#ifdef

This is a trick worth sharing.

Apple doesn’t supporting exporting the list of devices you use in your adhoc provisioning profiles. But, you might want to export them to share with another developer or import into another team account.

When you look at the devices on the iphone portal, the device IDs are truncated. That prevents you from doing a multiline copy/paste of the data from your browser.

However, if you view the page source, you’ll notice that the entire device ID is actually present in each table row. So, just whack the style and css info. The remaining html table can be imported into a spreadsheet or pasted into a file and converted to a .csv.

Thanks, Josh!

This was really helpful. I was trying to simulate connection failures locally and by applying these Apache config changes and issuing ‘touch tmp/stop.txt’, the app throws returns a 503.

Ah, but you will need to restart Apache, ’sudo apachectl graceful’.

… it’s possible to use mod_rewrite to prevent users from accessing your site during the deployment. Try this in your Apache virtual host configuration file:

[From Nodeta » Blog Archive » Stopping your Rails application with Phusion Passenger]

I’ve been seriously drinking from the firehose for the past few months, but I’m up to take a few breaths and commit to posting more about what I’m up to.

I’ve been fortunate enough to work with some really talented guys and clients doing iPhone and Rails app development. Objective-C was pretty easy to pickup. I call it a mashup of C and Smalltalk. Combine that with Cocoa Touch and you have a really nice development environment for the iPhone. The abstractions are high level enough that you don’t really have to be a mobile or embedded developer to get into it. Just take care to manage memory allocations and you’ll be fine.

Ryan, Josh and James over at YFactorial have done an awesome job with ObjectiveResource. It really makes it easy to quickly bring up applications with iPhone clients and Rails backends. Core Data is probably a fine library, but if you’re communicating with a Rails app, ObjectiveResource is a great way to serialize data without impacting the server development much.

The Ruby and Rails communities are just chock full of brilliant folks and the quality of teaching and training materials is awesome. It makes it a really exciting place to be working right now. I’m having about as much fun with the productivity hacks as I am with the platform itself. That’s been a really nice refresh.

There are a few product releases in the queue for 2009, so I’ll be busy. I hope you’re having as much fun as I am. I really mean that!

A client’s project requires a Java solution to fit their deployment strategy. One specific component of the implementation is an XML-RPC server. Using Groovy would be useful because there is a lot of XML being slung around as parameters. I could go with the Groovy XMLRPCServer, but it does not support SSL.

No problem, I’ll find a Java solution and Groovify it. How about the Apache XML-RPC implementation?. Excellent. However, I need to know that it works in its most basic, i.e. Java form. I’d rather not sandbox up an entire XML-RPC solution just to see how this thing works. Though small, there ought to be a better way than throwaway, experimental code. A nice way to deal with this is to use the published Calculator example with easyb.

The calculator class was unchanged. Here’s the easyb story that combines the xmlrpc server and client sides.

import org.apache.xmlrpc.client.*;
import org.apache.xmlrpc.webserver.*;
import javax.servlet.http.*;

scenario "apache xmlrpc server should work", {

        given "an xmlrpc servlet",{
          def sum = 0
          servlet = new XmlRpcServlet()
        }

        and "a servlet webserver", {
          webServer = new ServletWebServer(servlet, 4000)
          webServer.start()
        }

        when "the calculator.add method is invoked by an xmlrpc client", {
          config = new XmlRpcClientConfigImpl()
          config.setServerURL(new URL("http://127.0.0.1:4000/"))

          client = new XmlRpcClient()
          client.setConfig(config)

          sum = client.execute("Calculator.add", [33, 9])
        }

        then "the sum should be correct", {
          sum.shouldEqual 42
        }

        and "stop the webServer", {
          webServer.shutdown()
        }
}

Also, very nice how easyb allows some relaxation of the strict Java syntax in the xmlrpc client section. That starts to suggest what a Groovy subclass might look like. Next, a git commit to capture this working example in a readable form for the lifetime of the project.

There’s been a long running conversation about the relationship between static typing and unit testing. As early as 2003, Bob Martin found that unit tests reduce dependence on type safety. Around the same time Bruce Eckel argued that compilation is simply one test for correctness; and that code needs to pass all the tests that define correctness of your program. More recently, Stuart Halloway claims ‘In 5 years, we’ll view compilation as the weakest form of unit testing‘. Are you spotting a trend here?

This all bubbled up again for me recently on an embedded project I’m working on to optimize security policy lookups on a multicore security platform. The task was to optimize performance of the vendor’s C reference implementation. Policy insertion used a simple, but unscalable single linked list having O(n) performance. Of course, the code comes without tests of any kind, so how does one know that the optimization changes don’t break basic functionality?

Obviously, the best thing to do in this situation is to write tests for existing behavior so that as the API is refactored and reimplemented, the tests find any new logic errors. I got payback even before the optimization work got started. The linked list insert (implemented thousands of times by thousands of developers) had a bug in it. Policies that were supposed to be stored in priority order after insert were off by one.

Definition: Reference System n. A software implementation provided by hardware vendors to demonstrate programming of a target device; not intended for deployment in end user products. (2) A software implementation provided by hardware vendors that is for the most part, directly inserted into the systems of end users.

This really isn’t a rant about reference code, it’s about defensive testing and the fact that writing tests are not just for dynamic languages. The Java community is mostly on board with this, but it seems to have gotten slower adoption by the C variant world. So c’mon embedded developers. Let’s stop pretending that the type safety testing by our compilers is good enough.

Here’s one option. I really like check as a unit test tool for C. It has a niced xUnit flavor and ought to be in everyone’s toolbox.

START_TEST(it_should_insert_in priority_order)
{
    Policy* policy5 = alloc_policy_with_priority(5);
    Policy* policy6 = alloc_policy_with_priority(6);
    insert_policy(policy5);
    insert_policy(policy6);
    fail_if(policy_find(policy5) == NULL);
    fail_if(policy_find(policy6) == NULL);
    fail_unless(policy_first() == policy5);
}
END_TEST

And if you happen to be implementing reference code, a set of tests for your API would be a welcome addition to your product; not a program to exercise the hardware, but tests that verify and document the behavior of your APIs. It will reduce the bulk of documentation that needs to be provided to end users and may allow you to remove those weasel words, “not intended for deployment”.

Exactly who hired the B players then?

“A players hire A players,” he said. “B players hire C players. Do you get it?”

[From Folklore.org: Macintosh Stories: How to Hire Insanely Great Employees]

It turns out that some changes to the Linux kernel — Ubuntu 8.04 uses Linux 2.6.24 — have introduced some issues that make running Ubuntu in a VMWare virtual machine difficult. Ubuntu will install just fine, but you won’t have access to VMWare Tools, which provides some nice features like shared folders and clipboard syncing.

[From Ubuntu 8.04 Causes Problems With VMWare Tools, Open Source to the Rescue | Compiler from Wired.com]

It isn’t just VMWare. Mac Parallels has likewise bitten me and many others judging by the considerable forum angst. My peeps have been telling me to cutover to Fusion. I’d say if VMWare fixes their tools issues before Parallels, I’ll consider it.

I’m intrigued by the number of casual conversations lately that have touched on the theme of embracing constraints as a gateway to creative solutions. Are artists as constraint infected as their tech world brethren? There seems to be an awareness that unrestricted composition is a daunting task and that introducing constraints can get you to the downbeat.

Instead, someone says, “Write me a piece of music using only a flute, saw, and this broken toy piano. You can only use the notes D, E, and B – but never all 3 at the same time. It has to be in 3/4 time, start quiet, get loud, then get quiet by the end. Go!”

Aha! Now you’re cookin’!

[From Restrictions will set you free | Derek Sivers]

Recently, I’m hearing folks talk about their timed dashes. Duff says Nokahuna was a 48 hour burst effort and Nathaniel is crafting his weekly schedule to create artificial calendar constraints.

There, I did it. A blog post constrained to three paragraphs, a quote plus six links that associate 37signals with a broken toy piano. How’s that for a creative solution?

Freedom’s author is none other than Fred Stutzman, co-founder of claimid and local ibiblio dude. Now, can I get a weekend version to lock the keyboard…

Freedom is an application that disables wireless and ethernet networking on an Apple computer for up to three hours at a time. Freedom will free you from the distractions of the internet, allowing you time to code, write, or create. At the end of your selected offline period, Freedom re-enables your network, restoring everything as normal.

[From Freedom, OS X Networking Freedom Software]