rails/railties/README
Pratik Naik 46f30f902f 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 23:21:35 +01:00

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== 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, start a new Rails application using the <tt>rails</tt> command
and your application name. Ex: rails myapp
2. Change directory into myapp and start the web server: <tt>script/server</tt> (run with --help for options)
3. Go to http://localhost:3000/ and get "Welcome aboard: You're riding the Rails!"
4. Follow the guidelines to start developing your application
== Web Servers
By default, Rails will try to use Mongrel and lighttpd if they are installed, otherwise
Rails will use WEBrick, the webserver that ships with Ruby. When you run script/server,
Rails will check if Mongrel exists, then lighttpd and finally fall back to WEBrick. This ensures
that you can always get up and running quickly.
Mongrel is a Ruby-based webserver with a C component (which requires compilation) that is
suitable for development and deployment of Rails applications. If you have Ruby Gems installed,
getting up and running with mongrel is as easy as: <tt>gem install mongrel</tt>.
More info at: http://mongrel.rubyforge.org
If Mongrel is not installed, Rails will look for lighttpd. It's considerably faster than
Mongrel and WEBrick and also suited for production use, but requires additional
installation and currently only works well on OS X/Unix (Windows users are encouraged
to start with Mongrel). We recommend version 1.4.11 and higher. You can download it from
http://www.lighttpd.net.
And finally, if neither Mongrel or lighttpd are installed, Rails will use the built-in Ruby
web server, WEBrick. WEBrick is a small Ruby web server suitable for development, but not
for production.
But of course its also possible to run Rails on any platform that supports FCGI.
Apache, LiteSpeed, IIS are just a few. For more information on FCGI,
please visit: http://wiki.rubyonrails.com/rails/pages/FastCGI
== Apache .htaccess example
# General Apache options
AddHandler fastcgi-script .fcgi
AddHandler cgi-script .cgi
Options +FollowSymLinks +ExecCGI
# If you don't want Rails to look in certain directories,
# use the following rewrite rules so that Apache won't rewrite certain requests
#
# Example:
# RewriteCond %{REQUEST_URI} ^/notrails.*
# RewriteRule .* - [L]
# Redirect all requests not available on the filesystem to Rails
# By default the cgi dispatcher is used which is very slow
#
# For better performance replace the dispatcher with the fastcgi one
#
# Example:
# RewriteRule ^(.*)$ dispatch.fcgi [QSA,L]
RewriteEngine On
# If your Rails application is accessed via an Alias directive,
# then you MUST also set the RewriteBase in this htaccess file.
#
# Example:
# Alias /myrailsapp /path/to/myrailsapp/public
# RewriteBase /myrailsapp
RewriteRule ^$ index.html [QSA]
RewriteRule ^([^.]+)$ $1.html [QSA]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ dispatch.cgi [QSA,L]
# In case Rails experiences terminal errors
# Instead of displaying this message you can supply a file here which will be rendered instead
#
# Example:
# ErrorDocument 500 /500.html
ErrorDocument 500 "<h2>Application error</h2>Rails application failed to start properly"
== 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/ including:
* The Learning Ruby (Pickaxe) Book: http://www.ruby-doc.org/docs/ProgrammingRuby/
* Learn to Program: http://pine.fm/LearnToProgram/ (a beginners guide)
These two online (and free) 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 'gem install ruby-debug'
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 you know!\", \"body\"=>\"Only ten..\", \"id\"=>\"2\"}>]"
>> @posts.first.title = "hello from a debugger"
=> "hello from a debugger"
...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 enter "cont"
== Console
You can interact with the domain model by starting the console through <tt>script/console</tt>.
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.
Passing an argument will specify a different environment, like <tt>script/console production</tt>.
To reload your controllers and models after launching the console run <tt>reload!</tt>
== dbconsole
You can go to the command line of your database directly through <tt>script/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>script/dbconsole production</tt>.
Currently works for mysql, postgresql and sqlite.
== Description of Contents
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.
Most models will descend from ActiveRecord::Base.
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.
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 script/generate 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 script/generate scripts, 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.