posts by Jehiah Czebotar

2012 Personal Annual Report

jehiah@gmail.com (Jehiah Czebotar) — Mon, 07 Jan 2013 11:00:00 GMT

$ cat data/2012/* | graph > http://jehiah.cz/one-two

2011 Personal Annual Report

jehiah@gmail.com (Jehiah Czebotar) — Tue, 10 Jan 2012 11:30:00 GMT

$ cat 2011 | summarize | graph > http://jehiah.cz/one-one

Auto-incrementing build numbers in Xcode

jehiah@gmail.com (Jehiah Czebotar) — Wed, 07 Dec 2011 10:30:00 GMT

It's a pain to build project in Xcode only to find out later that you forgot to update the build number.

I've used various techniques to accomplish this in the past, and I'm quite happy with this approach. Essentially, at build time, it uses PlistBuddy (which i had never heard of before) to get the build number out of your Info.plist file, update it, and re-set it in the Info.plist

Under each target you want to auto-increment the build number, at the bottom select Add Build Phase and select Add Run Script.

In the contents of the script copy the source code from below, updating the correct path to your Info.plist file.

Next, re-order the Run Script phase so that it happens as the second step. You want to make sure that the post-incremented value is what is actually included in the application so you need to run this first.

Enabling Transliteration for Amharic in Gmail

jehiah@gmail.com (Jehiah Czebotar) — Tue, 06 Dec 2011 10:30:00 GMT

Transliteration is a way to type phonetic english to spell out sounds of words in a foreign language, and have the english characters translated into the correct characters from another language.

Google has great transliteration support in gmail and it's really easy to turn on.

under Mail Settings, in General the top grouping is Language. Select the Show All language options option, which will reveal the transliteration settings

After doing that you will have a checkbox to enable transliteration

Now when composing new messages in rich-text format, there is an icon to turn on transliteration.

You will need to have fonts installed that show amharic characters. This Wikipedia Article gives advise for installing Ethiopic fonts. I use Abyssinica SIL.

Using Chameleon UIKit to build an iOS app for OSX

jehiah@gmail.com (Jehiah Czebotar) — Mon, 05 Dec 2011 10:30:00 GMT

UIKit is an amazing piece of work, and it lowers the bar for iOS applications tremendously, which is attested to by the number of applications on the iOS App Store.

Chameleon (http://chameleonproject.org/) is a port of Apple's UIKit to the Mac OS X. This means it's designed as a drop in replacement framework which you can build against for OSX Applications. It's been developed and used for Twitterrific by The Iconfactory, but the source is up on github https://github.com/BigZaphod/Chameleon

Since then a number of other people have contributed to it helping to finish features. One challenge that I've had in getting started with it, is simply not having as many references as I would for iOS development.

This is meant to be a guide to get up and running with a simple UIViewController application on OSX.

First get a copy of Chameleon

cd projects
git clone git://github.com/BigZaphod/Chameleon.git

Next start a new application, we will call it TestUIViewController

Open up Xcode, select File→New→New Project. Then under Mac OS X select Cocoa Application. (I've un-checked ARC counting). When prompted for a directory to create the new project in, select the projects directory above.

From finder drag UIKit.xcodeproj from projects/Chameleon/UIKit directly inside of the TestUIViewController project

Next add UIKit.framework as a linked framework under TestUIViewController Summary.

Execution for an OSX application typically starts at the ApplicationDelegate.m We need to add a ChameleonAppDelegate.m which will load the UIKit components.

in AppDelegate.h should end up like this

in AppDelegate.m should look like this

Add a ChameleonAppDelegate.h

Add ChameleonAppDelegate.m

open up MainMenu.xib and add a CustomView inside of the existing View, and change the class for it to UIKitView. Connect the chameleonNSView outlet from App Delegate to the UIKitView instance just added.

Create a TestUIViewController Class. File→New→New File and select iOS→Cocoa Touch→UIViewController Subclass named TestUIViewController.

At this point in time, you can begin to write "normal" iOS code to load UI elements in viewDidLoad. Something simple might be to just change the window background color self.view.backgroundColor = [UIColor lightGrayColor], or allocating a UIButton and adding it to the view with [self.view addSubview:button]

Mini iOS Developer Guide

jehiah@gmail.com (Jehiah Czebotar) — Tue, 16 Aug 2011 10:30:00 GMT

As I've been learning Amharic I've been simultaneously learning ObjectiveC and writing my own language-learning application Amharic Pocket Guide. While both are going well, and I wanted to share a few things I've found helpful in iOS Development.

Metrics

If you have seen my Personal Annual Report then it's no surprise that I like data. When it comes to iPhone Applications, I rely on Flurry to give me information about session length, and how certain application features are being used. Knowing how long people are using the "Quiz" in Amharic Pocket Guide has been helpful in learning how to improve it. Flurry also proves it's weight in gold when it comes to tracking down crashes or other unexpected events in your application.

While iTunes Connect has improved over the years (and their mobile site has as well), the best source for sales metrics is App Annie. They will download your sales reports for you each day, and track app store rankings and reviews, which is more information than apple provides.

The one thing that iTunes Connect Mobile is perfect for is for getting push notifications on application state changes. There is nothing better than knowing the exact instant your application is Approved, and there is nothing worse than knowing the exact instant your application is Rejected.

Support

Every developer has a love/hate relationship with AppStore Reviews. Developers love them because good reviews can really promote an application, unfortunately misguided reviews can hurt an application far more, and there is no direct way for a developer to respond. If you don't have a good channel for users to contact you, then user issues end up in AppStore Reviews.

I've found the following approach good at helping to solve this.

1) Make sure there is a prominent "Report a Problem" or "Contact Support" button in the application. Typically I add a button that just pre-populates an email to a support address. This small detail can head off users that are confused or would otherwise need to vent in an AppStore Review.

2) Use a library like iRate to help prompt regular users to write a review. It's not worth pestering happy users, but you should encourage them to write a review.

3) Make an application website, link it from the App Store, and from inside the app, and have a way there to contact you.

I mentioned above that App Annie does a good job of pulling in reviews, but if you need something more comprehensive, there are scripts available to scrape the reviews yourself.

Cracked Apps

It's a fact of life (for now) that applications will be cracked and installed for free on jailbroken devices. One way to treat this is as an extended trial. I've seen it happen that if you can shut off old versions after releasing a new one, and you prompt users to update that many will (almost 20%) will just purchase the new version from the AppStore because they are not able to upgrade. iVersion is a library that can help with the code to check if a newer version is available, and prompt the user to update.

Useful Code

There are a bunch of things I find myself using regularly when doing ObjectiveC. I no longer know how I found some of them but here are the things I use:

fmdb - a sqlite wrapper
SBJson - yes iOS5 finally supports json natively
Google Toolbox for Mac - has some good generic methods like (NSString*)gtm_stringByEscapingForURLArgument
UIApplication-Network.h - network availability wrapper
Glyphish - great icons
lineform - for making vector graphics

LRU Cache in C with uthash

jehiah@gmail.com (Jehiah Czebotar) — Mon, 04 Apr 2011 14:30:00 GMT

One of the appeals to higher level languages is that hash tables are easy to use. While they might be easy to use, they often come with significant costs

uthash is a well designed and well implemented hash table library written in 2006 by Troy D Hanson (@troydhanson) that brings the ease of hash tables to the speed of C.

I've done a few things with it at bit.ly and I'm excited about how easy it is to use. One good example is how to code an in-memory LRU cache in less than 50 lines of C code

Data Processing @ bit.ly

jehiah@gmail.com (Jehiah Czebotar) — Fri, 25 Mar 2011 13:00:00 GMT

At POSSCON 2011 I gave a talk titled "Data Processing @ bit.ly" in which I shared about some of the open source tools we have written at bit.ly, and the approaches we use in data processing.

Much of this talk covers 3 core applications we have developed @bitly: sortdb, simplequeue, and pubsub; all of which can be found on github http://github.com/bitly/simplehttp

Application Settings

jehiah@gmail.com (Jehiah Czebotar) — Tue, 08 Mar 2011 13:05:00 GMT

Here is a sneak peak into the application settings file format we use at bit.ly.

The idea behind this settings file format, is that it should completely incapsulate all of the "where" information. The information about "where" an application is running, "where" data is stored, and "where" it connects to for remote resources should only exist in this file. (it can also be an effective spot to put default values that are set once and used consistently for each environment.)

One popular approach to settings files is to make a single config file, and run applications with --config-file flags pointed to different files depending on the location. The issue I have with that approach is that time and time again when new features are added, new settings only get added to the development config file, and not the production config file. I have found that using a --environment flag and putting the settings for all environments in a single file resolves that issue.

Specifying settings in a python file gives some useful flexibility as well. For example, we use a randomize wrapper that at returns a random setting each time it is requested. This makes for a very easy, simple and efficient way to distribute load across several remote endpoints.

Shell Script Args Parsing

jehiah@gmail.com (Jehiah Czebotar) — Fri, 04 Mar 2011 12:18:00 GMT

At bit.ly we find that having a good way to specify command line arguments goes a long way to writing self-documenting code. We use tornado.options for our python scripts because it helps simplify the way command line arguments are specified.

We realized there was a need to do something similar with our shell scripts that we use to automate system tasks, and @lintzston helped come up with this pattern which is awesome for it's simplicity, and how clean shell script the code reads. (if you have done any shell scripting, you know that readable shell scripts are elusive.)