Getting started with Rails 2.3.5 Dec 19 2009

This is a tutorial guided towards those who are new to Rails, or those who have not used it since v1.x and who might want a newbie-style refresher. I’ll be working my way through to some more advanced and interesting topics soon, so for those of you who know all of this already, please stay tuned!

I’ve now been using Ruby on Rails for almost four years, and have seen it progress from version to version. In doing so, I’ve kept up with the changes between each version, and the new features that updates have brought to the table.

For newcomers though, the scene is a little different. Much of the information out there pertains to older versions, from really out of date stuff related to Rails 1.2, to things that may or may not still work as expected when talking about Rails 2.0 features.

I figured that even though it will one day be outdated as well, some Rails newbies might well find it useful to have a straightforward, simple up to date getting started guide for Rails 2.3.5. I’m going to do just that, and a few other articles on the Rails basics, before getting into some more advanced stuff. This article will start specifically dealing with setting up an app, before building our first REST resource using scaffolding.

UPDATE: Jeff points out in the comments below that some users may need to install the sqlite3-ruby gem if they haven’t already (assuming this is your first time with Ruby/Rails/rubygems then that might be quite likely!). As Jeff says, to install the gem, run:

sudo gem install sqlite3-ruby

To begin with, let’s install Rails. I’m assuming you have Ruby and RubyGems installed, but if you have issues with the base setup on Mac OS X, then there is an excellent tutorial here. Once you’re all setup, install Rails as follows:

sudo gem install rails

This will install the latest version of Rails, which at the time of writing is 2.3.5. To specifically install version 2.3.5, for example if 2.3.5 is no longer the most recent version, use this instead:

sudo gem install rails -v 2.3.5

If you don’t want to install local ri and RDoc documentation (i.e. you’ll be looking up API docs online, for example), then you can save a little disk space and a bit of time on installation by doing:

sudo gem install rails -v 2.3.5 --no-ri --no-rdoc

That works for any gem installation.

Once it’s installed Rails 2.3.5 and it’s dependencies, it should leave you with the “rails” command available from the terminal. If you already had a previous version installed, you can make sure that you’ve got the right version at your fingertips by running:

rails -v

That should print “Rails 2.3.5” to the console.

Now on to the exciting part; to create an application, it’s as easy as running:

rails <appname>

So for example:

rails my_new_test_app

I’ll be going over a new feature, Rails templates, and how they can speed up your typical Rails application creation process, in a future post. For now, the default application skeleton created by that command will do.

Let’s go ahead and test our new application. Change into the directory for the new app, and fire it up.

cd my_new_test_app

ruby script/server

This will fire up a development server on port 3000 by default, and by visiting

http://localhost:3000

in a browser, you’ll be able to see the app running. You should be greeted with the default Ruby on Rails page.

Let’s do something a little more exciting, and build something interactive. Rails uses some sensible configuration decisions out of the box, and also provides a fair few generators to get you going with some code. We’ll use one of these generators to provide what’s called a “scaffold”, an automatically built representation of an entire resource, giving you everything you need to get something going quickly. In time, the scaffolding will become less useful as you get used to building the resources yourself more quickly to suit your exact requirements - however to get up and running really quickly, it’s a great start.

We’re going to build a basic note resource, allowing the creation, retrieval, update and deletion of notes (these four actions are referred to as CRUD). To scaffold the resource, run:

ruby script/generate scaffold note body:text

This basically is creating a note model with accompanying controller and views, and we’ve also told it that it should have a single column - body, a text field. It will also be given some timestamp columns (created_at, updated_at) which are updated automatically and can be very useful.

Now let’s go ahead and run the command to bring the database up to date with our changes:

rake db:migrate

This will setup the notes table that was created as part of the scaffold. Now if we visit http://localhost:3000/notes, we can see our fully working notes resource in action!

You can play around with creating, updating and deleting notes and see that it all works straight off the bat.

If we revisit http://localhost:3000 though, we still see the landing page. Let’s set it up so that the root of the site displays the notes index page. We need to do a couple of things to make this happen. Firstly, we need to remove that placeholder landing page, so run:

rm public/index.html

However this still leaves you with the following error when accessing your app now:

We now need to tell the application to use the notes resource for the root of the site. Rails routing can be as complex or as simple as you need it. If you open up config/routes.rb, you’ll see that at the top there is the line:

map.resources :notes

This is the line that exposes your notes resource at http://localhost:3000/notes. So how do we hook up the root of the site to hit the index page for the notes resource? We just need to add a single line to the top of our config/routes.rb file. Right below this line:

ActionController::Routing::Routes.draw do |map|

add in the following line:

map.root :controller => :notes, :action => :index

This tells the app that the root URL (/) corresponds to the index action of the notes controller, which is the one responsible for displaying the list of all notes (the same as seen at http://localhost:3000/notes). Now if you reload http://localhost:3000, you’ll see that it shows the same content as http://localhost:3000/notes.

As before, you can play with the notes to see that it all works correctly - it doesn’t look too pretty, and is almost rarely exactly what you want out of the box, but when getting started with Rails it can provide an exciting and quick way to get new things up and running quickly, and to toy around with.

Now that we’ve got a basic, working application running on Rails 2.3.5, we’ll draw this article to a close. In future articles we’ll delve into more detail on some of the configuration choices you can make when setting up your application, some further detail on building out REST resources, testing your application, and some other more advanced stuff.

For a more in depth and lengthy look at getting up and running with Rails, check out the Rails guide for Getting Started with Rails.

As usual, if you have any comments, queries, suggestions or questions about the above, please get in touch!

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