This is an example of how to use ActiveRecord without Rails:

   1  ['/model', '/db'].each do |folder|
   2    $:.unshift File.dirname(__FILE__) + folder
   3  end
   4  
   5  require 'test/unit'
   6  require 'rubygems'
   7  require 'activerecord'
   8  
   9  ActiveRecord::Base.logger = Logger.new(File.dirname(__FILE__) + '/debug.log')
  10  ActiveRecord::Base.configurations = YAML::load(IO.read(File.dirname(__FILE__) + '/config/database.yml'))
  11  ActiveRecord::Base.establish_connection('sqlite3')
  12  
  13  require 'schema'
  14  

Schema contains, for example:

   1  ActiveRecord::Schema.define :version => 0 do
   2    create_table :languages, :force => true do |t|
   3      t.string :name
   4    end
   5  end

This snippets shows you how to create a daemon process out of an ordinary Ruby script.

First you’ll need the daemons gem:

   1  gem install daemons

Then you’ll need the daemon script, for example daemon.rb:

   1  require 'rubygems'
   2  require 'daemons'
   3  
   4  pwd  = File.dirname(File.expand_path(__FILE__))
   5  file = pwd + '/../lib/background_service.rb'
   6  
   7  Daemons.run_proc(
   8    'background_service', # name of daemon
   9  #  :dir_mode => :normal
  10  #  :dir => File.join(pwd, 'tmp/pids'), # directory where pid file will be stored
  11  #  :backtrace => true,
  12  #  :monitor => true,
  13    :log_output => true
  14  ) do
  15    exec "ruby #{file}"
  16  end

Change the file variable to point to the script you want to daemonize and your good to go.

You can now execute the daemon.rb script without parameters to get a list of available commands for controlling the daemon process:

   1  ERROR: no command given
   2  
   3  Usage: lib/background_service.rb <command> <options> -- <application options>
   4  
   5  * where <command> is one of:
   6    start         start an instance of the application
   7    stop          stop all instances of the application
   8    restart       stop all instances and restart them afterwards
   9    run           start the application and stay on top
  10    zap           set the application to a stopped state
  11  
  12  * and where <options> may contain several of the following:
  13  
  14      -t, --ontop                      Stay on top (does not daemonize)
  15      -f, --force                      Force operation
  16  
  17  Common options:
  18      -h, --help                       Show this message
  19          --version                    Show version

Simple example of how to use the named_scope feature:

   1  class Feed < ActiveRecord::Base
   2   
   3    named_scope :active, :conditions => "(active = 1)"
   4    named_scope :stale,  :conditions => ["last_updated > ?", 30.minutes.ago.to_s(:db)]

Usage:

   1  Feed.active # return the active feeds

Chaining is also possible:

   1  Feed.active.stale # return the feeds that need to be updated

First read this... then this

   1  draft

You can use Ruby’s Enumerable sort_by to sort an array correctly using Gibberish and Gibberish DB

It’s not pretty, but it works on non-paginated lists. For pagination something else must bee cooked up. Here I sort an array of Category objects according to the localized name of the category.

   1  @categories = @categories.sort_by{|a| 
   2        a[:name][].to_s
   3      }