May 23 2010

Sloppy Solder Saves Shaver!

I’ve had a Remington Shortcut for quite some time now but lately its been running out of juice after only a few minutes. The blades are in great shape so I thought maybe I could just replace the batteries. In the worst case I’d have fun taking it apart and in the best case I’d have a working shaver again.

One of the original batteries looked a bit corroded around a connector and in hindsight I think this was the main problem. I ended up replacing the generic cells with my favorite Eneloops anyway. Rechargeable and hardly any discharge even over a year of storage. Lovely lovely batteries.

I haven’t soldered in years (and it shows) but I had a lot of fun fixing the shaver. It works great now too. Actually, better. The recharging indicator is once again working and my small tweak to disable the edge clipper mechanism means less resistance on the motor.

Taking apart things to learn how they work is great fun. Sometimes you can even put them back together again. ;)


Apr 15 2010

Add a password reset feature to Halogen eAppraisal

One really important feature missing from Halogen eAppraisal is the ability for users to reset their own passwords.

Seems like such a basic feature but even their friendly support folks confirmed that there was no addon or plan to release the feature in a future version. Weird!

No matter though, let’s make our own.

Investigation

I spent untold amounts of time clawing through unfamiliar Java code. A occasional scrap was enough to forge my determination but nothing really made sense yet. Too many files, too many directories but maybe if I just kept trying…

A-ha!

Hidden deep within the lair of <Tomcat>\webapps\Halogen\WEB-INF\classes\com\halogensoftware\common\security\ is a file called ‘Utility.class’. Inside, a string that resembles the worst regular expression ever created.

^a`Z{b1Y}c2X[d3W]e4V|f5U\g6T:h7S;i8R”j9Q’k0P<l-O>m=N?n~M,o!L.p@K/q#Jr$Is%Ht^Gu&Fv*Ew(Dx)Cy_Bz+A

I was sure this string was used to encrypt the passwords stored in the database but I needed a way to confirm that so…

Using a test account I set the password to the number 1 which was encrypted as the letter Y. Password 11 became Y}. Password 111 became Y}c.

Ah, so simple!

If your password was the ^ symbol it would find it in the string above and then move right one space and choose the letter “a” as your encrypted password. If your password was ^^ then the the first encrypted character would be “a” again but the second one would shift two places to the right and store the ` symbol

Here are a few more example conversions.

  • ^^^ becomes a`Z
  • wT7w becomes (hi)
  • A+z becomes ^^^

Notice that in the last example we’ve simply looped around once we hit the right side of the hash string.

Now that we know how it works let’s build our own utility in ASP that we can use to reset anyone’s password.

The Solution

Besides the obvious DSN string, you’ll want to carefully consider how you validate your users.

The setup I used at work talked to a Human Resources database and would validate no less than three pieces of information before even attempting a reset. I urge you dear reader to do the same.

sID = Request.Form("id")
sPassword = Request.Form("password")

Set oConn = Server.CreateObject("ADODB.Connection")
oConn.Open "DSN String for the Halogen eAppraisal Database"

Set oRS = Server.CreateObject("ADODB.Recordset")
oRS.Open "SELECT TOP 1 * FROM [view-user_info] WHERE username = '" & sID & "'", oConn, 0, 3 'adOpenForwardOnly, adLockOptimistic

If not oRS.EOF then
	sKeyCode = "a`Z{b1Y}c2X[d3W]e4V|f5U\g6T:h7S;i8R""j9Q'k0P<l-O>m=N?n~M,o!L.p@K/q#Jr$Is%Ht^Gu&Fv*Ew(Dx)Cy_Bz+A"
	sKeyCodeLength = Len(sKeyCode)
	x = 1
	sBadChar = 0
	Do until x > Len(sPassword)
		sChar = Mid(sPassword, x, 1)

		If InStr(sKeyCode, sChar) then
			sKeyCodePos = InStr(sKeyCode, sChar) + x
			If sKeyCodePos > sKeyCodeLength then
				'Need to loop around the beginning
				Do until sKeyCodePos <= sKeyCodeLength
					sKeyCodePos = sKeyCodePos - sKeyCodeLength
				loop
			End If
			sEncodeChar = Mid(sKeyCode, sKeyCodePos, 1)
			sEncodePassword = sEncodePassword + sEncodeChar
		Else
			'Could not find a character in sKeyCode
			sBadChar = sBadChar + 1
		End If
		x = x + 1
	loop

	If sBadChar > 0 then
		Response.Write "<p><strong>Unsupported characters were used to try to set the encrypted password. New password was not saved.</strong></p>"
	Else
		oRS("password") = sEncodePassword
		oRS("password_change_date") = NULL
		oRS.Update
		Response.Write "<p>The password for your account " & sID & " has been reset.</p>"
	End If
Else
	Response.Write "<p><strong>A corresponding account for the user " & sID & " does not exist. Please contact support.</strong></p>"
End If

oRS.Close
oConn.Close
Set oRS = nothing
Set oConn = nothing

Questions welcome so feel free to comment below.

See ya later, space cowboy.


Apr 11 2010

HTML5 Audio Loops

One of the neatest things about HTML5 is support for the new <audio> tag. Like <video> it allows you to natively support media in good browsers like Chrome, FireFox, Opera and Safari. Add a touch of JavaScript and a new era of  media applications become possible.

Synthesizers, music trackers and games require seamless audio loops though so we need something a bit simpler for our first foray into HTML5 audio.

Oooh, how about a retro beatbox with individual track adjustments (start/stop/loop/volume) that could be used to build a unique soundscape from many separate instruments. Perfect!

Fantasy can only become reality through hard work so let’s get started with some tests first.

Loop Method 1

Uses the ‘loop’ property.

<audio id="audio_1" controls preload loop>
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.ogg">
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.wav">
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.mp3">
</audio>

Loop Method 2

Uses a JavaScript function to loop when an ‘ended’ event is called.

<audio id="audio_2" controls preload>
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.ogg">
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.wav">
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.mp3">
</audio>
document.getElementById('audio_2').addEventListener('ended', function(){
this.currentTime = 0;
}, false);

Loop Method 3


Uses two JavaScript functions and two audio elements with the same source to alternate playback duties.

<audio id="audio_3" controls preload>
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.ogg">
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.wav">
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.mp3">
</audio>
<audio id="audio_4" controls preload>
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.ogg">
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.wav">
	<source src="/wp-content/uploads/2010/04/html5-audio-loop.mp3">
</audio>
document.getElementById('audio_3').addEventListener('ended', function(){
this.currentTime = 0;
this.pause();
document.getElementById('audio_4').play();
}, false);

document.getElementById('audio_4').addEventListener('ended', function(){
this.currentTime = 0;
this.pause();
document.getElementById('audio_3').play();
}, false);

Browser Support

Tests were done on Windows 7 with Chrome 5.0.342.9 beta, FireFox 3.6.3, Internet Explorer 9.0 Preview, Opera 10.51 and Safari 4.0.5.

Chrome seems to trigger loops before the current sound is completely finished leading to some odd jumpiness. All loop methods are affected.

FireFox doesn’t seem to like the ‘loop’ property of method 1, odd. Method 2 has the slightest of delays between loops and method 3 was actually perfect! I didn’t believe it until verification at the millisecond level with Audacity. Hooray Mozilla!

Internet Explorer 9 doesn’t support the audio tag yet. Hopefully it will before an official release.

Opera performs almost as well as FireFox although there is still a small delay even when using method 3.

Safari seems slow to start playback which is very easy to detect once you hear a loop. All loop methods affected.

Feedback on other browsers/OS compatibility would be very interesting so please feel free to discuss any findings in the comments below.

Final Thoughts

As of right now (April 11, 2010) only FireFox can do a perfect loop by cheating a bit and using two <audio> elements with JavaScript.

So yeah, it’s a bit too early for HTML5 audio loops but don’t let that stop you from creating sound boards, media players and other fun things.

Hopefully with some more optimizations audio support will continue to improve and a HTML5 beatbox fantasy can become reality.

Until then there are plenty of other fun things to play with.

Cheers!