Fun On Rails: A ruby and rails blog

using modules and mixins in ruby

by sandipransing 0 comments

Before getting started with modules and mixins, lets first find out the need of module & mixins in OOP.

In object oriented programming languages multiple inheritance is basic paradigm (child class extends behavior of base class).

C++ supports multiple inheritance. Java does support same using interfaces.
In ruby language, multiple inheritance is achieved very easily using mixin of modules & classes and that makes ruby as powerful language.

Ruby has classes, modules. Modules can be included inside other classes (mixins) to achieve multiple inheritance.

Modules


  module Greeting
    # here below is the instance method
    # and that can be accessed using object of class ONLY
    def hi
      puts 'Guest'
    end
  end

Module methods can be called using scope resolution operator (::) or dot operator (.)
Greeting::hi # => undefined method `hi' for Greeting:Module (NoMethodError) It is obivous to have an error because we are calling class method and that is not present inside module.

Mixins Lets include greeting module inside person class


class Person

  include Greeting
end

person = Person.new person.hi #=> "Guest" Lets see how module methods can be defined. It can be done using either self or class_name.


module Greeting
  # here below is the instance method
  # and that can be accessed using object of class ONLY
  def hi
    puts 'Guest'
  end
  # Below are module methods
  # this methods can be invoked
  # using Greeting::hi
  # OR Greeting.hi
  def self.hi
    puts 'hi Sandip'
  end
  # here is one more way to declare
  # module methods
  def Greeting.bye
    puts 'Bye Sandip!'
  end
end

Lets invoke methods
Greeting::hi #=> "hi Sandip" Greeting.bye #=> "Bye Sandip!" Extending class behavior using modules


class Person  
  def self.included(base)
    base.extend Greeting
  end
end

Got easy ?? Cheers!

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using thinking sphinx search in rails app

by sandipransing 0 comments

I am using acts_as_ferret and ferret server as of now with my rails application and it just works fine for me. The ONLY problem is performance as it takes a lot time to build index and to rebuild index when it gets screwed up and that's where sphinx rocks!
To get started with thinking sphinx you need to install sphinx server first. for installation help click here.
To use sphinx search in rails we need to use either thinking sphinx gem or plugin that can be easily find on github.
Plugin installation
./script/plugin install git://github.com/freelancing-god/thinking-sphinx.git
OR
To install gem run the following command.
gem install thinking-sphinx --source http://rubygems.org/ If you're upgrading, you should read this: http://freelancing-god.github.com/ts/en/upgrading.html Successfully installed thinking-sphinx-1.3.16 1 gem installed Edit environment file and add following lines to it inside initializer block.


config.gem(
     'thinking-sphinx',
      :lib     => 'thinking_sphinx',
      :version => '1.3.16'
 )

Edit Rakefile and add following lines to it.


require 'thinking_sphinx/tasks'

List rake task that should show up sphinx related tasks.
rake -T ts (in /home/sandip/v1) rake doc:plugins:acts_as_audited # Generate documentation for the acts_as_... rake doc:plugins:acts_as_ferret # Generate documentation for the acts_as_... rake rails:update:javascripts # Update your javascripts from your curre... rake rails:update:scripts # Add new scripts to the application scri... rake stats # Report code statistics (KLOCs, etc) fro... rake test:units # Run tests for unitsdb:test:prepare / Ru... rake tmp:sockets:clear # Clears all files in tmp/sockets rake ts:conf # Generate the Sphinx configuration file ... rake ts:config # Generate the Sphinx configuration file ... rake ts:in # Index data for Sphinx using Thinking Sp... rake ts:rebuild # Stop Sphinx (if it's running), rebuild ... rake ts:reindex # Reindex Sphinx without regenerating the... rake ts:restart # Restart Sphinx / Restart Sphinx rake ts:run # Stop if running, then start a Sphinx se... rake ts:start # Start a Sphinx searchd daemon using Thi... rake ts:stop # Stop Sphinx using Thinking Sphinx's set... rake ts:version # Output the current Thinking Sphinx vers... Start sphinx server this should give up an error.
rake ts:start (in /home/sandip/v1) Failed to start searchd daemon. Check /home/sandip/v1/log/searchd.log. Adding indexes in models


define_index do
     # following fields are database fields
     # we can not add model methods in sphinx index 
     # sphinx fields allows ONLY model based associations
     # fields
      indexes customer_name
      indexes phone
      indexes mobile
      indexes other_phone
      indexes car_make
      indexes car_model
      indexes registration_no
end

Configure sphinx
rake ts:config Generating Configuration to /home/sandip/v1/config/development.sphinx.conf Index sphinx
rake ts:in (in /home/sandip/v1) Generating Configuration to /home/sandip/v1/config/development.sphinx.conf Sphinx 0.9.8-rc2 (r1234) Copyright (c) 2001-2008, Andrew Aksyonoff using config file '/home/sandip/v1/config/development.sphinx.conf'... indexing index 'call_core'... collected 113521 docs, 2.1 MB collected 0 attr values sorted 0.1 Mvalues, 100.0% done sorted 0.3 Mhits, 100.0% done total 113521 docs, 2114790 bytes total 6.102 sec, 346589.68 bytes/sec, 18604.78 docs/sec distributed index 'call' can not be directly indexed; skipping. Generating Configuration to /home/sandip/v1/config/development.sphinx.conf Sphinx 0.9.8-rc2 (r1234) Copyright (c) 2001-2008, Andrew Aksyonoff using config file '/home/sandip/v1/config/development.sphinx.conf'... indexing index 'call_core'... collected 113521 docs, 2.1 MB collected 0 attr values sorted 0.1 Mvalues, 100.0% done sorted 0.3 Mhits, 100.0% done total 113521 docs, 2114790 bytes total 3.628 sec, 582909.70 bytes/sec, 31290.34 docs/sec distributed index 'call' can not be directly indexed; skipping. Search using sphinx
./script console >>Call.search 'sandip' => [#, #]
It returns array of records found. conditions are allowed by sphinx. If you need to add conditions on integer attributes then index block in model needs to have has method like author_id in following.


define_index do
  indexes content
  indexes :name, :sortable => true
  indexes comments.content, :as => :comment_content
  indexes [author.first_name, author.last_name], :as => :author_name
  
  has author_id, created_at
end

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