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Conferencia Rails

2010-11-01T21:54:00Z

I'll be speaking at Conferencia Rails this week. Looking forward to meeting some Rails folks from Spain.

Also, I'll finally be releasing one of my pet projects as an open source component on GitHub. Check there this weekend, and let me know what you think.

Full outer join pain

2010-09-30T06:00:00Z

I was struggling with a custom SQL query I had to write. The "first pass" at this functionality, just using my Rails models and predefined associations came at a cost of M x N queries. I figured I could get that down to 2 queries, which is better, right? Of course, it took me the better part of two days (many interruptions, not conducive to concentration) to get it right.

After a lot of trial and error, I knew that one part of my query involved a full outer join on two of the three tables. This was only required for 2 subsets of data, so it wasn't as huge a performance issue as you might think. The problem was that the two subsets of data I had to join had no common columns.

Sadly, it appears that no one out there who has solved this problem has blogged or written an article about it. Or, if they have, it's hidden in sites like "Experts Exchange" where you have to sign up and/or pay to see the results. So, here is my answer, to this part of the problem that I solved.

Assuming you have table (or subquery) w and another table (or subquery) s, you can do something like this: with w1 as ( select w.*, 1 as match from w ), s1 as ( select s.*, 1 as match from s ) select .... from w1 full outer join s1 on ( w1.match = s1.match )

Note that the ... part is where you have to select all the columns by name, because w1.*, s1.* would result in an ambiguous (and unnecessary) column "match".

I was using Oracle. I know that SQLServer also supports the "with" clause. If you know how to restructure this to work in MySQL, or any other common database, please do reply in the comments for the edification of all. And, of course, if there is some other magical way to accomplish this type of full outer join without my hack, please comment as well.

WNDXcasts launch

2010-09-17T15:15:00Z

After taking the plunge with the inaugural Year of Hustle Launch Class, I've procrastinated long enough (my problem, not the class) with my own product launch, and am finally announcing the the official launch of WNDXcasts - Mobile Web Development for regular web creators.

So, what's this all about? After being a smart-phone owner throughout the initial phases of the landslide rush to mobile, I know exactly the kinds of problems people experience with visiting websites using their mobile phones. I see those problems personally just about every day. As a developer for many years, and a web developer more recently, I also know exactly what is involved in fixing most of those problems. Some of it is so drop-dead easy that most website/web application creators would be embarrassed to think that they could have improved their customers' experiences so quickly. Other issues just require a little more work, but it's still not that difficult. And, at last we have the problems where you really need to dig in, and rewrite. I aim to teach people how to do all that.

As you probably know, if you follow my blog, I'm not much of a writer. I try, but writing isn't really my thing. So, instead of writing about all this stuff, I'm creating screen-casts. Videos that you can sit down and watch, following along with real examples and real source code, and immediately apply to your own website or web application.

If that sounds like something you'd be interested in, go to my WNDXcasts website now, and sign up. Everyone who signs up early will get extra special discounts when the first of the screen-casts becomes available in October.

config.gem 'ruby-ole'

2010-06-22T21:25:00Z

This had me screwed up for hours, trying to figure out why the ruby-ole gem was coming up as "not installed" but then it still worked. You need to specify a :lib for it.


config.gem "ruby-ole", :lib => 'ole/file_system', :version => "1.2.10.1"

Gem developers, PLEASE, if there is anything special/nonstandard about using your gem, PLEASE, mention in prominently in the documentation. I don't think that's too much to ask.

Snow Leopard bites me on the a$$ again

2009-12-03T22:02:00Z

Twice, actually.

First, there was the, I think, Ruby 1.8.7 upgrade. Suddenly, my home-grown acts_as_my_thing plugin stops working. The classes with "acts_as_my_thing" crash and burn when loading, saying that "acts_as_my_thing" doesn't exist. Crap. Now what?

Eventually I managed to find the proper incantation. I have an abstract super class for a bunch of my models. It's called LabRecord. In the file that defines my "acts_as_my_thing", I had:
LabRecord.class_eval do include Lti::Acts::MyThing end

I think there is a class-loading chicken-and-egg problem going on, so after trying a bunch of stuff like moving around "requires" in the environment.rb file, I eventually decided that I was "doin it rong", and did this instead:
class LabRecord < ActiveRecord::Base include Lti::Acts::MyThing ...

But, that wasn't the end of my day. I did say twice, didn't I? A little while later I was diddling around with svn in my Rails project, and then BOOM. 3rdRail/Subclipse couldn't read my workspace anymore:
Unsupported working copy format svn: This client is too old to work with working copy '/Users/lori/Documents/workspaces/labrador/dev2'. You need to get a newer Subversion client, or to downgrade this working copy. See http://subversion.tigris.org/faq.html#working-copy-format-change for details. I'm too tired for this shit. Sigh. At least if you follow the link, you can download the Python script which will convert your Subversion workspace back to 1.5 (Snow Leopard has SVN 1.6), and get back to it.

Interface Builder hates me - PragProWriMo

2009-11-01T21:30:00Z

Since I've already tried the write-a-book thing before, and I know I suck at it, I'm opting for the "blog entry a day" thing... which actually means more like "blog entry a week". I know that sounds bad, but when you consider how often I've been blogging, it's a vast improvement, so...

To get down to it, maybe it's more like I hate Interface Builder... but not really. It's just that I have not yet "become one" with my tool, and we have these little spats from time to time.

I've been fighting with an Array Controller in IB, because it has no bindings listed. If you know IB and Array Controllers, you will know why that is wrong/bad. I can't bind any content into my array, and that's a big problem. I finally noticed that the icon for my bad array controller didn't look like the icon for a different, working array controller. This was a key breakthrough. And I finally figured out what I did wrong. When I added the array controller to my XIB file, I dragged in a plain old Object, and then changed the class to be my custom NoiseArrayController. That was it. What I shoulda done - drag in a generic ArrayController object, and then change IT to be my custom class.

Simple error. Hours of frustration. So, if an Array Controller in your XIB file doesn't have any bindings, maybe you did what I did. You have to get rid of it and start over with the correct base NSArrayController. Then you'll be rockin. Sigh.

Pulling out your Mac app version number

2009-09-17T05:14:00Z

File this one under useful snippets for Mac Cocoa development. How to extract the application version number out of your app's info.plist file.


[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"];

Creating application support files on the Mac

2009-09-05T15:04:00Z

You are writing a Mac Cocoa application, and you know you want to store your user specific application support files in a predictable location, like ~/Library/Application Support/<Application>/. So... how exactly do we do that?

Once again, Google to the rescue, and we find the answer at Cocoa Dev Central. This will not only construct the file name for you, but it will create the directory if it doesn't exist, too.


- (NSString *) pathForDataFile { 
    NSFileManager *fileManager = [NSFileManager defaultManager]; 

    NSString *folder = @"~/Library/Application Support/MyApplication/"; 
    folder = [folder stringByExpandingTildeInPath]; 

    if ([fileManager fileExistsAtPath: folder] == NO) { 
        [fileManager createDirectoryAtPath:folder attributes: nil]; 
    }

    NSString *fileName = @"MyApplication.mysettings"; 
    return [folder stringByAppendingPathComponent: fileName];
}

Again, an example that just works. I'm on a roll today.

Cocoa Sheets

2009-09-02T21:28:00Z

I was struggling with my Photoshop plugin again. The plugin window is modal. But then I need to pop up a modal window, in order to prompt the user for new name/description for the user-saved presets. I was puzzling and Googling, and then I stumbled across a reference to "sheets". Bingo!

This page has the best little example of sheet usage. I was able to copy/paste and then a couple of tweaks, and a couple IB bindings and it all just worked.

- (IBAction)openSheet:(id)sender
{
	[NSApp beginSheet: theSheet
			modalForWindow: theParent
			modalDelegate: self
			didEndSelector: @selector(sheetDidEnd: returnCode: contextInfo:)
			contextInfo:NULL];
}

- (IBAction)theSheetOK:(id)sender
{
	[NSApp endSheet:theSheet returnCode: NSOKButton];
	[theSheet orderOut:nil];
}

- (IBAction)theSheetCancel:(id)sender
{
	[NSApp endSheet:theSheet returnCode: NSCancelButton];
	[theSheet orderOut:nil];
}

- (void)sheetDidEnd:(NSWindow *)sheet returnCode:(int)returnCode contextInfo:(void *)contextInfo
{
	if (returnCode == NSOKButton)
		NSBeep();
}

I really love code examples that just work.

Interesting endless loop

2009-07-08T20:24:00Z

Cocoa-in-Carbon application. Note to self. Do NOT "freeze-dry" a controller object in your NIB file, especially if your controller object opens your NIB file in it's init method.

Just sayin.

My cyborg name is...

2009-06-22T18:36:00Z

Get Your Cyborg Name

Because sometimes, you need to just have fun, too. BTW, My husband made me do it!

Resizing Windoze Parallels hdd files

2009-06-19T17:36:00Z

Parallels provides a nice tool for resizing the file you have chosen as your hard drive for your virtual machine, called the Parallels Image Tool. Unfortunately, Windows is not quite so cooperative, and will not just recognize the resized file as a larger HDD automagically. You need to resize your partition, and Windows doesn't provide any easy ways of doing this.

Googling for a solution, I discovered this very detailed example using Gparted - the Gnome Partion Editor Tool with Parallels. Unfortunately, it is old, and when I tried it the Gparted image refused to boot cleanly, with some sort of error on ... mouse detection, I think. You should just go directly to the Gparted project at SourceForge, and find the most recent stable ISO file to download. While booting, most of the instructions from uneasysilence no longer apply to the new version of Gparted, but I just went with the defaults, and it all worked. Once GParted is up and running, then the instructions from uneasysilence are useful again.

Who needs pagination in a blog?

2009-06-15T22:00:00Z

I don't really blog that often. Even when I was going at full tilt, I rarely posted more than 10-12 times a month. So... I don't care about the pagination plugin anymore. I especially don't care when it involves 3 inter-related plugins, at different/conflicting versions!

So I took the easy way out, I'm afraid. Googling for alternatives, I discovered this example pastie, which gives me the month-by-month archive in the sidebar you see now.

See? Who needs pagination?

Mephisto upgrade started

2009-06-13T04:58:00Z

I've upgraded the blog to Mephisto 0.8.1 Drax. I would have been in serious trouble, had it not been for Rob Seaman's blog. Waves! Hi, Rob. Thanks.

It wasn't just a simple upgrade, in fact, it was pretty freaking complicated. But, since I worked so hard, it should be smooth sailing for the future.

Upgrade to new Mephisto, and learn more about Git at the same time (Rob's blog was really useful for that part)
Moved from Nginx/Mongrel setup on a Nitix box, to Apache/Passenger on Solaris 10 (SunFire V100). (More on that later)
Capified the blog, for better/faster customizations and updates. (Yeeee!!!!!)

Seems like a lot, doesn't it? I thought so too. There was even a couple of days of yak-shaving involved, as I attempted to force certain plugins to work, which were not compatible with 0.8.1. Never mind. The blog is up and running, and it will survive for a day or two without a tag cloud, or pagination. I'll get to it. Promise.

Speaking at RailsConf 2009

2009-05-02T18:57:00Z

I'll be going to RailsConf next week, and (surprise), I'll also be speaking.
Discussion Panel: Women In Rails
Feel free to comment here, if you aren't going to the conference, but have any good discussion points to add.