
		$header.= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";		
		$header.= "From: ". $Name . " <" . $email . ">\r\n"; 
 
		$success=false;
		foreach ($this->emailAddresses AS $admin_email){
			$sent = @mail($admin_email, $subject, $mail_body, $header);
			if ($sent) $success=true; // holds state for any email being succesfully sent
		}
		return $success;
	}
}

compile your own lamp stack with mysqli

Adrian — Thu, 16 Jun 2011 10:44:21 +0000

Install LAMP with one line

One liner

sudo apt-get install lamp-server^

Add CURL and enable mod-rewrite

sudo apt-get install php5-curl
sudo a2enmod rewrite

To compile LAMP with mysqli and mysql

Assuming you have a fresh clean minimal install of ubuntu start by install gcc and wget

sudo apt-get gcc
sudo apt-get wget

Download apache and php and use filezilla or a similar SFTP client to upload them to the server (I was unable to find a direct link that didnt pass through a mirror), once uploaded move to the directory on the cmd line.

unpack apache

1 2	gzip -d httpd-2_x_NN.tar.gz tar -xf httpd-2_x_NN.tar

unpack PHP

1 2	gzip -d php-NN.tar.gz tar -xf php-NN.tar

Compile and install Apache

cd httpd-2_x_NN
./configure --enable-so
make
sudo make install

Compile PHP

1 2	cd ../php-NN ./configure --with-aspxs2=/usr/local/apache2/bin/apxs --with-mysql=/usr/bin/mysql_config --with-mysqli=mysqlnd --with-pdo-mysql=mysqlnd

This will fail with an error “error locating libxml2″ fix this with:

sudo apt-get install libxml2

Next the error below will appear

xml2 config not found Please check your libxml2 installation

Point your browser or ftp client at ftp://xmlsoft.org/libxml2/ and take note of the latest version for libxml2-2.6.28 and then grab it and install it from the server

sudo wget ftp://xmlsoft.org/libxml2/libxml2-2.X.XX.tar.gz
sudo tar -zxvf libxml2-2.X.XX.tar.gz
cd libxml2-2.X.XX/
./configure
make
sudo make install

Try to compile PHP again:

1	./configure --with-aspxs2=/usr/local/apache2/bin/apxs --with-mysql=/usr/bin/mysql_config --with-mysqli=mysqlnd --with-pdo-mysql=mysqlnd

next problem is Mysql

configure: error: Cannot find MySQL header files under /usr/bin/mysql_config

To fix this, Install mysql:

sudo apt-get install mysql-server

But now even though Mysql is found there are still no headers so first install php module for mysql:

sudo apt-get install php5-mysql

and add the header library

sudo apt-get install libmysqlclient15-dev

Now PHP should compile and install fine:

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./configure --with-aspxs2=/usr/local/apache2/bin/apxs --with-mysql=/usr/bin/mysql_config  --with-mysqli=mysqlnd --with-pdo-mysql=mysqlnd
make
make install

Set up an ini file for PHP:

sudo cp php.ini-development /usr/local/lib/php.ini

tell apache to load the module:

LoadModule php5_module modules/libphp5.so

You need to re/start apache

/usr/local/apache2/bin/apachectl start

personally I like to restart the entire server with changes this big

shutdown now -r

Thats it!

simple mvc

Adrian — Mon, 30 Aug 2010 13:18:47 +0000

Need a lightweight, fast, php mvc framework?

I have written a small framework named “Simple MVC” it does exactly what it says on the box, its quick to install and can be configured to handle most tasks.

Once the file is unzipped you will be presented with this structure:

Simply upload the whole structure, and the framework will work.

It is designed to be very fast and lightweight, however it can be configured, opening the file mvc_env.php within the “Simple MVC” folder displays the following preferences:

 
/*
 * 
 * Simple MVC settings file (this file does not need to be present)
 * Examples of different settings are contained here, just uncomment to use
 * 
 * By Adrian Callaghan 300810
 * 
 */
 
// error controller
// defines a controller to handle errors, namely the page not found
// the controller is automatically exempt from an actual page request
/*
$env->error['controller']='error';
$env->error['view']='index';
$env->error['pageNotFoundAction']='pageNotFound';
*/
 
// routerMap
// holds controller and action mappings to different controller, action (comma delimited)
/*
$env->routerMap['foo,bar']='index,index';
*/
 
// routerDeny
// holds controller and action mappings to deny (comma delimited)
/*
$env->routerDeny[]='controller,action'; // will deny the page /controller/action/
$env->routerDeny[]=''; // will deny homepage
*/
 
// prelayout
// defines an array of elements to be included before the main view
/*
$env->prelayout = array('header');
*/
 
// postlayout
// defines an array of elements to be included after the main view
/*
$env->postlayout = array('sidebar','footer');
*/

As you can see, page routing, error controllers, page denials etc can all be added here.

The whole framework is just one file and the source looks like this


 
/*
 * 
 * Simple MVC 
 * 
 * By Adrian Callaghan 300810
 * 
 */
 
 
// enviroment
$env = new stdClass();
 
// url mapping
$env->url['base'] = dirname($_SERVER['SCRIPT_NAME']);
$env->url['path'] = realpath('.');
$env->url['relative'] = str_replace('//','/',dirname(__FILE__)).'/../application/';
$env->url['request'] = htmlentities($_SERVER['REQUEST_URI']);
$env->url['request_array'] = explode('/',trim($_GET['__url'],'/'));
 
// mvc
$env->controller = !empty($env->url['request_array'][0]) ? $env->url['request_array'][0] : 'index';
$env->action = !empty($env->url['request_array'][1]) ? $env->url['request_array'][1] : 'index';
$env->view = $env->controller;
 
// settings
@include_once('mvc_env.php');
 
// tell the controllers where to load models from
function __autoload($class_name) {
	global $env;
    require_once "{$env->url['relative']}models/$class_name.php";
}
 
 
// add custom error controller to list of denys
if (isset($env->error['controller'])){
	$env->routerDeny[] = $env->error['controller'];
}
 
 
// mapping
if (isset($env->routerMap) && in_array("{$env->controller},{$env->action}",array_keys($env->routerMap))){
	$route = explode(',',$env->routerMap["{$env->controller},{$env->action}"]);
	$env->controller = $route[0];
	$env->action = $route[1];
	$env->view = $env->controller;
}
 
// get the controller
if (file_exists("{$env->url['relative']}/controllers/{$env->controller}.php")) {
	require_once("{$env->url['relative']}/controllers/{$env->controller}.php");
	$controller = new $env->controller();	
	} 
 
// unset the controller if this is a denied resource, this is done on URL only, so not to interfere with any mappings
if (isset($env->routerDeny) && in_array(implode(',',$env->url['request_array']),$env->routerDeny)){
	unset($controller, $env->controller);
	}	
 
// if neither the controller or action was found set an error for the error controller to handle
if (!isset($controller) || !method_exists($controller,$env->action)){
 
	// can we run the error handler?
	if (isset($env->error)){
		$env->controller = $env->error['controller'];
		$env->action = $env->error['pageNotFoundAction'];
		$env->view = $env->error['view'];
 
		@require_once("{$env->url['relative']}/controllers/{$env->controller}.php");
		$controller = new $env->controller();	
		if (!method_exists($controller,$env->action)) {
			die("Fatal error
Missing action: {$env->action} in controller: {$env->controller}");
			}
 
		// output will be handled by the dispatcher below	
		}
	else {
		// if we do not even have an error handler, throw a traditional 404 and die
		ob_start();	?>
		
		404 Not Found
		Not Found
		The requested URL  echo $env->url['request']; ?> was not found on this server.
		
		 header("HTTP/1.0 404 Not Found"); die(ob_get_clean());
	}
}
 
// dispatcher /////////////////////////////////////////////////
 
//attempt to execute the action in the controller,
$controller->{$env->action}();	
 
// check to see if the view has been altered
$env->view = isset($controller->view) ? $controller->view : $env->view;
 
// set up the content and view
$content = $controller->content;
if (isset($env->prelayout)) foreach ($env->prelayout AS $element) include_once("{$env->url['relative']}/views/$element.phtml");
include_once("{$env->url['relative']}/views/{$env->view}.phtml");
if (isset($env->postlayout)) foreach ($env->postlayout AS $element) include_once("{$env->url['relative']}/views/$element.phtml");

A helloworld quickstart can be downloaded from here

The helloworld also has examples of where to instaniate the models, and how to redirect the view in the comments.

sort a array by its value

Adrian — Thu, 29 Jul 2010 12:45:07 +0000

To sort an array by its value, similiar to mysql sort by just use

1	usort($array, create_function('$a, $b, $sortBy="distance"', 'return strnatcmp($a[$sortBy], $b[$sortBy]);'));

$array stores the array
$sortBy set the key to sort by

i.e

$array = array (
    1=>array('name'=>'me','location'=>'somewhere','distance'=>'200'),
    2=>array('name'=>'you','location'=>'somewhere','distance'=>'2') 
    );
 
usort($array, create_function('$a, $b, $sortBy="distance"', 'return strnatcmp($a[$sortBy], $b[$sortBy]);'));
print_r($array);

will result in the array being re-ordered with location 2 now being in location 1 (preserving the keys)

wordpress comment count as a button

Adrian — Thu, 30 Jul 2009 13:46:56 +0000

Styling the wordpress comment count as a button/icon etc can be tricky because the normal call to the comments

1	comments_popup_link(__('Comments (0)'), __('Comments (1)'), __('Comments (%)'));

formats the output as an anchor point with the correct link, alt tags etc already set up.

So in order to intercept this and then add you own anchor point with divs/imagery etc you need to make a custom request

 
// SQL
$SQL = "SELECT COUNT(*) AS Count FROM $wpdb->comments WHERE comment_approved='1'";
$SQL.= "AND comment_post_ID='".intval($post->ID)."'";
 
// Sort the array into a string prefixed with 'Comments '
list($comments) = $wpdb->get_results($SQL, ARRAY_A); 	
$comments='Comments ('.$comments['Count'].')';
 
// generate the alt and title tags
$alt = 'Comment on '.$post->post_title;
 
// echo the button if this is not a single and not a page
if (!is_single() && !is_page()) {
 
// anchor open
echo '.get_permalink($post->ID).'" alt="'.$alt.'" title="'.$alt.'">';
 
// complex formatting rules for the comment pop up, go here
echo $comments;
 
// anchor close
echo '';
}

The above does exactly the same, formats the link etc, but now you can access the anchor point directly and format it your own way.

ftp open in explorer by default in windows

Adrian — Mon, 27 Jul 2009 09:25:24 +0000

How to make explorer open by default when opening an ftp connection, I found can be easy..

I needed to make IE6 style FTP access without the extra pop up step, from a desktop shortcut at work and after much googling, and messing with the registery, attempting to make an ftp site open immediatly in explorer without the main browser opening (pre IE7), I found it can be simply done like this.

1. create a bat file (open notepad, save the file with the affix .bat, making sure .txt is not selected in the dropdown)
2. in the batch file add

1	start explorer ftp://USERNAME:PASSWORD@FTP_SERVER_ADDRESS

3. add the shortcut to the desktop, and style the icon

Now when the user clicks the shortcut, voila IE6 style FTP access without the extra step, much easier than poking around with the registery

0 in $_GET is empty in PHP

Adrian — Wed, 12 Nov 2008 20:39:24 +0000

Whilst at work,

I was writing a cart for an e-commerce site I am building.

The Cart consisted of a multi-dimensioned array, part associative, part indexed, anyway of note here is that,

A. It was an array.
B. The contents where indexed numerically
C. Arrays as you know begin at zero.

When removing an element from the cart, the elements indexed value, is passed via GET to be handled via the object, for removal.

It seemed to work fine, until I attempted to remove the first element, after a little debugging, I noticed the “0″ value was being interpreted by PHP as empty?

WTF?

A quick mock up code later

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if (!empty($_GET['get'])) echo "I RECIEVED A GET WITH VALUE: ".$_GET['get'];
?>

and a check in the url

nameOfFile.php?get=1 displayed “I RECIEVED A GET WITH VALUE: 1″
nameOfFile.php?get=0 displayed “”

It seems that according to PHP the value zero is interpreted as empty because it is being handled as a string when used within GET.

But…………….

A string, as the name suggests is just a string of characters, strung together, it is an array of characters, or bytes, the fact that it held zero, would be irrelevant would`nt it not?

I can understand if it was attempting to cast the datatype to an integer, but again, zero is still zero.

The only scenerio I can see this being valid if it where NULL!

PHP uses loose datatypes or lucid?

Adrian Callaghan`s graduation

Adrian — Wed, 08 Oct 2008 21:16:31 +0000

This is recent footage from the graduation ceremony, I have edited out all the boring stuff, so only about 20sec`s remains.

It was a lovely day, and I am glad I attended..