The Passionate Craftsman

PHP hosting on EC2

2011-12-29T03:04:00.000-08:00

EC2 (Amazon Virtual servers) can be used as any other VPS, if you use EBS for storing your data and the cost is really low. But where EC2 really exceed is on building automatically scaling web hosting solutions. Web servers can be load balanced with Elastic Load Balancers, servers can be added on demand. Best tools to create and manage an infrastructure on EC2 are Chef and Puppet.

Create a basic Ruby app with Rack middleware - part 1

2011-12-29T02:17:00.001-08:00

This post - or may be a series of posts - on Rack is intended to understand how modern Ruby frameworks work. Frameworks such as Sinatra or Ruby on Rails use Rack middleware to exchange requests and responses to application servers. Old time of CGI or FCGI are gone. The code below shows how simple is to start a ruby server to serve a 404 error page:

app = lambda do |env|
 body = File.open(File.dirname(__FILE__)+'/404.html', 'r').read
 [404, {'Content-Type' => 'text/html'}, [body]]
end

run app

Save the previous script in a file named config.ru. If you have a page 404.html in the same directory of config.ru and you run:

> rackup -p 3000

You will get the 404.html page by connecting to http://localhost:3000. Please notice the curly braces between body: it is needed by Ruby 1.9. The run app statement run the lambda we just created.

Convert ruby code to HTML to paste into your blog

2011-12-29T01:54:00.000-08:00

I use the following script to read ruby code and output the HTML to the stdin of the shell:

require 'syntax/convertors/html'

code = File.read('code.rb')

convertor = Syntax::Convertors::HTML.for_syntax "ruby"
code_html = convertor.convert( code )

puts code_html

Put you ruby code in 'code.rb' and run

> ruby script_name.rb

Then cut and paste the content. You have to add the following CSS if you want to see your code properly formatted:

pre {
    background-color: #f1f1f3;
    color: #112;
    padding: 10px;
    font-size: 1.1em;
    overflow: auto;
    margin: 4px 0px;
          width: 95%;
}



/* Syntax highlighting */
pre .normal {}
pre .comment { color: #005; font-style: italic; }
pre .keyword { color: #A00; font-weight: bold; }
pre .method { color: #077; }
pre .class { color: #074; }
pre .module { color: #050; }
pre .punct { color: #447; font-weight: bold; }
pre .symbol { color: #099; }
pre .string { color: #944; background: #FFE; }
pre .char { color: #F07; }
pre .ident { color: #004; }
pre .constant { color: #07F; }
pre .regex { color: #B66; background: #FEF; }
pre .number { color: #F99; }
pre .attribute { color: #5bb; }
pre .global { color: #7FB; }
pre .expr { color: #227; }
pre .escape { color: #277; }

The style of the CSS code above has been created by changing the type of highlighter:

convertor = Syntax::Convertors::HTML.for_syntax "css"

How to call a private method in Ruby

2011-12-29T00:39:00.000-08:00

If you want to call a private method in Ruby - for any reason - you can use send, method and instance_eval:

class Foo

  private
    def bar
      puts 'You called bar'
    end
end
 
> foo = Foo.new
foo.bar # this, of course, throws an error
NoMethodError: private method `bar' called for #
 from (irb):129
 from :0

> foo.send(:bar)
You called bar
=> nil
m = foo.method(:bar)
=> #
> m.call
You called bar
=> nil
> foo.instance_eval { bar }
You called bar
=> nil

Remember you cannot use eval to call a private method:

> eval('foo.bar')
NoMethodError: private method `bar' called for #
 from (irb):140
 from (irb):140
 from :0

Reference: http://www.khelll.com/blog/ruby/ruby-dynamic-method-calling/

How to become successful

2011-11-16T03:01:00.000-08:00

This is a quite inspiring speech. Reaching a target or becoming successful takes time and pain. Rewards are difficult to obtain, but when you get it... it is awesome:

Create a Rails 3 project with "activerecord", "capybara", "devise", "git", "haml", "jquery", "rspec", "sass", "settingslogic"

2011-11-13T10:19:00.000-08:00

You can run this commend:

rails new APP_NAME -m http://railswizard.org/50fc74d6dfa659c06971.rb -J -T

I have created the template using http://railswizard.org/

Unix: change password one line

2011-11-13T10:13:00.000-08:00

How to change the user password without re-typing the passowrd

2011-11-13T10:00:00.001-08:00

You can use the following script to change the user password as root without having to re-type the password:

I found this script helpful when called via ssh.

Catch all exceptions in your Ruby program

2011-11-11T02:27:00.001-08:00

Just put your code between begin and rescue statements and print the error. An example:

ree-1.8.7-head :010 > begin
ree-1.8.7-head :011 > Testing.new
ree-1.8.7-head :012?> rescue Exception => msg
ree-1.8.7-head :013?> puts "Something went wrong ("+msg+")"
ree-1.8.7-head :014?> end
Something went wrong (uninitialized constant Testing)
=> nil

You can boot your application between begin and rescue and you will be able to print the error, perform an action, send an email in the rescue begin section:


begin
 MyApp.run!
rescue Exception => msg
 puts "Something went wrong ("+msg+")"
end

List MySql database size with a query

2011-08-12T03:35:00.000-07:00

The query:

SELECT table_schema "Data Base Name",
sum( data_length + index_length ) / 1024 /
1024 "Data Base Size in MB",
sum( data_free )/ 1024 / 1024 "Free Space in MB"
FROM information_schema.TABLES
GROUP BY table_schema ;

The mysql console:

mysql> SELECT table_schema "Data Base Name",
-> sum( data_length + index_length ) / 1024 /
-> 1024 "Data Base Size in MB",
-> sum( data_free )/ 1024 / 1024 "Free Space in MB"
-> FROM information_schema.TABLES
-> GROUP BY table_schema ;
+--------------------+----------------------+------------------+
| Data Base Name | Data Base Size in MB | Free Space in MB |
+--------------------+----------------------+------------------+
| information_schema | 0.00878906 | 0.00000000 |
| mysql | 0.61361027 | 0.00000000 |
| performance_schema | 0.00000000 | 0.00000000 |
| test | 0.01562500 | 10.00000000 |
+--------------------+----------------------+------------------+
4 rows in set (0.00 sec)

Install MySql generic binary on Linux

2011-08-12T01:33:00.000-07:00

I want to have the latest GA version of MySql, the 5.5.x instead of the old 5.1 release. 5.5.x has many performance improvements, from x2 to x8, according to an article of Guiseppe Maxia, a MySql expert. Go to the download page and get the tar gizipped binary version of Mysql. I downloaded this one:

# apt-get install libaio1
# wget http://dev.mysql.com/get/Downloads/MySQL-5.5/mysql-5.5.15-linux2.6-x86_64.tar.gz/from/http://mysql.mirrors.ovh.net/ftp.mysql.com/
# mv index.html mysql.tar.gz
# tar xzfv mysql.tar.gz
# mv mysql-5.5.15-linux2.6-x86_64/ mysql-5.5.15
# mv mysql-5.5.15/ /usr/local/
# cd /usr/local/
# ln -s mysql-5.5.15/ mysql
# cd mysql
# chown -R mysql .
# chgrp -R mysql .
# scripts/mysql_install_db --user=mysql
# cp support-files/mysql.server /etc/init.d/mysql.server
# cp support-files/my-medium.cnf /etc/my.cnf
# chmod +x /etc/init.d/mysql.server
# update-rc.d mysql.server defaults
# /etc/init.d/mysql.server start
Starting MySQL.. *
# /etc/init.d/mysql.server restart
# bin/mysql -uroot

mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> update user set password=PASSWORD("your_passwd") where user='root';
Query OK, 4 rows affected (0.00 sec)
Rows matched: 4 Changed: 4 Warnings: 0

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> exit
Bye

Done! Simple isn't it?

Reference: http://dev.mysql.com/doc/refman/5.5/en/binary-installation.html

conman: automate your server configuration

2011-08-05T05:22:00.000-07:00

Probably you already know about Puppet and Chef and probably you felt overwhelmed when learning one of the the two server configuration management. I want to show you conman a simpler and easier approach then Puppet and Chef. Of course it has very basic features but it could be easily extended. So install conman:

gem install conman

conman has ingredients and recipes. Recipes contains ingredients. An ingredient is a class extending the Ingredient class having methods with commands. Here you can see and example of a class which can install or remove the apache2 package:


class Apache2Ingredient < Ingredient
   def install
       `sudo apt-get install apache2`
   end

   def remove
   `sudo apt-get remove apache2`
   end
end

The you can include you new ingredient in your recipe:


class MyRecipe < Recipe
     apache2 :install
end

apache2 method search and load the Apache2Ingredient, then calls the install method. Simple!

You can run the recipe using the command line:

conman -i /path/to/ingredients /path/to/recipes/my_recipe.rb

or using Ruby:

Conman.init :ingredients => '/path/to/ingredients/' Conman.run '/path/to/recipes/my_recipe.rb'

conman does not know about packages, apt-get, rpm... but I think it can be easily implemented. Another important thing that is missing is the possibility to run remotely the recipes; a SSH session using a Ruby library could do the trick (execute the command remotely).

Link: https://github.com/moocode/conman

Life is, in fact, a battle

2011-01-31T02:39:00.000-08:00

"Life is, in fact, a battle. Evil is insolent and strong: beauty enchanting but rare; good very apt to be weak; folly very apt to be defiant; wickedness to carry the day; imbeciles to be in great places, people of sense in small, and mankind generally unhappy.

But the world as it stands is no illusion, no phantasm, no evil dream of a night; we wake up to it again for ever and ever; we can neither forget it nor deny it nor dispense with it."

I do not remember who wrote it, but I fully subscribe to it.

Bettermeans Introduction

2010-11-30T13:36:00.000-08:00

Test unique values in Rails model with Rspec

2010-11-20T12:10:00.000-08:00

I wanted to test 'validates_uniqueness_of' for this model:


class CourseItem < ActiveRecord::Base
  validates_presence_of :course_id, :day, :url
  validates_uniqueness_of :course_id, :scope => :day, 
                          :message => "- this day has been already created."
end

I tried to create two objects with the same value and I was getting the validetion error when creating the second value, the spec was failing and I did not know you to test it. There is a custom matcher to test the uniqueness of fields and it is available with a gem developed by Bogdan Gusiev. This blog post will help you to get started: http://gusiev.com/2010/06/ultimate-rspec-matcher-to-test-validation/. That gem has other useful matchers too.

I checked that model with the following code:

Install pg gem with PostgreSql 9.0 on Leopard

2010-09-24T23:28:00.000-07:00

Download the installer from: http://www.enterprisedb.com/products/pgdownload.do#osx.
Install PostgreSQL, insert your password and you will have pgAdmin and other tools in your Applications directory.

If you will try to install the pg gem now you will get a compile error. You need to define the architecture of PostgreSQL and its bin directory:

sudo -s
export ARCHFLAGS='-arch x86_64'
export PATH=/Library/PostgreSQL/9.0/bin:${PATH}
gem install pg

This is the output I get:

bash-3.2# gem install pg
Building native extensions. This could take a while...
Successfully installed pg-0.9.0
1 gem installed
Installing ri documentation for pg-0.9.0...
Installing RDoc documentation for pg-0.9.0...
bash-3.2#

auto_complete plugin on Rails 3 not working

2010-09-24T07:25:00.000-07:00

If you are migrating your Rails app and auto_complete is not working, the reason is auto_complete does not remove the default escaping in Rails 3. A guy has fixed this problem. You just need to put his version in the place of the old plugin:

rails plugin install --force http://github.com/marklazz/auto_complete.git

Thanks marklazz

Is vi an UFO?

2010-09-09T12:19:00.000-07:00

In a thread of Rails Talk I found a discussion about a good text editor, nothing new, but I want to cite this guy, he is very funny:

the problem with vim is that people always say is so powerful but when i try
to use it is like im looking at the sky waiting to see a UFO to pass by but
nothing happens

VNC viewer on Snow Leopard

2010-08-24T01:33:00.000-07:00

If you need to connect to a VNC server with your Mac, you do not need to download and install a VNC client. Snow Leopard has and application in '/System/Library/CoreServices/Screen Sharing'. Just click 'Screen Sharing' and you will be prompted to enter an IP or host name of the server. It works much better than Chicken of the VNC. Screen Sharing is also compatible with Apple Remote Desktop (ARD) v2.1 or later.

Mac OS X 10.5 has this application too (Snow Leopard is 10.6).

Links:

Mac OS X 10.6 Help - About screen sharing

When ActiveRecord does not find a record

2010-08-13T08:31:00.000-07:00

In Rails, when ActiveRecord does not find a record with the specified ID raises and exception. A good way to control this exception is to intercept it and respond with an appropriate HTTP status code, in this case a 404. This is a simple example:

Execute Rails migrations on producion server with Capistrano

2010-08-11T04:23:00.000-07:00

If you cannot access, from your development computer, the production database (because of corporate policies and/or security settings), you can add a command to Capistrano when you deploy your application.

After copying the files and coping database.yml, you can run easily a migration on the production server in this way:

run "cd /rails_dir/#{application}/current/ && rake db:migrate RAILS_ENV=production"

That command goes into the root of your Rails application and execute the migration specifying production as environment.

After that command you can change the symlink and switch to the newly deployed application.

Installing Erlang on Mac OS X

2010-08-06T13:32:00.000-07:00

mkdir erlang
cd erlang/
wget http://www.erlang.org/download/otp_src_R14A.tar.gz
tar xz otp_src_R14A.tar.gz
cd otp_src_R14A
./configure --enable-hipe --enable-smp-support --enable-threads
make
sudo make install
cd ../..
rm -rf erlang

Start the Erlang console:

erl

If you do not have wget, you can install it with Darwin Ports:

sudo port install wget

Kitty - a funny gem

2010-08-02T13:38:00.000-07:00

I found a new screencast on Rubypulse about a gem named kitty. If you install the gem, then you will have a kitty command that will print a random ASCII-art cat. For instance:

How to test a redirect with Shoulda

2010-07-27T09:13:00.000-07:00

I was trying to test if the controller was redirecting but I was getting a 200 (success) instead of 302. With a standard Unit::Test it was working ok. Then, by printing the response body I so that with Shoulda I was getting a 200 with the text:

So I decided to test if the response was a link (a tag) with redirected as text of the link:

assert_select "a", "redirected"

This is the code showing the same test, one with Unit::Test, the other with Shoulda:

How to lock Mac OS X screen

2010-05-20T23:45:00.000-07:00

Go in applictions -> utilities and open 'Keychain Access'. In preferences check 'Show status in menu bar', then you will see a black padlock in the right of the task bar. To lock your screen you only need to click the padclock and select 'Lock Screen'. To lock require a password when your screen saver starts, go in 'System Preferences' -> 'Security', than check 'Require password to wake this computer from sleep or screensaver'. In Snow Leopard you can set the time when the screen will be blocked after the start of the screensaver.

References:

In Mac OS X, how do I password-protect my computer? - http://kb.iu.edu/data/ajqx.html
OS X Tip: Lock That Screen - http://www.whatdoiknow.org/archives/000957.shtml
Add a screen locking icon to the menubar Desktop - http://www.macosxhints.com/article.php?story=20020901073230521

Install RMagic on Mac

2010-05-16T11:19:00.000-07:00

This post documents the installation of RMagick on Snow Leopard. You need MacPorts installed. Install imagemagick library using MacPorts (have a cup of tea or coffe):

sudo port install tiff -macosx imagemagick +q8 +gs +wmf

Install rmagick gem (use sudo if you do not use rvm):

gem install rmagick

Now you should test if Ruby can use imagemagick:

irb -rubygems -r RMagick
ree-1.8.7-2010.01 > puts Magick::Long_version
This is RMagick 2.13.1 ($Date: 2009/12/20 02:33:33 $) Copyright (C) 2009 by Timothy P. Hunter
Built with ImageMagick 6.6.1-5 2010-05-16 Q8 http://www.imagemagick.org
Built for ruby 1.8.7
Web page: http://rmagick.rubyforge.org
Email: rmagick@rubyforge.org
=> nil
ree-1.8.7-2010.01 >

Done!

Thanks to: http://rmagick.rubyforge.org/install-osx.html

How to detect browser type and version in PHP

2010-04-21T08:35:00.000-07:00

You can use a simple class provided here: http://chrisschuld.com/projects/browser-php-detecting-a-users-browser-from-php/

A simple exmple:

if( $browser->getBrowser() == Browser::BROWSER_IE && $browser->getVersion() == 6 ) {
//do nothing
}
else {
// ok show something for non IE6 users
}

Scooter Framework

2010-04-16T10:02:00.000-07:00

After reading an article on InfoQ, I leant that the new Scooter Framework for J2EE is inspired by Ruby on Rails. The resemblance to Rails is incredible and it is very simple too! In am sure that it will become very popular.

I suggest you watch the Hello World screencast:

Then the Twitter example shows you how the delopment works. There is an easy testing framework, but the the controllers cannot be tested yet.

Date and time functions in MySQL

2010-04-16T09:37:00.000-07:00

MySQL has many date and time functions to manipulate and compare dates and time, the reference documentation form 5.1 version. If you want to add a day to a datetime or date field:

SELECT now(), now() + INTERVAL 10 DAY;

If you run the query above you will see the current date and the current date plus ten days. You can add or subtract even hours, second and more.

SELECT *
FROM article
WHERE approved=1
AND (
(birth <> now( ))
OR (news=1 OR never_expires=1)
)

The example above shows a query which loads the articles between the bith and now and between now and the expiry (death) date. If hte article is a news or should not expire, the date comparison is not taken into consideration.

If you want the current time:

SELECT CURTIME();

If you want to get the day of a date:

SELECT DAY('2009-12-15');

If you want the difference, in days, between two dates:

SELECT DATEDIFF('2007-12-30 23:59:59','2007-12-20');

The result is 10 because MyQSL subtract the second value from the first. The documentation is quite clear and complete.

Find duplicate fields in SQL

2010-04-12T10:10:00.000-07:00

Let's say that you have a table named users, where you keep your application users. If you has forgotten to set the username field as unique and you have some duplicate fields, you can use the following query:

SELECT username, COUNT(*)
FROM users
GROUP BY username
HAVING COUNT(*) > 1

Case sensitive MySql search

2010-03-12T06:46:00.001-08:00

If you want to make a table case sensitive or you just discovered that you are searching some text and the result comprises only a result matching only case sensitive pattern, here is an explanation that might help you.

The key point is collation. Collations names ending in _ci are case insensitive. Collections ending with _cs and _bin are case sensitive. You can change a collection of a table with the following query:

ALTER TABLE table_name COLLATE collation_name

It is possible to make a single column case sensitive:

`title` varchar(50) collate utf8_bin

That row has been taken from a CREATE TABLE statement. With that 'collate utf8_bin' text in you table definition, your serach will be case sensitive!

Userful links:

Farhan Mushraqi blog - Case sensitive SQL

Learning C on Youtube

2010-02-14T05:46:00.000-08:00

I am using more and more Youtube to learn new things. Math, computer science and C programming. I started to learn C many years ago with a book about programming C with Visual C/C++ 4. Then I had a course with the Open University on computer architecture and I learnt a bit of assembly an C. I have a very strong passion for C, since it has been using to program the Unix OS and many other fundamental softwares and it is still used, although most of the time, Java is preferred, but if you want to do system programming on Unix, C is just in the right place. I want to share this Youtube video, is about C programming, but the most interesting thing is that Unicom channel has produced many other C/C++ videos, so check that channel for more videos.

However I have ordered two books. 'The unix programming environment' is one of the most important books about Unix. It is written by one of the creators of Unix and has relevant information about C programming in a Unix environment. The other book is The C book: The C Programming Language (2nd Edition), by Brian W. Kernighan (Author), Dennis Ritchie (creators of the language).

Watir on Rails

2010-01-26T08:21:00.000-08:00

Watir is a tool for user acceptance testing and in general can be used to control a browser to do automated task. Since I am using the standard Rails's testing framework, and I run my tests with rake test, I thought why not to use watir test in a similar way. There is a plugin, Watir on Rails, that integrates Ruby on Rails with Waitr. You only need to run rake test:watir to test your application with rake. The test can be written in a similar way of the other Rails' tests. For instance:

How to use the example:

gem install watir # install watir
script/plugin install git://github.com/chip/watir-on-rails.git
put the file in test/watir or script/generate watir SuccessfulLogin to generate a test
run: rake test:watir
watch the browser doing your job ;-)
Start learning from the cheat sheet:http://wiki.openqa.org/display/WTR/Ruby+Cheat+Sheet

Watir need your web server on, if you are testing a local application, so you should run:

mongrel_rails start -e test # if you are using mongrel

Links:

Watir on Rails - Watir on Rails web page
Watir on Rails at Github
Watir - the official web site

Rails deployment with Capistrano and SVN

2010-01-20T09:25:00.000-08:00

I spent one day and half trying to deploy my first Rails application with Capistrano. Where I work, we use SVN as SCM. My PC runs Windows XP and the production server is Solaris 10. The server uses Apache, MySql and Passenger, aka mod_rails. I have used this recipe:


set :application, "apps"
set :user, 'my_username'
#default_run_options[:pty] = true
set :domain,      "solaris10.ds.domain.com"
set :repository,  "https://svn.domain.co.uk/svn/apps"
set :local_scm_command, "C:/applications/svn/svn"
set :scm_command, "/usr/local/bin/svn"
set :use_sudo,    false
set :deploy_to,   "/sites/rails-data/#{application}"
set :database_conf, "/sites/rails-data/database_conf"

role :app, domain
role :web, domain
role :db, domain, :primary => true

namespace :deploy do
 task :start, :roles => :app do
    run "touch #{current_release}/tmp/restart.txt"
 end

 task :stop, :roles => :app do
    # Do nothing.
 end

 desc "Restart Application"
 task :restart, :roles => :app do
    run "touch #{current_release}/tmp/restart.txt"
 end
end

desc "Echo environment vars"
namespace :env do
 task :echo do
   run "echo printing out cap info on remote server"
   run "echo $PATH"
   run "echo $LD_LIBRARY_PATH"
 end
end

# optional task to reconfigure databases
after "deploy:update_code" , :configure_database
desc "copy database.yml into the current release path"
task :configure_database, :roles => :app do
db_config = "#{database_conf}/database_#{application}.yml"
  run "cp #{db_config} #{release_path}/config/database.yml"
end

I have lost a huge amount of time trying to understand why Capistrano was not able to find the SVN client and some libraries. First tip, you must have an SVN client in your production server. When you run Capistrano, it connects to the production server with SSH. The main difference is that is an SSH session in non-interactive mode, so your user path is not loaded! Second tip, create a file in ~/.ssh name environment and add your PATH variable and your LD_LIBRARY_PATH, so the SVN client will be able to find the libraries that it needs. Third tip, do not use the export command in the environment file. Fourth tip, your sshd_config must have:

PermitUserEnvironment yes

Without this setting sshd will not load the environment file. In my Capistrano recipe there are three new tasks added to deploy, start, restart. The new two task are used to restart Passenger, so that tasks cannot be used if you have Mongrel. If you run 'cap env:echo' you will be able to see the PATH and LD_LIBRARY_PATH used by Capistrano during the SSH session.

If Capistrano is not able to set the PATH of the local and remote SVN clients you can use:

set :local_scm_command, "C:/applications/svn/svn" # set local svn client path
set :scm_command, "/usr/local/bin/svn" # set remote svn path

The standard path, for svn command, is typically /bin:/usr/bin:/usr/sbin.

You should not keep your database.yml in your SCM. I keep it in a directory and I tell to Capistrano to copy this file during the deployment, otherwise the migration will fail. Now what am I missing? Well a Continuos Integration (CI) solution. Yesterday I have evaluated CruiseControl.rb by ThoughtWorks. It seems very easy to install and use, but it still have not read the documentation completely and I still do not know if I can integrate CruiseControl.rb with Capistrano and if it is useful at all, but this will be another post.

After many releases, the release path will start to have many versions and if we want to clean the directory, this is the command to use:

cap deploy:cleanup

This tasks will leave only the last five releases. If you want to set the number of releases to keep in the production server;

set :keep_releases, 3 # where 3 is the number of releases

I have a directory of videos, named uploads, in Rails root directory. Every relaease will move your files with the old code. So I removed uploads directory from SVN (ignore list), then I configured an additional task in deploy.rb:

deploy.task :symlinks do
run "ln -nfs #{shared_path}/uploads #{release_path}/uploads"
end

This task create a symlink to the shared path of Capistrano. The shared path is there to be used by any release. With this technique you can keep your files outside your code, all you need is a symlink!

I see Capistrano as a very useful tool, very flexible and it solves most of my deployment needs. Everytime I think it is time to update the production environment, I commit all the modified files with SVN, than I run 'cap deploy', enter the password to access the server and... I have my fresh code updated. Of course before updating, all the tests should be executed successfully.

Links:
pretheory - Capistrano path and environment issues
Capistrano - From the Beginning
The Pragmatic Bookself - Agile Web Development with Rails, Third Edition

Qcubed/Qcodo Oracle adapter on Github

2010-01-16T06:52:00.000-08:00

I will stop using Qcodo and Qcubed as web framework and moving my current project, a corporate intranet, to Ruby on Rails. However since I was the first to complete the Oracle adapter, and I have developed few applications working with Oracle (for Acquedotto del Fiora), I decided to put the adapter in a Github project, after fixing a serious bug.

http://github.com/rtacconi/Qcodo-Qcubed-Oracle-adapter

Happy Birthday Blog!

2010-01-14T09:53:00.000-08:00

I started this blog last year, the 5th of January 2009. So, happy bithday blog, your one year older. I hope that this blog might be interesting so someone. I am using it not only to publish articles for the Internet readers, but even for myself. I write technical things that I need to use it not every day, but sometimes. This blog has been helpful for refresh my mind on how to create a trigge on Mysql, referetial integrity and more.

Migration from Qcodo to Rails

2010-01-08T05:21:00.000-08:00

I am re-developing an intranet in Rails. It is currently written in PHP with Qcodo as framework. It is very new intranet, so why I should re-develop it with Rails? Well, I do not like to program with PHP anymore and I have found many problems in Qcodo and I realized that the way to develop with that framework is not the way I like it.

This is a list of aspects that I do not like in PHP:

Every variable has to use the dollar character, the semicolon in the end of a statement, curly braces for blocks.
Namespaces in PHP 5.3 has an horrible syntax, it is similar to a DOS path (same slash).
PHP 5.3 has the infamous goto! Is that a way to improve a language? Crazy!
PHP is loosely-typed, which means that converts values behind the scenes and you need to have a good knowledge of the language to understand what it might happen to your data.
Variables are case sensitive, functions are not. There is not a real naming convention in the primitives.
Every function must be declared with the 'function' keyword, how redundant!
PHP attracts bad programmers (although there are good programmes that use PHP).
Many famous programs written in PHP are not really OOP, they do not use design patterns, or something to similar to a clean code, see Drupal, Joomla & co.
There are other reasons, but I want to talk about moving from PHP to Rails.

Qcodo problems are:

QFroms, the form used by Qcodo are dependent form JavaScript, without it, your web site/application will not work.
The JavaScript used is bugged, does not use a mainstream JS framework.
QForm controls, such as text boxes, select lists, sometimes loose the status, so the data have nasty Ajax errors that block the page (it becomes non-responsive).
Ajax error just make the QForm dead. This is not acceptable.
It is an MVC framework, but you do not have a front controller, so forget to use a nice URL out of the box; you have to build a front controller by your own and use mod_rewrite.
It is event-driven too, which is not bad. But, you define all your controls as you do in a desktop-like application, like in VB (the first version was made in Visual Basic!). Lots of HTML is embedded in objects, you do not get the feeling of making a template but you just write just $object->render(). HTML templates should have HTML or tags, as in Java, Pythons or Rails frameworks.
You cannot add JavaScript in your tags, because you do not has tags, but just $object->render() (well you can do it but it is awkward). Instead you have to create a custom object to put your Javascript (official way to do it).
Because of the previous point, to write JavaScript in Qcodo is a pain in the a...
Qcodo is a dead project because the creator, Mike Ho, has blocked the commits to the source code for a lot of time. Now the project is on Github, but it has not changed a lot, for me it is too late and I cannot see anything positive in the roadmap, if there is one.
Qcodo has been forked by some guys because of the problem stated above. The fork is Qcubed. I left that community becouse of their mentality and the ignorance of that people, of course not all of them, but most of the core developers. BDD and DDD for them is something trendy, to make some bucks with consulting. They do not know the framework properly, they are not as good as Mike Ho, they are going in nowhere. Symfony is a much better alternative, but is still PHP.
Again, there are other reasons but I want to talk about how to migrate to Rails.

In the end after evaluating Java, Groovy and Ruby, JRuby, I chose Ruby. Of course I am using the most famous framework, Rails. But how start to use Rails in a corporate intranet near to be released? I decided to write new modules with Rails and leave the rest with PHP, at least for now.

I started by cleaning the CSS and HTML template. When the template was ready I have adopted the same template for Rails and PHP, so the user could not spot the difference that the intranet is using two different environments and languages. Well, before doing that I had installed Pushion Passenger and Ruby Enterprise Edition on the testing and production server (well, the server's admin installed Passenger there).

Then I integrated the sessions by using the PHPSESSID cookie. The user first logs in the PHP intranet, using LDAP, than I store the PHPSESSID value in the database with a corresponding email address, which is unique and it is the user name too. In the application controller (Rails) I get PHP session id (PHPSESSID) from the cookie and than I query an intranet's web service, passing the sessoin id and getting back the corresponding email address. With the email of the user I get the identifier that I need to integrate PHP with Rails, at least the user's credentials. But, why not performing a query directly to the database instead of using the web service. I already have a standalone application that use this solution, so I just cut and pasted the code, with very little modifications, otherwise I just could query the database table.

The tables of the database (MySql) do not follow Rails naming conventions. The first idea was to use another database, but I realized that I could use the same database and Rails' migrations could managed everything, at least the tables used by Rails. I have found several way to use a legacy database with PHP and Rails. Here are some notes during my braindumps:

use ActiveRecord's table_name and primary_key methods to cope with the old table names.
to move functionality and data from PHP-land to Rails-land, use Tim Riley's acts_as_importable plugin
Use views: CREATE VIEW departments as select deptID as id,
`honcho_userID` as head,
`parent_deptID` as parent_id,
`ordinal` as position,
`deptName` as name,
`code`,
`description`,
`contact_us`,
`display`
FROM dept
Use a table prefix to differentiate Rails table from legacy tables: in your config/environment.rb you would add: config.active_record.table_name_prefix = 'rails_'
How to import a legacy data: http://openmonkey.com/articles/2009/05/importing-legacy-data-in-rails
How to protected legacy database access from Rails: http://github.com/jaz303/read_only_model

The above list was used by myself over the last month. It is confusing but makes sense to me. I decided to use views because is an easy way to use Rails naming conventions and helped my to refactor a little bit the database, since I have inherited it from another developer and has lots of ugly names and errors that brakes referential integrity. If you decide to prefix your Rails tables, remenber that there is a but in the testing framework and a table like this:

_users

will become:

__users

I was using an underscore as prefix, but when running 'rake test' the tables where created with two times the prefix. there is a fix for that but it is not included in new versions of Rails and it will never be, since the ticket in Trac has been closed. So I do not use and prefix, old tables use the singular notation, Rails one are plural, that is my way to separate Qcodo's tables form Rails' tables.

I decided to use Rails migrations for any database change, since Rails migrations are capable to do what I want so I get the real benefit to take advantage to version my database changed. I you need to do something that Rails migrations are not capable, just use the execute command and put your SQL as argument.

That's all for now but I will post other interesting things that I will discover in the future.

Create MySql Trigger before deleting a field

2010-01-04T08:27:00.000-08:00

I asked some help from StackOverFlow and I had some partial help. I have a table with departments and the table user is referencing the department table, so every user belongs to one department (one to many). When I have to delete an old deparment it happens that there are some users associated to that department. Since a business rule is to have each user associated to one department or at least to department #1, which is the company it self, I want to set all users' department to 1, if the referenced department is deleted. This can be done with your programming language code or with a trigger, I decided to have a trigger (althogh I usually prefer to use the programming language and MySql as persistent layer, but this is another story).

I have used this code:

CREATE TRIGGER dept_set_user_to_wuk BEFORE DELETE ON dept
FOR EACH ROW UPDATE user SET deptid = 1 WHERE deptid = OLD.deptid;

I have created a trigger named dept_set_user_to_wuk saying that before deleting a row in dept (BEFORE DELETE ON dept), it should update each user's department to the default ID #1. It is worth to mention that the where clause is very important, since I used the OLD keyword. OLD keyword reference the field of the table specified after ON, in this case is the 'dept' table.

How to install mysql gem on Mac

2009-11-24T14:50:00.000-08:00

Download and install the x86 version of MySql, the run the following command:

sudo env ARCHFLAGS="-arch i386" gem install mysql -- \
--with-mysql-dir=/usr/local/mysql --with-mysql-lib=/usr/local/mysql/lib \
--with-mysql-include=/usr/local/mysql/include

This should be enough to have the mysql gem installed

ERROR 1005 (HY000) at line...: Can’t create table ... (errno: 150)

2009-11-23T09:33:00.000-08:00

If you get an error simialr to this:

ERROR 1005 (HY000) at line 244: Can’t create table ‘./intranet2/dept.frm’ (errno: 150)

It means that you should turn off the mysql integrity check with this command:

SET FOREIGN_KEY_CHECKS = 0;

In my case was not enough, I had to remove the to foreign key of that table, load the dump and then recreate the foreign keys. The where some orphan rows, some I removed the problem and applied the foreign keys again.

MIT 6.00 Introduction to Computer Science and Programming

2009-11-10T04:46:00.000-08:00

The following Youtube video is the first lesson of th 6.00 MIT course. It is a fantastic introduction to computer science.

Find orphan rows in MySql

2009-11-10T04:32:00.000-08:00

If you have two tables, with already date on both of them, when you try to apply a foreign key to have referential integrity, you might get this error:

Cannot add or update a child row: a foreign key constraint fails ...

This means that you have one or more rows, in the referenced table, which is missing, so you are trying to reference a row that does not exist. You can use this SQL query to find the missing ids of the referenced table:

SELECT t1.id_referencing_t2
FROM a_table AS t1
LEFT JOIN referenced_table AS t2
ON t1.id_referencing_t2 = t2.primary_id_of_t2
WHERE t2.primary_id_of_t2 IS NULL

You have to substitute the following name with your real one:

id_referencing_t2: the id the reference the primary key on the referenced table.
primary_id_of_t2: the primary key of the referenced table.
a_table: the table that references the referenced table.
referenced_table: is the table that you want to reference, the table that have the missing ids.

The result of the query is the primary key of the rows that points to missing id in the other table. With those ids you can alter the value to a default one, or delete the rows.

Now you should be able to apply referencial integrity to your tables.

Rails default route

2009-10-23T08:59:00.000-07:00

If yuo want to map your Rails' root directory, something like www.example.com/, to a controller, use this directive in your cong/routes.rb:

map.root :controller => 'configurations'

'configurations' is the controller that you might want to map. 'map.root' means 'map the root'.

How to install Mysql/Ruby on Solaris SPARC 64

2009-10-23T03:40:00.000-07:00

I found only partial documentation on how to install the Ruby driver for MySql. There are two version of drivers, one is MySql/Ruby and is written in C, the second is Ruby/MySql and is written in Ruby. Ruby/MySql is included in Rails but has slower performance, plus it was not working with MySql 5.0, it does not work with MySql 4.something too!

So I decieded to compile the C driver. Below you can find the commands:

curl http://tmtm.org/downloads/mysql/ruby/mysql-ruby-2.7.tar.gz -o mysql-gzip -d gzip -d mysql-ruby-2.7.tar.gz
tar xfv mysql-ruby-2.7.tar
cd mysql-ruby-2.7
ruby extconf.rb --with-mysql-include=/usr/local/mysql/include/mysql --with-mysql-lib=/usr/local/mysql/lib/mysql
make
sudo make install

Make sure that 'make install' will be executed as root. Now you can test the connection with:

ruby test.rb [hostname] [username] [dbpassword]

Of course you have to put the host, username and password. Another nice script to test your MySql connection is:

require 'mysql'

mysql = Mysql.init()
mysql.connect('localhost', 'username', 'password')
results = mysql.query("SELECT now();")
results.each{|row|; puts row;}
mysql.close()

Ruby database recipes with MySql

2009-10-22T02:44:00.000-07:00

First of all I am using Windows as OS (yes, I have to use it here).

Rails has a very nice ORM: ActiveRecord. However ActiveRecord is quite complex and a simple library to manipulate data in a script can be more than enough. In this post I will use MySql as DBMS. First of all you need the MySql adapter and the MySql gem:

gem install mysql

If you have troubles when installing the gem and you have the MySql 5.1 client, download and install the 5.0 instead, there are, at the moment of writing some issues in Windows. Now you can check if you can connect to the database. The following example is the code to manipulate data in a MySql table named users. As you can see it is not so different from the previous example, but it can be use with other DBMSs, this is the beauty of a database abstracion layer, using the adapter design pattern.

require 'dbi'

# Connect to a database, old style
dbh = DBI.connect('DBI:Mysql:test:localhost', 'root', 'asdf')

# Insert some rows, use placeholders
1.upto(13) do |i|
sql = "insert into users (username) VALUES (?)"
dbh.do(sql, "user#{i}")
end

# Select all rows from users
sth = dbh.prepare('select * from users')
sth.execute

# Print out each row
while row=sth.fetch do
p row
end

# Close the statement handle when done
sth.finish

# Don't prepare, just do it!
dbh.do('delete from users where id > 10')

# And finally, disconnect
dbh.disconnect

Some useful links:

JRuby, a thread safe Ruby implementation for multi cores

2009-10-18T02:33:00.001-07:00

Ruby 1.8 was not thread safe, now the problem with 1.9 is ended, but there is the global interpreter lock, that prevents the MRI interpreter to scale on multiple cores. JRuby is not written in C, it is written using Java and uses Java threads. Java threads are thread safe and can scale on multiple cores, as any J2EE application.

Please, have a look this Google Tech video by Ola Bini, a JRuby core developer. He talks about JRuby, his threads, garabage collection and more.

Ola Bini works for ThoughtWorks, he has developed another language called Loke. Loke is built to run on the JVM and borrows many ideas from Lisp.

History of Mathematics on Youtube

2009-10-18T02:30:00.000-07:00

Ruby ActiveMQ and Stomp

2009-09-21T09:50:00.000-07:00

Apache ActiveMQ can be used as messaging system with Ruby. The easy way to use it is with the Stomp protocol.

To use tis example you need to use the Stomp gem:

gem install stomp

The following example uses the producer/consumer paridigm. Create and run a consumer script:

require "rubygems"
require "stomp"

client = Stomp::Client.open "stomp://localhost:61613"
# client.send('/queue/testing', "hello world")
# Processing loop
client.subscribe('/queue/testing') do |msg|
puts msg
end
client.join # Wait until listening thread dies

The code above waits for incoming messages, tehn prints the message. Write the producer script:

require "rubygems"
require "stomp"
# connect to ActiveMQ
client = Stomp::Client.open "stomp://localhost:61613"
# send a message to '/queue/testing'
client.send('/queue/testing', "hasta la vista!!")

From this example you can see how easy is to communicate between applications and servers.

The Stomp protocol is an HTTP like protocol to wirte clients to access other protocol or technologies. Here Stomp is used to connect to ActiveMQ, which is a JMS compliant server.

A better way to use MOM services in Ruby is to use the ActiveMessaging gem. You can find an article in InfoQ: Introduction to ActiveMessaging for Rails.

CURL on Windows

2009-08-24T01:44:00.000-07:00

If you need to run curl on Windows you can download it form

the project's wbesite: http://curl.haxx.se/download.html

Then you have to unzip it, and copy culr.exe in "C:\Windows\System32".
If you will try to execute curl you will get an error because OpenSSL is mission.
You should download the installer form here: http://www.shininglightpro.com/products/Win32OpenSSL.html

After running the OpenSSL installer, you can run curl from the command line.

If you want to test a page of a web application, for instance a generated xml file, you can use curl in this way:

curl -H "Accept: application/xml" http://localhost:3000/info/who_bought/3

In that example you specify, in the header, that you want an XML file,
than you pass the URI.

BitNami Project

2009-08-21T05:45:00.000-07:00

BitNami is an Open Source project fousing in ready to install web applications. The software is provided with easy and not invasive installers. But there are more interesting features. The installers are provided for the man platforms, Windows, Linux, Mac OS X and Solaris. Another interesting aspect is that you can install an appication in your machine, your can get a Vmware/VirtualBox images or you can get an ready made image to deploy in a cloud.

The applications provided are endless and I think that is a very easy way to test a software.

Sun's JRuby team jumps ship to Engine Yard

2009-07-28T01:45:00.000-07:00

"The JRuby Guys", Charles Nutter and Thomas Enebo, the main developers of the JRuby project are moving from Sun to Engine Yard. The reason seems to be the uncertainity created by the acqusition by Oracle of Sun. They said that they do not not if Oracle will support JRuby in the future, so they accepted the offer of Engine yard.

Engine yard offers Ruby on Rails hosting on a cloud computing platform. They are very popular in the Ruby world and probably JRuby will continue to be developed and sustained.

2009-07-25T12:00:00.000-07:00

My VX220 when I went two week ago in the Cotwolds. Here is near Broadway, just in the end of the High St.

The Merb Way

2009-07-22T06:33:00.000-07:00

I am really happy to see that there is a new book to learn Merb. This book is published by Addison-Wesley, one of the best IT publishing company. The book covers most of the features, including routing, REST, DataMapper, ERB (Erubis) and HAML, Merb mailers, Behavior Driven Development and testing with RSpec. I think that there is more than enough to write an enterprise application with Ruby and Merb.

This is a list of the topics taken from InformIT web site:

Master Merb innovations that will be incorporated into Rails 3
Understand the fundamentals of Merb development, one step at a time
Use Merb’s sophisticated application router to guide incoming requests
Explore the Merb stack, master its configuration options, and dive into its internals
Use Merb controllers to integrate application code, handle responses, and manage sessions, filters, and exceptions
Build templates with both ERB (Erubis) and HAML
Use the DataMapper ORM to represent object properties and behaviors
Learn best practices for RESTful development with Merb
Leverage Helpers to simplify many common development tasks
Refactor code, encapsulate it in gems, and share it across multiple applications
Customize the responses your application sends to each user
Gain a deep, practical understanding of Merb plugins and extensibility
Authenticate users with Merb’s modular authentication plugin
Configure, generate, describe, and test Merb mailers
Use the merb-parts gem to create component-like regions on Web pages
Cache content to relieve stress on Web servers
Make the most of Behavior Driven Development and testing with RSpec

CMS for Ruby on Rails

2009-07-17T03:49:00.000-07:00

I asked on Stackoverflow a suggestion for a CMS made in RoR. One sugggestion was BrowserCMS. The creators want to create an alternative to Drupal for RoR, well this is what I was looking for. There is an interesting video about BrowserCMS:

PHP 5.3

2009-07-08T06:17:00.001-07:00

PHP 5.3 has been released the 30 of June. I made a post about the infamous GOTO statement, but there are some good news:

Clojures are available in many dynamic language, such as Groovy and Ruby. The problem is that we still have to use the function keywork - I hope that that unecessary keyword will disappear -. In few wors, a closure is a function with some code inside that can be assigned to a variable, then the code can be executed from the variable.

Namespaces are important to avoid name collisions and to create aliases. Any serious programming language should have namespaces, to organize the code and to use classes with the same name but in different packages. With namespaces, in the future, there will be less conflicts in libraries.

nWire for PHP

2009-07-08T06:11:00.000-07:00

nWire will release very soon a stable version of nWire for PHP. nWire is an Eclipse and Zend Studio plug-in to explore PHP code with call hirearchy and diagrams.

Memcached + PHP + Win 32 + ZendServer CE

2009-07-08T02:52:00.000-07:00

If you have the misfortune to develop PHP applications on a Windows box and you want to develop and learn mamcache, this is a quick recipe, but I assume that you have already installed ZendServer CE.

Download a port of memcache to Win32 platform: http://jehiah.cz/projects/memcached-win32/. Then do the following:

1. Unzip the binaries in your desired directory (eg. c:\memcached)
2. Install the service using the command: 'c:\memcached\memcached.exe -d install' from either the command line
3. Start the server from the Microsoft Management Console or by running the following command: 'c:\memcached\memcached.exe -d start'

The the server, by default is listening on port 11211.

When you have started the memcache service you need to activate the PHP module. In ZendServer CE you already have the dll, so go to C:\Program Files\Zend\ZendServer\etc - I presume that you have your ZendServer CE installed in C:\Program Files\Zend\ZendServer\ - uncomment this line:

extension=php_memcache.dll

Restart the server (Apache ZendServer) and you should see that the module is active. Now you can test your installation with the following script:

connect('localhost', 11211) or die ("Could not connect");

$version = $memcache->getVersion();
echo "Server's version: ".$version."
\n";

$tmp_object = new stdClass;
$tmp_object->str_attr = 'test';
$tmp_object->int_attr = 123;

$memcache->set('key', $tmp_object, false, 10) or die ("Failed to save data at the server");
echo "Store data in the cache (data will expire in 10 seconds)
\n";

$get_result = $memcache->get('key');
echo "Data from the cache:
\n";

var_dump($get_result);
?>

Visit the PHP page for memcache: http://php.net/memcache

merb new Ruby framework

2009-06-27T09:47:00.000-07:00

merb is a new framework for Ruby. Why we need merb if we have Rails? merb has data mapper as default ORM tool, which is more powerful than ActiveRecord when dealing with complex databases, plus is more modular and orientated to the enterprise. Matt Amionetti has mad a presentation at QCon, in San Francisco, which is highly suggested if you are interested in merb.

I tried to install merb but the installer crashes because a file is missing in the repository. I have to say than the documentation seems quite incomplete and the web site is quite poor in the design and contents.

However merb is a quite interesting framework, new enterprise ORM, RSec built-in, modular... I will have a look in the future, probably, now I will stick with Grails (built on top of Hibernate and Spring). For web development the better choices are Grails, Rails and now merb (although too young).

References:
Merb: When Flexibility and Performance Matter
merb framework

Metaprogramming in Ruby

2009-06-27T07:20:00.000-07:00

Dave Thomas is on infoq. He explain how metaprogramming in Ruby works. He explains many hidden and unknown features of the Ruby language, for instance the definition of a class can be changed in real time and is possible to define a method using a conditional statement. I have appreciated the the comments about Java, a programming language that was designed for mediocre programmer to commit less mistakes. In Ruby you have less restrictions and the talent is preferred instead of the fear that you have poor quality programmers in your team.

Reference:
http://www.infoq.com/presentations/metaprogramming-ruby

Firefox with full screen mode on Mac

2009-06-27T07:16:00.000-07:00

Some of you should have noticed that Firefox on the mac does not has a full screen mode. There is a simple hack for that. Just install a Firefox plug-in, the you will have an icon in the bottom right of Firefox where you can switch to full or normal view mode.The plug-in is FullerScreen.

References:
https://addons.mozilla.org/en-US/firefox/addon/4650
http://www.mactales.com/article/how-to-fullscreen-firefox-on-os-x-mac-using-fullscreener-plugin/

GOTO in PHP

2009-06-25T02:27:00.000-07:00

I am sad to announce the PHP 5.3 has a new goto statement. From a paper of Dijkstra (1968) the goto statement has been considered harmful and so many year after PHP introduce a goto statement. I think that the spaghetti coders will be happy of using goto in their programs. But what about the credibility of PHP in the enterprise. Zend is claiming that PHP is a good technology for the enterprise environment, well, I do not think so.

Why do not why start to use GWBasic for web programming?

References:

http://www.procata.com/blog/archives/2004/07/29/goto-in-php/

http://uk.php.net/manual/en/control-structures.goto.php

Edsger Dijkstra (March 1968). "Go To Statement Considered Harmful" (PDF). Communications of the ACM 11 (3): 147–148. doi:10.1145/362929.362947. http://www.cs.utexas.edu/users/EWD/ewd02xx/EWD215.PDF. "The unbridled use of the go to statement has as an immediate consequence that it becomes terribly hard to find a meaningful set of coordinates in which to describe the process progress. ... The go to statement as it stands is just too primitive, it is too much an invitation to make a mess of one's program.".

Web Services

2009-06-14T11:20:00.000-07:00

This week I have learnt so many things about web services. Eclipse and Axis2 are very useful to create, consume and register web services. The main protocol are SOAP, WDSL and UDDI. SOAP is use to exchange the messages, WDSL to describe a web service and UDDI is directory service used to register/publish web services. It is possible to access a web service using only UDDI, but this approach does not follow really the UDDDI standards. There is an alternative to UDDI, created and maintained by IBM, is known as WSIL, but UDDI is more well known. OASIS maintains UDDI.

Useful links:

UDDI on Wikipedia
Code Generator Wizard - eclipse Plug-in
Eclipse WTP Tutorials - Creating Bottom Up Web Service via Apache Axis2

The Origins of Linux - Linus Torvalds

2009-06-14T08:04:00.000-07:00

In this video, a bit old, you can here the history of Linux for Linus Torvalds.

FreeBSD on a desktop

2009-06-14T06:29:00.000-07:00

In the following video you can see FreeBSD on a desktop with Beryl.

Political election farce in Iran.

2009-06-14T06:22:00.000-07:00

It is incredible what is happening in Iran. They tricked the elections. After 20 minutes the end of the voting time, they have declared that they won the election. This is a bad news for the world too. It is not a democracy, it is a dictatorship! It is a shame!

A video to understand what is the credit crunch

2009-06-12T00:17:00.000-07:00

Learn limits online

2009-06-07T13:17:00.000-07:00

I have found a website, http://www.justmathtutoring.com/, full of tutorials on mathematics. The author has published more than 300 videos on youtube. An example is the following video about limits.

Use Hazelcast library in PHP

2009-06-05T04:37:00.000-07:00

If you want the power of Java in PHP, easily, the answer is Quercus / PHP. Quercus is a 100% implementation of PHP in Java. I have downloaed the GPL version of Resin, unzipped in C:\. The file to start the server is httpd.exe.

In "C:\resin-3.1.9\webapps\ROOT\WEB-INF" you will find "resin-web.xml", the configuration file of Resin. Copy the following text:

servlet-class="com.caucho.quercus.servlet.QuercusServlet">

Than create this file "hello-world.php" in "C:\resin-3.1.9\webapps\ROOT" and copy this text:

echo "Hello World";
?>

Now you should be able to see the script executed: http://localhost:8080/hello-world.php

Go to the Hazelcast web site and download the zip. Inside the zip copy "hazelcast.jar" in "C:\resin-3.1.9\webapps\ROOT\WEB-INF\lib", create the lib directory if does not exist.

Create another php file, say "htest.php". Copy the code:

import com.hazelcast.core.Hazelcast;
import java.util.Map;
import java.util.Collection;
require_once './Customer.php';

$mapCustomers = Hazelcast::getMap("customers");
$mapCustomers->put("1", new Customer("Joe", "Smith"));
$mapCustomers->put("2", new Customer("Ali", "Selam"));
$mapCustomers->put("3", new Customer("Avi", "Noyan"));

$colCustomers = $mapCustomers->values();
foreach ($mapCustomers as $cus) {
echo $cus->getName().'
';
}
?>

In "htest.php" you call the Hazelcast library, get an instance of a Map, a distributed Map! You put 3 new object into the map and than you print its property. To run this example you have to create the "Customer" class in PHP. In the same directory create "Customer.php" and copy this code:

class Customer {
protected $strName;

public function __construct($strName) {
$this->strName = $strName;
}

public function getName() {
return $this->strName;
}
}
?>

Tahn run the example: http://localhost:8080/htest.php

You should get this output:

Joe
Ali
Avi

Links:

Quercus
Hazelcast
Hazelcast docs
Infoq: PHP on Java: Best of Both Worlds?
Use Java to Improve Drupal's Scalability

Performance of PHP platforms

2009-06-05T02:37:00.000-07:00

I tested some different platforms to see which one has the best perfomance. I tested Zend Server CE, a SAMP environment and Resin with Quercus.

The Zend Server is running on my PC:

OS: Windows XP
Processor: P4 HT
RAM: 1GB

This is the script that I used to test the performance:

missing

This script is executed in 4.317 seconds on the Send Server CE.

The Resin Server Pro, with the compile option for better performance, executes the script in 12.72 seconds. The Resin Server with GPL license, without the compile option on, executes the script in 13.60 seconds. Both of versions of Resin are installed in my PC.

The SAMP server, is on a Solaris server, 32GB RAM and many CPUs. The execution time on Soalris is 36.79 seconds! On Solaris is used the Apache Handler and there is only eAccelerator, not APC.

My conclusion is that having a caching module on, it makes a big difference. Having Zend Server CE makes a huge difference. I do not think that Resin Pro is quite better than the GPL version, since the difference is very little.

In the end I would choose Resin Server with GPL license. A unique benefit is to have the integration of PHP with Java and the other dynamic languages, running on the JVM.

M888 - Databases in enterprise systems

2009-05-27T01:41:00.000-07:00

I find interesting a course of The Open University, at postgraduate level, that talks about databases in the enterprise. The course covers ODBC and JDBC, the some popular persistence frameworks (e.g. Java EE, .NET, Hibernate, Toplink) and SQL/J (a multi-part specification for using SQL with Java). The course covers even web application frameworks (e.g. ASP.NET, PHP). This course probably is useful to have a general understanding a the possible solutions availables on the market; thus I think is more for software architect than programmers.

Test Driven Development Tutorial

2009-05-19T02:54:00.001-07:00

The presentation is an introduction to TDD. It is quite useful to developers new to TDD.

Test Driven Development Tutorial

View more presentations from Skud.

Map a directory in Apache outside the documentroot

2009-05-18T01:49:00.001-07:00

Assuming that you are using Zend Server CE under Windoes and that is installed in "C:\Program Files\Zend", here is how to map a directory, which is outside the documentroot.

* Create a new directory: C:\Program Files\Zend\Apache2\lol
* Add a new alias in C:\Program Files\Zend\Apache2\conf\http.conf, inside "": Alias /lol "C:\Program Files\Zend\Apache2\lol"
* Add the permissions to the direcotry:

Order allow,deny
Allow from all

Than you can reach the directory "lol": http://localhost/lol/

Enumerator class in PHP

2009-05-14T06:36:00.000-07:00

If you want an elegant way to an have enumerated type try this:

class QFlashMessageType {
const Info = 0;
const Error = 1;
}

You can use it in this way:
QFlashMessageType::Info;

An enum class example on stackoverflow: http://stackoverflow.com/questions/254514/php-and-enums

Accelerated C++: Practical Programming by Example

2009-05-12T15:08:00.001-07:00

I have bought this book two days ago: Accelerated C++: Practical Programming by Example. Tomorrow I will have the pleasure to have a look if it is as good as the rating a Amazon UK. I have found interesting a review by ddddd and this is an extract of the review:

"I've seen other books that try to teach you C++ from the ground up, not giving useful advice until they've bored you with pointers and memory management and so on. Let me say, the way these folks do it (high-level library functions first, primitive data structures later, then OO at the end) is surely the way to go. What's more, this book gets you in the habit of elegant, modular programming, although its main focus is on problem-solving, not style."

It seems that someone, in the end, has found a way to teach C++ in a non-painful way. I think that by learning C++ using example and high level classes is better than explaining any detail about the data type and pointer - although this is important too -.

The World's first web server

2009-03-01T05:03:00.000-08:00

The world's first web server was the NeXTstation used by Tim Banners Lee at CERN. The manufacturer is NeXT, inc founded by Steve Jobs. NeXT was acquired by Apple and NeXTSTEP was used to build the operating system of the lastest Mac: Max OS X.

Link: http://info.cern.ch/

How to get the properties of an object with PHP

2009-02-26T08:20:00.000-08:00

How to get the properties of an object:

$ref = new ReflectionClass('User');
$props = $ref->getProperties();
foreach($props as $prop) {
echo $prop->name .'
';
}

In this case the properties of the class User will be printed.

JBoss AS Tools

2009-02-20T07:18:00.000-08:00

After testing JSP and Servlet with Tomcat, inside Eclipse, I thought to try JBoss AS, the famous application server of Jboss. How to install JBoss AS and JBoss AS Tools in Eclipse:

Download JBoss AS 5, decompress it in a directory.
In Eclipse, click on Help -> Software updates and Add-ons, type jboss in the filter and press enter.
Flag 'JBoss Tools Relaese' and follow the simple installation procedure.
Then click in Window -> Preferences -> Server -> Runtime Environments, click on 'Add', select the directory where you have extracted JBoss AS, select the JRE (I think that it should be and SDK). Click on 'Finish'.

Now JBoos AS is installed and can be start, stop inside Eclipse.

Developing Web applications with Tomcat and Eclipse

2009-02-20T07:12:00.000-08:00

I have found a nice article about the development of Java web applications with Eclipse. It is the best and quickest article that I have ever seen.

Zend Server Public Beta

2009-02-19T01:20:00.000-08:00

Zend has released a new PHP application server. Now Zend Core and Zend Platform are distributed together. From the product description:

Fully supported and certified distribution of PHP 5.2
Fully supported Zend Framework 1.7 release
Integrated native installers (RPM/DEB/MSI)
Web-based administration Interface
Comprehensive out-of-the-box database connectivity
Powerful PHP monitoring capabilities to identify problems and help fix them quickly
URL-based output caching required by today's modern web applications
Zend Optimizer+ - byte code cache to boost application performance
New "Guard Loader" to enable processing of Zend Guard encoded files

Andi Gutmans is the new CEO of Zend Technologies

2009-02-04T02:13:00.000-08:00

Andi Gutmans, founder of Zend is the new CEO. He was senior vice president of R&D.

Cameron Lester said that Zend Technologies, with Andi as CEO, will be more effective in its innovation strategies. This, in my opinion, is a signal that Zend is continuing in his strategy to bring more innovation in his IT consulting services and technologies.

Mark Burton, former executive vice president of MySql, is now executive chairman.

The Decline and Fall of Agile

2009-01-23T01:58:00.000-08:00

I have found an interesting post in a blog that is talking about that there are many failures in the software development using Agile methods. One thing to learn from that post is that Agile is hard to apply and most of the time the teams use only a part of the methods. Using only a part of those methods means that the team will fails to use Agile. This type of problem is even wrose using Scrum.

The post: http://jamesshore.com/Blog/The-Decline-and-Fall-of-Agile.html

Beginning POJOs: Lightweight Java Web Development Using Plain Old Java Objects in Spring, Hibernate, and Tapestry

2009-01-16T02:41:00.000-08:00

This new book from Apress seems to me very interesting: it covers a lightweight development way for J2EE. The main tools and technologies are covered:

Eclipse
Ant
Spring
Hibernate
Jboss Seam

I think I will order one because I was looking for a book providing an integrated approach to the overmentioned tools and frameworks.

My new car

2009-01-10T11:50:00.000-08:00

I am going to buy this VX220. I have driven this car and I must admin that I was very impressed. A very nice experience. The engine is not so powerful - the previous Honda Integra that I owned had a fantastic engine -, but the difference is the frame and the light weight. With this car I will really enjoy driving, even in the every day life. Yes, it is not a very handy car and I am happy that it is not.

ActiveVOS

2009-01-06T05:48:00.000-08:00

http://www.activevos.com is the web site of Active Endpoints. ActiveVOS is "the world's first all-in-one, standards-based visual orchestration system -- is the only SOA-based process orchestration and business process management (BPM)".

If you are interested in SOA development and business process management you can find more information here: http://www.activevos.com/indepth.php

New Blog

2009-01-05T04:01:00.000-08:00

Hi,

This is my first post on this new blog. I am a web developer working for an FTSE 100 company in the UK. I develop in PHP using the Qcodo framework, but I am studying GRAILS and FLEX.

In this blog I will post articles and news about software development/engineering. I hope that you will find it helpful. do not hesitate to contact me.