Thoughts Unlimited

Using Qooxdoo in Rails

maravan — Fri, 20 Oct 2006 13:07:42 +0000

Let us create a simple rails application called namelist with just one model.

gg[qtest]$ rails namelist -d sqlite3

I am using my favorite sqlite3 to power the app. Feel free to use the database of your choice.

Now create a model called Person

gg[namelist]$ ruby script/generate model Person
      exists  app/models/
      exists  test/unit/
      exists  test/fixtures/
      create  app/models/person.rb
      create  test/unit/person_test.rb
      create  test/fixtures/people.yml
      create  db/migrate
      create  db/migrate/001_create_people.rb

The model person has just one attribute called ‘name’. The migration script for the Person model as below

  1 class CreatePeople < ActiveRecord::Migration
  2   def self.up
  3     create_table :people do |t|
  4       t.column :name, :string
  5     end
  6   end
  7
  8   def self.down
  9     drop_table :people
 10   end
 11 end

Run the migration to setup the database tables.

gg[namelist]$ rake migrate

Create a new controller called qx

gg[namelist]$ ruby script/generate controller qx
      exists  app/controllers/
      exists  app/helpers/
      create  app/views/qx
      exists  test/functional/
      create  app/controllers/qx_controller.rb
      create  test/functional/qx_controller_test.rb
      create  app/helpers/qx_helper.rb

Copy the qoxdoo framework files to our app’s public directory.

gg[namelist]$ cp ~/dump/qooxdoo/qooxdoo-0.6.1-build/frontend/framework/script/qx.js public/javascripts/.
gg[namelist]$ cp -rf ~/dump/qooxdoo/qooxdoo-0.6.1-build/frontend/framework/resource public

Add two actions to the qx controller as follows

 1 class QxController < ApplicationController
 2   def index
 3   end
 4   def hai
 5     person = Person.new
 6     person.name = params[:name]
 7     person.save
 8     person.reload
 9
 10     @people = Person.find(:all)
 11
 12     respond_to do |res|
 13       res.xml do
 14         render :partial => 'list'
 15       end
 16     end
 17   end
 18 end

The partial file is as follows

  1 xml.tag!('qx.client.builder.Container') do
  2   @people.each do |person|
  3     xml.tag!('qx.ui.form.ListItem', :label => person.name, :value => person.id)
  4   end
  5 end

Create our main html file as follows

  1 
  2   
  3     
  4       NameList Application
  5     
  6     
  7   
  8   
  9     
 56   
 57

Getting started with Qooxdoo

maravan — Fri, 20 Oct 2006 10:53:12 +0000

Qooxdoo is an excellent Javascript based GUI framework. It has a rich set of widgets and inbuilt AJAX support.

To get started, download the precompiled Qooxdoo from http://qooxdoo.org/download. The framework javascript file and the related widget image files are found under qooxdoo-0.6.1-build/frontend/framework

Now let us develop a traditional Hello World program in Qooxdoo.

Create a new directory for your application

gg[~]$ mkdir qtest

gg[~]$ cd qtest

Copy the contents of the framework directory to your application folder

gg[qtest]$ cp -rf ../dump/qooxdoo/qooxdoo-0.6.1-build/frontend/framework/* .

gg[qtest]$ ls

resource  script

Now create your main html file with the following content.

1 
2   
3     
4       Qooxdoo Test
5     
6     
7   
8   
9     
29   
30

- In line no 6 the main javascript file qx.js is included.
- In line no 10, an anonymous function is created and is assigned as the main qooxdoo function.
- An ClientDocument object is created in line no 12. ClientDocument is the basic widget of all qooxdoo application. It acts as the parent of all the widgets in your application.
- A new button object is created in line no 13, it’s top and left attribute are set. We then add an event listener in line no 18. So basically the function buttonExecute will be called whenever any button event occur.

Rails paginate for collections

maravan — Thu, 19 Oct 2006 11:30:28 +0000

To generate pagination for your collections, add the following action to your controller.

def paginate_collection(collection, options = {})
  default_options = {:per_page => 10, :page => 1}
  options = default_options.merge options
  pages = Paginator.new self, collection.size, options[:per_page], options[:page]
  first = pages.current.offset
  last = [first + options[:per_page], collection.size].min
  slice = collection[first...last]
  return [pages, slice]
end

Now you can call the custom paginate_collection in your controller as follows.

@female_students = Student.find(:all).select do |student|
    student.sex == 'female'
end
@student_pages, @students = paginate_collection @female_students, :per_page => 10

The ruby strip() method

maravan — Mon, 16 Oct 2006 12:04:06 +0000

Ruby’s strip() method is useful for stripping extra spaces in strings. Unfortunately, you cannot use strip() method to remove non-space characters from a string.

The following method can strip non-space characters from a string as well.

def strip(str,char)
   new_str = ""
   str.each_byte do |byte|
      new_str << byte.chr unless byte.chr == char
   end
   new_str
end

Example: strip('Hello World','o') #=> Hell Wrld