1. Ruby on Rails Guide – P1
Brady Cheng
http://bradyisstudying.blogspot.tw/

2. Agenda
Prerequisite
First App

3. Prerequisite
What is Ruby?
A programming language
What is Rails?
A web application framework programmed by Ruby

4. Prerequisite
MVC
Model-View-Controller
Refer to this slide for other details
http://www.slideshare.net/jaceju/mvc-8761203
Img src: http://www.ils.unc.edu/~uskala/MVC.htm

5. Prerequisite
REST
CRUD REST Note
Create Post New data
Read Get Read data
Update Put Update data
Delete Delete Delete data

6. Prerequisite
Installation
Windows base
http://railsinstaller.org/
Trouble shooting
ERROR: Error installing json: The 'json' native gem requires
installed build tools.
http://stackoverflow.com/questions/8100891/the-json-
native-gem-requires-installed-build-tools

7. Prerequisite
Create a new project
rails new your_project_name
Start the created project
cd project_name
bundle install
rails server
Check http://localhost:3000 or http://127.0.0.1:3000

8. Prerequisite
Project organization
/app
Organize your models, views, and controllers
/config
Configs such as database config (database.yml), rails
environmental config (environment.rb)…etc
/db
Manage your database

9. Prerequisite
Project organization
/doc
Docs generated by RubyDoc framework
/lib
Libs for your applications
/log
Error log such as “server.log”, “development.log”…etc
/public
Some html files for your applications

10. Prerequisite
Project organization
/script
Some scripts for your applications
/test
Some tests written by you or by rails such as unit
test, fixture tests…etc.
/tmp
Temp files
/vendor
Third party libs

11. Prerequisite
Snapshot

12. First App
We can use the following command to new a
controller and related files
rails generate GENERATOR ARG
Generator can be assets, controller, helper…etc
ARG here is the file name

13. First App
Snapshot of the responses

14. First App
Testing your http://127.0.0.1:3000/greeting
Edit your config/routes.rb
resources :greeting
http://stackoverflow.com/questions/11696695/routing-error-ruby-on-rails

15. First App
After updating the routes.rb
Add an index function in your controller
def index
render :text=>”Hello Ruby world!”
end

16. First App
Aforementioned approach is somehow dirty
We need to follow the MVC rules
Update the index function in controller
def index
@welcome_msg = "Hello RoR world“
end
Update view/index.html/erb
<%= @welcome_msg %>

17. First App
Worth to mention what erb file is
ERB file = html code + ruby code
Ruby code will be surrounded by <%...%> or <%=…%>
<% code here %> : pure logic, nothing display to screen
<%= code here %> : display something to screen

18. First App
Worth to mention the Request scope
Request scope
Each http request will get a copy of the controller
Pros : thread safe
Cons: hard to share data between different requests
Solution: use sessions