Author Archives: lantean

Back to BitTorrent

Well… after MegaUpload was shut down, it’s been a hell of a nightmare to find a working filesharing service. Everyone is sooo afraid of the MPAA and RIAA, that they’re just closing the door. So… it’s time to get back to our roots.

YEAH!. I’m talking about P2P networks. I used to be a huge fan of BitTorrent, in the good old days where MegaUpload wasn’t even technically possible. It is in fact thanks to BitTorrent protocol that The Pirate Bay is still operative. Magnet links are, as far as i know, legal. Nobody can punish you for posting magnet links. In the end, it’s a GUID, right?.

So… i had to get back to BitTorrent. That was the easiest way to stop searching files that are just not there. The big question is… what is the best OSX Client for BitTorrent?.

Well, i’d like to recommend this one:

It’s called Transmission. Just click on the link, and get it for free. There are few tools that help you automate the download of torrents. I’ll post some of them in the next couple of days. Stay in sync!

 

Buenos Aires Places: La Viruta

After writing so much about iOS… Apps…. and other geeky stuff, i though it would be a good idea to write a little about one of the greatest places to visit… (whenever) you step by Buenos Aires.

Tango is one of the greatest assets that Argentina has. It’s an old fashioned musical genre. But let me tell you something you may not know. Dancing tango, actually, is one of the most fun things i’ve don in the past year (or so). It can get pretty technical, tricky, and difficult.

It is said that after a year of practice you actually get to grasp a little bit about this dance. There are many many places to watch tango (or even take lessons). But there is a particular place that has all the lights on. Yeah, i’m talking about La Viruta.

You can learn how to dance Rock’n Roll, Salsa, Tango, and even Milonga. They have a restaurant + bar, and i dare to say that it’s more fun than any other disco you might get to know.

I know exactly what you’re thinking. ‘This guy is oooold’. No. I’m not!.

NSMutableSet: Filtering Duplicate Elements

Suppose that your app has X amount cached objects. And suppose that there is a slight chance that.. since the backend doesn´t actually know what it is exactly that you have cached (and what you don´t have cached), it might send duplicates.

So… what do we do?. Shall we write a for routine checking dupes?. No way. There is a far more performant way to achieve this, and it requires less lines of code.

Steps…

  • Implement your own ‘isEquals’ and ‘hash’ methods, in your model object. For instance…
- (BOOL)isEqual:(id)object
{
    SomeClass* secondObject = (SomeClass*)object;
    return ([secondObject isKindOfClass:[self class]] && 
            [[secondObject id] isEqual:[self id]]);
}

- (NSUInteger)hash 
{
    return [_id hash];
}
  • Simply instantiate a NSMutableSet and add the cached objects plus the objects retrieved from the backend. If the set already has an object for any given ID, and you attempt to insert a new one… but with the same id, it´ll just not work.

So… no more filtering things by hand. NextSTEP’s code will do the trick, from now on!

Grand Central Dispatch: Perform Block After Delay

We have seen in a previous post the proper way to write a singleton, with the help of our good friend Grand Central Dispatch.

In this opportunity, i´d like to share a goodie i´ve learnt few days ago. I suppose many of you had problems with the following scenario. You have to perform a task, which is time consuming, and you need to place, onscreen, an Activity Indicator.

Although the Activity Indicator performs the animation on its own thread, you need to “spare some time” in the main thread for it to begin working. I mean… you can execute [indicator startAnimating] right away. But… if you don´t release the main thread, even for a short moment, surprise!. The spinner won´t work.

So… the common solution is to split that method into two parts, and execute ‘performSelector: withObject: afterDelay:’. That´s where GCD comes in.
We can do the exact same thing… but with blocks!!. That´s SO MUCH COOL…!

dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW,
                                        0.1f * NSEC_PER_SEC);

dispatch_after(popTime, dispatch_get_main_queue(), ^(void)
{
     // ...  Your code
});

Note: The delay, in this example, is of about 0.1 seconds.

OSX iStats

Apple did a pretty good job with OSX. You buy a new mac… and you get almost everything you need, ‘for free’. Any mac comes with iPhoto preinstalled, Mail, Calendar, Safari and even Garage Band. Basically it covers everything an average user needs to do.

There are really really few weak spots to OSX. I dare to say that… one of the few things OSX lacks is a nice widget to check out things such as the download speed… cpu load and temperature and even uptime. Good news is that there is a nice company called iSlayer, that has a reaaaaally cool Dashboard widget named ‘iStat‘ , which does exactly that.

It’s free… so you definitely don’t have an excuse not to download it. It has two modes: horizontal and vertical. You can tweak which indicators you want (and which ones you don’t want). Plus.. there is an iOS version, too. Go check it out!