Robert Thau from Smartleaf proposes a cool idea for implementing DSL for use in Active Record permissions. It makes it easy for a lot of users to have access rights and very exciting at the same time…

This is the Tease….

class Order < ActiveRecord::Base

  access_control_keys ['id', 'owner_id', 'paid']

  require_privilege :place,
    :for_action => :create,
    :to_update_attribute => [:payment_authenticator, :paid]

  require_privilege :edit,      # LineItem also checks this for attr changes
    :to_associate_as  => ['LineItem#order'],
    :to_dissociate_as => ['LineItem#order'],
    :to_update_attribute => [ :shipping_address ]

  require_privilege :ship,       :to_update_attribute => :shipped

  ...

end

 

The implementation:

• Data model
• Checking privileges: does user x have privilege y on this order?
• Finding all orders where user x has privilege y
• Adding privilege checks in interesting places…
  • On events: create, update…
  • On attribute sets
  • For associations

It’s just Ruby! Class variables and class methods:

• All declared privileges (for choosers in the UI)
• Dual-keyed hash: reflected_privilege[type][key]
• … e.g., reflected_privilege[:read_attribute][attr]
• … e.g., reflected_privilege[:associate][assoc_key]
• Class helpers (permits_update_attr?, etc.) just read the hash, and do the appropriate check.

Read more on:

http://www.smartleaf.com/rst/perm_present/perm_present.html

No downloadable code (yet), but still cool

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This entry was posted on Monday, November 19th, 2007 at 10:49 am and is filed under Cool, Enterprise, Opinions, Praises, Rails, Ruby, Tips, Tools. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.