distriwatch.de

Ruby script for persistent irb history

Alex — Fri, 20 May 2011 15:48:34 +0000

IRB (Interactive Ruby Shell) is one of those tools that a hacker learning Ruby hopefully discovers right away. It’s an extremely useful way to learn the language to get immediate feedback. Unfortunately there is no persistent history and TAB completion. So put this tiny script below in your .irbrc file located in your home directory (~/.irbrc). From now on you have a great persistent command history and TAB completion, like in the bash.

require 'irb/completion'
ARGV.concat ["--readline", "--prompt-mode", "simple"]
module Readline
module History
LOG = "#{ENV['HOME']}/.irb-history"

def self.write_log(line)
File.open(LOG, 'ab') { |f| f << "#{line}\n" }
end

def self.start_session_log
write_log("\n# session start: #{Time.now}\n\n")
at_exit { write_log("\n# session stop: #{Time.now}\n") }
end
end

alias :old_readline :readline

def readline(*args)
ln = old_readline(*args)
begin
History.write_log(ln)
rescue
end
ln
end
end

Readline::History.start_session_log

require 'irb/ext/save-history'
IRB.conf[:SAVE_HISTORY] = 100
IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-save-history"
IRB.conf[:PROMPT_MODE] = :SIMPLE

Nice online XPath parser

Alex — Wed, 11 May 2011 09:57:42 +0000

Checkout: http://www.futurelab.ch/xmlkurs/xpath.de.html

Issue: brew install mysql on Snow Leopard “ERROR! Manager of pid-file quit without updating file.”

Alex — Sun, 13 Mar 2011 16:13:54 +0000

To install MySQL Server on Snow Leopard some manual work is necessary. After upgrading to Mac OS 10.6.5, I had some errors. I was stumped, until I realized that Apple’s update had changed the write permissions on /usr/local I ran:

chmod g+w /usr/local

sudo chmod -R 777 /usr/local/var/mysql

If you do not do this, the server does not give your user permission to write to the pid file and it does not start.

Now run:

brew install mysql

Install sample database:

mysql_install_db

That’s it ;-)

How to install Chromium Browser under Mac OS X (no Google Chrome browser)

Alex — Fri, 11 Mar 2011 18:38:25 +0000

Everybody knows Google Chrome. It’s an elegant and fast browser. But I hope anyone is not using Chrome because of privacy issues. Luckily the core application is Open-Source named “Chromium Browser”.

It looks the same and is free of Google crap. Never the less there is no binary package or DMG-Image. So you normally need to compile it yourself.

For the Macies out there just have a look at Chromatic. It’s a GUI installer. Have a look at http://mrgeckosmedia.com/applications/info/Chromatic

Refactoring a Rails App with metric-fu

Alex — Tue, 08 Mar 2011 20:05:29 +0000

Jeah, everybody talks about code refactoring but who really makes this annoying job?
But the practice of making the working code even better and more manageable through better design is a really important step. It is one core method in test-driven and behavior-driven development.

The Swiss army knife of Rails refactoring is in my opinion “metric_fu” It combines several independent gems:

Saikuro(cyclomatic complexity analyzer),
Flog(Flog reports the most tortured code in an easy to read painreport),
Flay(Flay analyzes code for structural similarities),
Rcov(a code coverage tool),
Reek(finding code smells),
Roodi(Ruby Object Oriented Design Inferometer),
Churn(give the number of times a file, class, or method is changing),
RailsBestPractices(rails_best_practices is a code metric tool to check the quality of rails codes.),
Subversion,
Git,
and Rails built-in stats task to create a series of reports.

By the way it comes along with a nice HTML report and nice generated graphics:

Take a look at the metric-fu Website http://metric-fu.rubyforge.org/

Are you using Hudson? Just try the metric-fu hudson plugin: http://blog.josephwilk.net/ruby/ruby-metric-fu-hudson-plugin.html

CeBIT Blogger-Tour 2011

Alex — Mon, 07 Mar 2011 20:55:04 +0000

This year the CeBIT Blogger-Tour was organized for the first time by the Deutsche Messe AG in cooperation with the t3n-magazine. Here are some visual impressions:
picasaView plugin: there are no albums available for this user in picasaweb.

GoogleVisualr a Ruby on Rails Plugin For Google Visualization API

Alex — Fri, 31 Dec 2010 12:13:40 +0000

The Google Visualization API enables you to create interactive JavaScript-Charts and graphs easily. Winston Teo Yong Wei (the Developer of wego.com) created GoogleVisualr (see at GitHub) This Ruby Plugin, is a wrapper around the Google Visualization API and allows you to create the same visualizations with just pure Ruby. You don’t have to write any JavaScript at all. Good for any Ruby on Rails setup whereby you prefer to work your logic in models or controllers.

Please refer to the GoogleVisualr reference site for a complete list of visualizations that you can create with GoogleVisualr. In your model or controller, write Ruby code to create your visualization (e.g. Area Chart, Bar Chart, even Spark Lines etc). Configure your visualization with all the options as listed in Google Visualization API Docs. In your view, just call a visualization.render(div_id) method that will magically generate and insert JavaScript into the final HTML output. You get your visualization, and you didn’t write any JavaScript!

Installation
Just install the GitHub repository into your app/vendor/plugin folder.

rails my_app; cd my_app;
script/plugin install git://github.com/winston/google_visualr.git

This section describes a basic implementation of the GoogleVisualr::AreaChart class. Please review the Docs for detailed documentation and advanced implementation of constructors and methods.

In your Rails layout, load Google Ajax API in the head tag, at the very top.

In your Rails controller, initialize a visualization (area chart) with an empty constructor.

@chart = GoogleVisualr::AreaChart.new

Populate visualization with column headers, and row values.

# Add Column Headers
@chart.add_column('string', 'Year' )
@chart.add_column('number', 'Sales')
@chart.add_column('number', 'Expenses')

# Add Rows and Values
@chart.add_rows(4)
@chart.set_value(0, 0, '2004')
@chart.set_value(0, 1, 1000)
@chart.set_value(0, 2, 400)
@chart.set_value(1, 0, '2005')
@chart.set_value(1, 1, 1170)
@chart.set_value(1, 2, 460)
@chart.set_value(2, 0, '2006')
@chart.set_value(2, 1, 1500)
@chart.set_value(2, 2, 660)
@chart.set_value(3, 0, '2007')
@chart.set_value(3, 1, 1030)
@chart.set_value(3, 2, 540)

Configure visualization with options.

@chart.width = 400
@chart.height = 240

In your Rails view, render visualization.

<%= @chart.render('chart') %>

(via google_visualr doc at github)

Putin calls for using Linux in Russia

Alex — Thu, 30 Dec 2010 15:39:30 +0000

In Russia, there have been already several plans to use open source software. But it never came to a breakthrough. But now Prime Minister Vladimir Putin signed a plan for the “transition of power structures and the federal budget to free”. According to the document, the introduction of Linux in the government should begin in 2nd quarter of 2012.

The document is called “transition plan of the federal authorities and federal budgetary institutions on the use of free software, and covers the period from 2011 to 2015.“(translated via Google)

The key document with that timetable (in Russian) can be viewed via Google’s translation Link.

1. Approve the attached plan for the transition of federal executive bodies and agencies of the federal budget for the use of free software for 2011 – 2015 years.

2.Federal executive agencies to implement activities in accordance with the plan approved by this Order, within the established government of the Russian Federation, limiting the size of their staff and budget allocations provided to them in the federal budget execution authority to the specified area of activity.

Prime Minister

The Russian Federation Vladimir Putin

The fact that Putin has signed the order for this project could be critical: there have been several previous plans for moving parts of the Russian government to using free software, notably in the educational sector, but in practice they have mostly failed to materialise because there has been insufficient political weight behind them. But if Putin says: “make it so”, I suspect that a lot of people will jump pretty fast to make sure that it *is* so. And once that happens, other plans to roll out free software might well suddenly look rather more attractive.

Nicer Terminal Font in OS X

Alex — Wed, 29 Dec 2010 06:34:12 +0000

With the release of MAC OS X 10.5 (Leopard) the terminal app surprisingly got a great improvement: The Tabs! Unfortunately the default terminal-font sucks. So I had to look up which default font GNOME terminal uses and install it on my OS X.

Here are the steps to follow:

Download Bitstream Vera Mono 1.10
Extract the archive
Double click on VeraMono.ttf
Click Install Font
From Terminal click Terminal->Preferences
To the right of Font click Change…
Select Bitstream Vera Sans for the Family
Select 12 for the Size
Close the Fonts window
Enable Antialias text under Text
Restart the Terminal