Sinatra-Bouncer

Simple authorization permissions extension for Sinatra. Require the gem, then declare which routes are permitted based on your own logic.

Gemfile

gem 'sinatra-bouncer'

Terminal

gem install sinatra-bouncer

Quickstart

Step 1: Require/Register Bouncer

After registration, Bouncer will reject any request that either:

• has no rule associated with it, or
• has no associated rule that returns true

Sinatra Classic

require 'sinatra'
require 'sinatra/bouncer'

   # ... routes and other config

Modular

require 'sinatra/base'
require 'sinatra/bouncer'

class MyApp < Sinatra::Base
  register Sinatra::Bouncer

  # ... routes and other config
end

Step 2: Declare Bouncer Rules

Call rules with a block that uses can and can_sometimes to declare which paths are legalduring this request. The rules block is run in the context of the request, which means you will have access to sinatra helpers, the request object, and params.

require 'sinatra'
require 'sinatra/bouncer'

rules do
  # example: allow any GET request
  can(:get, :all)

  # example: logged in users can edit their account
  if(current_user)
    can(:post, '/user_edits_account')
  end
end

# ... route declarations as normal below

API

can

Any route declared with #can will be accepted without further challenge.

rules do
   can(:post, '/user_posts_blog')
end

can_sometimes

can_sometimes is for occasions that you to check further, but want to defer that choice until the path is actually attempted. can_sometimes takes a block that will be run once the path is attempted. This block must return an explicit boolean (ie. true or false) to avoid any accidental truthy values creating unwanted access.

rules do
    can_sometimes('/login') # Anyone can access this path
end

:any and :all special parameters

Passing can or can_sometimes:

• :any to the first parameter will match any HTTP method.
• :all to the second parameter will match any path.

# this allows get on all paths
can(:get, :all)

# this allows any method type to run on the /login path
can(:any, '/login')

Custom Bounce Behaviour

The default bounce action is to halt 403. Call bounce_with with a block to specify your own behaviour. The block is also run in a sinatra request context, so you can use helpers here as well.

require 'sinatra'
require 'sinatra/bouncer'

bounce_with do 
  redirect '/login'
end

# bouncer rules, routes, etc...