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@@ -0,0 +1,261 @@ +== Welcome to Rails + +Rails is a web-application framework that includes everything needed to create +database-backed web applications according to the Model-View-Control pattern. + +This pattern splits the view (also called the presentation) into "dumb" +templates that are primarily responsible for inserting pre-built data in between +HTML tags. The model contains the "smart" domain objects (such as Account, +Product, Person, Post) that holds all the business logic and knows how to +persist themselves to a database. The controller handles the incoming requests +(such as Save New Account, Update Product, Show Post) by manipulating the model +and directing data to the view. + +In Rails, the model is handled by what's called an object-relational mapping +layer entitled Active Record. This layer allows you to present the data from +database rows as objects and embellish these data objects with business logic +methods. You can read more about Active Record in +link:files/vendor/rails/activerecord/README.html. + +The controller and view are handled by the Action Pack, which handles both +layers by its two parts: Action View and Action Controller. These two layers +are bundled in a single package due to their heavy interdependence. This is +unlike the relationship between the Active Record and Action Pack that is much +more separate. Each of these packages can be used independently outside of +Rails. You can read more about Action Pack in +link:files/vendor/rails/actionpack/README.html. + + +== Getting Started + +1. At the command prompt, create a new Rails application: + <tt>rails new myapp</tt> (where <tt>myapp</tt> is the application name) + +2. Change directory to <tt>myapp</tt> and start the web server: + <tt>cd myapp; rails server</tt> (run with --help for options) + +3. Go to http://localhost:3000/ and you'll see: + "Welcome aboard: You're riding Ruby on Rails!" + +4. Follow the guidelines to start developing your application. You can find +the following resources handy: + +* The Getting Started Guide: http://guides.rubyonrails.org/getting_started.html +* Ruby on Rails Tutorial Book: http://www.railstutorial.org/ + + +== Debugging Rails + +Sometimes your application goes wrong. Fortunately there are a lot of tools that +will help you debug it and get it back on the rails. + +First area to check is the application log files. Have "tail -f" commands +running on the server.log and development.log. Rails will automatically display +debugging and runtime information to these files. Debugging info will also be +shown in the browser on requests from 127.0.0.1. + +You can also log your own messages directly into the log file from your code +using the Ruby logger class from inside your controllers. Example: + + class WeblogController < ActionController::Base + def destroy + @weblog = Weblog.find(params[:id]) + @weblog.destroy + logger.info("#{Time.now} Destroyed Weblog ID ##{@weblog.id}!") + end + end + +The result will be a message in your log file along the lines of: + + Mon Oct 08 14:22:29 +1000 2007 Destroyed Weblog ID #1! + +More information on how to use the logger is at http://www.ruby-doc.org/core/ + +Also, Ruby documentation can be found at http://www.ruby-lang.org/. There are +several books available online as well: + +* Programming Ruby: http://www.ruby-doc.org/docs/ProgrammingRuby/ (Pickaxe) +* Learn to Program: http://pine.fm/LearnToProgram/ (a beginners guide) + +These two books will bring you up to speed on the Ruby language and also on +programming in general. + + +== Debugger + +Debugger support is available through the debugger command when you start your +Mongrel or WEBrick server with --debugger. This means that you can break out of +execution at any point in the code, investigate and change the model, and then, +resume execution! You need to install ruby-debug to run the server in debugging +mode. With gems, use <tt>sudo gem install ruby-debug</tt>. Example: + + class WeblogController < ActionController::Base + def index + @posts = Post.all + debugger + end + end + +So the controller will accept the action, run the first line, then present you +with a IRB prompt in the server window. Here you can do things like: + + >> @posts.inspect + => "[#<Post:0x14a6be8 + @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}>, + #<Post:0x14a6620 + @attributes={"title"=>"Rails", "body"=>"Only ten..", "id"=>"2"}>]" + >> @posts.first.title = "hello from a debugger" + => "hello from a debugger" + +...and even better, you can examine how your runtime objects actually work: + + >> f = @posts.first + => #<Post:0x13630c4 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}> + >> f. + Display all 152 possibilities? (y or n) + +Finally, when you're ready to resume execution, you can enter "cont". + + +== Console + +The console is a Ruby shell, which allows you to interact with your +application's domain model. Here you'll have all parts of the application +configured, just like it is when the application is running. You can inspect +domain models, change values, and save to the database. Starting the script +without arguments will launch it in the development environment. + +To start the console, run <tt>rails console</tt> from the application +directory. + +Options: + +* Passing the <tt>-s, --sandbox</tt> argument will rollback any modifications + made to the database. +* Passing an environment name as an argument will load the corresponding + environment. Example: <tt>rails console production</tt>. + +To reload your controllers and models after launching the console run +<tt>reload!</tt> + +More information about irb can be found at: +link:http://www.rubycentral.org/pickaxe/irb.html + + +== dbconsole + +You can go to the command line of your database directly through <tt>rails +dbconsole</tt>. You would be connected to the database with the credentials +defined in database.yml. Starting the script without arguments will connect you +to the development database. Passing an argument will connect you to a different +database, like <tt>rails dbconsole production</tt>. Currently works for MySQL, +PostgreSQL and SQLite 3. + +== Description of Contents + +The default directory structure of a generated Ruby on Rails application: + + |-- app + | |-- assets + | |-- images + | |-- javascripts + | `-- stylesheets + | |-- controllers + | |-- helpers + | |-- mailers + | |-- models + | `-- views + | `-- layouts + |-- config + | |-- environments + | |-- initializers + | `-- locales + |-- db + |-- doc + |-- lib + | `-- tasks + |-- log + |-- public + |-- script + |-- test + | |-- fixtures + | |-- functional + | |-- integration + | |-- performance + | `-- unit + |-- tmp + | |-- cache + | |-- pids + | |-- sessions + | `-- sockets + `-- vendor + |-- assets + `-- stylesheets + `-- plugins + +app + Holds all the code that's specific to this particular application. + +app/assets + Contains subdirectories for images, stylesheets, and JavaScript files. + +app/controllers + Holds controllers that should be named like weblogs_controller.rb for + automated URL mapping. All controllers should descend from + ApplicationController which itself descends from ActionController::Base. + +app/models + Holds models that should be named like post.rb. Models descend from + ActiveRecord::Base by default. + +app/views + Holds the template files for the view that should be named like + weblogs/index.html.erb for the WeblogsController#index action. All views use + eRuby syntax by default. + +app/views/layouts + Holds the template files for layouts to be used with views. This models the + common header/footer method of wrapping views. In your views, define a layout + using the <tt>layout :default</tt> and create a file named default.html.erb. + Inside default.html.erb, call <% yield %> to render the view using this + layout. + +app/helpers + Holds view helpers that should be named like weblogs_helper.rb. These are + generated for you automatically when using generators for controllers. + Helpers can be used to wrap functionality for your views into methods. + +config + Configuration files for the Rails environment, the routing map, the database, + and other dependencies. + +db + Contains the database schema in schema.rb. db/migrate contains all the + sequence of Migrations for your schema. + +doc + This directory is where your application documentation will be stored when + generated using <tt>rake doc:app</tt> + +lib + Application specific libraries. Basically, any kind of custom code that + doesn't belong under controllers, models, or helpers. This directory is in + the load path. + +public + The directory available for the web server. Also contains the dispatchers and the + default HTML files. This should be set as the DOCUMENT_ROOT of your web + server. + +script + Helper scripts for automation and generation. + +test + Unit and functional tests along with fixtures. When using the rails generate + command, template test files will be generated for you and placed in this + directory. + +vendor + External libraries that the application depends on. Also includes the plugins + subdirectory. If the app has frozen rails, those gems also go here, under + vendor/rails/. This directory is in the load path. |