== Welcome to Rails
Rails is a web-application and persistance framework that includes everything
needed to create database-backed web-applications according to the
Model-View-Control pattern of separation. This pattern splits the view (also
called the presentation) into "dumb" templates that are primarily responsible
for inserting pre-build 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 a 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/activerecord/README.html.
The controller and view is 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/actionpack/README.html.
== Requirements
* Database and driver (MySQL, PostgreSQL, or SQLite)
* Rake[http://rake.rubyforge.org] for running tests and the generating documentation
== Optionals
* Apache 1.3.x or 2.x (or any FastCGI-capable webserver with a
mod_rewrite-like module)
* FastCGI (or mod_ruby) for better performance on Apache
== Getting started
1. Run the WEBrick servlet: <tt>ruby script/server</tt>
(run with --help for options)
2. Go to http://localhost:3000/ and get "Congratulations, you've put Ruby on Rails!"
3. Follow the guidelines on the "Congratulations, you've put Ruby on Rails!" screen
== Example for Apache conf
<VirtualHost *:80>
ServerName rails
DocumentRoot /path/application/public/
ErrorLog /path/application/log/apache.log
<Directory /path/application/public/>
Options ExecCGI FollowSymLinks
AllowOverride all
Allow from all
Order allow,deny
</Directory>
</VirtualHost>
NOTE: Be sure that CGIs can be executed in that directory as well. So ExecCGI
should be on and ".cgi" should respond. All requests from 127.0.0.1 goes
through CGI, so no Apache restart is necessary for changes. All other requests
goes through FCGI (or mod_ruby) that requires restart to show changes.
== Debugging Rails
Have "tail -f" commands running on both the apache.log, production.log, and
test.log files. 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.
== Breakpoints
Breakpoint support is available through the script/breakpointer client. This
means that you can break out of execution at any point in the code, investigate
and change the model, AND then resume execution! Example:
class WeblogController < ActionController::Base
def index
@posts = Post.find_all
breakpoint "Breaking out from the list"
end
end
So the controller will accept the action, run the first line, then present you
with a IRB prompt in the breakpointer window. Here you can do things like:
Executing breakpoint "Breaking out from the list" at .../webrick_server.rb:16 in 'breakpoint'
>> @posts.inspect
=> "[#<Post:0x14a6be8 @attributes={\"title\"=>nil, \"body\"=>nil, \"id\"=>\"1\"}>,
#<Post:0x14a6620 @attributes={\"title\"=>\"Rails you know!\", \"body\"=>\"Only ten..\", \"id\"=>\"2\"}>]"
>> @posts.first.title = "hello from a breakpoint"
=> "hello from a breakpoint"
...and even better is that 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 press CTRL-D
== Console
You can interact with the domain model by starting the console through script/console.
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. Start the script without arguments to see the options.
== Description of contents
app
Holds all the code that's specific to this particular application.
app/controllers
Holds controllers that should be named like weblog_controller.rb for
automated URL mapping. All controllers should descend from
ActionController::Base.
app/models
Holds models that should be named like post.rb.
Most models will descent from ActiveRecord::Base.
app/views
Holds the template files for the view that should be named like
weblog/index.rhtml for the WeblogController#index action. All views uses eRuby
syntax. This directory can also be used to keep stylesheets, images, and so on
that can be symlinked to public.
app/helpers
Holds view helpers that should be named like weblog_helper.rb.
config
Configuration files for Apache, database, and other dependencies.
lib
Application specific libraries. Basically, any kind of custom code that doesn't
belong controllers, models, or helpers. This directory is in the load path.
public
The directory available for Apache, which includes symbolic links to other
parts of the structure that are to be made available. Refrain from placing
actual files in here if you're using CVS and don't want to check in this
directory.
script
Helper scripts for automation and generation.
test
Unit and functional tests along with fixtures.
vendor
External libraries that the application depend on. This directory is in the load path.
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