rails--rails/railties/README

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== Welcome to Rails
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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/
== Web Servers
By default, Rails will try to use Mongrel if it's installed when started with
<tt>rails server</tt>, otherwise Rails will use WEBrick, the web server that
ships with Ruby.
Mongrel is a Ruby-based web server with a C component (which requires
compilation) that is suitable for development. If you have Ruby Gems installed,
getting up and running with mongrel is as easy as:
<tt>sudo gem install mongrel</tt>.
You can find more info at: http://mongrel.rubyforge.org
You can alternatively run Rails applications with other Ruby web servers, e.g.,
{Thin}[http://code.macournoyer.com/thin/], {Ebb}[http://ebb.rubyforge.org/], and
Apache with {mod_rails}[http://www.modrails.com/]. However, <tt>rails server</tt>
doesn't search for or start them.
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For production use, often a web/proxy server, e.g., {Apache}[http://apache.org],
{Nginx}[http://nginx.net/], {LiteSpeed}[http://litespeedtech.com/],
{Lighttpd}[http://www.lighttpd.net/], or {IIS}[http://www.iis.net/], is deployed
as the front end server with the chosen Ruby web server running in the back end
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and receiving the proxied requests via one of several protocols (HTTP, CGI, FCGI).
== 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.find(: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.
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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.com/pickaxe/irb.html
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Merge documentation changes from docrails. commit 0fc3381aa5359f31b36057d7bfba2e0eb6a3c064 Author: Xavier Noria <fxn@hashref.com> Date: Fri May 16 23:44:51 2008 +0200 Conventions. Formatting. Revising docs all over the rails. This revision encourages the modern resource-oriented form_for usage. In addition corrects some markup and other details. commit 70e4bcf5cb039bea073851faed2df9f465e6f2f8 Author: Chris Kampmeier <chris@kampers.net> Date: Fri May 16 12:09:46 2008 -0700 Fix a couple spelling errors in docs commit 6ea5e4208f724b50e774e6a1af027336c3ee3de1 Author: Chris O'Sullivan <thechrisoshow@gmail.com> Date: Fri May 16 16:09:11 2008 +0100 Added docs about source_type for has_one association commit a01a0178be297b0eb62909819a15a01c6b69a841 Author: miloops <miloops@gmail.com> Date: Wed May 14 09:22:39 2008 +0000 Change migration generator USAGE to explain the timestamped migrations behaviour commit 4e2bc02163aa646ab1304b1b5bec98a7af8927f5 Author: Xavier Noria <fxn@hashref.com> Date: Fri May 16 00:43:03 2008 +0200 minor revision in url_for docs Made explicit that RESTful and controller/action styles are not interchangeable, and revised some markup. commit d6ecce66f4e125531875006eea8022b73fe135b5 Author: Michael Hartl <michael@michaelhartl.com> Date: Thu May 15 10:46:40 2008 -0700 Expanded and updated the link_to documentation commit b8c46c86f0b785f6afc3c58eeb1b347543f5901e Author: Cody Fauser <cody@jadedpixel.com> Date: Wed May 14 09:10:02 2008 -0400 Improve and cleanup ActionMailer documentation commit 9546ee299952c86329c4854f9b3776382c0575ff Author: Yehuda Katz <wycats@gmail.com> Date: Mon May 12 23:41:43 2008 -0700 Add documentation for Inflector.inflections commit cbd5db8f5165f013069b02414f9bf762d88f619f Author: Manik Juneja <mjuneja@manik-junejas-computer.local> Date: Mon May 12 23:43:31 2008 +0530 minor changes in railties/README. Added dbconsole introduction commit 130a280ddee1f96ccf378b52c17ee742b5e54f4a Author: Gaurav Sharma <gaurav@norbauer.com> Date: Mon May 12 18:00:19 2008 +0530 adding documentation for cached_attributes commit 164c9586480f0a02522ea15ec7fb42c6a783a74d Author: TomK32 <tomk32@tomk32.de> Date: Mon May 12 10:59:33 2008 +0200 proper heading for "Example:" commit 35634feb474cc55fbc95edeffe98cec241d45f23 Author: Matt Boehlig <thetamind@gmail.com> Date: Sun May 11 16:46:07 2008 -0500 Cleanup whitespace and change_table documentation commit 80bba28a1a56a0cafeb0fc94659905e88129bc31 Author: Xavier Noria <fxn@hashref.com> Date: Sun May 11 02:54:02 2008 +0200 documented the source annotation extractor commit e6823bb1650d9b0fea58bd2d355f388961a408b3 Author: Mike Mondragon <mikemondragon@gmail.com> Date: Fri May 9 13:49:56 2008 -0700 Added additional information about processing email with ActionMailer and the strategy one might want to employ to do so. commit e6afd8b2736364322b673bbdcca3e9b38b6d3da0 Author: Xavier Noria <fxn@hashref.com> Date: Thu May 8 23:49:36 2008 +0200 corrected and completed docs of increment/decrement/toggle in AR::Base commit 2fead68b3192332eee27945ed95a94a64ca73f70 Author: Austin Putman <austin@emmanuel.local> Date: Wed May 7 19:35:46 2008 -0700 Documented class methods on ActionController::Routing. These are dangerous, and mostly used for testing. commit f5b84182dbc39bea79c8ee319c688d00fa99f9d1 Author: Teflon Ted <github@rudiment.net> Date: Wed May 7 16:08:49 2008 -0400 Added explanation about errant inflections not being patched in the future in order to avoid breaking legacy applications. commit 370f4f51722cec49ace17093d29e9ce9e8f15cfb Author: Sunny Ripert <negatif@gmail.com> Date: Wed May 7 14:00:59 2008 +0200 Applied list conventions in AR::Base commit 5bd18429f09d44e75191bec42a6db04bd33f3030 Author: Sunny Ripert <negatif@gmail.com> Date: Wed May 7 13:53:35 2008 +0200 Renamed Options list to Attributes list whenever they weren't option hashes in AR::Base commit 2fa628e34b25166afb49e3afeea87e770ab84256 Author: Xavier Noria <fxn@hashref.com> Date: Wed May 7 11:52:33 2008 +0200 revised details in Exceptions section of AR::Base docs commit d912bd5672316454457ae83f6e9dda5197beeb6f Author: Yaroslav Markin <yaroslav@markin.net> Date: Wed May 7 13:50:28 2008 +0400 Add a filter_parameter_logging usage hint to generated ApplicationController. This may help to remind the developer to filter sensitive information from application logs. Closes #11578 commit f81d771f0657ae8375b84a77a059812cce5d6fd9 Author: Jack Danger Canty <git@6brand.com> Date: Tue May 6 23:35:05 2008 -0700 doc: ActiveRecord::Reflection::AssociationReflection#through_reflection Added documentation demonstrating the use of #through_reflection for finding intervening reflection objects for HasManyThrough and HasOneThrough. commit ae6b46f00b5b8b2939c6b37ce3329c83de7e71db Author: Cheah Chu Yeow <chuyeow@gmail.com> Date: Wed May 7 13:47:41 2008 +0800 Document AttributeAssignmentError and MultiparameterAssignmentErrors. commit 8f463550b597db2156b67733f31aed13487fbc3a Author: John Barnette <jbarnette@gmail.com> Date: Tue May 6 22:46:44 2008 -0700 Killing/fixing a bunch of outdated language in the AR README. commit 284a930a93fbee16e25d06392779dbf2f03e9e12 Author: Jonathan Dance <jd@wuputah.com> Date: Tue May 6 14:58:26 2008 -0400 improvements to the page caching docs commit 9482da621390c874da7c921c8bd6230caae7035a Author: Sunny Ripert <negatif@gmail.com> Date: Mon May 5 18:13:40 2008 +0200 validates_numericality_of() "integer" option really is "only_integer" commit e9afd6790a8f530528f6597a7f59bb283be754f6 Author: Sunny Ripert <negatif@gmail.com> Date: Mon May 5 12:11:59 2008 +0200 Harmonized hash notation in AR::Base commit 67ebf14a91ffd970b582be4ff2991d691a9cf3e1 Author: Sunny Ripert <negatif@gmail.com> Date: Mon May 5 12:06:19 2008 +0200 Turned options into rdoc-lists in AR::Base commit 0ec7c0a41d889d4e5382b9dff72f1aaba89bf297 Author: Marshall Huss <mwhuss@Macbook.local> Date: Sun May 4 23:21:33 2008 -0400 Added information of how to set element_name in the case the user has a name confliction with an existing model Signed-off-by: Pratik Naik <pratiknaik@gmail.com>
2008-05-16 22:01:32 +00:00
== 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:
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|-- app
| |-- controllers
| |-- helpers
| |-- models
| `-- views
| `-- layouts
|-- config
| |-- environments
| |-- initializers
| `-- locales
|-- db
|-- doc
|-- lib
| `-- tasks
|-- log
|-- public
| |-- images
| |-- javascripts
| `-- stylesheets
|-- script
| `-- performance
|-- test
| |-- fixtures
| |-- functional
| |-- integration
| |-- performance
| `-- unit
|-- tmp
| |-- cache
| |-- pids
| |-- sessions
| `-- sockets
`-- vendor
`-- plugins
app
Holds all the code that's specific to this particular application.
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. Contains subdirectories for
images, stylesheets, and javascripts. 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.