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Archive for December, 2008

Grooveshark just got more album art

20 Dec

I’m still getting used to not calling it “Grooveshark Lite.” For those who haven’t noticed, it’s been re-branded as just plain old Grooveshark. On one hand, it’s an awesome testament to just how successful the project has been. On the other hand, it’s a little harder to talk about it now. I can take credit for a large portion of Grooveshark Lite, but I can’t really take credit for a large portion of Grooveshark; Grooveshark represents so much more to me than just our player.

Anyway, thanks to a nifty little Perl script that Travis helpfully rewrote for me to be more compatible with our hosting environment, I was able to grab art for an extra 57,000 or so albums that we had not been able to get from our partners previously. What does this mean for you, the user? You should see less of this:

in your queue and song info panels, and more real album art, like this:

What’s the magic trick? Simple, the script looks for art embedded inside the mp3s that we have associated with an album, guesses at which piece of art is best. It’s surprising how many mp3s actually have art embedded in them.

Hopefully this will make Grooveshark more usable. I know I find it very frustrating when I have a large queue filled mostly with the default album art; it’s very hard to tell where you are when everything looks the same.

 
 

How I Broke Grooveshark Lite – update

10 Dec

After some poking around and scratching our heads a bit, Katy and I were able to discover the source of the problem. Turns out what I hit is a compiler/language/optimization bug. Katy has more about it here, including the generic code we were able to distill it down to in order to cause the breakage.

We thought it was a permutation of this bug which is fixed, but apparently this is a new one, so we are going to file it.

I find it a bit disturbing that the related bug was brought to their attention in 2006 and the limited fix was only released to the general public 2 months ago. Over two years to release a fix to a language bug?!? From the comments on the bug, they do not seem to take it very seriously:

Fixed in the avmplus mainline. I’d suggest a 10.0 target date, since the change will need soaking time, there is a work-around and it is rare to encounter this problem.

Change 243008 by [email protected] on 2006/09/08 12:37:23

Severity: important
Summary: Verifier error bugfix

Detailed Description:

An optimization in the verifier allows us to avoid checking for null in various circumstances. Unfortunately, we were being a little too aggressive and we missed a case. If a block is a target of a backwards branch then we need to assume upon entry of the block that no check has been performed.

The other way to fix this would be to emit null checks just prior to the branch for any values that have notNull true, but this could also create a bunch of unnecessary checks.

Aren’t obscure language bugs the absolute worst kind to have? In my case, it first went undetected because it didn’t trigger any errors/warnings with the debug version of flash (although our sample condensed code does), and then it was extremely difficult to track down because THE CODE WAS CORRECT, and when the production version of flash fails, it does so silently.

 

How I broke Grooveshark Lite

07 Dec

I am a PHP and MySQL developer, primarily, and my main responsibility is the server-side Grooveshark Lite components. A couple of days ago I got to write my first ever Actionscript for the Grooveshark Lite front end; an ad rotator to handle ads more statefully and therefore more intelligently.

First I ran into a horrible language bug that causes a nasty runtime crash wherein Flash complains that it can’t resolve a class with itself. I wasn’t doing any weird voodoo with class definitions and Katy, our primary Flex developer, couldn’t find anything wrong with my code, but rewrote some of it anyway. Poof, problem fixed.

Everything looked fine so we thought we were ready to launch. So we did last night. Skyler complained that album art wasn’t loading for him, but he had just reinstalled 64 bit flash on 64 bit Linux, and he’s had weird problems with that before. We were unable to reproduce, attributed it to Flash+Linux weirdness and ignored the issue. Today, more people complained about it. We were not able to reproduce. Eventually I figured out that the bug was only affecting non-debug versions of Flash, but I couldn’t imagine what would be causing album art to not display: my code has nothing to do with displaying images, and I could see in Firebug that the art was being fetched properly, nothing was wrong with the headers, etc.. But it definitely worked fine in the debug version of Flash. Katy looked at it, and through process of elimination was able to determine that the problem was somewhere in my code, but couldn’t tell where exactly. Everything looked valid, and from the perspective of the debug version of Flash, it was, but my code wasn’t very “actionscripty” – because I’m used to writing PHP and haven’t had any sort of training on actionscript beyond looking at existing code and occasionally looking at a language reference book. Katy couldn’t figure out what was wrong with my code, so she rewrote it, and now everything is back to normal again.

I don’t yet know what part of my code was causing the problem, so on Monday I plan to reinstate my code, downgrade to the non-debug version of flash, and figure out what the heck is causing the bug. My instinct tells me that it’s probably a combination of an optimization setting in non-debug Flash combined with my use of Actionscript in a way that is technically valid but that no Actionscript coder would ever normally use it. For example, Katy says I was using a generic Object as a Dictionary, because I was actually trying to replicate associative arrays in PHP, I didn’t know about the Dictionary object, and when I had asked previously how to do that, I was told to use an Object. :P

The good news is that I don’t think many people outside the company paid much attention to this bug. They were too busy being excited about the new features that Katy introduced: broadcast to twitter, broadcast to facebook, and deep linking support: When you “byte” a song (open the info panel), your URL bar changes. You can simply copy the URL to share with a friend, *and* clicking back and forward work, so if you want to go from the song you opened back to the playlist you found it on, just click back in your browser. Freaky, but it works.

 
 

If everything is top priority, then nothing is top priority

05 Dec

One of my heroes, Raymond Chen, writes about how he dealt with the annoying habit of management to give conflicting things top priority (here).

In the past we’ve had the same problems with management at Grooveshark. I was not clever/important enough to single handedly shape the behavior of management, however, so the end result here was that I would pick from the “top priority” list, which ended up being a list of every single thing that needed to be done, ever, and just do the ones that most interested me.

Grooveshark management is taking a new approach now, and we lowly devs are now more empowered to decide what our priorities should be. Essentially, it’s a lot like the old system, but lest frustrating for both parties, because there’s no pretense. :)