Yangtheman

Life hacker

Archive for category Ruby on Rails

How to install KidsRuby on Mac OS X and Ubuntu

Jan 17

Posted by Yang Chung in Ruby on Rails, high-tech, technology | No Comments

I have two kids, and I have been wanting to find ways to introduce my kids to programming. Especially for my son, who has asperger syndrome. I thought programming would be a good way to use his interests in logic and mathematics to good use.

I was so much in joy when I found KidsRuby. It’s an awesome project. I think Ruby is a great first language because of its elegance and object-oriented nature to the core.

Previously I had a hard time installing KidsRuby my Mac OS X, due to qt installation error. I was able to at least get it going by cloning their git repository. I had filed a bug for the qt installation error, and the author responded some time ago, but I hadn’t had time to verify it.

I finally had time to verify it, and it worked like a charm.

I also had converted two first-generation Google Chromebooks to use Ubuntu to give to my kids. And while I was familiar with Fedora, this was my first time using Ubuntu, and as new user, I had to search around the net to install Ruby and to install KidsRuby. I am close to finishing it, and I will describe it here.

Mac OS X

This one is pretty easy. Just download the installer dmg file from here, and follow the instruction. It will take a while, but it would be well worth it. You can find the KidsRuby folder in Application folder.

Ubuntu

Now, this one took a while. If you have Ruby installed already, you are good to go. If not, follow the direction below.

If Ruby isn’t installed

You can simply follow the direction from Ryan Bigg to install Ruby 1.9.3.

If Ruby is already installed

I am not sure which version of Ruby is supported, but this applies to Ruby 1.9.3.

The biggest problem I faced was the problem with ffi gem. I kept getting the following error.

Installing ffi (1.0.10) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
 
        /usr/bin/ruby1.9.1 extconf.rb
:29:in `require': no such file to load -- mkmf (LoadError)
	from :29:in `require'
	from extconf.rb:4:in `'
 
Gem files will remain installed in /usr/share/kidsruby/ffi/ruby/1.9.1/gems/ffi-1.0.10 for inspection.
Results logged to /usr/share/kidsruby/ffi/ruby/1.9.1/gems/ffi-1.0.10/ext/ffi_c/gem_make.out
An error occured while installing ffi (1.0.10), and Bundler cannot continue.
Make sure that `gem install ffi -v '1.0.10'` succeeds before bundling.

After searching the net for a while, I realized that I needed to install “-dev” package as well. Since I am using 1.9.3, I had to install ruby1.9.1-dev.

sudo apt-get install ruby1.9.1-dev

After that you can clone the git repository and install necessary packages.

git clone https://github.com/hybridgroup/kidsruby.git
 
cd kidsruby
 
sudo apt-get install libqt4-dev
sudo apt-get install cmake
gem install qtbindings
bundle install

The bundle install part will take a while.

For the lesson part, I had a surprising result – my son totally lost interest very quickly, but my daughter was more into it. :)

KidsRuby on Ubuntu

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Resources for fresh installation of Postgresql 8.x and Ruby on Rails on Mac OS X 10.6.x

Nov 18

Posted by Yang Chung in Ruby on Rails | No Comments

Most people need to do this only when they get a new system. I had to go through this to help out a potential brogrammer, and it would have been much easier if I pointed him to one place where he could just following direction. Instruction here applies to Mac OS X 10.6.x.

1. Install Xcode

Xcode is included in the Mac OS X install disc. You can install from the DVD or you can down load it from here,
http://developer.apple.com/xcode/.

2. Install RubyGems if not already installed

Doing the following command in terminal and see if it returns version number. If not, follow the link below to install RubyGems.

gem -v

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Pretty Permalinks on Rails

Dec 9

Posted by Yang Chung in Ruby on Rails | No Comments

Hot dang it’s so easy! I am using Rails 3, and it’s as easy as adding .parameterize to an attribute.

For example, if you want something like

http://mywebsite/posts/123-it-is-so-easy

You do

class Post
  def to_param
    "#{id}-#{title.parameterize}"
  end
end

That’s it!

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RVM and Heroku

Dec 9

Posted by Yang Chung in Ruby on Rails | 2 Comments

Make sure you run it twice – once with sudo and once without – for it to work properly.

$sudo gem install heroku
$gem install heroku

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Full text search on Heroku

Feb 28

Posted by Yang Chung in Ruby on Rails | 2 Comments

If you want to have full text search capability on Heroku, you should definitely use texticle or acts_as_tsearch. It is possible to use acts_as_farret on Heroku, but since you can only write to /tmp directory and your index file will be deleted sooner or later, you should not use it.

I first used texticle, and later switched over to acts_as_tsearch because I wasn’t happy with performance. Acts_as_tsearch is working really fine for me, and since your database on Heroku is already Postgres, there should be minimal configuration required. I even switched my local database from MySQL to Postgres to make both development and production environments consistent.

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Path of enlightenment to Ruby

Feb 22

Posted by Yang Chung in Ruby on Rails | No Comments

For all those who are learning Ruby, please do yourself a favor and follow the path described below.

http://github.com/edgecase/ruby_koans

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My answer to text-dynamo

Feb 22

Posted by Yang Chung in Ruby on Rails | No Comments

As an exercise to practice Ruby, you can try to compete a random text generator using an underlying Markov chain model. The codes in the following github account are incomplete. You are supposed to fill in or create methods that will create randomly generated texts given seed texts.

http://github.com/eandrejko/text-dynamo

Markov chain is like a state machine, but the key is the what causes state transition only depends on the current state. In this case, how do you determine probability of selecting which word next? It’s quite simple. You go through the seed text and count frequency of next words, and that determines the frequency. For example, “am” is likely to folllow “I” most frequently. Next might be “do” or other verbs.

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How to convert from MySQL to Postgres

Jan 30

Posted by Yang Chung in Ruby on Rails, startup | 3 Comments

I have been using MySQL for probably as long as I could remember. For Bloglation, search capability is an important feature since it’s hard to browse each post one by one. I will probably implement tagging functionality, but even so, it’s important to be able to search the contents with a keyword(s). While Ultrasphinx works well, Heroku only supports WebSolr… I was using acts_as_ferret using /tmp for index files, but the problem using the /tmp directory is that ferret index files most likely to disappear at some point.

Then, I found out that Postgres supports full-text search and since Heroku uses Postgres, I could use other plug-ins like acts_as_tsearch or texticle for free. Free is important to me, since it’s not making any money.

Searching online, there are various ways to do it like Pivotal Labs’ script or Heroku’s Taps gem, but I wanted to do it in an old way like AEdifice to check everything is going alright at each step.

1. First thing to do is to backup MySQL

For me, it was important to backup preserving encoding, since it had many different languages. First I pulled db from Heroku thinking that I Read the rest of this entry »

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To mock or stub ‘open’ method

Dec 16

Posted by Yang Chung in Ruby on Rails | No Comments

Don’t fool with Kernel call. Just use OpenURI.open_uri.

OpenURI.expects(:open_uri).returns("some content")

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Installing acts_as_ferret with pagination and deploying on Heroku

Nov 5

Posted by Yang Chung in Ruby on Rails | 4 Comments

OMG!

This shouldn’t have been this difficult, but it has because while there are many cool tutorials are out there, they are mostly outdated, and for some reason, the instruction on Heroku was not accessible.

While I picked acts_as_ferret because Heroku supports it, many seemed to prefer Thinking Sphinx. So, if you are not constrained (like me with Heroku), you should try that out too.

1. Install acts_as_ferret

Full instruction is outlined on github, so you should check it out. You can also find the installation instruction and complete list of methods here, too.

While the instruction asks you to put version name, since Heroku only has version 0.4.3 installed, specifying a version will break it.

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