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1== Welcome to Rails
2
3Rails is a web-application framework that includes everything needed to create
4database-backed web applications according to the Model-View-Control pattern.
5
6This pattern splits the view (also called the presentation) into "dumb" templates
7that are primarily responsible for inserting pre-built data in between HTML tags.
8The model contains the "smart" domain objects (such as Account, Product, Person,
9Post) that holds all the business logic and knows how to persist themselves to
10a database. The controller handles the incoming requests (such as Save New Account,
11Update Product, Show Post) by manipulating the model and directing data to the view.
12
13In Rails, the model is handled by what's called an object-relational mapping
14layer entitled Active Record. This layer allows you to present the data from
15database rows as objects and embellish these data objects with business logic
16methods. You can read more about Active Record in
17link:files/vendor/rails/activerecord/README.html.
18
19The controller and view are handled by the Action Pack, which handles both
20layers by its two parts: Action View and Action Controller. These two layers
21are bundled in a single package due to their heavy interdependence. This is
22unlike the relationship between the Active Record and Action Pack that is much
23more separate. Each of these packages can be used independently outside of
24Rails.  You can read more about Action Pack in
25link:files/vendor/rails/actionpack/README.html.
26
27
28== Getting Started
29
301. At the command prompt, start a new Rails application using the <tt>rails</tt> command
31   and your application name. Ex: rails myapp
322. Change directory into myapp and start the web server: <tt>script/server</tt> (run with --help for options)
333. Go to http://localhost:3000/ and get "Welcome aboard: You're riding the Rails!"
344. Follow the guidelines to start developing your application
35
36
37== Web Servers
38
39By default, Rails will try to use Mongrel and lighttpd if they are installed, otherwise
40Rails will use WEBrick, the webserver that ships with Ruby. When you run script/server,
41Rails will check if Mongrel exists, then lighttpd and finally fall back to WEBrick. This ensures
42that you can always get up and running quickly.
43
44Mongrel is a Ruby-based webserver with a C component (which requires compilation) that is
45suitable for development and deployment of Rails applications. If you have Ruby Gems installed,
46getting up and running with mongrel is as easy as: <tt>gem install mongrel</tt>.
47More info at: http://mongrel.rubyforge.org
48
49If Mongrel is not installed, Rails will look for lighttpd. It's considerably faster than
50Mongrel and WEBrick and also suited for production use, but requires additional
51installation and currently only works well on OS X/Unix (Windows users are encouraged
52to start with Mongrel). We recommend version 1.4.11 and higher. You can download it from
53http://www.lighttpd.net.
54
55And finally, if neither Mongrel or lighttpd are installed, Rails will use the built-in Ruby
56web server, WEBrick. WEBrick is a small Ruby web server suitable for development, but not
57for production.
58
59But of course its also possible to run Rails on any platform that supports FCGI.
60Apache, LiteSpeed, IIS are just a few. For more information on FCGI,
61please visit: http://wiki.rubyonrails.com/rails/pages/FastCGI
62
63
64== Apache .htaccess example
65
66# General Apache options
67AddHandler fastcgi-script .fcgi
68AddHandler cgi-script .cgi
69Options +FollowSymLinks +ExecCGI
70
71# If you don't want Rails to look in certain directories,
72# use the following rewrite rules so that Apache won't rewrite certain requests
73#
74# Example:
75#   RewriteCond %{REQUEST_URI} ^/notrails.*
76#   RewriteRule .* - [L]
77
78# Redirect all requests not available on the filesystem to Rails
79# By default the cgi dispatcher is used which is very slow
80#
81# For better performance replace the dispatcher with the fastcgi one
82#
83# Example:
84#   RewriteRule ^(.*)$ dispatch.fcgi [QSA,L]
85RewriteEngine On
86
87# If your Rails application is accessed via an Alias directive,
88# then you MUST also set the RewriteBase in this htaccess file.
89#
90# Example:
91#   Alias /myrailsapp /path/to/myrailsapp/public
92#   RewriteBase /myrailsapp
93
94RewriteRule ^$ index.html [QSA]
95RewriteRule ^([^.]+)$ $1.html [QSA]
96RewriteCond %{REQUEST_FILENAME} !-f
97RewriteRule ^(.*)$ dispatch.cgi [QSA,L]
98
99# In case Rails experiences terminal errors
100# Instead of displaying this message you can supply a file here which will be rendered instead
101#
102# Example:
103#   ErrorDocument 500 /500.html
104
105ErrorDocument 500 "<h2>Application error</h2>Rails application failed to start properly"
106
107
108== Debugging Rails
109
110Sometimes your application goes wrong.  Fortunately there are a lot of tools that
111will help you debug it and get it back on the rails.
112
113First area to check is the application log files.  Have "tail -f" commands running
114on the server.log and development.log. Rails will automatically display debugging
115and runtime information to these files. Debugging info will also be shown in the
116browser on requests from 127.0.0.1.
117
118You can also log your own messages directly into the log file from your code using
119the Ruby logger class from inside your controllers. Example:
120
121  class WeblogController < ActionController::Base
122    def destroy
123      @weblog = Weblog.find(params[:id])
124      @weblog.destroy
125      logger.info("#{Time.now} Destroyed Weblog ID ##{@weblog.id}!")
126    end
127  end
128
129The result will be a message in your log file along the lines of:
130
131  Mon Oct 08 14:22:29 +1000 2007 Destroyed Weblog ID #1
132
133More information on how to use the logger is at http://www.ruby-doc.org/core/
134
135Also, Ruby documentation can be found at http://www.ruby-lang.org/ including:
136
137* The Learning Ruby (Pickaxe) Book: http://www.ruby-doc.org/docs/ProgrammingRuby/
138* Learn to Program: http://pine.fm/LearnToProgram/  (a beginners guide)
139
140These two online (and free) books will bring you up to speed on the Ruby language
141and also on programming in general.
142
143
144== Debugger
145
146Debugger support is available through the debugger command when you start your Mongrel or
147Webrick server with --debugger. This means that you can break out of execution at any point
148in the code, investigate and change the model, AND then resume execution!
149You need to install ruby-debug to run the server in debugging mode. With gems, use 'gem install ruby-debug'
150Example:
151
152  class WeblogController < ActionController::Base
153    def index
154      @posts = Post.find(:all)
155      debugger
156    end
157  end
158
159So the controller will accept the action, run the first line, then present you
160with a IRB prompt in the server window. Here you can do things like:
161
162  >> @posts.inspect
163  => "[#<Post:0x14a6be8 @attributes={\"title\"=>nil, \"body\"=>nil, \"id\"=>\"1\"}>,
164       #<Post:0x14a6620 @attributes={\"title\"=>\"Rails you know!\", \"body\"=>\"Only ten..\", \"id\"=>\"2\"}>]"
165  >> @posts.first.title = "hello from a debugger"
166  => "hello from a debugger"
167
168...and even better is that you can examine how your runtime objects actually work:
169
170  >> f = @posts.first
171  => #<Post:0x13630c4 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}>
172  >> f.
173  Display all 152 possibilities? (y or n)
174
175Finally, when you're ready to resume execution, you enter "cont"
176
177
178== Console
179
180You can interact with the domain model by starting the console through <tt>script/console</tt>.
181Here you'll have all parts of the application configured, just like it is when the
182application is running. You can inspect domain models, change values, and save to the
183database. Starting the script without arguments will launch it in the development environment.
184Passing an argument will specify a different environment, like <tt>script/console production</tt>.
185
186To reload your controllers and models after launching the console run <tt>reload!</tt>
187
188== dbconsole
189
190You can go to the command line of your database directly through <tt>script/dbconsole</tt>.
191You would be connected to the database with the credentials defined in database.yml.
192Starting the script without arguments will connect you to the development database. Passing an
193argument will connect you to a different database, like <tt>script/dbconsole production</tt>.
194Currently works for mysql, postgresql and sqlite.
195
196== Description of Contents
197
198app
199  Holds all the code that's specific to this particular application.
200
201app/controllers
202  Holds controllers that should be named like weblogs_controller.rb for
203  automated URL mapping. All controllers should descend from ApplicationController
204  which itself descends from ActionController::Base.
205
206app/models
207  Holds models that should be named like post.rb.
208  Most models will descend from ActiveRecord::Base.
209
210app/views
211  Holds the template files for the view that should be named like
212  weblogs/index.html.erb for the WeblogsController#index action. All views use eRuby
213  syntax.
214
215app/views/layouts
216  Holds the template files for layouts to be used with views. This models the common
217  header/footer method of wrapping views. In your views, define a layout using the
218  <tt>layout :default</tt> and create a file named default.html.erb. Inside default.html.erb,
219  call <% yield %> to render the view using this layout.
220
221app/helpers
222  Holds view helpers that should be named like weblogs_helper.rb. These are generated
223  for you automatically when using script/generate for controllers. Helpers can be used to
224  wrap functionality for your views into methods.
225
226config
227  Configuration files for the Rails environment, the routing map, the database, and other dependencies.
228
229db
230  Contains the database schema in schema.rb.  db/migrate contains all
231  the sequence of Migrations for your schema.
232
233doc
234  This directory is where your application documentation will be stored when generated
235  using <tt>rake doc:app</tt>
236
237lib
238  Application specific libraries. Basically, any kind of custom code that doesn't
239  belong under controllers, models, or helpers. This directory is in the load path.
240
241public
242  The directory available for the web server. Contains subdirectories for images, stylesheets,
243  and javascripts. Also contains the dispatchers and the default HTML files. This should be
244  set as the DOCUMENT_ROOT of your web server.
245
246script
247  Helper scripts for automation and generation.
248
249test
250  Unit and functional tests along with fixtures. When using the script/generate scripts, template
251  test files will be generated for you and placed in this directory.
252
253vendor
254  External libraries that the application depends on. Also includes the plugins subdirectory.
255  If the app has frozen rails, those gems also go here, under vendor/rails/.
256  This directory is in the load path.
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