Class | Authorization::Reader::AuthorizationRulesReader |
In: |
lib/declarative_authorization/reader.rb
|
Parent: | Object |
In an if_attribute statement, contains says that the value has to be part of the collection specified by the if_attribute attribute. For information on the block argument, see if_attribute.
Sets a description for the current role. E.g.
role :admin description "To be assigned to administrative personnel" has_permission_on ... end
The negation of contains. Currently, query rewriting is disabled for does_not_contain.
Removes any permission checks for the current role.
role :admin has_omnipotence end
Allows the definition of privileges to be allowed for the current role, either in a has_permission_on block or directly in one call.
role :admin has_permission_on :employees, :to => :read has_permission_on [:employees, :orders], :to => :read has_permission_on :employees do to :create if_attribute ... end has_permission_on :employees, :to => :delete do if_attribute ... end end
The block form allows to describe restrictions on the permissions using if_attribute. Multiple has_permission_on statements are OR‘ed when evaluating the permissions. Also, multiple if_attribute statements in one block are OR‘ed if no :join_by option is given (see below). To AND conditions, either set :join_by to :and or place them in one if_attribute statement.
Available options
In a has_permission_on block, if_attribute specifies conditions of dynamic parameters that have to be met for the user to meet the privileges in this block. Conditions are evaluated on the context object. Thus, the following allows CRUD for branch admins only on employees that belong to the same branch as the current user.
role :branch_admin has_permission_on :employees do to :create, :read, :update, :delete if_attribute :branch => is { user.branch } end end
In this case, is is the operator for evaluating the condition. Another operator is contains for collections. In the block supplied to the operator, user specifies the current user for whom the condition is evaluated.
Conditions may be nested:
role :company_admin has_permission_on :employees do to :create, :read, :update, :delete if_attribute :branch => { :company => is {user.branch.company} } end end
has_many and has_many through associations may also be nested. Then, at least one item in the association needs to fulfill the subsequent condition:
if_attribute :company => { :branches => { :manager => { :last_name => is { user.last_name } } }
Beware of possible performance issues when using has_many associations in permitted_to? checks. For
permitted_to? :read, object
a check like
object.company.branches.any? { |branch| branch.manager ... }
will be executed. with_permission_to scopes construct efficient SQL joins, though.
Multiple attributes in one :if_attribute statement are AND‘ed. Multiple if_attribute statements are OR‘ed if the join operator for the has_permission_on block isn‘t explicitly set. Thus, the following would require the current user either to be of the same branch AND the employee to be "changeable_by_coworker". OR the current user has to be the employee in question.
has_permission_on :employees, :to => :manage do if_attribute :branch => is {user.branch}, :changeable_by_coworker => true if_attribute :id => is {user.id} end
The join operator for if_attribute rules can explicitly set to AND, though. See has_permission_on for details.
Arrays and fixed values may be used directly as hash values:
if_attribute :id => 1 if_attribute :type => "special" if_attribute :id => [1,2]
if_permitted_to allows the has_permission_on block to depend on permissions on associated objects. By using it, the authorization rules may be a lot DRYer. E.g.:
role :branch_manager has_permission_on :branches, :to => :manage do if_attribute :employees => contains { user } end has_permission_on :employees, :to => :read do if_permitted_to :read, :branch # instead of # if_attribute :branch => { :employees => contains { user } } end end
if_permitted_to associations may be nested as well:
if_permitted_to :read, :branch => :company
You can even use has_many associations as target. Then, it is checked if the current user has the required privilege on any of the target objects.
if_permitted_to :read, :branch => :employees
Beware of performance issues with permission checks. In the current implementation, all employees are checked until the first permitted is found. with_permissions_to, on the other hand, constructs more efficient SQL instead.
To check permissions based on the current object, the attribute has to be left out:
has_permission_on :branches, :to => :manage do if_attribute :employees => contains { user } end has_permission_on :branches, :to => :paint_green do if_permitted_to :update end
Normally, one would merge those rules into one. Dividing makes sense if additional if_attribute are used in the second rule or those rules are applied to different roles.
Options:
if_permitted_to :read, :home_branch, :context => :branches if_permitted_to :read, :branch => :main_company, :context => :companies
Roles may inherit all the rights from subroles. The given roles become subroles of the current block‘s role.
role :admin do includes :user has_permission_on :employees, :to => [:update, :create] end role :user do has_permission_on :employees, :to => :read end
In an if_attribute statement, intersects_with requires that at least one of the values has to be part of the collection specified by the if_attribute attribute. The value block needs to evaluate to an Enumerable. For information on the block argument, see if_attribute.
In an if_attribute statement, is says that the value has to be met exactly by the if_attribute attribute. For information on the block argument, see if_attribute.
In an if_attribute statement, is_in says that the value has to contain the attribute value. For information on the block argument, see if_attribute.
Defines the authorization rules for the given role in the following block.
role :admin do has_permissions_on ... end