your first rails app - 2

YOUR FIRST RAILS APP Environments, MVC, Scaffold

Sunday, November 13, 11

CREATING YOUR FIRST RAILS APP

rails new roster

This command generates code fora new Rails web application

in a sub-directory called “roster”


THE APPLICATION DIRECTORY

•The whole rails app is in this one directory• No hidden configuration files in system directories• You will modify many of these files in the course of your development• We're using sqlite so even the database is in this directory, but usually the

database is the only part of your application that lives somewhere else

•You can simple copy this directory to server to deploy the app•You can delete the directory and its contentsif you want to throw it away and start over


RUNNING YOUR APP

cd rosterbundle

rails server


RAILS ENVIRONMENTS

By default, Rails is configured with 3 environments:• development• test• production


RAILS ENVIRONMENTS


RAILS ENVIRONMENTSThe environment can be specified with RAILS_ENV as an environment variable "development" by default.

In your code, you refer to Rails.env (or RAILS_ENV in Rails 2)


CONFIG/DATABASE.YML


ADDITIONAL CONFIGURATION

config/environments/• development.rb• production.rb• test.rb


MODIFYING THE HOME PAGE

public/index.html

All files in the public directoryare static content.

Rails checks this directory before executing any dynamic code.


MVC


LEARNING WITH SCAFFOLD

rails generate scaffold person first_name:string last_name:string


NAMING CONVENTIONS


SCAFFOLDModel

app/models/person.rbdb/migrate/20090611073227_create_people.rb

5 viewsapp/views/people/index.html.erbapp/views/people/show.html.erbapp/views/people/new.html.erbapp/views/people/edit.html.erbapp/views/people/_form.html.erb

Controllerapp/controllers/people_controller.rbroute.rb: resources :people


MVCModel: ActiveRecord•Represents what is in the database

View: ActionView, erb•Model rendered as HTML

Controller: ActionController•Receives HTTP actions (GET, POST, PUT, DELETE)•Decides what to do, typically rendering a view


VIEWS

<% @people.each do |person| %><tr> <td><%= person.first_name %></td> <td><%= person.last_name %></td></tr><% end %>


VIEW EXERCISE

On the main people page a. Change “Listing people” to “My Class List” b. List people with first initial and last name in one visual

column (e.g. W. Flintstone)


your first rails app - 2

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