3 Rails is a web-application and persistence framework that includes everything
4 needed to create database-backed web-applications according to the
5 Model-View-Control pattern of separation. This pattern splits the view (also
6 called the presentation) into "dumb" templates that are primarily responsible
7 for inserting pre-built data in between HTML tags. The model contains the
8 "smart" domain objects (such as Account, Product, Person, Post) that holds all
9 the business logic and knows how to persist themselves to a database. The
10 controller handles the incoming requests (such as Save New Account, Update
11 Product, Show Post) by manipulating the model and directing data to the view.
13 In Rails, the model is handled by what's called an object-relational mapping
14 layer entitled Active Record. This layer allows you to present the data from
15 database rows as objects and embellish these data objects with business logic
16 methods. You can read more about Active Record in
17 link:files/vendor/rails/activerecord/README.html.
19 The controller and view are handled by the Action Pack, which handles both
20 layers by its two parts: Action View and Action Controller. These two layers
21 are bundled in a single package due to their heavy interdependence. This is
22 unlike the relationship between the Active Record and Action Pack that is much
23 more separate. Each of these packages can be used independently outside of
24 Rails. You can read more about Action Pack in
25 link:files/vendor/rails/actionpack/README.html.
30 1. Start the web server: <tt>ruby script/server</tt> (run with --help for options)
31 2. Go to http://localhost:3000/ and get "Welcome aboard: You’re riding the Rails!"
32 3. Follow the guidelines to start developing your application
37 Rails uses the built-in web server in Ruby called WEBrick by default, so you don't
38 have to install or configure anything to play around.
40 If you have lighttpd installed, though, it'll be used instead when running script/server.
41 It's considerably faster than WEBrick and suited for production use, but requires additional
42 installation and currently only works well on OS X/Unix (Windows users are encouraged
43 to start with WEBrick). We recommend version 1.4.11 and higher. You can download it from
44 http://www.lighttpd.net.
46 If you want something that's halfway between WEBrick and lighttpd, we heartily recommend
47 Mongrel. It's a Ruby-based web server with a C-component (so it requires compilation) that
48 also works very well with Windows. See more at http://mongrel.rubyforge.org/.
50 But of course its also possible to run Rails with the premiere open source web server Apache.
51 To get decent performance, though, you'll need to install FastCGI. For Apache 1.3, you want
52 to use mod_fastcgi. For Apache 2.0+, you want to use mod_fcgid.
54 See http://wiki.rubyonrails.com/rails/pages/FastCGI for more information on FastCGI.
56 == Example for Apache conf
60 DocumentRoot /path/application/public/
61 ErrorLog /path/application/log/server.log
63 <Directory /path/application/public/>
64 Options ExecCGI FollowSymLinks
71 NOTE: Be sure that CGIs can be executed in that directory as well. So ExecCGI
72 should be on and ".cgi" should respond. All requests from 127.0.0.1 go
73 through CGI, so no Apache restart is necessary for changes. All other requests
74 go through FCGI (or mod_ruby), which requires a restart to show changes.
79 Have "tail -f" commands running on both the server.log, production.log, and
80 test.log files. Rails will automatically display debugging and runtime
81 information to these files. Debugging info will also be shown in the browser
82 on requests from 127.0.0.1.
87 Breakpoint support is available through the script/breakpointer client. This
88 means that you can break out of execution at any point in the code, investigate
89 and change the model, AND then resume execution! Example:
91 class WeblogController < ActionController::Base
93 @posts = Post.find_all
94 breakpoint "Breaking out from the list"
98 So the controller will accept the action, run the first line, then present you
99 with a IRB prompt in the breakpointer window. Here you can do things like:
101 Executing breakpoint "Breaking out from the list" at .../webrick_server.rb:16 in 'breakpoint'
104 => "[#<Post:0x14a6be8 @attributes={\"title\"=>nil, \"body\"=>nil, \"id\"=>\"1\"}>,
105 #<Post:0x14a6620 @attributes={\"title\"=>\"Rails you know!\", \"body\"=>\"Only ten..\", \"id\"=>\"2\"}>]"
106 >> @posts.first.title = "hello from a breakpoint"
107 => "hello from a breakpoint"
109 ...and even better is that you can examine how your runtime objects actually work:
112 => #<Post:0x13630c4 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}>
114 Display all 152 possibilities? (y or n)
116 Finally, when you're ready to resume execution, you press CTRL-D
121 You can interact with the domain model by starting the console through script/console.
122 Here you'll have all parts of the application configured, just like it is when the
123 application is running. You can inspect domain models, change values, and save to the
124 database. Starting the script without arguments will launch it in the development environment.
125 Passing an argument will specify a different environment, like <tt>script/console production</tt>.
127 To reload your controllers and models after launching the console run <tt>reload!</tt>
131 == Description of contents
134 Holds all the code that's specific to this particular application.
137 Holds controllers that should be named like weblog_controller.rb for
138 automated URL mapping. All controllers should descend from
139 ActionController::Base.
142 Holds models that should be named like post.rb.
143 Most models will descend from ActiveRecord::Base.
146 Holds the template files for the view that should be named like
147 weblog/index.rhtml for the WeblogController#index action. All views use eRuby
148 syntax. This directory can also be used to keep stylesheets, images, and so on
149 that can be symlinked to public.
152 Holds view helpers that should be named like weblog_helper.rb.
155 Holds API classes for web services.
158 Configuration files for the Rails environment, the routing map, the database, and other dependencies.
161 Self-contained mini-applications that can bundle together controllers, models, and views.
164 Contains the database schema in schema.rb. db/migrate contains all
165 the sequence of Migrations for your schema.
168 Application specific libraries. Basically, any kind of custom code that doesn't
169 belong under controllers, models, or helpers. This directory is in the load path.
172 The directory available for the web server. Contains subdirectories for images, stylesheets,
173 and javascripts. Also contains the dispatchers and the default HTML files.
176 Helper scripts for automation and generation.
179 Unit and functional tests along with fixtures.
182 External libraries that the application depends on. Also includes the plugins subdirectory.
183 This directory is in the load path.