During my time at University, I had to do many assignments. The most interesting (as part of my Master of Information Technology at Macquarie Univeristy) was developing a Randomised Quiz System for Programming. The motivation behind it was simple:

• Students plagiarise. A lot. Practical Exercises are given to every student every week, but since the answers to these questions are essentially the same (and easy to copy), students will share their work.
• Students also don’t get enough practice doing questions. Lecturers will teach a concept, but not have time to go through making hundreds of variations on the same concept.
• Students work best when they work at their own pace.

So taking all these things into account, I developed a program where you could put in your Question Template into an XML file, specify which bits are to be randomised, and consequently generate random questions for each student – eliminating the ability to copy from classmates.

Generally speaking, the program has 3 types of questions:

• Read and Interpret (essentially like putting something into a compiler and giving the output)
• Multiple Choice Questions based on Reading and Interpreting
• Having questions where you ‘fill-in’ pieces of code to make the program execute as instructed in the question directive.

The third presents many interesting security concerns (many of which I didn’t bother to pay attention to due to time constraints), but the rest are quite interesting (and work quite well). I finished this project, and handed it in. If I recall correctly, I scraped in a High Distinction.

Over a year later, I was approached by a good friend who was to lecture an Undergraduate Computing unit. We got talking, and discussed the project I had completed in 2010. I told him that it really wasn’t “up to scratch” (I didn’t really know even what a Framework WAS back then), but that I’d rewrite it a little so that it at least conformed to a loose MVC architecture.
Several months later, I completed the bulk of this work, and after some collaboration with the University, I’ve decided to release my work as Open Source (GPL3) in the interest of helping the community.

I’m a bit embarrassed with a lot of the code (it’s funny how much you learn within a couple of years), but it (mostly) works.
If you’re interested, check out the original proposal here or the code on github here. If you like/hate it, leave a comment below or email me.
Even better, if you want to contribute please get in touch!

I was having issues trying to get a PHP script to change a password for a user in OpenLDAP. I wrote the following script. Hopefully it’s useful to someone. Parts taken from http://snippets.dzone.com/posts/show/4059

<?php

$ldap_server = "example.com.au";

$username = "test.user";
$old_password = "test";
$dn = "ou=testou,dc=example,dc=com,dc=au";
$new_password = "123456";
$user_dn = "uid=" . $username . "," . $dn;

$ldap = ldap_connect($ldap_server, 389);
ldap_set_option($ldap, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_set_option($ldap, LDAP_OPT_REFERRALS, 0);

if ($ldap){

	try{
		$bind = @ldap_bind($ldap, $user_dn, $old_password);
		if( !$bind ) {
			throw new Exception();
		}

	}catch(Exception $e) {
		@ldap_close($ldap);
		throw new Exception("Incorrect Current Password");
	}

	if( $bind ) {

		$filter = "uid=" . $username;
		$ldap_result = ldap_list($ldap, $dn, $filter);
		$info = ldap_get_entries($ldap, $ldap_result);

		//print_r($info); die();

		if( $info['count'] == 1 ) {

			$passwd1 = new_password;
			$userpassword = "{SHA}" . base64_encode( pack( "H*", sha1( $new_password ) ) );
			$userdata = array( "userpassword" => array( 0 => $userpassword ) );
			$result = ldap_mod_replace($ldap, $user_dn , $userdata);

				if ($result) echo "Your password has been changed!" ;
				else echo "There was a problem changing your password, please call IT for help"; 

		}

	}else{
		echo "Invalid Password.";
	}

}

	@ldap_close($ldap);
?>

So, I use CiviCRM and had a piece of software recently upgrade to V3 (from V2). CiviCRM were nice enough to provide a V2 API for compatibility. However, this V2 API unfortunately isn’t 100% compatible with the original V2. Especially in regards to the Location API. To make things a little easier, I wrote a function that transforms V3′s V2 compatible API results into true V2 compatible results.

Here it is:

	function getLocation($contact_id){

		require_once 'v2/Location.php';
		$params = array(
			'contact_id' => $contact_id
		);

		$result = civicrm_location_get( $params );

		if ( civicrm_error ( $result )) {
			return $result['error_message'];
		} else { 

			//OK. In order to deal with the new API, sometimes we have to wrap this in a "location" wrapper that the view understands
			if( is_array($result) ) {

				$rework_results = false;

				foreach( $result as $r_key=>$r_data ) {
					if( !is_numeric($r_key) && !$rework_results ) {
						$rework_results = true;
					}
				}

				//OK. So, the CiviCRM API has changed, and the format has completely changed.
				//	So, we're going to rework it here
				if( $rework_results ) {

					$n_result = array();

					foreach( $result as $r_key=>$r_data ) {

						if( is_array($r_data) && sizeof($r_data) > 0 ){

							//We have element(s)
							foreach( $r_data as $element ){

								if( array_key_exists("location_type_id", $element)) {

									if( !array_key_exists( $element['location_type_id'], $n_result ) ) {
										$n_result[ $element['location_type_id'] ] = array( "location_type_id" => $element['location_type_id'] );
									}

									//Now, the old API did funny things with addresses - instead of putting them as their own element
									//	each location could only have one address. Everything else (I think), could have multiples
									if( $r_key != "address" ) {

										if( !array_key_exists( $r_key,  $n_result[ $element['location_type_id'] ] ) ) {
											$n_result[ $element['location_type_id'] ][ $r_key ] = array();
										}

										if( array_key_exists( $r_key . "_type_id", $element ) ) {
											$n_result[ $element['location_type_id'] ][ $r_key ][ $element[$r_key . "_type_id"] ] = $element;
										}else{
											$n_result[ $element['location_type_id'] ][ $r_key ][] = $element;
										}

									}else{
										$n_result[ $element['location_type_id'] ]['address'] = $element;
									}
								}
							}
						}
					}

					$result = $n_result;
				}//End if reworking Results

			}

			return $result;
		}//End if no CiviCRM Error
	}//End Function

Today I thought I’d give my small unbiased review of Sourceguardian.

What is it?
Sourceguardian is a product that allows you to encrypt your php applications so that you can deliver your PHP application to a client (for use on their servers) without having to give them your source code. Although I’m definitely NOT specialised in the field of computer security, I’ve read several reviews that say Sourceguardian uses industry standard encryption – so that’s got to be good, right?

What are its alternatives?
There are several alternatives, and several sites comparing them to each other – I’m not going to go into that here, as I honestly haven’t used them. However, I’m going to mention though that I fully intend to try Zend Guard in the near future.

How does it work?
Not going to give you a technical explanation here – think of it as a “plugin” (they call them loaders) that you install on your web server that allows you to run PHP apps that are encrypted with Sourceguardian.

What’s good?
Installation. Installation is an absolute breeze. So much so that you as a developer probably don’t have to worry about compatibility. If you’re a sysadmin installing the Sourceguardian “plugin”, it’s as simple as downloading a version of the Sourceguardian loader that works with your OS/Architecture and adding a couple of lines to Apache’s configuration. Easy. Sourceguardian even gives you this nifty little utility that allows you help detect what loader you need. Very nice.

Another good point is speed. In the application I’m working on, speed is relatively important (Although not mission critical). I compared speeds for my unencrypted files vs my encrypted files, and on average each page took about 0.03 seconds longer to load. That may differ depending on your configuration, but it was an acceptable result for me.

What’s bad?
Well… There’s only a couple of things I’ve noticed so far wrong with the actual program. They’re Minor annoyances, and I think it’s pretty poor that the Sourceguardian team don’t have an FAQ to address this. I like to know what to watch out for BEFORE I deploy to a client (and consequently look like an idiot when things don’t work).

The first is the DIRECTORY_SEPARATOR constant. If you’re writing for cross platform compatibility (read windows and Linux) the directory separator constant is essential. If you’re not, then it’s not a big deal. All it does is tell PHP to use the correct slash. eg: “model\filename.php” will not work nicely on Linux. Using “model” . DIRECTORY_SEPARATOR . “filename.php” makes sure that the file path is valid regardless of the OS you’re using.
Bottom line is that Sourceguadian’s implementation of the constant will always be reflective of the platform that you ENCRYPTED the source on. It’s stupid, and it should have been documented (if it can’t be fixed).

The next is a PHP 5.3 feature. If you’re including files, you might be like me and use the __DIR__ constant. I’m not saying that you should use it, but it is a valid part of PHP 5.3. Again, this doesn’t work. If you use this function in your source, Sourceguardian will reflect the directory that it was encrypted in. Imagine my surprise when I echoed __DIR__ on a Linux system and got the text “C:\encrypted\testapp”. Again, this shouldn’t happen, and if it’s known, it should be in an FAQ somewhere. Fortunately this one is easy to solve – just replace all instances of __DIR__ with dirname(__FILENAME__). Again, it’s not a dealbreaker, but it’s unacceptable that this isn’t documented.

Their GUI application that encrypts (on windows anyway) is also buggy. Even basic features like “rescan this application’s directory for changes” frequently results in the program hanging if the directory has lots of files. Considering the GUI app doesn’t do all that much, this is pretty poor.

The last thing I don’t like about Sourceguardian is the support. Let me be clear – I have contacted them 3 times about 3 separate issues (one of which is outlined above) and I have NEVER received a reply. This is not good.

A colleague of mine also mistakenly bought the wrong OS version of Sourceguardian, but tried to activate it on another platform. The (wrong) platform took his key, promptly expired and left him with nothing. He emailed their support team several times and got no reply. $200 down the drain.

Thoughts:
Overall, Sourceguardian looks good on the surface. It’s cheap in comparison to other products that deliver a similar function set, but it comes with a few “gotchas” that aren’t documented. I still intend to use it in future, but will definitely be giving Zend Guard a look. Although, I’d definitely be a lot more partial to Sourceguardian if it had decent support.

So, a while ago I decided that I wanted to make a JSON-based calendar that felt like a desktop app. I modelled the look off OSX’s iCal, and I was pretty happy with the result.

I’m calling it olal-cal (OSX Look-a-like Calendar). It is licensed under the LGPL (so you can use it in commercial apps if you decide you want to) and available for download HERE. If you’ve used it or like it, leave a comment or send me an email! If you want to see a basic demo (No adding of events allowed, and restricted to one month), you can view it here.

The first section of the README file is below:

Olal-cal is a simple HTML/JQuery calendar that allows you to easily display events in a calendar that
is similar in appearance to the OS X iCal calendar. It is fairly interactive and gives the
look-and-feel of a desktop application.

Olal-cal relies heavily on JSON files. The structure of these JSON files is outlined in both the
provided .php files and in the documentation below.
Olal-cal was designed to work with PHP, but you can easily change this to whatever server-side
scripting language you wish.

olal-cal is not a complete calendaring solution, but rather it allows you to implement your own
backend. olal-cal was designed with a simple calendar database in mind, where each calendar event
has a unique Identifier, and belongs to a uniquely named Calendar (eg. Home or Work).


I’m learning XSLT at the minute, and I found out that there are a lot of ways to get the day of the week from a UTC date, but most of them involve using XSLT 2.0 features, or functions. Unfortunately, Firefox (which I’ve had to use to transform XML docs into XHTML) doesn’t support any of that (yet anyway).

So, I wrote a template that can be included in any XSLT 1.0 document. Later on, a friend showed me that there are a couple of templates already out there that I could have used, but they’re essentially templates that call other templates, and they’re quite long. So… I don’t know if this would be useful to anybody, but I’m going to post it anyway.

<!-- My Template for spitting out day names from utc dates -->
<xsl:template name="get_day_name">
<xsl:param name="utc" />
<xsl:variable name="month" select="number(substring($utc,6,2))" />
<xsl:variable name="year" select="number(substring($utc,1,4))" />
<xsl:variable name="day" select="number(substring($utc,9,2))" />
<xsl:variable name="a" select="floor((14-$month) div 12)" />
<xsl:variable name="y" select="$year - $a" />
<xsl:variable name="m" select="$month + 12*$a - 2" />
<xsl:variable name="result" select="($day + $y + floor($y div 4) - floor($y div 100) + floor($y div 400) + floor((31*$m) div 12) ) mod 7" />

<xsl:if test="$result=0">Sunday</xsl:if>
<xsl:if test="$result=1">Monday</xsl:if>
<xsl:if test="$result=2">Tuesday</xsl:if>
<xsl:if test="$result=3">Wednesday</xsl:if>
<xsl:if test="$result=4">Thursday</xsl:if>
<xsl:if test="$result=5">Friday</xsl:if>
<xsl:if test="$result=6">Saturday</xsl:if>
</xsl:template>

So. Today I spent WAY too long trying to find a Max OS X driver for a cheapo little USB-to-Serial I bought off eBay.

It’s model is HL-340  - it’s a generic little adapter out of China, and after a bit of digging around, I discovered it’s got a PL-2303 chip in it…

Some champions have written a driver for devices with this chip. You can download it at http://osx-pl2303.sourceforge.net/ – Worked OK for me on Snow Leopard 10.6

If you’re looking for Terminal Applications for OSX, there’s some good information here and here on that.

So. My other love in life is Music. A few years ago I very quickly wrote an arrangement of “Don’t know much about love” that was present on a Vince Jones and Grace Knight CD I had lying around – Come in Spinner.

Anyway, I have a band that recently performed at the Merimbula Jazz Festival, and I got a few compliments on the arrangement. It’s not a very common song, and I couldn’t any arrangements suiting my band’s lineup (which is a little unique, I’ll give you that). So… here is a lovely free arrangement I wrote, based more or less of the recording. The piano part is a little lacking (I play piano, and tend to make it up as I go along), and the drum part is a guideline only. Feel free to download it and play it. Leave a comment if you played/liked/hated it.

DKMAL_Score
DKMAL_Vocals
DKMAL_Alto_Sax
DKMAL_Bass
DKMAL_Drums
DKMAL_Piano
DKMAL_Tenor_Sax
DKMAL_Trombone
DKMAL_Trumpet_1
DKMAL_Trumpet_2

We have an automated system set up at work that automatically records programs from TV using TV Scheduler. It’s a fantastic system, but our media-management program (Clickview – which I highly recommend for schools) only accepts videos that have been encoded with DivX/XviD. TV Scheduler records in TS format, so I needed a program that converts TS files automatically to DivX. Traditionally, I’ve used Auto Gordian Knot, which is great for one-off conversions, but not really good for automation as it lacks a command-line interface.

I stumbled upon a really good program that has an excellent command-line interface called StaxRip. It allows you to make templates using a GUI so you can customise the video settings you want with ease, and then use a batch command to batch convert videos. It’s great, and has worked flawlessly for me.

I’ve written a script using AutoIT that scans a remote directory for TS files, moves them over to a local location (presumably a directory on a server that can convert files really fast), converts the TS files to DivX AVI using the “XviD” template, and moves them back. Really, you could use any language, or even use a VBScript. Anyway, here’s the source. Mine also spits out a log file so you can see if it’s working. Of course you’d put it as a scheduled task if you wanted it to run automatically.

scheduled_videncode_nebev

Today I came across a very interesting problem in regard to Group Policy folder redirection in Windows 7. All folder redirection was failing with reason codes similar to the one below:


Application Source: Microsoft-Windows-Folder Redirection
12:12:58 PM
Event ID: 502
Task Category: None
Level:
Error Keywords:
User: username
Computer: computername
Description: Failed to apply policy and redirect folder "Documents" to "\\server\share$\username\". Redirection options=0x9020. The following error occurred: "Failed to build the list of known sub folders".
Error details: "The system cannot find the file specified. "


This was happening for all redirected folders – Start Menu, Documents, Music, Desktop etc etc. I assumed firstly that this was a permissions issue. I checked and rechecked all permissions. I logged on as a user – saw the redirection fail, and tried to access the “failed” directory as that user. The user could access (and write) to the documents directory without any problems. I sort of already guessed this was the case because XP clients weren’t having any problems. I also knew that I was in a bit of trouble because googling this error returs no results (sigh).

I cast my mind back to a couple of days ago and remembered that I approved a bunch of updates that had been piling up (I know, I shouldn’t let them pile up but I don’t often get time to approve them). Anyway, after a LOT of painful update installs (pretty much one at a time – took me and some colleagues 3 hours), I found the update that broke folder redirection: KB980408

Microsoft’s description of this KB is: Install this update to resolve reliability issues with Windows 7 and Server 2008 R2.

Well, that didn’t work. After some careful googling, I found that other people have had problems with this update too. Not the same problem mind you. There was a fix recommended in this forum. I wasn’t sure that it was going to solve my problem, but it did.

The [temporary] solution I used involved the following: Make a reg File with the following in it:

Windows Registry Editor Version 5.00</code>

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{2112AB0A-C86A-4ffe-A368-0DE96E47012E}]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{2112AB0A-C86A-4ffe-A368-0DE96E47012E}\PropertyBag]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{491E922F-5643-4af4-A7EB-4E7A138D8174}]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{491E922F-5643-4af4-A7EB-4E7A138D8174}\PropertyBag]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{7b0db17d-9cd2-4a93-9733-46cc89022e7c}]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{7b0db17d-9cd2-4a93-9733-46cc89022e7c}\PropertyBag]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{A302545D-DEFF-464b-ABE8-61C8648D939B}]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{A302545D-DEFF-464b-ABE8-61C8648D939B}\PropertyBag]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{A990AE9F-A03B-4e80-94BC-9912D7504104}]

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions\{A990AE9F-A03B-4e80-94BC-9912D7504104}\PropertyBag]

Run the reg file. It’s important that you reboot after the fix has been applied. I’ve got a friend who is emailing Microsoft about this issue, and hopefully they’ll release a hotfix or something. I’d be interested to know if anyone else has had similar issues (or fixed it using these steps).

EDIT: A side-effect of this fix is that renaming via Windows Explorer sometimes fails. Still… better than having no folder redirection