Open Rails

Installing the postgresql 9.1 on Ubuntu 11

2012-02-13T23:29:00.000-08:00

Installation of Postgresql

1. $ sudo add-apt-repository ppa:pitti/postgresql

$ sudo apt-get update and sudo apt-get install postgresql
check if postgresql installed properly

psql -V //you must get psql (PostgreSQL) 9.0.4
finger postgres to get the installation overview
lets login to postgres

$su postgres
psql // you would be logged in to psql terminal postgres=# select version();

Setting up root user for postgres

$ su postgres # switch to the user postgres

    $ cd /etc/postgresql/9.0/main

cp pg_hba.conf         pg_hba.conf.bak.original

cp postgresql.conf       postgresql.conf.bak.original

Make changes to pg_hba.config (authetification methods).

host    all         all       127.0.0.1/32       trust

# md5 -> trust

Now we can start our postgres server

$ sudo /etc/init.d/postgresql restart

* Restarting PostgreSQL 9.0 database server

$ sudo /etc/init.d/postgresql status Running clusters: 9.0/main

Install Pgadmin3 tool for managing postgres

 $ sudo apt-get install pgadmin3

# install the latest pgAdminIII

type pgadmin3 in terminal to launch

Thinking Sphinx for Rails 3

2012-01-15T07:55:00.000-08:00

Step 1
Sphinx Installation:

wget http://www.sphinxsearch.com/downloads/sphinx-0.9.9.tar.gz

tar -xzf sphinx-0.9.9-rc2.tar

.gz

cd sphinx-0.9.9-rc2/
./configure
make
sudomakeinstall

Note: sphinx By default comes with Mysql configuration, to configure it with pgsql
./configure --prefix=/usr/local  --with-pgsql --without-mysql

Step 2
Thinking Sphinx Installation
In you Gem File add
1. gem 'thinking-sphinx', :git => 'http://github.com/freelancing-god/thinking-sphinx.git', :require => 'thinking_sphinx'


2. run bundle install

rake thinking_sphinx:index – Create the index
rake  thinking_sphinx:reindex – Reindex Sphinx without regenerating the  configuration file
rake  thinking_sphinx:start – Start up Sphinx's daemon
rake  thinking_sphinx:stop – Shut down the daemon

Example Usage of Thinking sphinx
In your Model:
define_index  do    indexes location
    indexes [first_name, last_name], :as  => :name, :sortable => true
end

let Sphinx know your fields that has to be indexed.

Thats it you can search now using Model.search("first_name last_name")
 

Thumbs up in Rails

2012-01-09T02:58:00.000-08:00

1. instal the gem :

gem 'thumbs_up'

.2. Create and run the ThumbsUp migration:

rails generate thumbs_up
rake db:migrate

.3. setting the model that act as voter

class User < ActiveRecord::Base
acts_as_voter
end

setting the model that can be voted

class Comment < ActiveRecord::Base
acts_as_voteable
end

4. To save the Vote
voter.vote_for(voteable) # Adds a +1 vote

voter.vote_against(voteable)    # Adds a -1 vote
voter.vote(voteable, vote)

# Adds either a +1 or -1 vote: vote => true (+1), vote => false (-1)

voter.vote_exclusively_for(voteable)

# Removes any previous votes by that particular voter, and votes for.


voter.vote_exclusively_against(voteable)    # Removes any previous votes by that particular voter, and votes against.

5. Other Useful methods

positiveVoteCount = voteable.votes_for
negativeVoteCount = voteable.votes_against
plusminus         = voteable.plusminus  # Votes for minus votes against.

voter.voted_for?(voteable) # True if the voter voted for this object.
voter.vote_count(:up | :down | :all) # returns the count of +1, -1, or all votes

voteable.voted_by?(voter) # True if the voter voted for this object.
voters = voteable.voters_who_voted

Note :  ThumbsUp by default only allows one vote per user.

This can be changed by removing:

In vote.rb:

validates_uniqueness_of :voteable_id, :scope => [:voteable_type, :voter_type, :voter_id]

In the migration:
 add_index :votes, ["voter_id", "voter_type", "voteable_id", "voteable_type"], :unique => true, :name => "uniq_one_vote_only"

Install Ruby 1.8 and rails 3 from source and repository

2012-01-09T02:31:00.000-08:00

From Ubuntu repo:

you should add the ubuntu-on-rails ppa repository

sudo add-apt-repository ppa:ubuntu-on-rails sudo apt-get update

Now get the essential ruby packages:

sudo apt-get install ruby rubygems irb ri rdoc rake

The dependencies should look like:
irb1.8 libreadline-ruby1.8 libreadline5 libruby1.8 rdoc1.8 ri1.8 ruby1.8 rubygems1.8

But you need more packages!

sudo apt-get install build-essential ruby1.8-dev libopenssl-ruby

These extra packages are very important – odds are high that you will need them. Unfortunately they are not in the standard package dependencies, partly because of some licensing issues – readline and openssl have incompatible licenses.

After getting all packages, there is another little step necessary: You have to add the gem path to your global PATH, so that executables new gems can be easily called from the command line. Do it by adding the following line to your ~/.bashrc:

export PATH=/var/lib/gems/1.8/bin:$PATH

Then restart your terminal or enter source ~/.bashrc

Ruby is ready now :)

From Source:

This way is recommended, when you want to have full control over your installation.

Do not get deterred, it is not that hard. Firstly, get the needed dev packages:

sudo apt-get install libruby1.8 libruby1.9
zlib1g-dev libssl-dev libreadline-dev build-essential

1.9
@wget http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.3-p0.tar.gz
tar -xzf ruby-1.9.3-p0.tar.gz
1.8
wget ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p334.tar.gz wget http://production.cf.rubygems.org/rubygems/rubygems-1.8.5.tgz tar -xzf ruby-1.8.7-p334.tar.gz tar -xzf rubygems-1.8.5.tgz
Now navigate to the extracted ruby directory and run:
./configure make sudo make install
To install both versions at the same time (without RVM), you can pass a --program-suffix option to one of the ./configurecommands before compiling.
You can check if this was successful with: ruby -v

Installing Rails 
Choose a database, for example sqlite3
sudo apt-get install sqlite3 libsqlite3-dev sudo gem install sqlite3-ruby
or MySQL
sudo apt-get install mysql-server libmysqlclient-dev sudo gem install mysql
and install the framework:
sudo gem install rails

Common fixes while installation:
openssl (1.8)
/var/lib/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:271:in `require_frameworks': no such file to load -- net/https (RuntimeError)
sudo apt-get install libopenssl-ruby
openssl (1.9.1)
/var/lib/gems/1.9.1/gems/rails-2.3.5/lib/initializer.rb:271:in `rescue in require_frameworks': no such file to load -- net/https (RuntimeError)
sudo apt-get install libopenssl-ruby1.9.1
ruby1.8-dev
ERROR: Failed to build gem native extensions. /usr/bin/ruby1.8 extconf.rb extconf.rb:8:in `require': no such file to load -- mkmf (LoadError)
sudo apt-get install ruby1.8-dev
ruby1.9.1-dev
ERROR: Failed to build gem native extensions. /usr/bin/ruby1.9.1 extconf.rb extconf.rb:1:in `require': no such file to load -- mkmf (LoadError)
sudo apt-get install ruby1.9.1-dev
build-essential
make: g++: Command not found
sudo apt-get install build-essential
wrong gem path settings
The program 'rails' is currently not installed. You can install it by typing: sudo apt-get install rails
Add export PATH=/var/lib/gems/1.8/bin:$PATH to the ~/.bash.rc file and restart your terminal (adjust the version number, if needed).

Adding BreadCrums in Rails 3 application

2011-12-19T23:36:00.000-08:00

I recently came across a plugin that easily helps you add breadcrums to your app ad helps you customize it.

1. install the plugin in rails 3 app:

rails plugin install git://github.com/weppos/breadcrumbs_on_rails.git

2. add this line in application.rb file

include BreadcrumbsOnRails::ControllerMixin

3. in controller:

class MyController
 
add_breadcrumb "home", :root_path
 
add_breadcrumb "my", :my_path
 
def index
 
# ...
 
add_breadcrumb "index", index_path
 
end

end

4. in views:

 
<%= render_breadcrumbs %>
 

Note:

1. changes in lib/breadcrums.rb

def render_element(element)
 
content = context.link_to_unless_current(compute_name(element), compute_path(element))
 
if @options[:tag]
 
@context.content_tag(@options[:tag], content.html_safe)
 
else
 
content.html_safe
 
end

end

2. changes in lib/controller_mixin.rb

def render_breadcrumbs(options = {}, &block)
 
builder = (options.delete(:builder) || Breadcrumbs::SimpleBuilder).new(self, breadcrumbs, options)
 
content = builder.render
 
if block_given?
 
concat(capture(content, &block)).html_safe
 
else
 
content.html_safe
 
end

end

Switch User with a single Login in Rails 3

2011-10-21T04:22:00.000-07:00

switch_user is very useful in such use cases

switch current users in development so that you don't waste your time to logout,
login and input email (login) or password any more.

reproduce the user specified error in production.

Sometimes the error is only raised for specified user,

which is difficult to reproduce for developers,

switch_user can help you reproduce it by login as that user.

INSTALL:

Add in Gemfile.

gem "switch_user"

Add following code into your layout page.
erb
<%= switch_user_select %> 
For further Configuration Refer Link:
https://github.com/flyerhzm/switch_user
Visit here: http://switch-user-example.heroku.com/, 
switch the current user in the select box.

jquery on rails 3

2011-09-20T01:33:00.000-07:00

How to include only jquery in your rails 3 app.

1. In your Gem file include: gem "jquery-rails"

2. Run bundle install to install the jquery-rails gem

3. Run:

rails generate jquery:install or rails g jquery:install 
This will remove prototype js files and make sure your rails 3
 app will run on jquery from now.

Working with git

2011-09-14T21:57:00.000-07:00

--Git install--

sudo apt-get install git-core

--Other Installation(Not Mandatory)--

sudo apt-get install gitk

--Check Install--

which git

git --version

--Initial Setup(Recommended)--

git config --list

git config --global user.name "FirstName LastName"

git config --global user.email "user@example.com"

--Initail Setup(Optional Configuration)--

git config --global alias.co checkout # Create aliases..... this command will create co as alias for checkout

git config --global apply.whitespace nowarn # Ignore whitespaces in commits

git config --global color.branch "auto" # Color for current branch

git config --global color.status "auto" # Color for Status Command

git config --global color.diff "auto" # Color for diff command

git config --global color.ui "auto" # Color for UserInterface git > 1.5.5+ (Not tested)

--Clone a remote Repository--

git clone git://git@somerepo/app.git

--Setting Up Local Repository--

cd myapplication

git init #Initialize Local git Repository, will create a new folder ./git

--Basic Git Commands--

- Adding Files for Commit.

*Senario: you have created new file or modified a file....you want to add it to the local repository for commiting

git status # will show files modified or created

git add . # (not recommended) will add all the modified or new or deleted file automatically

git add {path_to_file_modified/new} # (recommended) the file should show in the status with the file status as modified/new

git rm {path_to_file_deleted} #the file should show in the status with the file status as deleted

- Undo Adding and Remove Files

git reset HEAD {path_to_the_file}

-Commit Locally.

*Senario : You have sucessfully added new/modified/deleted File's using git add/rm.....and you want to commit locally (nothing to do with the server yet)

git commit #Will open a window.....add the name of the commit(Name should generally be the functanality added/modified..... must be understandable later.)

git commit -m "Name of the Commit" #Better option than "git commit"

git commit -a -m "Name of Commit" #Add all the files existing modified/deleted only....no new files added.....can be used when many files are modified.

--Branches--

git branch # List all the branches in the current project( master is by default ), the branch with * beside is the current working branch.

git branch example # Will create a new branch called example which will be in level with the current branch.

git checkout example # Will switch to the new branch example......... use git branch command to verify

git diff master example # Will show difference between the branch master and example

git rebase master # Will bring the example branch in level with the master branch and add your current branch commits on top of it.

git merge example # Will add the features added to example to the master.

git reset --hard ORIG_HEAD # Will undo the previous merge with the current branch

--More Branching--

git checkout -b example1 # Takes Added and modified uncommitted changes to branch example1 created automatically by the command.......will automatically switch to example1 branch.

git branch -d example # Delete Merged Branch in tree

git branch -D example1 # Delete UnMerged Branch in tree

git stash "name of stash" # Will save all the changes in the branch.May go to other branch & work commit and come back.

git stash list #Go to the branch where stash was applied..........this command will show the name of the stash

git stash apply # Apply stash, get back previous uncommitted changes for the branch

git stash clear # Clear Stash

--Git with Remote Repositories--

--Setting Up New Remote Repository--

ssh user@servername.com # ssh login for the user at the servername

mkdir myapplication.git

cd myapplication.git #.git in the end

git --bare init # Initialize Bare Repository on server

--Setting Up Local Repository--

cd myapplication

git init #Initialize Local git Repository

git remote add origin user@servername.com:/{path_to_application}/myapplication.git

--Some Commands for verification--

git remote show origin #Will Show the Origin of the current repository.

nano .git/config #Will show the details of the configuration.

--Basic Push & Pull--

** Always pull before you push to remote to avoid conflicts or errors

git pull # Will update master branch with remote updated contents

git push #Will update remote origin/master with local updates

--Advanced Git Repositories--(To be tried and tested by us)

git remote add laptop duo2book.local:repos/example1 #Add New Remote Location called laptop with the path .

git remote show laptop #Will how the url of the remote laptop

git fetch laptop # Will get all the branches in the laptop

--Advance Git Branch/Tracking--

#On branch example

git push origin example # Will push on the origin/example branch

git branch --track example3 origin/example3 # Will create a example3 branch on local with the contents of the origin/example and will add to .git/config

--Patches in Git --

#After creating a Commit

git format-patch origin/master #Will create a patch with the commit name with .patch extension *Always pull before you create a patch

# Applying Patch

xls import using Spreadsheet

2011-06-20T05:11:00.000-07:00

Step1. install the required spreadsheet gem by entering:

$ sudo gem install spreadsheet

step2: in the view place the form to be submitted to
a specific action.

<% form_for :dump, :url=>{:controller=>"students",
:action=>"excel_import"}, :html => { :multipart => true } do |f| -%>
Select an Excel File :
<%= f.file_field :excel_file -%>
<%= submit_tag 'Submit' -%>
<% end -%>

step3: In the controller action:

require 'spreadsheet'

def excel_import
Spreadsheet.client_encoding = 'UTF-8'
book = Spreadsheet.open params[:dump][:excel_file]
sheet1 = book.worksheet 0
sheet1.each do |row|
# you can do any interesing thing with row
Student.new(:first_name => row[0], :last_name => row[1]).save
end
end

Thats it for importing spreadsheet to your database.

Tree structure mapping using acts as Tree

2011-06-15T04:53:00.000-07:00

We have come across one-one, one-many and many-to-many model associations
in rails which helps us to map the tables,
but when we have a case where we have to come across mapping
between a Category and its sub category we can achieve it using many-to-many mapping,
but what if we have mapping like this,
Category -> Subcategory -> Supersubcategory......
and so on, its similar to a tree stricture hierarchy like parent,
child and grand children's. for this scenario we can use acts as Tree plugin,
below is the example and usage of this plugin.

Step1

rails navigator
script/plugin install git://github.com/rails/acts_as_tree.git
script/generate nifty_layout
script/generate nifty_scaffold page parent_id:integer name:string content:text

Step2:
in model/page.rb
acts_as_tree

Step3:
in pages/_form.html.erb
<%= f.collection_select :parent_id, Page.all(:order => "name"), :id, :name, :include_blank => true %>

you can modify the the way you want to suit your requirement.
check the way pages tables gets reflected.

Parse Excel file using ruby

2011-06-09T22:02:00.001-07:00

Step1: Install the Gem in you system

$ sudo gem install parseexcel

Step2: Here we can determine our excel workbook as

Spreadsheet::ParseExcel.parse(filenameandpath)

This returns the actual excel file's workbook, from
there we need to determine what worksheet we're on.

Getting started: worksheet = workbook.worksheet(0)

Iterating over the excel rows and columns

The worksheet object has a very nice each method that
will allow us to iterate over the rows like so,

worksheet.each { |row|
j=0
i=0
if row != nil
row.each { |cell|
if cell != nil
contents = cell.to_s('latin1')
puts "Row: #{j} Cell: #{i} #{contents}"
end
i = i+1
}
j = j +1
end
}

Getting a specific cell,
cell = row.at(3) #returns cell at column 3

Ex:

require 'parseexcel'

#Open the excel file passed in from the commandline
workbook = Spreadsheet::ParseExcel.parse(ARGV[0])

#Get the first worksheet
worksheet = workbook.worksheet(0)

#cycle over every row
worksheet.each { |row|
j=0
i=0
if row != nil
#cycle over each cell in this row if it's not an empty row
row.each { |cell|
if cell != nil
#Get the contents of the cell as a string
contents = cell.to_s('latin1')
puts "Row: #{j} Cell: #{i}> #{contents}"
end
i = i+1
}
end
}

command: $ruby -rubygems excelparse.rb myfile.xls

Jruby on Rails instalation.

2011-04-13T23:53:00.000-07:00

Steps to install jruby on Rails.

First you have download latest jruby package,
and install it from the following link.
http://www.jruby.org/download
After download install it from the ex: steps given below.
$ tar zxvf jruby-bin-1.3.1.tar.gz
export JRUBY_HOME=/home/leonardo/jruby-1.3.1
export PATH=$JRUBY_HOME/bin:$PATH
$ jruby -v
To check the installation once you type the above command,
you should see:
jruby 1.3.1 (ruby 1.8.6p287) (2009-06-15 2fd6c3d)
(Java HotSpot(TM) Client VM 1.6.0_13) [i386-java]

Now you have to install few gems to support the installation.
$ jruby -S gem install jruby-openssl
jruby-openssl is necessary due JRuby
doesn’t support the default Ruby’s openssl.

Now you may install the rails gem and other
supporting gems as given below:

jruby -S gem install
mongrel activerecord-jdbcmysql-adapter rails

Test application:

jruby -S rails myapp -d mysql

Change database.yml:

development:
   adapter: jdbcmysql
   encoding: utf8
   database: myapp_development
   username: root
   password:
then:
jruby -S rake db:create:all

jruby script/generate scaffold post title:string body:text published:boolean

jruby -S rake db:migrate

jruby script/server

http://localhost:3000/posts

If you face problems in migrating,
below i have mentioned few gems to be installed, can configure those if needed.

   gem 'jdbc-mysql'
gem 'activerecord-jdbc-adapter'
gem 'activerecord-jdbcmysql-adapter'
gem 'warbler'

Also if mysql gem is required you have to install it using jgem command:

$ jgem install mysql

Twelve hour time format plugin in rails

2011-04-12T08:42:00.000-07:00

Recently i found a simplest way to put forward a DateTime field
in 12 hour format in in forms, just make use of this plugin its simple.

Plugin:

Rails 2.2 Stable

script/plugin install http://rails-twelve-hour-time-plugin.googlecode.com/svn/branches/stable-2.2/12_hour_time

Rails 2.1 Stable

script/plugin install http://rails-twelve-hour-time-plugin.googlecode.com/svn/branches/stable-2.1/12_hour_time Usage:
  <%= select_time Time.now, :twelve_hour => true %>

  <%= time_select 'event', 'time', { :twelve_hour => true } %>

  <% form_for :user do |f| %>
     <%= f.datetime_select :created_at, :twelve_hour => true %>
  <% end %>

Create dynamic attributes in Rails

2011-04-09T21:30:00.000-07:00

Dynamic Attributes is a Rails plugin
that lets you create dynamic attributes on any ActiveRecord model,
and saves them in a schema-less fashion within a single table column.

Installing and Usage:

Just run script/plugin from your Rails root and your done:

script/plugin install git://codaset.com/joelmoss/dynamic-attributes.git

So let's say that we have a model that we use to save data about our users.

But this data and the fields collected can change at any time,

or are different depending on the type of user.

Just tell your User model that it has dynamic attributes:

User < ActiveRecord::Base
has_dynamic_attributes
end

Then create the migration for your User model (or simply add a new column):

class CreateUsers < ActiveRecord::Migration
def self.up
 create_table :users do |t|
   t.string :username
   t.text :dynamic_attributes
   t.timestamps!
 end
end

def self.down
 drop_table :users
end
end

Now we can create a new user record in the usual way:

@user = User.new :username => 'nagendra' @user.save

Nothing special there, but we can also create a new record with a bunch of additional dynamic attributes.

@user = User.new :username => 'nagendra', :first_name => 'hd', :last_name => 'Jain' @user.save

You can set as many dynamic attributes that you wish,

and can call them anything you want without the need to define them.

All of Rails usual ways of getting and setting

model attributes are supported with your dynamic attributes:

To View the dynamic attributes,

@user.dynamic_attributes
=> { :first_name =>'Nagendra', :last_name => 'jain' }

If you want to be really secure, then you can allow a set list of dynamic attributes, and only those dynamic attributes will be allowed. Trying to set or get a dynamic attribute that is not set, will raise the usual ActiveRecord exception.

User < ActiveRecord::Base has_dynamic_attributes :first_name, :last_name end

If you don't specify a list of allowed dynamic attributes,

then you can get and set as many dynamic attributes as you wish.

Sometimes, you may not want to use the default column name

'dynamic_attributes'.

For example, you may want to use 'data' instead.

So do this and your dynamic attributes will be saved in the 'data' column:

User < ActiveRecord::Base has_dynamic_attributes :column_name => :data end

Install Rails 3 in Ubuntu

2011-04-07T00:50:00.000-07:00

Here are simple steps to instal rails 3 on ubuntu,
i assume that you have already installed the rails 2.x version,
this post will help you to install rails 3 over that.

Step1.

# sudo gem uninstall rails
# sudo apt-get purge ruby rubygems

install Ruby 1.9.2 version.

# wget ftp://ftp.ruby-lang.org//pub/ruby/1.9/ruby-1.9.2-p0.tar.gz

# tar -xvvf ruby-1.9.2-p0.tar.gz

# cd ruby-1.9.2

# ./configure

# make

# sudo make install

Step2.

Now install Rails 3 version:
# sudo gem install rails --version 3.0.0

# sudo bundle install

Now in case you face problem in installing the rails gem,
below are the fixes i found to fix them.
ruby-1.9.2-p0. After I unpacked it, I built zlib as follows:

Issue1:

cd ruby-1.9.2-p0/ext/zlib
ruby extconf.rb
make
sudo make install
sudo gem install rails

Issue2:

This worked for me as well.

$ sudo aptitude install libssl-dev libopenssl-ruby1.8

$cd /ruby_install_dir/ext/openssl
$ ruby extconf.rb
$ make
$ make install

Step3.

Now you need to install the mysql Gem for rails 3.
$ sudo gem install mysql2

in case you face an issue with mysql gem
below is the fix for installing mysql gem

Issue3:
# sudo apt-get install libmysqlclient15-dev  (for mysql-5.*)
                                   or
# sudo apt-get install libmysqlclient12-dev  (for mysql-4.*)

# sudo apt-get install  libmysql-ruby  ruby-dev

Now again try with $sudo gem install mysql2

Thats it now you can create applications in Rails 3:

Issue4:

if you get readline error:

sudo apt-get install libncurses5-dev libreadline5-dev

cd ruby-1.9.2-p0/

cd ext/

cd readline/

ruby extconf.rb


Example: $ rails new test_app -d mysql

Useful Jquery plugins.

2011-03-29T23:35:00.000-07:00

1. For in-place Ajax editing this is one best plug-in to implement.
https://github.com/janv/rest_in_place

Image Uploading with paperclip

2011-03-29T03:51:00.000-07:00

In this post we can see how easy it is to upload an image in rails using the paperclip plug-in in rails.

Just 3 steps.

Step1.

script/plugin install git://github.com/thoughtbot/paperclip.git
script/generate paperclip product photo
rake db:migrate

Step2.
# models/product.rb
has_attached_file
:photo, :styles => { :small => "150x150>" },
:url  => "/assets/products/:id/:style/:basename.:extension",
:path => ":rails_root/public/assets/products/:id/:style/:basename.:extension"

validates_attachment_presence :photo
validates_attachment_size :photo, :less_than => 5.megabytes
validates_attachment_content_type :photo, :content_type => ['image/jpeg', 'image/png']

Step3.

<%= image_tag @product.photo.url(:small) %>


<% form_for @product, :html => { :multipart => true } do |f| %>
...
<%= f.file_field :photo %>
...
<% end %>

Thats it check you application for Image uploading in your existing model.

Upload videos in Rails using floplayer and ffmpeg.

2011-03-07T22:37:00.000-08:00

Uploading videos that happens just like you-tube can be easily accomplished in Rails, the following procedure will help you implement a video uploading app that converts the video you have uploaded to flv format.

Create a rails application:
1. rails Myapp -d mysql
and change the database.yml and map.resources :videos on environment.rb
and keep you app ready.

2. Now we need to figure out what flash video player we want to use. For this tutorial, I will be using FlowPlayer, an open-source flash video player. You will need to download flowplayer.zip from http://flowplayer.org/download/index.html. Unzip it to /public. Grab the /example/flowplayer-3.0.2.min.js file and put it in /public/javascripts/flowplayer.js. Put example/style.css in /public/stylesheets.

3. Now we have to install attachment_fu.
$script/plugin install git://github.com/technoweenie/attachment_fu.git

4.Now install ffmpeg in ubuntu its just a single command:
$ sudo apt-get install ffmpeg
this helps to convert a video to .flv format

5.Now install acts_as_state_machine plugin:
$ ./script/plugin install http://elitists.textdriven.com/svn/plugins/acts_as_state_machine/trunk

6. Now generate a model as given below:
$ ./script/generate model Video

Now open the migration file under db/migrate and modify it as given below:class

class CreateVideos < ActiveRecord::Migration
 def self.up
   create_table :videos do |t|
     t.string :content_type
     t.integer :size
     t.string :filename
     t.string :title
     t.string :description
     t.string :state
     t.timestamps
   end
 end

 def self.down
   drop_table :videos
 end
end

7. Now edit you app/model/video.rb:


has_attachment :content_type => :video,
     :storage => :file_system,
     :max_size => 300.megabytes

#turn off attachment_fu's auto file renaming
#when you change the value of the filename field
def rename_file
true
end

#acts as state machine plugin
acts_as_state_machine :initial => :pending
state :pending
state :converting
state :converted, :enter => :set_new_filename
state :error

event :convert do
transitions :from => :pending, :to => :converting
end

event :converted do
transitions :from => :converting, :to => :converted
end

event :failure do
transitions :from => :converting, :to => :error
end

# This method is called from the controller and takes care of the converting
def convert
self.convert!
success = system(convert_command)
if success && $?.exitstatus == 0
self.converted!
else
self.failure!
end
end

protected

def convert_command

#construct new file extension
flv =  "." + id.to_s + ".flv"

#build the command to execute ffmpeg
command =
<<-end_command   
ffmpeg -i #{ RAILS_ROOT + '/public' + public_filename }
-ar 22050 -ab 32 -s 480x360 -vcodec flv -r 25 -qscale 8 -f flv -y
#{ RAILS_ROOT + '/public' + public_filename + flv } 
end_command    
logger.debug "Converting video...command: " + command    command  end 
# This updates the stored filename with the
new flash video file
def set_new_filename 
update_attribute(:filename, "#{filename}.#{id}.flv")   
update_attribute(:content_type, "application/x-flash-video")
end


8. Run the migrations:
rake db:create
rake db:migrate

9.Now Create the required controller and views:
$ ./script/generate controller videos index show new

Paste the below code in videos controller:

class VideosController < ApplicationController


 def index
   @videos = Video.find :all
 end

 def new
   @video = Video.new
 end

 def create
   @video = Video.new(params[:video])
   if @video.save
     @video.convert
     flash[:notice] = 'Video has been uploaded'
     redirect_to :action => 'index'
   else
     render :action => 'new'
   end
 end

 def show
   @video = Video.find(params[:id])
 end

 def delete
   @video = Video.find(params[:id])
   @video.destroy
   redirect_to :action => 'index'
 end
end


10. Now prepare you views just like the samples given below:

In /app/views/layouts/application.html.erb

Jquery Event calendar in rails.

2011-03-03T07:33:00.000-08:00

I found this event calendar easily configurable in our rails application,
This uses Jquery and the look and feel of the calendar is really neat and simple to use .(you can check the demo at http://fullcalendar.vinsol.com/)

Just install the plugin in your rails app by command:

$ script/plugin install https://github.com/vinsol/fullcalendar_rails.git

By installing this, you find a event calendar folder in your vendor plug-ins folder,
which has the rails application file from controller to views, also don't forget to copy and paste all the necessary files from the folder thats is present in vendor plug-ins event calendar folder, including the migrations also.

After that you may delete the folder that exists in vendor plug-ins, and run the related migrations.

Thats it, run the server and check localhost:3000/events

Textmate features in Gedit for RoR development

2011-02-16T02:38:00.000-08:00

GMate is a collection of plugins, themes/styles
and other improvements to get TextMate-like features in Gedit.

To install GMate in Ubuntu, use the following commands:

sudo apt-add-repository ppa:ubuntu-on-rails/ppa

sudo apt-get update

sudo apt-get install gedit-gmate

This package will not replace Gedit!
It will only add some themes and plugins you can enable/disable from the Gedit preferences.

Refer this link for more information: https://github.com/gmate/gmate#readme

Group chat room in Rails.

2011-02-08T22:55:00.000-08:00

Introduction:
Chat Engine is a lightweight rails engine that heavily uses jQuery and memcached to implement a very simple group chat room.

Features:

You must enter a nickname to be part of the chat room.
All logged in users are shown in the user list
Lines in the chat that mention a users nickname are highlighted.
Inactivity timer will logout users from the client side.
rake task to logout users whose browsers do not allow ajax requests in the unload event.
The ability to mute specific users (from script/console). Muted users will see their own messages, but no one else will.

Implementation:

install chat-engine

   ./script/plugin install git://github.com/amiel/chat-engine.git

copy assets

   rake chat:sync

include assets, don’t forget jquery

   <%= stylesheet_link_tag 'chat' %>
<%= javascript_include_tag 'jquery-x.x.x.js', 'auto_scroll', 'chat' %>

use the chat_overlay partial

   <%= render :partial => 'chats/chat_overlay' %>

Note: make sure you have Jrails installed and the prototypes are properly included.

How to Set up Redmine-project tracking system

2011-02-01T23:48:00.000-08:00

Installation Steps

1) Make sure ruby 1.8.7 and Rubygem are installed

2) Install Rails and few required gems

gem install rails -v=2.3.5
gem install rack -v=1.0.1
gem install -v=0.4.2 i18n

3) Checkout the Redmine source code

svn co http://redmine.rubyforge.org/svn/branches/1.0-stable redmine-1.0

4) Go to redmine-1.0/config and rename few files

mv database.yml.example database.yml
mv email.yml.example email.yml

and do the database and email configuration

5) Run rake db:create to create database. then run database migrations using rake db:migrate

It will create tables and an administrator account.
If you get this error:

Rake aborted!
no such file to load -- net/https

you need to install libopenssl-ruby1.8, in ubuntu, just like this: apt-get install libopenssl-ruby1.8

6) Generate a session store secret.

rake generate_session_store

7) Insert default configuration data in database, by running the following command:

rake redmine:load_default_data

This step is optional but highly recommended, as you can define your own configuration from scratch. It will load default roles, trackers, statuses, workflows and enumerations.

8 ) Setup is complete. Start the server

ruby script/server

9) Use default administrator account to log in:

login: admin
password: admin

For more information visit http://www.redmine.org/wiki/1/RedmineInstall

Create svn repository in simple steps.

2011-01-25T02:23:00.000-08:00

By assuming you have already installed svn on the server, the below lines will help you set up svn repo for your rails project.

step1. ssh to your hosting server from your terminal and type $which svn, this should display the path if not please contact admin and get svn installed.

step2.

Create your repository. Once svn is installed on your host, you can proceed with the repository set up. Just ssh into your server and create a repository wherever you'd like it. In my case I put my repository in my home directory. To create the repository, issue the following command:

$ svnadmin create ~/myrepository

step3.

Create your SVN user: Now that your repository is successfully set up, you'll need to create an svn user. Simply open the svnserve.conf file in the editor of your choice:

pico ~/myrepository/conf/svnserve.conf

and add the following:

anon-access = none
auth-access = write
password-db  = passwd

Now you'll need to create a password file:

pico ~/myrepository/conf/passwd

Add a line in that file for your user in the format =

exampleuser = examplepassword

step4. you can organize multiple project under revision control, this through the trunk of the main repositary, in our case myrepositary.

You'll need to use svn's mkdir command though like so:

$ svn mkdir file:///path to your repository/myrepository/d5

$ svn  mkdir file:///path to your repository/myrepository/d6

here d5 and d6 are the branches likewise you can have multiple projects.

step5. Next, you'll need to import the files you want to keep under version control into your new repository. Do that with the svn import command.

$ svn import /path to your  project/myD5project file:///path to your repository/myrepository/d5

$ svn  import /path to your project/myD6project file:///path to your  repository/myrepository/d6

step6.

Run the svn server as daemon:

$ svnserve -d

step7. Now from your local machine you can checkout the project anywhere you want by entering:
$ cd /your_project_area
$ svn co svn+ssh://username@hostname/path to  repository/myrepository/d5

Thats it, you can enjoy Coding now.

Cool plugins in rails

2011-01-20T02:17:00.000-08:00

1. To implement jquery auto-complete feature
https://github.com/chris/auto_complete_jquery/blob/master/README

2. Image uploading plugin in rails
https://github.com/Squeegy/fleximage

3. tinyMce editor in Rails.
https://github.com/sandipransing/rails_tiny_mce

4. inviting to your application.
https://github.com/vigetlabs/acts_as_inviteable/

5. Forgot password plugin for authentication system.
https://github.com/greenisus/forgot_password/blob/master/README

6. Build online resume.
https://github.com/sandipransing/buildyourcv#readme

7. Create your own forum using bagpipes.
https://github.com/bscofield/bagpipes

jquery on rails

2010-12-17T23:53:00.000-08:00

Installing jRails

ruby script/plugin install

http://ennerchi.googlecode.com/svn/trunk/plugins/jrails

Include the jquery prototype,
open application.html and in the head tag add the prototype.

<%= javascript_include_tag 'jquery' %>
<%= javascript_include_tag 'jquery-ui' %>
<%= javascript_include_tag 'jrails' %>

This will now include all the jRails files instead of the
prototype/script.aculo.us files. You might want to just include the
files that you need instead of all these:

<%= javascript_include_tag :defaults %>

Calender plugin in Rails

2010-12-17T02:07:00.000-08:00

Just a simple way to configure your date and time field using this calender helper.

Install the plugin:

./script/plugin install

git://github.com/sandipransing/rails_activecalendar.git

Integrate the below mentioned lines in your
layout -> application.html inside the head tag

<%= stylesheet_link_tag
"/javascripts/jscalendar-1.0/calendar-win2k-cold-1.css"%>

<%= javascript_include_tag "jscalendar-1.0/calendar.js" %>

<%= javascript_include_tag "jscalendar-1.0/lang/calendar-en.js" %>

<%= javascript_include_tag "jscalendar-1.0/calendar-setup.js" %>

Install Image-magick and rmagick for rails

2010-12-15T21:15:00.000-08:00

Start by removing any old versions previously installed via apt-get:

sudo apt-get remove imagemagick

Then update apt-get and install some supporting packages:

sudo apt-get update

*(sudo apt-get install
libperl-dev gcc libjpeg62-dev libbz2-dev
libtiff4-dev libwmf-dev libz-dev libpng12-dev
libx11-dev libxt-dev libxext-dev libxml2-dev
libfreetype6-dev liblcms1-dev libexif-dev perl
libjasper-dev libltdl3-dev graphviz gs-gpl pkg-config)*

*its a single line command.

get the Imagemagick package from this link:

Imagemagick source

Once the source is downloaded, uncompress it:
tar -xzf ImageMagick.tar.gz

Now configure and make:

cd ImageMagick-6.5.0-0
./configure
sudo make
sudo make install

Add the following line to ~/.bashrc:
export LD_LIBRARY_PATH=/usr/local/lib

Update: If you still get an error like the one above, try running ldconfig:

sudo ldconfig

You can confirm the install and available formats with:

identify -list format
Once Image magick is installed install rmagick gem by typing the command:

$sudo gem install rmagick

Using table Joins

2010-12-04T00:14:00.000-08:00

You use INNER JOIN to return all rows from both tables where there is a match. ie. in the resulting table all the rows and colums will have values.

In OUTER JOIN the relulting table may have empty colums. Outer join may be either LEFT or RIGHT

LEFT OUTER JOIN returns all the rows from the first table, even if there are no matches in the second table.

RIGHT OUTER JOIN returns all the rows from the second table, even if there are no matches in the first table.

Ex for Inner Join:
SELECT *
FROM authors AS a INNER JOIN publishers AS p
ON a.city = p.city
ORDER BY a.au_lname DESC

Outer Join:

There are three types of outer joins namely:
Left Outer Join---For retreiving all the columns from the first table irrespective of the column match.
Right Outer Join---For retreiving all the columns from the second table irrespective of the column match
Full Outer Join---For retreiving all the columns from both the tables irrespective of column match.

Eg.

If we have two tables named stud1,stud2 with the following data

Stud1: id Name stud2: id Name
1 xxx 1 aaa
2 yyy 2 bbb
3 zzz 4 ccc
4 www 6 ddd
When we use Left Outer Join we get the output as:
1 aaa
2 bbb
3
4 ccc

When we use Right Outer Join we get the output as:
1 aaa
2 bbb
4 ccc
ddd

When we use Full Outer Join we get the output as:
1 aaa
2 bbb
3
4 ccc
ddd

Outer join syntax is as follows: -

SELECT column list
FROM left joined table
LEFT|RIGHT|FULL [OUTER] JOIN
ON join condition

Star rating in rails application

2010-12-01T00:29:00.000-08:00

The star rating for your posts is one of the cool feature for any application to get end users response, so lets get started:

By taking an example of Movie as your rails model and rating the movies,

the desired steps are mentioned below:

Lets say you have a column :rating in your movie model and replace the form,

thats the new and edit page with the below code,

# app/views/movies/edit.html.erb

# app/views/movies/new.html.erb

Rating

<%= f.radio_button :rating, 1 %> <%= f.label :rating_1, "1" %>

<%= f.radio_button :rating, 2 %> <%= f.label :rating_2, "2" %>

<%= f.radio_button :rating, 3 %> <%= f.label :rating_3, "3" %>

<%= f.radio_button :rating, 4 %> <%= f.label :rating_4, "4" %>

<%= f.radio_button :rating, 5 %> <%= f.label :rating_5, "5" %>

In the next step,

replace the below line in the index page where you want to display the stars

# app/views/movies/index.html.erb

Now we are done with the code, we need to add css style for the class star in our application.css file.

# public/stylesheets/style.css

.rating {

background: url(/images/stars.png) no-repeat;

height: 26px;

overflow: hidden;

text-indent: -1000px;

}

.star-5 { width: 115px; }

.star-4 { width: 92px; }

.star-3 { width: 69px; }

.star-2 { width: 46px; }

.star-1 { width: 23px; }

from the css we observe that there is an image named star.png, i have attached it at the beginning of the post just copy the image and place it in public -> images folder.

Thats it you can further customize if required.

Configure Sphinx in Rails application

2010-11-26T02:02:00.000-08:00

Install Sphinx

Just run the following three commands on your server or dev machine to install Sphinx:

./configure make sudo make install

That will setup Sphinx with default for use with MySQL. If you want to use it with PostgreSQL, then run configure with the following flag:

./configure --with-pgsql

Note: you can download the sphinx from http://sphinxsearch.com/downloads/beta/

Install Thinking Sphinx
Even though there are a couple of Sphinx plugins for Rails, 
I chose to go with Thinking Sphinx, 
as it seems to be the most popular and feature complete. 
So you can install it as a Rails plugin using   
script/plugin install command:
script/plugin install git://github.com/freelancing-god/thinking-sphinx.git 
Writing code to use sphinx search:
we now need to index our models. 
This consists of adding a few small lines of code 
into each model that you want to be able to search.
So lets say we have a Blog app (doesn't everyone!), 
which has a Post model. 
And that Post model contains the usual title and description fields. 
We therefore add the following bit of code beneath our association declarations in 
app/models/post.rb:
define_index do   indexes title, description end 
Those very short three lines will tell 
Thinking Sphinx to index the title and description fields of the Post model, 
and allow us to search through all our posts. 
Now we just need to index and start Sphinx. 
And Thinking Sphinx makes this very easy with it's handy Rake tasks. 
Just run this:
rake ts:rebuild 
That will stop (if it is started), index and start Sphinx for you.
Now we need to create a quick search form. 
This will eventually be a global site search, 
and not just a Post search. So we will create a new controller:
script/generate controller search 
Then create a view at app/views/search/index.html.erb 
and place the form within it:
     
Now in your new Search controller, create a new create action:
def create   @posts = Post.search params[:search] end 
Create your create view at app/views/search/create.html.erb 
with a bit of code to display your @posts in the usual way. 
Note: 
We can even paginate our results using the WillPaginate plugin:
def create   
@posts = Post.search params[:search], :page => params[:page], :per_page => 10 end

Setup Rails Development environment

2010-11-25T22:49:00.000-08:00

Do following steps to setup rails environment in the local system

1) CSV : Git and Subversion

sudo aptitude install subversion
 sudo apt-get install git-core

And you can also installed the suggested package

: git-doc git-arch git-cvs git-svn git-email

git-daemon-run git-gui gitk gitweb diff-doc.

1) Database setup:

Mysql database:  sudo aptitude install mysql-server mysql-client
PostgresSQL:
 sudo apt-get install postgresql postgresql-client postgresql-contrib
 sudo apt-get install pgadmin3
 sudo apt-get install libpq-dev
refer link  http://hocuspokus.net/2007/11/install-postgresql-on-ubuntu-710
3) Development IDE : Netbeans
  First download the latest version for Ruby on
 http://www.netbeans.org/ and install it with sh.
  You need Java to run Netbeans
from command prompt type: 
sudo sh ./netbeans.sh (path where your netbeans exists))
1) Now lets install Ruby on Rails:
On the Terminal (Applications -> Accessories -> Terminal)
key in the following commands
#sudo su
#apt-get install build-essential
#apt-get install ruby rdoc libopenssl-ruby
#wget http://production.cf.rubygems.org/rubygems/rubygems-1.3.7.tgz
#tar zxvf rubygems-1.3.7.tgz
#cd rubygems-1.3.7
#ruby setup.rb
#ln -s /usr/bin/gem1.8 /usr/local/bin/gem
#gem install rails -v 2.3.8
This should install rails 2.3.8 version.
Now we can install desired gems for the databases we use either postgres or mysql:
MySQL gem:
   sudo gem install mysql
Postgres gem:
sudo gem install postgres-pr
sudo gem install postgres
Thats it this should be able help you install rails development environment.

After Doing facebooker

2010-10-30T10:40:00.000-07:00

Recently i faced a problem after configuring the facebooker in my rails application, the layout was completely changed, later founded out the fix for this, hope this could be helpful

Before your stylesheet_link_tab just override the host URL:

ActionController::Base.asset_host = "localhost:3000"
# or
ActionController::Base.asset_host = ""

So using ERB it might look like this:

Language support tool in ubuntu

2010-10-15T09:45:00.000-07:00

Installation of scim on ubuntu lets you write in any language as your input language in a very simple way.

Just by pressing ctrl + space bar will shift from english to selected language and vice versa, for all those who are either crazy of writing posts in you preferred language follow this amazing link that describes the steps to enable fonts very easily and start scribbing in scim.

http://www.few.vu.nl/~tejaswi/miscellaneous/kannaDa/kannaDa_in_ubuntu.html

Rails techniques

2010-07-30T22:03:00.000-07:00

1.How to handle named scopes in rails.
//Write this method_name scope in your model.
named_scope :method_name, lambda{|argument1, argument2|
{
:select => "column1,column2",
:from => "table_name",
:conditions => "condition1 AND/OR condition2",
:order => "column DESC",
:limit => 5/or based on what you need
}
}
In your view you can call this named scope method_name any where and also reuse.
@object_name = Model.method_name(argument1,argument2)
//and you can use the object and also reuse the named scope.

Install Jdk and Jre in Ubuntu

2010-07-28T05:57:00.000-07:00

$ sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner"
$ sudo apt-get update
$ sudo apt-get install sun-java6-jdk
or {Depending upon what you need)
$ sudo apt-get install sun-java6-jre

Uploading a CSV file in rails app.

2010-05-31T22:18:00.000-07:00

Uploading a csv file and importing
all the data present in the csv file to a particular table
is one of simple task in rails,
just follow the below 3 steps,
that would easily help u to
upload and even import the data to your database table.

Step1. Install this gem in your application.

$ gem install fastercsv

Step2. In the View Add this code.

<% form_for :dump,
:url=>{:controller=>"customer_informations", :action=>"csv_import"},
:html => { :multipart => true } do |f| -%>
    
    Select a CSV File :

   <%= f.file_field :file -%>

   <%= submit_tag 'Submit' -%>

<% end -%>

Step3. In the Controller Add this code.

require 'csv'

def csv_import 
 @parsed_file=CSV::Reader.parse(params[:dump][:file])
 n=0
 @parsed_file.each  do |row|
 c=CustomerInformation.new
 c.job_title=row[1]
 c.first_name=row[2]
 c.last_name=row[3]
 if c.save
    n=n+1
    GC.start if n%50==0
 end
 flash.now[:message]="CSV Import Successful,
#{n} new records added to data base"
end

Auto migration in rails

2010-04-08T02:55:00.000-07:00

Migration in rails is so very important as it helps us from being independent of sql queries and those database related issues, through migration we can easily create table and columns and make any changes to database table by either adding or removing columns, though rails comes with its own migration method thats standard let me add up some spice to rails standard migration.
How about avoiding the rake up and down command to make any modification to your tables rake auto migration lets you modify tables in seconds.
it’s one of my favourite kind of plugins because you can remove it at any time and it won’t affect your application. Let’s take a look…

Steps:
1.First, let’s install the auto_migrations plugin…

ruby script/plugin install svn://errtheblog.com/svn/plugins/auto_migrations

This should export it into your vendor/plugins directory and provide you with two new rake tasks: rake db:auto:migrate and rake db:schema:to_migration.

2.What the auto_migrations plugin does, is allow you to edit your schema.rb file directly, and then run

rake db:auto:migrate to have the changes applied automatically.

Imagine you have a table that already exists as given below,

create_table "companies", :force => true do |t|
t.column "name",        :string, :limit => 40
t.column "description", :string
end

later you may require to modify the table lets say adding a email column,
We just edit schema.rb and insert an extra t.column line:

create_table "companies", :force => true do |t|
t.column "name",        :string, :limit => 40
t.column "description", :string
t.column "email",       :string, :limit => 60
en

Now, when we run rake db:auto:migrate, the email column will be added. Just run rake:

rake db:auto:migrate

And you’ll see the new column added:

-- add_column("companies", "email", :string) -> 0.0216s

Let’s remove the name column:

Then run rake:

rake db:auto:migrate

Thats start modifying your tables when required with this amazing plugin.

File Uploading with Paper clip

2010-03-26T21:16:00.000-07:00

This is one of the most useful plug in that can be used in your application when you require to upload a file as attachment to your application, its quite easy to use and with the help of paperclip scaffolding you can achieve file upload feature very easily, below i have explained the steps to create a simple application using scaffolding that enables the file upload feature with the help of paperclip plugin.

Steps:

Install the required gems to run the paperclip plugin from the below mentioned command,

$ gem sources -a http://gemcutter.org
http://gemcutter.org added to sources 
$ sudo gem install view_mapper
Successfully installed view_mapper-0.2.0
1 gem installed Installing ri documentation for view_mapper-0.2.0...
Installing RDoc documentation for view_mapper-0.2.0...

1. First you need to create a rails app and change the database.yml setting and set things to install the plug in $rails student -d mysql

2 Then you have to just install the paperclip plugin into your application from the below mentioned command,

$ ./script/plugin install git://github.com/thoughtbot/paperclip.git

3. Once the plugin is installe, let me show you to create a simple scaffold with paperclip file attachment feature in it.

Just create a simple scaffold and chect it out,

$ ./script/generate scaffold_for_view Student name:string branch:string comment:string --view paperclip:photo

Then you need to enter $ rake db:create and $ rake db:migrate

This will create the paperclip file attachment feature, just run $ script/server and check it out. The display looks just like the image i have mentioned at the beginning.

The new way of scaffolding on rails

2010-03-25T20:15:00.000-07:00

Since rails makes it all easy to build application with the scaffolding metho, i noticed an amazing method of using scaffolding in application that look really great and easy to use, just follow the below steps to build application using the new way of rails scaffolding.

Steps:

1. create a rails application in your console ex: rails test_app -d mysql and enter the test_app and change the database.yml file to username and password to your mysql system username and password.

2. Next you have to create a directory under test_app -> public -> ext and make sure you copy the contents of the code that you download from the below link prior installing the plug in.

You need to download the Ext Javascript framework from

http://www.extjs.com/products/extjs/download.php,

and unzip it into #test_app/public/ext.

3.Once you are done with it you need to install the plug in from the below link, just type

script/plugin install git://github.com/martinrehfeld/ext_scaffold.git

this will complete the installation and allow you to use the scaffolding as given in the below example:

Example:

./script/generate ext_scaffold employee title:string name:string phone:string

./script/generate ext_scaffold purchase order_id:integer amount:string

Thats it, you can start the server localhost:3000 and check this new kind of scaffolded app.

Ruby on Rails - Nifty Generators

2010-03-11T21:32:00.000-08:00

Among the various generators available, this rails generator is one of the fastest i have come across and lets the user to create fast web applications using nifty.
This generator allows you create authentication part of your application like login and signup and also lets you use the scaffolding in better way to create the CRUD operations for your application.
you may use this generator to create crud forms and authentication forms and later customize it further as it is very clear for any user to understand and reconfigure your application.
Procedure:
First you may have to create your application in rails and later within your application install the nifty gem so that it allows you to use nifty generators.

sudo gem install nifty-generators

once installed you may use any of the below generators of your choice and build your applicatin faster.

Nifty authentication:
It encrypts the password with a SHA1 hash and provides a complete, but simple authentication solution.

script/generate nifty_authentication

Nifty Layout:
It provides basic yet wonderful template to your application.make sure you install this after nifty authentication.

script/generate nifty_layout

Nifty scaffolding:
Now you are ready to use the nifty scaffolding generator for building CRUD operations in your application.
The nifty scaffold generator provides a lot of things that make it easy to develop a solid RESTful application. You get the following from the generator:

* Routes
* Migration
* Model
* Controller complete with RESTful actions
* Views
* Tests

script/generate nifty_scaffold student name:string address:string phone:string description:string

later use rakedb:migrate and run your rails application to explore your new application generated by nifty.

Config files:

Another useful generator is the nifty config generator. This generator creates a configuration .yml file in the /config directory and an initializer that automatically loads the config. If you generate the default config, you’ll wind up with a config file at /config/app_config.yml.

script/generate nifty_config

You can access config values using the APP_CONFIG constant. If you call your config by another name, it’s that file’s name in uppercase.

Build Web application in 3 min using Hobo.

2010-03-02T23:34:00.000-08:00

The fastest way to build a rails applicayion becomes more faster with Hobo.
try out this gem if rails is already installed and make sure gem 2.2 is configured to avoid conflicts.
Just two steps in your console and you are presented with an amazing application that has a blog feature, search engine, sign up and various other features that can be customized.

steps:
1. $ rails -v
2.$ gem install hobo
3.$ hobo thingybob
...Lots of output as Hobo runs the rails command,
...installs plugins and runs generators
$ cd thingybob
$ ruby script/generate hobo_model_resource thing name:string body:text
$ ruby script/generate hobo_migration
...Respond to the prompt with 'm'
...then press enter to chose the default filename
4.$ ruby script/server
and finally browse localhost:3000 to view this amazing application you just built in few steps.

Number conversion code in Ruby.

2010-01-02T00:30:00.000-08:00

Simple Ruby code which can be used for the number conversion in your application.


## Function to convert a given binary string into decimal number
def bin2dec(number)
   ret_dec = 0;
   number.split(//).each{|digit|
      ret_dec = (Integer(digit) + ret_dec) * 2;
   }
   return ret_dec/2;
end
print bin2dec('101'),"\n";

_________________________________________________________

## Function to convert a given integer string/number into binary formatted string
def dec2bin(number)
 number = Integer(number);
 if(number == 0)
    return 0;
 end
 ret_bin = "";
 ## Untill val is zero, convert it into binary format
 while(number != 0)
    ret_bin = String(number % 2) + ret_bin;
    number = number / 2;
 end
 return ret_bin;
end
print dec2bin("19"),"\n";

______________________________________________________________

## Function to convert a given integer string/number into hexa decimal string
def dec2hex(number)
 number = Integer(number);
 hex_digit = "0123456789ABCDEF".split(//);
 ret_hex = '';
 while(number != 0)
    ret_hex = String(hex_digit[number % 16 ] ) + ret_hex;
    number = number / 16;
 end
 return ret_hex; ## Returning HEX
end
print dec2hex("255"),"\n";

___________________________________________________________

MVC architecture in Rails

2009-12-12T02:02:00.000-08:00

MVC which stands for model, view and controller is the core concept to understand ruby on rails.

I have tried to explain a simple mvc architecture that is quite common to most of the programming languages that are based on mvc, as you start building an application in rails, you can feel the mvc being implemented in your application.
It took time for me to understand mvc as i was clear with it as i started developing app in Rails, im sure this should do it.
The Model View Controller principle divides the work of an application into three separate but closely cooperative subsystems

#MODEL:
Maintains the relationship between Object and Database and handles validation, association, transactions, and more.
A model is more than just data; it enforces all the business rules that apply
to that data. For example, if a discount shouldn’t be applied to orders of less
than 200, the model will enforce the constraint. This makes sense; by putting
the implementation of these business rules in the model, we make sure that
nothing else in the application can make our data invalid. The model acts as
both a gatekeeper and a data store
#VIEW:
"A presentation of data in a particular format".
The view is responsible for generating a user interface, normally based on
data in the model. For example, a shop will have a list of products
to be displayed on screen. This list will be accessible via the model,
but it will be a view that accesses the list from the model and formats it for
the end user. Although the view may present the user with various ways of
inputting data, the view itself never handles incoming data. The view’s work
is done once the data is displayed.
#CONTROLLER:
The facility within the application that directs traffic, on the one hand querying the models for specific data, and on the other hand organizing that data (searching, sorting, massaging it) into a form that fits the needs of a given view.
Controllers orchestrate the application. Controllers receive events from the
outside world (normally user input), interact with the model, and display an
appropriate view to the user.

1. Browser sends request
2. Controller interacts with model
3. Controller invokes view
4. View renders next browser screen Controller

This should be suffucient to understand MVC and how Rails works on this mechanism.....

Restful-Authentication

2009-11-25T01:07:00.000-08:00

For those who are looking out for simple login and a sign up functionality hope this post is helpful for the beginners to create a simple authentication in just few steps.

step1: create a rails application and enter the following in your rails application

script/plugin install http://github.com/technoweenie/restful-authentication.git restful_authentication

Step2: Once the plugin is installed just generate the required controller using the command

script/generate authenticated user sessions --include-activation

step3: Now just rake db:migrate your application and in browser you will able to see the login page available