your first rails app - 2

YOUR FIRST RAILS APP Environments, MVC, Scaffold

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CREATING YOUR FIRST RAILS APP

rails new roster

This command generates code fora new Rails web application 

in a sub-directory called “roster”  

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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

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RUNNING YOUR APP

cd rosterbundle

rails server 

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RAILS ENVIRONMENTS

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

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RAILS ENVIRONMENTS

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RAILS ENVIRONMENTS

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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)

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CONFIG/DATABASE.YML

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ADDITIONAL CONFIGURATION

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

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MODIFYING THE HOME PAGE

public/index.html

All files in the public directoryare static content.

Rails checks this directory before executing any dynamic code.

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MVC

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LEARNING WITH SCAFFOLD

rails generate scaffold person first_name:string last_name:string

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NAMING CONVENTIONS

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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

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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

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VIEWS

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

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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) 

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