Upgrade Ruby version which is installed with RVM

• Get latest Ruby version for RVM
• rvm get latest
• Find out current Ruby version
• rvm current (the string between first '-' and '@')
• Find out new Ruby version
• rvm list known
• Upgrade
• rvm upgrade [current version] [new version]

[Rails] Redirect to previous page

In controller, you can specify redirection to go back to previous page that call to this controller by using code below:

redirecto_to :back  

Note: Rails 3.1

[Rails] Route alias

You can execute "rake routes" to view display routes in your app.

The first column of output are route aliases which you can refer to in your app or test by append "_path" to that alias.

If you use resource in routes.rb, it will automatically generate CRUD routes and their alias for you.

But if you want to alias your other routes, you can do by append below after your routes

, :as => :{alias you want}

Note: Rails 3.1

[Heroku] Access Rails's model in migration, heroku rake db:migrate, uninitialized constant

I wanted to use Rails's migration to add new column to a table and fill this column with default value.

add_column :students, :student_id, :integer 

Student.all.each { |s| s.update_attributes!(:student_id => s.id+10000) }

I run this locally.

rake db:migrate

It worked without any problem.

Then I deployed to Heroku and run;

heroku rake db:migrate

I found this error.

 uninitialized constant AddStudentIdToStudents::Student

After googling for a while, I found this blog post Heroku Migration Fails to Update Attributes: reset_column_information

The way to solve this issue(don't know why) is to open up the class inside migration file like this;

class AddStudentIdToStudents < ActiveRecord::Migration

  class Student < ActiveRecord::Base; end

  def change

    add_column :students, :student_id, :integer

    Student.all.each { |s| s.update_attributes!(:student_id => s.id+10000) }

  end

end

This works for me.

Note: Rails 3.1.0 

Update Rails 3.x

• Update gems
• bundle update
• Update Rails
• rake rails:update

Credit:  How to update a Rails 3 project to latest gems?

My Note from "The Intro to Rails Screencast I Wish I Had"

I found that The Intro to Rails Screencast I Wish I Had is very good in demostrating some tricks that make Rails different to other web development frameworks.

Below are notes from my 2nd time watching this screencast. What I note are things that I've never known before or I can't really remember the way to use it.

• Add -T in rails new to prevent rails from generating Test::Unit
• Gems
• turn (Pretty printing for test results)
• guard-rspec (Autotest)
• growl_notify
• rb-fsevent
• launchy
• save_and_open_page (use along with Capybara statements)
• Guard
• guard init rspec
• guard (start guard)
• RSpec integration test
• rails g integration_test {name}
• Routes
• rake routes
• resources (auto routes)
• Capybara (route_name comes from first column of rake route)
• visit {route_name}_path
• page.should have_content {string}
• fill_in {id/name/label}, :with => {string}
• click_button {id/name/label}
• current_path.should == {route_name}_path
• find_field('').value
• ActiveModel
• {Model}.create {value}
• {model_instance}.update_attributes {fields hash}
• ERB
• form_for {object} do | f |
• f.label :{name}
• f.text_field :{name}
• f.submit
• render '{partial view(No _)}'  <- partial view file name must prefix with _ 
• flash.each do | name, message | (come from params passed with redirect_to)
• Controller
• render :text => params.inspect
• redirect_to :back (previous page)
• (redirect_to) {:notice | :alert} => {string} (will be available in flash)

Make Rails accept Non-English Characters

Put following line to the first line of the page that contain Non-English characters

# encoding: utf-8