<%= @message %>
------------------------------------------------------ Deal. Go check it out in your browser. Fire up your server. Remember? `./script/server` at the root of your Rails application should do it. [source,shell] ------------------------------------------------------ $ ./script/server => Booting WEBrick... ------------------------------------------------------ The URL will be `http://localhost:3000/greetings/hello`. I'll wait for you to be suitably impressed. NOTE: With a normal, plain-old Rails application, your URLs will generally follow the pattern of http://(host)/(controller)/(action), and a URL like http://(host)/(controller) will hit the *index* action of that controller. "What about data, though?", you ask over a cup of coffee. Rails comes with a generator for data models too. Can you guess its generator name? [source,shell] ------------------------------------------------------ $ ./script/generate model Usage: ./script/generate model ModelName [field:type, field:type] ... Examples: `./script/generate model account` creates an Account model, test, fixture, and migration: Model: app/models/account.rb Test: test/unit/account_test.rb Fixtures: test/fixtures/accounts.yml Migration: db/migrate/XXX_add_accounts.rb `./script/generate model post title:string body:text published:boolean` creates a Post model with a string title, text body, and published flag. ------------------------------------------------------ But instead of generating a model directly (which we'll be doing later), let's set up a scaffold. A *scaffold* in Rails is a full set of model, database migration for that model, controller to manipulate it, views to view and manipulate the data, and a test suite for each of the above. Let's set up a simple resource called "HighScore" that will keep track of our highest score on video games we play. [source,shell] ------------------------------------------------------ $ ./script/generate scaffold HighScore game:string score:integer exists app/models/ exists app/controllers/ exists app/helpers/ create app/views/high_scores create app/views/layouts/ exists test/functional/ create test/unit/ create public/stylesheets/ create app/views/high_scores/index.html.erb create app/views/high_scores/show.html.erb create app/views/high_scores/new.html.erb create app/views/high_scores/edit.html.erb create app/views/layouts/high_scores.html.erb create public/stylesheets/scaffold.css create app/controllers/high_scores_controller.rb create test/functional/high_scores_controller_test.rb create app/helpers/high_scores_helper.rb route map.resources :high_scores dependency model exists app/models/ exists test/unit/ create test/fixtures/ create app/models/high_score.rb create test/unit/high_score_test.rb create test/fixtures/high_scores.yml exists db/migrate create db/migrate/20081217071914_create_high_scores.rb ------------------------------------------------------ Taking it from the top - the generator checks that there exist the directories for models, controllers, helpers, layouts, functional and unit tests, stylesheets, creates the views, controller, model and database migration for HighScore (creating the `high_scores` table and fields), takes care of the route for the *resource*, and new tests for everything. The migration requires that we *migrate*, that is, run some Ruby code (living in that `20081217071914_create_high_scores.rb`) to modify the schema of our database. Which database? The sqlite3 database that Rails will create for you when we run the `rake db:migrate` command. We'll talk more about Rake in-depth in a little while. NOTE: Hey. Install the sqlite3-ruby gem while you're at it. `gem install sqlite3-ruby` [source,shell] ------------------------------------------------------ $ rake db:migrate (in /home/commandsapp) == CreateHighScores: migrating =============================================== -- create_table(:high_scores) -> 0.0070s == CreateHighScores: migrated (0.0077s) ====================================== ------------------------------------------------------ NOTE: Let's talk about unit tests. Unit tests are code that tests and makes assertions about code. In unit testing, we take a little part of code, say a method of a model, and test its inputs and outputs. Unit tests are your friend. The sooner you make peace with the fact that your quality of life will drastically increase when you unit test your code, the better. Seriously. We'll make one in a moment. Let's see the interface Rails created for us. ./script/server; http://localhost:3000/high_scores We can create new high scores (55,160 on Space Invaders!) === console === The `console` command lets you interact with your Rails application from the command line. On the underside, `script/console` uses IRB, so if you've ever used it, you'll be right at home. This is useful for testing out quick ideas with code and changing data server-side without touching the website. === dbconsole === `dbconsole` figures out which database you're using and drops you into whichever command line interface you would use with it (and figures out the command line parameters to give to it, too!). It supports MySQL, PostgreSQL, SQLite and SQLite3. === plugin === The `plugin` command simplifies plugin management; think a miniature version of the Gem utility. Let's walk through installing a plugin. You can call the sub-command *discover*, which sifts through repositories looking for plugins, or call *source* to add a specific repository of plugins, or you can specify the plugin location directly. Let's say you're creating a website for a client who wants a small accounting system. Every event having to do with money must be logged, and must never be deleted. Wouldn't it be great if we could override the behavior of a model to never actually take its record out of the database, but *instead*, just set a field? There is such a thing! The plugin we're installing is called "acts_as_paranoid", and it lets models implement a "deleted_at" column that gets set when you call destroy. Later, when calling find, the plugin will tack on a database check to filter out "deleted" things. [source,shell] ------------------------------------------------------ $ ./script/plugin install http://svn.techno-weenie.net/projects/plugins/acts_as_paranoid + ./CHANGELOG + ./MIT-LICENSE ... ... ------------------------------------------------------ === runner === `runner` runs Ruby code in the context of Rails non-interactively. For instance: [source,shell] ------------------------------------------------------ $ ./script/runner "Model.long_running_method" ------------------------------------------------------ === destroy === Think of `destroy` as the opposite of `generate`. It'll figure out what generate did, and undo it. Believe you-me, the creation of this tutorial used this command many times! [source,shell] ------------------------------------------------------ $ ./script/generate model Oops exists app/models/ exists test/unit/ exists test/fixtures/ create app/models/oops.rb create test/unit/oops_test.rb create test/fixtures/oops.yml exists db/migrate create db/migrate/20081221040817_create_oops.rb $ ./script/destroy model Oops notempty db/migrate notempty db rm db/migrate/20081221040817_create_oops.rb rm test/fixtures/oops.yml rm test/unit/oops_test.rb rm app/models/oops.rb notempty test/fixtures notempty test notempty test/unit notempty test notempty app/models notempty app ------------------------------------------------------ === about === Check it: Version numbers for Ruby, RubyGems, Rails, the Rails subcomponents, your application's folder, the current Rails environment name, your app's database adapter, and schema version! `about` is useful when you need to ask help, check if a security patch might affect you, or when you need some stats for an existing Rails installation. [source,shell] ------------------------------------------------------ $ ./script/about About your application's environment Ruby version 1.8.6 (i486-linux) RubyGems version 1.3.1 Rails version 2.2.0 Active Record version 2.2.0 Action Pack version 2.2.0 Active Resource version 2.2.0 Action Mailer version 2.2.0 Active Support version 2.2.0 Edge Rails revision unknown Application root /home/commandsapp Environment development Database adapter sqlite3 Database schema version 20081217073400 ------------------------------------------------------