RAILS(1) BSD General Commands Manual RAILS(1)
rails -- Web-application framework
rails path [options...]
Rails is a web-application and persistence 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 pri-
marily responsible for inserting pre-built data in between HTML tags. The model contains the "smart" domain objects (such as Account, Prod-
uct, 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.
Rails is written with the ruby(1) language. For more information about Rails you can use its ---help flag. There is also online documentation
available at "http://rubyonrails.org".
ruby(1) mongrel_rails(1) cap(1)
Rails was created by David Heinemeier Hansson <firstname.lastname@example.org> then extended and improved by hundreds of open-source contributors.
February 27, 2006 BSD
Check Out this Related Man Page
Jifty::Manual::ObjectModel(3pm) User Contributed Perl Documentation Jifty::Manual::ObjectModel(3pm)
Jifty::Manual::ObjectModel -- An overview of the Jifty object model
Jifty applications are generally built in a similar way. There's no reason you need to use the model we've built, but we find it a
reasonably OK way to do things.
This document should serve as a roadmap to the Jifty class library, as well as an introduction to the way Jifty applications are put
We start with the classes in your application and move on to the bits of Jifty itself.
If you create a brand new application, let's call it "MyWeblog", and create one model class called "MyWeblog::Post", you'll end up with the
following files and directories:
#some test files.
At least that's the scaffolding Jifty creates for you. Behind the scenes, Jifty is actually doing a lot more. Rather than create a bunch of
little "stub" classes and libraries for you, Jifty generates them on the fly. It's always possible to actually create these libraries when
you need to customize the default behavior, but we work really hard to make sure you don't need to.
Right now, Jifty is automatically creating libraries, static web pages and web templates.
We're not 100% satisfied with how Jifty automatically creates web templates and static pages and are working to redesign that.
The library you see when creating a Jifty app is:
"MyWeblog::Model::Post" describes the schema and business logic of your post class. It uses two namespaces,
"MyWeblog::Model::Post::Schema" that has actual column definitions and "MyWeblog::Model::Post" that contains the (optional) business
logic, access control and so on.
That's it. But if you look carefully at "MyWeblog::Model::Post", you'll see the line:
use base qw/MyWeblog::Record/;
How can that possibly work? There is no "MyWeblog::Record" class in your application. And Jifty, while it tries to be a comprehensive
framework, draws the line somewhat short of including application-specific base classes for every application you might possibly contrive.
The answer lies in Jifty::ClassLoader, a utility module Jifty uses to create the boring stuff for you when you need it.
It'd certainly be possible for Jifty to create every class you might need as a file on disk when you first create your application (and
indeed we may decide to do so if enough people yell at us), but when the stub classes we'd provide are just little shims that inherit from
or call to the Jifty core, it doesn't make much sense to create them before you need them. You could build a Jifty application without
these shims by having your model classes inherit directly from Jifty::Record, but then you'll run into trouble the second you want to add
application-specific code and have to go back and retrofit each and every one of your classes to use your new base class. It's a little
thing, but one that can save you a bunch of pain and suffering later on.
"MyWeblog::Record" is the first autogenerated class you'll run into but probably not the last. A full list of everything Jifty provides for
your new application follows:
You get one each of the these:
This class is, as discussed above, a thin wrapper around Jifty::Record. You might choose to create your own "MyWeblog::Record" if you
want to build in custom access control by overriding "current_user_can" in Jifty::Record or want to implement methods that every model
class should have access to.
We haven't talked much about collections yet, but as their name implies, collections are bundles of Jifty::Record objects that match
some set of criteria. It's relatively uncommon that you'll want to override this, but if you want the rope, it's here.
"MyWeblog::Notification" is an app-specific implementation of the Jifty::Notification email driver. You might want to override this
class if you want to set an application-specific header or footer for all outgoing email.
"MyWeblog::Dispatcher" is an application-specific "dispatcher" class that allows you to write code that runs when a client makes a
request to the server before Jifty runs actions or renders templates. See Jifty::Dispatcher for more information about the dispatcher.
Most every web application that grows past a personal hack eventually starts to provide personalization, require access control or
otherwise want to know who's currently in the driver's seat. The "current user" for an application is a first-class object in Jifty. To
get user-based authentication working out of the box, you'll have to override the default "MyWeblog::CurrentUser". (Out of the box, it
treats everyone as the same user.) We're working to generalize the authentication system we've used in a few Jifty apps so far to the
point where it feels "right" as a core Jifty component, but we're not quite there just yet.
Most of what you'll need to override in "MyWeblog::CurrentUser" is the "_init" function, which needs to load up an application-specific
model class that represents one of your users into its "user_object" accessor. To make all this work, you'll also need an application-
specific "MyWeblog::Action::Login" and likely also a passel of user-management code.
(And yes, this is the topic of a future generalization and a future tutorial. At that point, a bunch of this documentation will be
extracted to Jifty::CurrentUser.)
But wait! There's more! You also get one each of these for your default model class:
It's no fun having a weblog that only shows you one post at a time, is it? Jifty provides you with default Jifty::Collection classes
for every Jifty::Record subclass in your model. You get all the standard "limit", "order_by", "columns", paging support and so-on out
of the box, but sometimes when you're going to be getting collections matching certain criteria often, it makes sense to actually
create your own subclass and start dropping methods in.
MyWeblog::Action::CreatePost, MyWeblog::Action::UpdatePost, MyWeblog::Action::DeletePost
One of Jifty's strengths is that it makes it easy to build applications by tying application-specific controller functions to your
model classes and intuiting what parameters they take by having a look inside the models.
For each class in your model, Jifty creates three actions, "Create","Update" and "Delete". They're named, perhaps a bit
unadventureously, "MyWeblog::Action::CreatePost", "MyWeblog::Action::UpdatePost", "MyWeblog::Action::DeletePost" and inherit directly
from Jifty::Action::Record::Create, Jifty::Action::Record::Update and Jifty::Action::Record::Delete, respectively. Sometimes, it makes
sense to override these default actions when you want to change the behaviour of one or more of the actions. One common use is to add
or remove AJAX validation or autocompletion for an argument or to change an argument's default value for webforms. This, isn't,
however the place to start inserting business logic or access control. That belongs in your model class, which these wrappers will hand
things off to. By putting logic in your actions, you make your model classes less useful and run into trouble when you want to start
scripting your model outside a web environment.
There's no reason you need to stick with these default "implementations" if they're not meeting your needs. Just create your own classes
and Jifty will use your real classes instead.
perl v5.14.2 2010-12-08 Jifty::Manual::ObjectModel(3pm)