Before we get into the details of ActiveModel we’ll first describe the part of the application that we’re going to modify to use it.

The screenshot above shows a contact form that has been created using Rails’ scaffolding. The application has a model called Message that is currently backed by ActiveRecord which means that we’re managing messages through the database. We’re going to change the way this form works so that it just sends emails and doesn’t store messages in a database table.

When you’re thinking of doing something like this it’s always a good idea to first consider your requirements and make sure that you really don’t want to store the data from the form in a database as there are often good side-effects to doing this. A database can act as a backup and also makes it easier to move the message-sending into a queue in a background process. For the purposes of this example, however, we don’t want any of that functionality so we’re free to go ahead and make our model tableless.

The code for the Message class looks like this:

File name: /app/models/message.rb

class Message < ActiveRecord::Base
 validates_presence_of :name
 validates_format_of :email, :with => /^[-a-z0-9_+\.]+\@([-a-z0-9]+\.)+[a-z0-9]{2,4}$/i
 validates_length_of :content, :maximum => 500
end

Message inherits from ActiveRecord::Base as you would expect a model class to, but as we don’t want this model to have a database back-end we’re going to remove that inheritance. As soon as we do this, though, our form will no longer work as the validators are provided by ActiveRecord. Fortunately, we can restore this functionality by using ActiveModel.

If we take a look at the Rails 3 source code we’ll see the that there are activerecord and activemodel directories. The core Rails team has taken everything from ActiveRecord that wasn’t specific to the database backend and moved it out into ActiveModel. ActiveRecord still relies heavily on ActiveModel for the functionality that isn’t specific to the database and as ActiveModel is full-featured and thoroughly tested it’s great for use outside ActiveRecord.

It we take a look in the directory that contains the code for ActiveModel we can see the functionality that it provides.

We can see from the list above that ActiveModel includes code to handle callbacks, dirty tracking, serialization and validation, among other things. The last of these is exactly what we’re looking for.

The code for validations has the following comment near the top and we can see from it that it’s fairly easy to add validations to a model. All we need to do is include the Validations module and provide getter methods for the attributes that we’re calling validators on.

Now that we know this we can apply it to our Message model.

File name: /app/models/message.rb

class Message
 include ActiveModel::Validations

 attr_accessor :name, :email, :content

 validates_presence_of :name
 validates_format_of :email, :with => /^[-a-z0-9_+\.]+\@([-a-z0-9]+\.)+[a-z0-9]{2,4}$/i
 validates_length_of :content, :maximum => 500
end

Message inherits from ActiveRecord::Base as you would expect a model class to, but as we don’t want this model to have a database back-end we’re going to remove that inheritance. As soon as we do this, though, our form will no longer work as the validators are provided by ActiveRecord. Fortunately, we can restore this functionality by using ActiveModel.

If we take a look at the Rails 3 source code we’ll see the that there are activerecord and activemodel directories. The core Rails team has taken everything from ActiveRecord that wasn’t specific to the database backend and moved it out into ActiveModel. ActiveRecord still relies heavily on ActiveModel for the functionality that isn’t specific to the database and as ActiveModel is full-featured and thoroughly tested it’s great for use outside ActiveRecord.

It we take a look in the directory that contains the code for ActiveModel we can see the functionality that it provides.

We can see from the list above that ActiveModel includes code to handle callbacks, dirty tracking, serialization and validation, among other things. The last of these is exactly what we’re looking for.

The code for validations has the following comment near the top and we can see from it that it’s fairly easy to add validations to a model. All we need to do is include the Validations module and provide getter methods for the attributes that we’re calling validators on.

Now that we know this we can apply it to our Message model.

File name: /app/models/message.rb

class Message
 include ActiveModel::Validations

 attr_accessor :name, :email, :content

 validates_presence_of :name
 validates_format_of :email, :with => /^[-a-z0-9_+\.]+\@([-a-z0-9]+\.)+[a-z0-9]{2,4}$/i
 validates_length_of :content, :maximum => 500
end

This isn’t enough to get our model to behave as the controller expects it to, though. There are two problems in the create method. Firstly the call to Message.new won’t work as our Message model no longer has an initializer that takes a hash of attributes as an argument. Secondly, save won’t work as we don’t have a database backend to save the new message to.

Filename : /apps/controllers/messages_controller.rb

class MessagesController < ApplicationController
 def new
 @message = Message.new
 end

def create
 @message = Message.new(params[:message])
 if @message.save
 # TODO send message here
 flash[:notice] = "Message sent! Thank you for contacting us."
 redirect_to root_url
 else
 render :action => 'new'
 end
 end
end

We’ll fix the second of these problems first. While we can’t save a message we can check that it is valid, so we’ll replace @message.save with @message.valid?.

File name :/app/controllers/messages_controllers.rb

def create
 @message = Message.new(params[:message])
 if @message.valid?
 # TODO send message here
 flash[:notice] = "Message sent! Thank you for contacting us."
 redirect_to root_url
 else
 render :action => 'new'
 end
end

We can solve the first problem by writing an initialize method in the Message model that takes a hash as a parameter. This method will loop through each item in the hash and assign the value to the appropriate attribute for the message using the send method.

File name: /app/models/message.rb

class Message
 include ActiveModel::Validations

attr_accessor :name, :email, :content
 validates_presence_of :name
 validates_format_of :email, :with => /^[-a-z0-9_+\.]+\@([-a-z0-9]+\.)+[a-z0-9]{2,4}$/i
 validates_length_of :content, :maximum => 500
 def initialize(attributes = {})
 attributes.each do |name, value|
 send("#{name}=", value)
 end
 end
end

If we reload the form now we’ll see that we’re not quite there yet, however.

This time the error is caused by a missing to_key method in the Message model. The error is thrown by the form_for method so it seems that Rails itself is expecting our model to have functionality that it doesn’t yet support. Let’s add that functionality now.

Rather than guessing everything that Rails expects the model to have there’s a nice lint test included with ActiveModel that allows us to check whether our custom model behaves as Rails expects it to. If we include the ActiveModel::Lint::Tests module in a tests for the model it will check that the model has all of the required functionality.

The source code for the Lint::Tests module shows the methods that the model needs to respond to in order for it to work as it should, including to_key. We can make our model work by including a couple of ActiveRecord modules. The first of these is Conversion, which provides that to_key method and several others. The other module is the Naming module, but in this case we extend it in our class rather than including it as it includes some class methods.

As well as including the Conversion module we need to define a persisted? method in our model, which needs to return false as our model isn’t persisted to a database. With these changes in place our Message model now looks like this:

File name: /app/models/message.rb

class Message
 include ActiveModel::Validations
 include ActiveModel::Conversion
 extend ActiveModel::Naming
 attr_accessor :name, :email, :content
 validates_presence_of :name
 validates_format_of :email, :with => /^[-a-z0-9_+\.]+\@([-a-z0-9]+\.)+[a-z0-9]{2,4}$/i
 validates_length_of :content, :maximum => 500
 def initialize(attributes = {})
 attributes.each do |name, value|
 send("#{name}=", value)
 end
 end
 def persisted?
 false
 end
end

If we reload the form now it will work again which means that the Message model now satisfies all of the requirements that Rails 3 relies on for a model. If we try to submit the form we’ll see that the validators are working, too.

We’ve only covered a little of what ActiveModel provides in this episode but this should have been enough to whet your appetite and give you a reason to look more deeply into its source code to see what it can do. The code is well documented and structured so if you see something you might find useful then there should be enough information in the comments for that file to get you started using it.

Today Ruby released the new version of ruby – Ruby 1.8.7-p299. It is avaible for download from following URLs:
* ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p299.tar.gz
* ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p299.tar.bz2
* ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p299.zip

Hello all. It’s time for a new release of 1.8.7.

This time Ruby fixed various bugs, including the Unicode inspection bug that annoyed you a lot. For a complete list of what has been fixed, please take a look at the ChangeLog.

* ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p299.tar.gz
* ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p299.tar.bz2
* ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p299.zip

Checksums:

MD5(ruby-1.8.7-p299.tar.gz)= 43533980ee0ea57381040d4135cf9677
SHA256(ruby-1.8.7-p299.tar.gz)= 32c99c8e3d0a0190942055b8239f1573677a02de2645d81539617011f3a5427b
SIZE(ruby-1.8.7-p299.tar.gz)= 4867600

MD5(ruby-1.8.7-p299.tar.bz2)= 244439a87d75ab24170a9c2b451ce351
SHA256(ruby-1.8.7-p299.tar.bz2)= 3d8a1e4204f1fb69c9e9ffd637c7f7661a062fc2246c559f25fda5312cfd65d8
SIZE(ruby-1.8.7-p299.tar.bz2)= 4183359

MD5(ruby-1.8.7-p299.zip)= b548dbdfc036979bdcb5e0962c87c9eb
SHA256(ruby-1.8.7-p299.zip)= 30e3ed4ce977a770223f34997ea0d025c180c4664a0bd0d35ef09e48d5c89860
SIZE(ruby-1.8.7-p299.zip)= 5965156

While working with PHP, I realized that deployment of a PHP application is far more easier as compared to deployment of a Ruby on Rails application. So I was wondering if there could be a way to deploy a Ruby on Rails application in a similar fashion, as easy as you check out the Rails project in a directory on the server, configure a VirtualHost in the webserver, restart the webserver and there you go, everything should work as expected.

Luckily I did find a saviour,

“Phusion Passenger” a.k.a “mod_rails” or “mod_rack”

Here I am putting down steps to ride Rails on Passenger.

Install Passenger

Passenger is available as a Rubygem. As root,

gem install passenger

Install Passenger module for Apache

passenger-install-apache2-module

During installation it will prompt:

The Apache2 module was successfully installed.

Please edit your Apache configuration file, and add these lines:

LoadModule passenger_module /usr/lib64/ruby/gems/1.8/gems/passenger-2.2.11/ext/apache2/mod_passenger.so
PassengerRoot /usr/lib64/ruby/gems/1.8/gems/passenger-2.2.11
PassengerRuby /usr/bin/ruby

NOTE: Do NOT copy-paste from here. Make sure you add the lines that passenger prompts you with.
It is specific to the OS installation. Mine was a Fedora Core 10 64-bit installation.

Next, it will help you to configure a VirtualHost for Apache

<VirtualHost *:80>
ServerName www.yourhost.com
DocumentRoot /somewhere/public

<Directory /somewhere/public>
AllowOverride all
Options -MultiViews
</Directory>

</VirtualHost>

Restart Apache:

As root,

/sbin/service httpd restart

That’s it, we are done.
Point your browser to your domain, and you should be able to see your Ruby on Rails Application.

Do keep in mind that the default Rails environment while using Passenger is “production”
To access your application in “development” or any other environment add the following line in your VirtualHost configuration:

RailsEnv development

Restarting your application deployed in production environment:

To restart your Rails application deployed in production environment you can restart Apache.
But that’s not a good solution if you are hosting multiple applications on the same server, or even generally, it doesn’t sound like a good idea to restart Apache every now and then.
To overcome that, you can restart your application in the following way:

From Rails Root Directory,

touch tmp/restart.txt

That’s it, this will restart you Rails application.

The best part is, Passenger is compatible with all the Rubygems and Rails plugins.

So nothing should break. I personally tried running a complex Rails application that uses Solr as the search engine along with acts_as_solr plugin, backgroundRB server for background processes, attachment_fu for file uploads etc, etc.

Everything worked like a charm.

For further configuration, please refer to the Passenger documentation found here:

You can also use Passenger to serve Non-Rails Ruby web applications. That can be a good alternative to the already prevalent mod_ruby module for Apache.
If you are using Nginx as your webserver, you can use Passenger module for Nginx.

There’s just one disadvantage to Passenger:

It doesn’t work on Windows. In any case, I personally never prefer to develop Rails (or any other) applications on Windows

Good news for Mac users:

fingertips has come up with an OS X preference pane for Phusion Passenger (a.k.a. mod_rails) that makes it a cinch to deploy Rails applications using Passenger on the Mac. It can be as simple as dragging a Rails application folder onto the preference pane! This is absolutely ideal for quick and easy Rails development on OS X.

You can download the Passenger Preference Pane here

References:

http://www.modrails.com/documentation/Users%20guide%20Apache.html

I am working Ruby on Rails for around last four years. There is always I am thinking and all ROR developers are thinking about performance of application.

We always compare Ruby on Rails with PHP, Java, Python, dot net. We came to know that where we are lacking in ROR. Just one issue performance and memory issue.

When we got news about Ruby 1.9 is comming with performance improvement of 63%. Yes, It is not a joke. This is really great news for every ROR developers. Ruby 1.9 and Rails 3.0 is the future of internet.

Now I will talk about Ruby Software engineer who developed and worked on the Ruby 1.9.

Masahiro Kanai, who improved the performance of several methods in Ruby 1.9. He is the age of high school, just 17.

This year, Ruby 1.9 by the Fibonacci sequence of operations (multiple-precision addition) is,
Ruby 1.8 is slower than I realized Mr. Kanai is a challenge to freedom of choice camp Ruby faster.

In front of all the participants had a similar problem occurring, Ruby of type String, Array types (structures that may have an embedded data structure type object itself) and some of the faster method, attention collection. Oden’s is known to be well-covered tongue teachers. Ruby continued even after the camp’s efforts to speed up to approximately some methods to remove the macro in a constant loop of 63 percent to about 8 percent of success in speeding. This patch has been adopted by the community of developers Ruby, Ruby has been incorporated into the trunk (October 5, 2009).

many professional engineers and developers, with patience to hold out that the problem is resolved, probably as a programmer in one or two talents.

Ketai that builds skills and career tips for the professional engineer. Interviewers are already familiar with this series, the Mr. Ikuo Takeuchi, Professor Department of Creative Informatics, Graduate School of Information Science and Engineering, University of Tokyo. This time, who undertook the voluntary and discover if training for a talented programmer.

His mentor was Koichi Sasada (ko1). The performances of the methods he worked have been bumped up 63% in maximum, 8% in average. His patches were applied to Ruby trunk in Oct. 5 this year.

What he did for Ruby Performance tuning?

He took unnecessary macro references out from a loop. Masahiro spotted macros below in array.c, string.c, and struct.c were referred every time Ruby checked whether data was hold in a structure or not. Even though data were constants, Ruby saw the macros to judge data’s presence in every loop.

What I say now more… I am really happy and I can say this is the biggest news of 2010 in IT world.

One thing I want to mention here about Ruby on Rails. This thing is in mind of all ROR developers.

“Thank God, No need to look Jruby”

On 5th Feb we got news about release of Rails 3.0 beta. We all developers are really waiting for that day. We checked the new version of Rails but what is more interesting.

The interesting part is what is new in Rails 3.0. So many developers contributed in Rails 3.0. They really worked and planned so hard.

Here I am making list what Rails 3.0  has, means new features:

• Brand new router with an emphasis on RESTful declarations
• New Action Mailer API modelled after Action Controller (now without the agonizing pain of sending multipart messages!)
• New Active Record chainable query language built on top of relational algebra
• Unobtrusive JavaScript helpers with drivers for Prototype, jQuery, and more coming (end of inline JS)
• Explicit dependency management with Bundler

If you want to use the Rails 3.0 then you should install first following gems.

#gem install tzinfo builder memcache-client rack rack-test rack-mount erubis mail text-format thor bundler i18n
#gem install rails --pre

Or you can use following command to install whole Rails 3.0 with dependencies

gem uninstall rubygems-update
gem update --system
#gem install rails3b

Important Note: Rails 3 requires Ruby 1.8.7+ , you should install latest Ruby version. You can download latest Ruby version from here.

Ruby 1.9.1

Here I am giving the list of gems and plugins which are compilable of Rails 3.0. you should check the following URL:

http://wiki.rubyonrails.org/rails/version3/plugins_and_gems

Now I am started working on Rails 3.0 and I am searching for the issues with Rails 3.0 because Rails 3.0 is in Beta so all ROR developer need to come up with issues of Rails 3.0 and try to fix that or submit that issue to community.

According to David Heinemeier Hansson, the founder of the Ruby based web development framework, although a beta of Rails 3 is expected by the end of this month the release may slip into February. Hansson gave the estimated release timing in an article on InfoWorld. If all goes to plan Rails 3 is expected to arrive in the first quarter of this year. Rails 3 is a major reworking of the framework which sees ideas from the alternative Merb framework being integrated in a development process which began in December 2008.

Source Articles

http://www.engineyard.com/blog/2009/my-five-favorite-things-about-rails-3/

http {
include       /etc/nginx/mime.types;
default_type  application/octet-stream;
access_log  /var/log/nginx/access.log  main;
sendfile        on;

upstream mongrel_cluster_example1 {
server 127.0.0.1:8000;
server 127.0.0.1:8001;
server 127.0.0.1:8002;
}

upstream mongrel_cluster_example2 {
server 127.0.0.1:3000;
server 127.0.0.1:3001;
server 127.0.0.1:3002;
}

# Load config files from the /etc/nginx/conf.d directory
include /etc/nginx/conf.d/*.conf;

server {
listen       80;
server_name  example1.com example2.net;
client_max_body_size 120M;

set $myroot /var/www/html;
if ($host ~* example1\.com$) {
set $myroot /home/example1/public;
}

if ($host ~* example2\.net$) {
set $myroot /home/example2/public;
}

root $myroot;

location ~* ^/(images|stylesheets|javascripts).+\.(html|jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|txt|tar|mid|midi|wav|bmp|rtf|js)$
{
root $myroot;
}

location / {

if ($host ~* example1\.com$) {
proxy_pass      http://mongrel_cluster_example1;
} #if check for domain qa.teenangel ends here

if ($host ~* example2\.net$) {
root /home/rail_project/myproject/public;
proxy_pass      http://mongrel_cluster_example2;

} #if check for domain ends here

}

}

}

Open the /db/migrate/20091117115011_create_us_states.rb file and paste following code:

class CreateUsStates ‘Alabama’, :abbreviation => ‘AL’
UsStates.create :name => ‘Alaska’, :abbreviation => ‘AK’
UsStates.create :name => ‘Arizona’, :abbreviation => ‘AZ’
UsStates.create :name => ‘Arkansas’, :abbreviation => ‘AR’
UsStates.create :name => ‘California’, :abbreviation => ‘CA’
UsStates.create :name => ‘Colorado’, :abbreviation => ‘CO’
UsStates.create :name => ‘Connecticut’, :abbreviation => ‘CT’
UsStates.create :name => ‘Delaware’, :abbreviation => ‘DE’
UsStates.create :name => ‘District of Columbia’, :abbreviation => ‘DC’
UsStates.create :name => ‘Florida’, :abbreviation => ‘FL’
UsStates.create :name => ‘Georgia’, :abbreviation => ‘GA’
UsStates.create :name => ‘Hawaii’, :abbreviation => ‘HI’
UsStates.create :name => ‘Idaho’, :abbreviation => ‘ID’
UsStates.create :name => ‘Illinois’, :abbreviation => ‘IL’
UsStates.create :name => ‘Indiana’, :abbreviation => ‘IN’
UsStates.create :name => ‘Iowa’, :abbreviation => ‘IA’
UsStates.create :name => ‘Kansas’, :abbreviation => ‘KS’
UsStates.create :name => ‘Kentucky’, :abbreviation => ‘KY’
UsStates.create :name => ‘Louisiana’, :abbreviation => ‘LA’
UsStates.create :name => ‘Maine’, :abbreviation => ‘ME’
UsStates.create :name => ‘Maryland’, :abbreviation => ‘MD’
UsStates.create :name => ‘Massachutsetts’, :abbreviation => ‘MA’
UsStates.create :name => ‘Michigan’, :abbreviation => ‘MI’
UsStates.create :name => ‘Minnesota’, :abbreviation => ‘MN’
UsStates.create :name => ‘Mississippi’, :abbreviation => ‘MS’
UsStates.create :name => ‘Missouri’, :abbreviation => ‘MO’
UsStates.create :name => ‘Montana’, :abbreviation => ‘MT’
UsStates.create :name => ‘Nebraska’, :abbreviation => ‘NE’
UsStates.create :name => ‘Nevada’, :abbreviation => ‘NV’
UsStates.create :name => ‘New Hampshire’, :abbreviation => ‘NH’
UsStates.create :name => ‘New Jersey’, :abbreviation => ‘NJ’
UsStates.create :name => ‘New Mexico’, :abbreviation => ‘NM’
UsStates.create :name => ‘New York’, :abbreviation => ‘NY’
UsStates.create :name => ‘North Carolina’, :abbreviation => ‘NC’
UsStates.create :name => ‘North Dakota’, :abbreviation => ‘ND’
UsStates.create :name => ‘Ohio’, :abbreviation => ‘OH’
UsStates.create :name => ‘Oklahoma’, :abbreviation => ‘OK’
UsStates.create :name => ‘Oregon’, :abbreviation => ‘OR’
UsStates.create :name => ‘Pennsylvania’, :abbreviation => ‘PA’
UsStates.create :name => ‘Rhode Island’, :abbreviation => ‘RI’
UsStates.create :name => ‘South Carolina’, :abbreviation => ‘SC’
UsStates.create :name => ‘South Dakota’, :abbreviation => ‘SD’
UsStates.create :name => ‘Tennessee’, :abbreviation => ‘TN’
UsStates.create :name => ‘Texas’, :abbreviation => ‘TX’
UsStates.create :name => ‘Utah’, :abbreviation => ‘UT’
UsStates.create :name => ‘Vermont’, :abbreviation => ‘VT’
UsStates.create :name => ‘Virginia’, :abbreviation => ‘VA’
UsStates.create :name => ‘Washington’, :abbreviation => ‘WA’
UsStates.create :name => ‘West Virginia’, :abbreviation => ‘WV’
UsStates.create :name => ‘Wisconsin’, :abbreviation => ‘WI’
UsStates.create :name => ‘Wyoming’, :abbreviation => ‘WY’

end

def self.down
drop_table :us_states
end
end

Goodlunk, This code will save your problem of fetching USA state names and abbreviations as per id

Check my controller code…Just put in your controller

@us_states = USStates.find(:all)

<% form_for :customer, @customer, :url => { :action => “new_application” } do |f| %>
<%= f.select :state_id,  @us_states.collect {|state| [ state.abbreviation, state.id ] } %>
<% end %>

/usr/bin/ruby extconf.rb
checking for mysql_ssl_set()… yes
checking for rb_str_set_len()… no
checking for rb_thread_start_timer()… yes
checking for mysql.h… no
checking for mysql/mysql.h… no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.

Provided configuration options:
–with-opt-dir
–without-opt-dir
–with-opt-include
–without-opt-include=${opt-dir}/include
–with-opt-lib
–without-opt-lib=${opt-dir}/lib
–with-make-prog
–without-make-prog
–srcdir=.
–curdir
–ruby=/usr/bin/ruby
–with-mysql-config
–without-mysql-config

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/mysql-2.8.1 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api/gem_make.out

To find the mysql path on machine used following command
[root@localhost siwan]# which mysql
/usr/bin/mysql

I tried following command:
[root@localhost siwan]# sudo gem install mysql — –with-mysql-dir=/usr/bin/mysql

I Got the same error

[root@localhost siwan]# sudo gem install mysql — –with-mysql-dir=/usr/bin/mysql
Building native extensions. This could take a while…
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.

/usr/bin/ruby extconf.rb
checking for mysql_ssl_set()… yes
checking for rb_str_set_len()… no
checking for rb_thread_start_timer()… yes
checking for mysql.h… no
checking for mysql/mysql.h… no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.

Provided configuration options:
–with-opt-dir
–without-opt-dir
–with-opt-include
–without-opt-include=${opt-dir}/include
–with-opt-lib
–without-opt-lib=${opt-dir}/lib
–with-make-prog
–without-make-prog
–srcdir=.
–curdir
–ruby=/usr/bin/ruby
–with-mysql-config
–without-mysql-config

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/mysql-2.8.1 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api/gem_make.out
ERROR: could not find gem — locally or in a repository
ERROR: could not find gem –with-mysql-dir=/usr/bin/mysql locally or in a repository

Then I checked the mysql-devel
[root@localhost siwan]# yum list mysql-devel
Loaded plugins: refresh-packagekit
Available Packages
mysql-devel.i586 5.1.37-1.fc11 updates

Then I Installed the mysql-devel
[root@localhost siwan]# yum install mysql-devel
Installed:
mysql-devel.i586 0:5.1.37-1.fc11
Complete!

Then I tried the mysql Gem installing…..I am able to install the mysql gem…
[root@localhost siwan]# gem install mysql
Building native extensions. This could take a while…
Successfully installed mysql-2.8.1
1 gem installed
Installing ri documentation for mysql-2.8.1…
Installing RDoc documentation for mysql-2.8.1…
[root@localhost siwan]#

You are able to start your applicaton at http://127.0.0.1:3000, http://127.0.0.1:3001 and http://127.0.0.1:3002

for all the cluster
# mongrel_rails cluster::stop

Advanced prepairation for production realeaze
$ mkdir /etc/mongrel_cluster

#vim /etc/mongrel_cluster/project_name.yml
copy and paste following text;
user: project_name
cwd: //home/siwan/project_name
log_file: /home/siwan/project_name/mongrel.log
port: “3000″
environment: production
group: dev
address: localhost
pid_file: /home/siwan/project_name/tmp/pids/mongrel.pid
servers: 3

or you can run the following command

or copy and paste the content from config/mongrel_cluster.yml file to /etc/mongrel_cluster/project_name.yml

# ln -s /home/siwan/project_name/config/mongrel_cluster.yml /etc/mongrel_cluster/project_name.yml

Then open your httpd.conf file for apache configration:

<Proxy balancer://project_name>
BalancerMember http://127.0.0.1:3000
BalancerMember http://127.0.0.1:3001
BalancerMember http://127.0.0.1:3002
</Proxy>

<VirtualHost *:80>
ProxyPreserveHost On
# Avoid open you server to proxying
ProxyRequests Off
# Options +FollowSymLinks
RewriteEngine On

RewriteRule ^/(images|stylesheet|javascript|html)/?(.*) /home/siwan/project_name/public/$0 [L]
ServerAdmin siwan@yahoo.co.in
DocumentRoot /home/project_name/
ServerName example.com
RewriteRule  ^/(.*)$  balancer://project_name%{REQUEST_URI} [P,QSA,L]
</VirtualHost>

Restart the apache server
#/etc/init.d/httpd restart

Command for restart the mongrel servers from any where
# mongrel_rails cluster::restart -C /etc/mongrel_cluster/project_name.yml

Example is So many Rails site is using WordPress for blogging system.

Main reason behind using PHP files or script is SEO. PHP is a very SEO friendly.

Customer does not want to spend money or time already existing scripts or program.

If you want to use PHP files or project under Rails project. Just create any folder in Public directory and put your php files in to that folder.

lets say you created the “fourm” dir in public directory.

You need to add following lines in your apache rule file(httpd.conf)

LoadModule proxy_module modules/mod_proxy.so

LoadModule proxy_http_module modules/mod_proxy_http.so

Under <VirtualHost  *:80> tag add following lines:

ProxyRequests Off

RewriteEngine On

RewriteCond  %{HTTP_HOST}    ^example.com [NC]
RewriteCond %{REQUEST_URI}  !^/forum(.*)$ [NC]

RewriteCond  %{HTTP_HOST}    ^example.com [NC]

RewriteRule ^/forum/?(.*)$ /document_root/forum/$1 [QSA,NC,L]

Than you are able to use PHP code or scripts in Rails project

Juggernaut uses the eventmachine as a server.

So install the supported gem first.

#gem install json

#gem install eventmachine

#gem install juggernaut

Juggernaut is aims to revolutionize your Rails app by letting the server initiate a connection and push data to the client.

Juggernaut is used for speciallycreating Chat application.

If you want to full details about Juggernaut then go to http://juggernaut.rubyforge.org/

First install the juggernaut to your application using this command.
ruby script/plugin install git://github.com/maccman/juggernaut_plugin.git

install the gem : gem install juggernaut

Configure the gem: juggernaut -g juggernaut.yml

Start the Juggernaut server: juggernaut -c juggernaut.yml

(This is not rails server or mongrel server)

In your controller you can use this method to send data to Juggernaut server

Juggernaut.send_to_all(“alert(‘hi from juggernaut’)”)

If you want customize the Juggernaut methods or add new methods then open file:

/vender/plugin/juggernaut_plugin/lib/juggernaut.rb

Add your methods there and use in your projects.

How to displays a image inside link_to instead of text?

Here is answer:
<%= link_to image_tag(“/images/submit.jpg”, :border=>0), :action => ‘create’ %>

Section Option:

<%= link_to image_tag(“/images/submit.jpg”, :border=>0,:class=>’sub20′), :url =>{:controller=> ‘user’,:action=>’create’}  %>

In every language we need XML parsing. In Ruby there is in build XML strong parsing support.

In this post I am going to cover the How to create XML file with simple Ruby code.

TIP: If you are new in Rails than follow step one or go to step two.

1. You need to install Ruby on your computer

http://www.ruby-lang.org/en/

2. Open command prompt(for windows) or console(linux)

3. Create file named CreateXML.rb and copy and paste following code

require “rexml/document”
include REXML

string = <<EOF
<xml>
<element attribute=”attr”>first XML document with ruby </element>
</xml>
EOF
doc = Document.new string

print doc

Output will be like this:

I used scaffolding for some methods. I got some very weird issue about tex_area tag in rails.

When i check the forms textagea fields are coming with 20 rows and 40 cols default. When i tried to change that is not changing even though CSS also.

<textarea id=”dummy_text” rows=”20″ name=”dummy_text” cols=”40″/>

After digging into rails code i got know that Rails ->Actionpack-> form_helper.rb file has default setting of textarea field.

def text_area(object_name, method, options = {})
InstanceTag.new(object_name, method, self, options.delete(:object)).to_text_area_tag(options)
end

We can change this also. but this is not good idea

so good idea is select our project and use find replace:

text_area to text_area_tag

This is the simplest solution.

It is really very easy to Install any RTE in the Rails. There are many open source RTE available.

I used the Cross-Browser Rich Text Editor for my project.
I downloaded files from there and uploaded to my public folder. I added required CSS and JS file to my layout.

You need to add following lines to your application.html.erb file.(you will find this file in view/layout/ folder)

1. You can add that files on conditional base also. Means for that particular page.
2. Add following lines to your form
:html => { :name => ‘BlogRTE’, nsubmit => “submitForm();”}

In to add following lines to your form;

<script language=”JavaScript” type=”text/javascript”>
<!–
function submitForm() {
updateRTEs();
return false;
}
initRTE(“/cbrte/images/”, “/cbrte/”, “”, true);
//–>
</script>
<noscript><p><b>Javascript must be enabled to use this form.</b></p></noscript>
<script language=”JavaScript” type=”text/javascript”>
<!–
//build new richTextEditor
var rte1 = new richTextEditor(‘text_content’);
rte1.html = ‘Write your thoughts here.’;
rte1.toggleSrc = true;
rte1.width = 500;
rte1.build();
//–>
</script>

You will get the text_content params in Rails.

For Edit page functionality i got error in form. So you need to this default code for all languages.
rte1.html =”";

When i used this i got an error.

But i solved this issue after some R&D and modification in code.

Use following code for Rails(Edit functionality)
rte1.html =”<%=text_content.gsub(/”/, “‘”).gsub(/\n/, ”).gsub(/\r/, ”) %>”;

this will solve your problem.

Full code: (IF YOUR CODE NOT WORKS THAN USE MY FULL CODE)

<script language=”JavaScript” type=”text/javascript”>
<!–
function submitForm() {
updateRTEs();
return false;
}
initRTE(“/cbrte/images/”, “/cbrte/”, “”, true);
//–>
</script>
<noscript><p><b>Javascript must be enabled to use this form.</b></p></noscript>
<script language=”JavaScript” type=”text/javascript”>
<!–
//build new richTextEditor
var rte1 = new richTextEditor(‘text_content’);
rte1.html = ‘Write your thoughts here.’;
rte1.toggleSrc = true;
rte1.width = 500;
rte1.build();
//–>
</script>

Normal code for ELSIF
if var == 10
print “Variable is 10″
elsif var == “20″
print “Variable is 20″
else
print “Variable is something else”
end

Technic:
How to Put this in one line:
<%= user.name if user %> This is the simplest way.

How to use IF and ELSE statement in one line:
<%= user ? user.name : “Anonymous” %>

Few days back i tried to install acts_as_solr plugin in my project. I got an error. So i coppied acts_as_solr plugin from my old project and pasted in new project.

When i tried to SVN commit the files in the new project. That files started commiting to Old project.
So i need to remove all .svn folders form all the subfolders. Than only i can add all the folder to new project.

I google around for solution. I found many ways:

• Remove the all .svn folder from all subfolder.
• Through linux command find all .svn file and delete. (but i think this harmful)
• SVN export – command

SVN export is the very simple and reliable way to fetch project out of svn.
In windows, using svn export is very easy.

When i was going through Spree i got to know about paperclip plugin which is used for image manipulation. Earlier i used “attachment_fu” for image manipulation and file uploading in rails projects.

How to use “Paperclip‘

First install perperclip plugin to your project.

Windows and Linux user can use my code. (I used this in WindowsXP and Fedora 9)

#ruby script /plugin install https://svn.thoughtbot.com/plugins/paperclip/trunk/

through this command perperclip get installed in your project folder.

Many time you need photo upload functionality for customer

Here i used Customer contoller and Customer model for this lession

First run following command

#ruby script/generate paperclip ModelName FieldName

In my case command is:

#ruby script/generate paperclip Customer customer_pic

One migration file will be created through this command. Run that migration.

In Customer model file paste this code:

class Customer < ActiveRecord::Base
# Paperclip
has_attached_file :customer_pic,
:styles => {
:thumb=> "100x100#",
:small => "150x150>" }
end

Using this command you will save three pic(photo) in your system folder.

Default upload url of peperclip is (RAILS_ROOT/public/system/…)

You can use following lines in your model file. (copy & paste this code under styles code)

:url => “/uploads/:class/:attachment/:id/:style_:basename.:extension”,
:path => “:rails_root/public/uploads/:class/:attachment/:id/:style_:basename.:extension”

I added uploads folder front on :class. That is optional you can remove also.

If you are already having forms for customer and if you want to add that to form. Just use this code in your form tag.

:html => { :multipart => true

and in from <%= f.file_field :customer_pic%>

That sit. you need to add or use following code in View

<%= image_tag @user.customer_pic.url %>

<%= image_tag @user.customer_pic.url(:thumb) %>

Paperclip Validations

Here i giving some validation for Paperclip. You need to just copy & paste in to your model where you want to use image upload.

validates_attachment_content_type :avatar, :content_type => 'image/jpeg'

validates_attachment_presence :avatar

I found this plugin is very usefull for Me. It really saves lots of time.

If you are new in rails. Just wanted to remind you.

First go to Rails project’s “public” folder and delete or rename the index.html file. If index.html file is there then default routing will not run.

If you want Users controller’s index page as a home page of site then go for this code in routes.rb file.

map.connect ”, { :controller => ‘users’, :action => ‘index’ }

In view you can use link for home page and logo of site(basic hack)

<%= link_to(“HOME”,{:controller=>’/'}) %>