When I upgraded to OSX Lion and opened the colour meter for the first time I realised that it had changed and I could no longer quickly grab colour values to use. I realised though by changing one of the menu settings I could get back the previous functionality; here’s how:

First open the DigitalColor Meter app, you can find it using Spotlight.

It looks like this, you’ll notice that the displayed values are in absolute RGB 0-255 values.

Select View => Display Values => As Hexadecimal

Now you can sample a colour simply by hovering over the colour you want. Once you are ready press Command + Shift + C. It should copy the hexadecimal colour to your clipboard.

You should be able to notice it is copying the colour as the Color item on the top menu will highlight monetarily.

So, yesterday at work I released the activemerchant-bpoint gem. A small plugin for Active Merchant that provides a billing gateway for the commonwealth bank’s BPOINT merchant gateway service. It’s really great to work in an environment that encourages open source work. Hopefully this is just the start and I hope in the future that i’ll be able to open source much more of the work I do.

Slides are available here: http://mariovisic.github.com/declarative_cucumber

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 rvm install ruby-1.9.3-tv1_9_3_rc1 --with-libyaml-dir=$HOME/.rvm/usr
 rvm alias create 1.9.3-rc ruby-1.9.3-tv1_9_3_rc1

 rvm use 1.9.3-rc

Ruby 1.9.3 works quite well (all of my tests still seem to be green), although there are a few small issues at the moment. For example ruby-debug19 doesn’t currently install. Running a quick test shows that 1.9.3 does indeed seem to load up a rails environment much quicker, here is a comparison of running rspec and cucumber tests for a rails 3.1 project.

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 Using /Users/mario/.rvm/gems/ruby-1.9.3-tv1_9_3_rc1

 time rspec spec
 Finished in 22.81 seconds

 real  0m28.469s
 user  0m11.000s
 sys   0m0.895s

 time cucumber
 0m4.816s

 real  0m12.955s
 user  0m10.579s
 sys   0m0.701s

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 Using /Users/mario/.rvm/gems/ruby-1.9.2-p290

 time rspec spec
 Finished in 25.69 seconds

 real  0m43.826s
 user  0m18.193s
 sys   0m1.367s

 time cucumber
 0m6.007s

 real  0m24.559s
 user  0m19.324s
 sys   0m1.200s

As you can see the actual tests themselves ran faster but not by much, the total execution time went down a lot though as 1.9.3 has some new fixes to dramatically speed up the time it takes to require libraries.

Update

1.9.3rc1 is now available directly through RVM. Simply run:

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 rvm get head
 rvm reload
 rvm install 1.9.3

I have been helping out Locomotive CMS for a while now in my spare time. I’ve been fixing bugs here and there and helping out users that require assistance. A couple of days ago I was appointed as one of the maintainers for the project, YAY.

Locomotive is really neat, you should totally check it out!

Today I managed to get a patch into squeel (YAY!). I found a bug which was only occurring on ruby 1.9.2 sporadically. I wrote a failing spec and the author Ernie created a fix on the very same day.

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 SELECT * FROM table WHERE column_one = something AND column_two = something
 OR column_three = something AND column_four = something

After reading some arel documentation, I came up this:

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 version  = Version.arel_table
 versions = Version.where(version[:c1].eq(something).and(version[:c2].eq
 (something)).or(version[:c3].eq(something).and(version[:c4].eq(something))))

If this is a bit too fiddly for you then there are some nice gems that do this for you, such as Squeel.

To Automatically indent the current line where it should reside when programming use ==

Use Ctrl + c instead of having to reach for the ESC key all the time.

The comment plugin adds the mapping \c Space which comments a line (Or multiple visually selected lines). It also uncomments already commented lines.

:A to cycle between the test and the implementation (Using the rails plugin).

:R to cycle between related files, eg from a view to the controller and back (Using the rails plugin).

. Repeats the last action.

Align [param] Align the visually selected lines based on the parameter given. So for example Align = would align lines based on the equal signs.

Once all done, I benchmarked the knightsarmy site the same way I had done in an earlier post. With REE i was hitting 25.07 requests per second. With 1.9.2 I managed 33.93 per second.

Neat!

To check if there were any items present in a collection I would do something like this:

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object.relation.present?

Keith told me to use:

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object.relation.any?

Turns out that the any? method will perform a COUNT (*) SQL query where as the present? method will perform a SELECT (*) which is infinitely slower than performing a count.

So from now on i’ll be using the any? method instead of present?

The machine i’m backing up hosts my live websites, database server (mysql) and git repositories. I also have a linux machine at home that can be accessed over ssh which will be receiving the backups. The rsync setup process will differ if you’re using a local machine.

The first thing to do is to setup mysqldump to output the contents of the database. This can be fairly system intensive for large databases, but mine is quite small so it’s ok to run and finishes fairly quickly.

The mysqldump tool should be included in your mysql installation, there are similar tools for other DBMS’s too. By default mysqldump outputs to the STDOUT, so we can redirect the output to a file of our choice, here’s how:

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mysqldump -AR -u [username] -p[password] > [location]

Just fill in your database username, password and the output location you want and run it on the terminal, and yes there SHOULD NOT be a space between -p and your password :)

You should have a sql file with all of your database data. The dump can be setup as a cron task, i’ve set mine up to run every day at midnight. Simply run crontab -e to modify your cron configuration and put in the following line.

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0 0 * * * mysqldump --all-databases -u [username] -p[password] > [location]

We can now go ahead and setup rsync to backup our information. Rsync was already installed on my system but if you don’t have it already you can grab it using apt or any other package manage, here’s how in apt.

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sudo apt-get install rsync

Once installed we need to setup our backups. Rsync can be setup using configuration files that can be altered to suit your needs. Just for convenience i’ve just run rsync directly rather than using configuration files. Here’s how.

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rsync -e ssh -p 50001 -azvP /var/backups/mysql/ [username]@[hostname]:[path]

OK, so there’s a bit much there, here’s what each part does. We’re calling the rsync command, my machine that will be getting the backups is available through ssh on port 50001, so the -e command sets up rsync to use ssh on port 50001. The -a flag sets archive mode which will recursively look through directories and preserve symlinks/times/groups and owners of files, -v gives us a verbose output with more info and -P gives us a nice little progress bar.

You can just copy the example code and fill in the username, hostname and path with your own receiving servers details and then run the command on the command line.

Once it’s all working we can put it into cron and specify that it gets run once daily. We can set it up to run at 10 minutes past midnight, this should give our mysql dump a chance to finish before we back it up. For the cron task we won’t need a verbose output or a progress bar so we’re only using -az and not -azvP. The P flag does allow for partial transfers which we still want, so i’ve added --partial to the cron.

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10 0 * * * rsync -e ssh -p 50001 -az --partial /var/backups/mysql/
[username]@[hostname]:[path]

That’s it. We’re all done!

The website only gets a very small amount of visitors a day, so performance isn’t a concern of mine at all. The website does feel very snappy when navigating already. I was looking over the code that I had written a few months back and noticed that for each post (can be up to 10 shown per page) I was running RedCloth over the body contents like this:

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# app/views/posts/_post.html.haml
= post.body_html

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# app/models/post.rb
# Yes i realise post is a really bad name for a model
def body_html
  RedCloth.new(self.body).to_html.html_safe
end

I had a simple idea to improve the performance of loading the posts. I created a new text database column called cached_body on the posts table, then added some logic so that it only runs RedCloth when the post contents change, or when there is no cached_body already.

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# db/migrate/20110109030634_add_cached_body_to_posts.rb
class AddCachedBodyToPosts < ActiveRecord::Migration
  def self.up
    add_column :posts, :cached_body, :text
  end

  def self.down
    remove_column :posts, :cached_body
  end
end

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# app/models/post.rb

before_save :set_cached_body

def body_html
  if cached_body.blank?
    set_cached_body
    save!
  end
  cached_body.html_safe
end

protected

def set_cached_body
  self.cached_body = RedCloth.new(self.body).to_html
end

I ran some benchmarks using the apache benchmark tool for a rough guide of the performance gains. I ran the command ab -c 100 -n 1000 http://www.knightsarmy.net a total of 5 times and then took the 3 middle scores to make an average, here’s the results:

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Before:
  Average Time: 57.49 seconds
  Average RPS:  17.40 [#/sec] (mean)

After:
 Average Time:  39.89 seconds
 Average RPS:   25.07 [#/sec] (mean)

That’s a 44% increase in requests per second and a 30% reduction in response time. Neat!

The CD player has a funny way of getting you to input the 4 digit code. You basically have to press numbers 1 through 4 the appropriate amount of times to increment each of the 4 numbers to get your code.

So for my code, which is 6104 (please don’t steal my stereo) would logically have me pressing the 1 digit six times, 2 once, 3 zero times and 4 four times. Or at least I thought! Turns out you need to press the number 10 times to get to 0, otherwise it doesn’t register.

I wasted a good 5 minutes figuring that out! Odd!

You can find me on twitter at @mariovisic

We were creating some tests for a method which returned an array of objects, we knew the objects that would come out but it was hard to get them in the right order. Trying to match the two arrays didn’t work:

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  @result.should == @expected_array

We didn’t want to simply sort both arrays as the test would get longer and we shouldn’t really have to, so after poking around a bit we (well mostly Darcy) discovered that rspec provides the ~= matcher to match an array for any given order. So this works flawlessly

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  @result.should =~ @expected_array

:)

Getting started creating radiant extensions is really easy thanks to the generator that is provided. In a couple of hours, armed with my favourite text editor and a rubygems.org account the extension was published as a gem and ready to use. Here’s how you go about using it:

Either create or get hold of an existing radiant project. The extension should work with radiant version 0.9 or greater, then simply run:

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gem install radiant-autoresize_textarea-extension

Now add the following line to your config/environment.rb

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config.gem radiant-autoresize_textarea-extension, :lib => false

Now we’re almost done, we just need to run update on our extension to copy over the required files.

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rake radiant:extensions:autoresize_textarea:update

Also, if I could think of a better name instead of “autoresize_textarea” I would have named it something else, add a note with your suggestion if you can think of one.

It’s basically a great way to practise your math and programming skills. You can compete with your friends also which is fun :) I started when my friend Tyson suggested he could solve me than me.

I’ve been solving my euler problems in Ruby because … well why not? Today I managed to solve 3 problems, taking my grand total to 33 out of a possible 300 problems. <=== Sounds more exciting when it’s in bold, right?

So while solving all these problems i’m slowly developing a set of simple libraries that are used across multiple problems. Seems to be saving me a bit of time now. The helper libraries (well only 1 at the moment) are available over at github.