become

Based on:http://railsillustrated.com/getting-started-with-tokyo-on-osx.html

There is one tweak for the Ruby binding:ARCHFLAGS=”-arch x86_64″

I hope this helps someone, I know it has me.

A while ago (Nov. 2006) was looking for a solution to Roles and Permissions for Ruby on Rails.  One idea on the RoR site is to create an Access Control List (ACL), create a before filter and allow certain roles to certain actions.   This seemed like a lot of extra work.  Especially if you have to do this to each controller.  Plus you have to maintain it!  I wanted something more dynamic–cooler.  Plus, it places an unnecessary dependency between me and my code.  I want to solve problems, not add/remove permissions.

Enter acts as role.  Written with my friend Jon Morton, AAR allows for role/permission simplicity through-out a Rails application.   We followed these guidelines when writing AAR - Had to:

• have model based security
• protect Controller actions
• simple to code in the View
• hide items easily in the View
• database driven, have no ACL list in the code
• allow multiple roles
• and handle permission conflict intelligently

Understanding Users/Roles/Permissions
AAR’s basic principle is that you should not give special permissions directly to the User.  All permissions are given to a Role.  If there is a snowflake** who needs X permission then I copy an existing Role and add the permission.  This way if (or when) that user is gone the permissions and are preserved.

Installation can be a simple as downloading the app, putting it in your vender/plugins directory and adding “include ActsAsRole” at the top of your controllers/application.rb.    Correction.  There are models and relationships that need to be set up that I have not explained.  I’ll work on updating the README to include this. And add some rake tasks to the plugin to create the models.  See the DB Schema PDF to see the model associations.

EXAMPLE of using AAR:

if has_access?(users_path)do something…end

OR

if has_access?(:controller => ‘users’, :action => ‘index’)do something…end

In Part 2, I’ll have a screencast and a test app.

Links:
git AAR
model schema diagram pdf

** Jon Bartels, fellow programmer who coined the edge cases as “snowflakes”…because everyone wants to be special and unique.

Another small issue I came across this weekend is when I type in a bogus URL in my rails app.  i.e. http://localhost:3000/asdf

routes.rb maps routes for a Rails app and they are checked in order.  So if we add a route at the end of that list it will assume that the route didn’t match any previous route. Here’s a sample:

map.connect ‘*some_attribute’, :controller => application

Any route that hits this will be sent to the application/index. Here is  simple fix for the index method:

def index
logger.error exception.backtrace.join(”\n”)
render :template => “my_error_page”, :status => :not_found
end

When building a Rails invariably I have some conditions that needs to be handled that fall outside of  “normal” behavior.  I also want to display something nice to the user, log the error and respond to the browser with the correct HTTP response code.  This can be used per controller or system wide in the application controller.

rescue_from ActiveRecord::RecordNotFound do |exception|  logger.error exception.backtrace.join(”\n”)  render :template => “record_not_found”, :status => :not_foundend

API Reference: rescue_from