Monday, June 20, 2011

Xcode: iPhone or iPad application code sign error

This morning on a re-imaged OSX machine I attempted to compile an ipad application and I was rewarded with the error below.

codesign error: code signing identity 'iphone developer' does not match any code-signing certificate in your keychain. once added to the keychain, touch a file or clean the project to continue.

I was puzzled. I'd already made a developer certificate request to Apple, had it signed and installed it in my Keychain Access, I'd also downloaded and installed the Apple Worldwide Developer Relations Certification Authority certificate. I'd installed the required development profile that matched my ipad device Unique Identifier, my personal developer certificate and the application I am developing but still, every time I hit build it gave me a code sign error. I didn't get it.

At some point it a suspicion formed. In my Keychain Access I noticed my certificates where installed in the System keychain. I'm not even sure why they got installed there, I don't think I did it explicitly.

I moved my certificates to the login keychain which I assume belongs to the logged in user on OSX (i.e. myself). Attempting to re-compile the source code of my ipad project yield a positive result. Moving the certificates to the login keychain seemed to work! So I post my small solution here today in the hope that somebody else might benefit.

Thursday, June 16, 2011

Oh Magic Mouse! How do I hate thee.

While Apple have, over the years, had many design wins, there have also been some unfortunate design failures. The design failure that happens to torment me on a daily basis is Apple's Magic Mouse. Admittedly this bluetooth mouse is quite responsive and accurate as a pointing device, but it's the mouse's more esoteric features which are pimped as a unique selling point that really irk me. Namely the "multi touch surface", especially when used for scrolling.

The multi touch surface is just far too sensitive and easily triggered when you're just using the mouse to move the pointer. As a coder I spend most of my day in text editors. I'm always accidentally scrolling the text window up and down; even worse - when using the command key and accidentally scrolling, the most common behaviour is to zoom. Not helpful. Give me an old fashioned scroll wheel any day. Likewise in a 3D modelling package I often find myself accidentally zooming.

It's back to the simple $20 mouse for me. On a similar note I have a theory about the efficacy of mice based on price. The sweet spot on mouse functionality is definitely around the $20 mark. Pay more and "features" get in the way. Pay less and accuracy, reliability and that comforting solid hand weight quality possessed by a good mouse are absent.

Tuesday, June 14, 2011

Schedule Mac OSX Update(s) for Offpeak Download using launchd

In order to schedule you Mac OSX software update to run in Offpeak time you can use the launchd system scheduler in order to to accomplish this. On most Unix systems (including cousins and derivates like Mac OSX) you would use cron. While cron is still available on Mac OSX, Apple have provided an Apple centric way of doing the same the work in the form of launchd.

Launchd has a command line control interface that goes by the name of launchctl, which will be using in conjuction with our xml editing skills to achieve this goal.

The software update tool normally accessible via the Apple Menu (Apple->Software Update to be exact) has a command line parallel "softwareupdate". We can use this command line version to run the update in the background at suitably early hour of the morning.

First of all lets construct a launchd configuration file to setup this job for us. In the common Mac OSX fashion this is achieved via the use of a property list file. Essentially an XML file with the information we want in it. A suitable .plist file for this work is listed below. Save this text into a file name like com.krugerheavyindustries.SoftwareUpdate.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN""">
<plist version="1.0">

This particular property list configuration file schedules the software update to run at 2 am every morning.

Now because this task is a system related task we need it to be run by the superuser in order to have sufficient privileges for this to happen. As this is the case I'd be storing this configuration file in /Library/LaunchDaemon

Next we load the configuration file in order to schedule it. We can accomplish this with superuser privileges by the doing the following:

sudo launchctrl load /Library/LaunchDaemon/com.krugerheavyindustries.SoftwareUpdate.plist

We can view the task is loaded and ready to roll by issuing:

sudo launchctl list | grep SoftwareUpdate

You should see the task there, if not, you might have a problem.

The task will run every period you specified until you unload it (or reboot - we did not specify it should load itself).

You can unload the task using the command:

sudo launchctl unload /Library/LaunchDaemon/com.krugerheavyindustries.SoftwareUpdate.plist

On a typically configured Mac, it will be setup to go to sleep if left on for a period of time. Obviously this will affect the running of your scheduled task. In order to make sure you schedule task will run I would schedule your machine to wakeup 5 minutes before the scheduled task is due to run. In this case at 1:55 AM. This just gives subsystems like WiFi time to reconnect to the wireless router.

Sleep scheduling for wake up is done via Apple->System Preferences->Energy Saver->Schedule->Start or Wakeup

When you come back to your system in the morning you should find your software updates ready to install. Replacing the keyword "--download" with "--install" in the property list file above you can get your updates to install (not just download) overnight also.