Module: Authorization::AuthorizationInController::ClassMethods

Defined in:
lib/declarative_authorization/in_controller.rb

Instance Method Summary collapse

Instance Method Details

#all_filter_access_permissions ⇒ Object

Collecting all the ControllerPermission objects from the controller hierarchy. Permissions for actions are overwritten by calls to filter_access_to in child controllers with the same action.



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# File 'lib/declarative_authorization/in_controller.rb', line 317

def all_filter_access_permissions # :nodoc:
  ancestors.inject([]) do |perms, mod|
    if mod.respond_to?(:filter_access_permissions, true)
      perms + 
        mod.filter_access_permissions.collect do |p1| 
          p1.clone.remove_actions(perms.inject(Set.new) {|actions, p2| actions + p2.actions})
        end
    else
      perms
    end
  end
end

#decl_auth_context ⇒ Object

Returns the context for authorization checks in the current controller. Uses the controller_name and prepends any namespaces underscored and joined with underscores.

E.g. AllThosePeopleController => :all_those_people AnyName::Space::ThingsController => :any_name_space_things



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# File 'lib/declarative_authorization/in_controller.rb', line 553

def decl_auth_context
  prefixes = name.split('::')[0..-2].map(&:underscore)
  ((prefixes + [controller_name]) * '_').to_sym
end

#filter_access_to(*args, &filter_block) ⇒ Object

Defines a filter to be applied according to the authorization of the current user. Requires at least one symbol corresponding to an action as parameter. The special symbol :+all+ refers to all action. The all :+all+ statement is only employed if no specific statement is present. class UserController < ApplicationController filter_access_to :index filter_access_to :new, :edit filter_access_to :all ... end

The default is to allow access unconditionally if no rule matches. Thus, including the filter_access_to :+all+ statement is a good idea, implementing a default-deny policy.

When the access is denied, the method permission_denied is called on the current controller, if defined. Else, a simple "you are not allowed" string is output. Log.info is given more information on the reasons of denial.

def permission_denied
flash[:error] = 'Sorry, you are not allowed to the requested page.'
respond_to do |format|
  format.html { redirect_to(:back) rescue redirect_to('/') }
  format.xml  { head :unauthorized }
  format.js   { head :unauthorized }
end
end

By default, required privileges are inferred from the action name and the controller name. Thus, in UserController :+edit+ requires :+edit+ users. To specify required privilege, use the option :+require+ filter_access_to :new, :create, :require => :create, :context => :users

Without the :+attribute_check+ option, no constraints from the authorization rules are enforced because for some actions (collections, new, create), there is no object to evaluate conditions against. To allow attribute checks on all actions, it is a common pattern to provide custom objects through before_filters:

class BranchesController < ApplicationController
before_filter :load_company
before_filter :new_branch_from_company_and_params,
  :only => [:index, :new, :create]
filter_access_to :all, :attribute_check => true

protected
def new_branch_from_company_and_params
  @branch = @company.branches.new(params[:branch])
end
end

NOTE: before_filters need to be defined before the first filter_access_to call.

For further customization, a custom filter expression may be formulated in a block, which is then evaluated in the context of the controller on a matching request. That is, for checking two objects, use the following:

filter_access_to :merge do
permitted_to!(:update, User.find(params[:original_id])) and
  permitted_to!(:delete, User.find(params[:id]))
end

The block should raise a Authorization::AuthorizationError or return false if the access is to be denied.

Later calls to filter_access_to with overlapping actions overwrite previous ones for that action.

All options: [:+require+] Privilege required; defaults to action_name [:+context+] The privilege's context, defaults to decl_auth_context, which consists of controller_name, prepended by any namespaces [:+attribute_check+] Enables the check of attributes defined in the authorization rules. Defaults to false. If enabled, filter_access_to will use a context object from one of the following sources (in that order):

* the method from the :+load_method+ option,
* an instance variable named after the singular of the context
(by default from the controller name, e.g. @post for PostsController),
* a find on the context model, using +params+[:id] as id value.
Any of these methods will only be employed if :+attribute_check+
is enabled.

[:+model+] The data model to load a context object from. Defaults to the context, singularized. [:+load_method+] Specify a method by symbol or a Proc object which should be used to load the object. Both should return the loaded object. If a Proc object is given, e.g. by way of lambda, it is called in the instance of the controller.
Example demonstrating the default behavior: filter_access_to :show, :attribute_check => true, :load_method => lambda { User.find(params) }



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# File 'lib/declarative_authorization/in_controller.rb', line 286

def filter_access_to (*args, &filter_block)
  options = args.last.is_a?(Hash) ? args.pop : {}
  options = {
    :require => nil,
    :context => nil,
    :attribute_check => false,
    :model => nil,
    :load_method => nil
  }.merge!(options)
  privilege = options[:require]
  context = options[:context]
  actions = args.flatten

  # prevent setting filter_access_filter multiple times
  skip_before_filter :filter_access_filter
  before_filter :filter_access_filter
  
  filter_access_permissions.each do |perm|
    perm.remove_actions(actions)
  end
  filter_access_permissions << 
    ControllerPermission.new(actions, privilege, context,
                             options[:attribute_check],
                             options[:model],
                             options[:load_method],
                             filter_block)
end

#filter_resource_access(options = {}) ⇒ Object

To DRY up the filter_access_to statements in restful controllers, filter_resource_access combines typical filter_access_to and before_filter calls, which set up the instance variables.

The simplest case are top-level resource controllers with only the seven CRUD methods, e.g. class CompanyController < ApplicationController filter_resource_access

def index...
end

Here, all CRUD actions are protected through a filter_access_to :all statement. :+attribute_check+ is enabled for all actions except for the collection action :+index+. To have an object for attribute checks available, filter_resource_access will set the instance variable @+company+ in before filters. For the member actions (:+show+, :+edit+, :+update+, :+destroy+) @company is set to Company.find(params). For new actions (:+new+, :+create+), filter_resource_access creates a new object from company parameters: Company.new(params.

For nested resources, the parent object may be loaded automatically. class BranchController < ApplicationController filter_resource_access :nested_in => :companies end Again, the CRUD actions are protected. Now, for all CRUD actions, the parent object @company is loaded from params. It is also used when creating @branch for new actions. Here, attribute_check is enabled for the collection :+index+ as well, checking attributes on a In many cases, the default seven CRUD actions are not sufficient. As in the resource definition for routing you may thus give additional member, new and collection methods. The options allow you to specify the required privileges for each action by providing a hash or an array of pairs. By default, for each action the action name is taken as privilege (action search in the example below requires the privilege :index :companies). Any controller action that is not specified and does not belong to the seven CRUD actions is handled as a member method. class CompanyController < ApplicationController filter_resource_access :collection => [[:search, :index], :index], :additional_member => => :update end The +additional_+* options add to the respective CRUD actions, the other options (:+member+, :+collection+, :+new+) replace their respective CRUD actions. filter_resource_access :member => { :toggle_open => :update } Would declare :toggle_open as the only member action in the controller and require that permission :update is granted for the current user. filter_resource_access :additional_member => { :toggle_open => :update } Would add a member action :+toggle_open+ to the default members, such as :+show+.

If :+collection+ is an array of method names filter_resource_access will associate a permission with the method that is the same as the method name and no attribute checks will be performed unless :attribute_check => true is added in the options.

You can override the default object loading by implementing any of the following instance methods on the controller. Examples are given for the BranchController (with nested_in set to :+companies+): [+new_branch_from_params+] Used for new actions. [+new_branch_for_collection+] Used for collection actions if the nested_in option is set. [+load_branch+] Used for member actions. [+load_company+] Used for all new, member, and collection actions if the nested_in option is set.

All options: [:+member+] Member methods are actions like show, which have an params from which to load the controller object and assign it to @controller_name, e.g. @+branch+.

By default, member actions are [:+show+, :+edit+, :+update+,
:+destroy+].  Also, any action not belonging to the seven CRUD actions
are handled as member actions.

There are three different syntax to specify member, collection and
new actions.
* Hash:  Lets you set the required privilege for each action:
{:+show+ => :+show+, :+mark_as_important+ => :+update+}
* Array of actions or pairs: [:+show+, [:+mark_as_important+, :+update+]],
with single actions requiring the privilege of the same name as the method.
* Single method symbol: :+show+

[:+additional_member+] Allows to add additional member actions to the default resource member actions. [:+collection+] Collection actions are like :+index+, actions without any controller object to check attributes of. If nested_in is given, a new object is created from the parent object, e.g. @company.branches.new. Without nested_in, attribute check is deactivated for these actions. By default, collection is set to :+index+. [:+additional_collection+] Allows to add additional collection actions to the default resource collection actions. [:+new+] new methods are actions such as new and create, which don't receive a params to load an object from, but a params hash with attributes for a new object. The attributes will be used here to create a new object and check the object against the authorization rules. The object is assigned to @controller_name_singular, e.g. @branch.

If +nested_in+ is given, the new object
is created from the parent_object.controller_name
proxy, e.g. company.branches.new(params[:branch]).  By default,
+new+ is set to [:new, :create].

[:+additional_new+] Allows to add additional new actions to the default resource new actions. [:+context+] The context is used to determine the model to load objects from for the before_filters and the context of privileges to use in authorization checks. [:+nested_in+] Specifies the parent controller if the resource is nested in another one. This is used to automatically load the parent object, e.g. @+company+ from params for a BranchController nested in a CompanyController. [:+shallow+] Only relevant when used in conjunction with nested_in. Specifies a nested resource as being a shallow nested resource, resulting in the controller not attempting to load a parent object for all member actions defined by member and additional_member or rather the default member actions (:+show+, :+edit+, :+update+, :+destroy+). [:+no_attribute_check+] Allows to set actions for which no attribute check should be performed. See filter_access_to on details. By default, with no nested_in, no_attribute_check is set to all collections. If nested_in is given no_attribute_check is empty by default.



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# File 'lib/declarative_authorization/in_controller.rb', line 464

def filter_resource_access(options = {})
  options = {
    :new        => [:new, :create],
    :additional_new => nil,
    :member     => [:show, :edit, :update, :destroy],
    :additional_member => nil,
    :collection => [:index],
    :additional_collection => nil,
    #:new_method_for_collection => nil,  # only symbol method name
    #:new_method => nil,                 # only symbol method name
    #:load_method => nil,                # only symbol method name
    :no_attribute_check => nil,
    :context    => nil,
    :nested_in  => nil,
  }.merge(options)

  new_actions = actions_from_option( options[:new] ).merge(
      actions_from_option(options[:additional_new]) )
  members = actions_from_option(options[:member]).merge(
      actions_from_option(options[:additional_member]))
  collections = actions_from_option(options[:collection]).merge(
      actions_from_option(options[:additional_collection]))

  options[:no_attribute_check] ||= collections.keys unless options[:nested_in]

  unless options[:nested_in].blank?
    load_parent_method = :"load_#{options[:nested_in].to_s.singularize}"
    shallow_exceptions = options[:shallow] ? {:except => members.keys} : {}
    before_filter shallow_exceptions do |controller|
      if controller.respond_to?(load_parent_method, true)
        controller.send(load_parent_method)
      else
        controller.send(:load_parent_controller_object, options[:nested_in])
      end
    end

    new_for_collection_method = :"new_#{controller_name.singularize}_for_collection"
    before_filter :only => collections.keys do |controller|
      # new_for_collection
      if controller.respond_to?(new_for_collection_method, true)
        controller.send(new_for_collection_method)
      else
        controller.send(:new_controller_object_for_collection,
            options[:context] || controller_name, options[:nested_in])
      end
    end
  end

  new_from_params_method = :"new_#{controller_name.singularize}_from_params"
  before_filter :only => new_actions.keys do |controller|
    # new_from_params
    if controller.respond_to?(new_from_params_method, true)
      controller.send(new_from_params_method)
    else
      controller.send(:new_controller_object_from_params,
          options[:context] || controller_name, options[:nested_in])
    end
  end
  load_method = :"load_#{controller_name.singularize}"
  before_filter :only => members.keys do |controller|
    # load controller object
    if controller.respond_to?(load_method, true)
      controller.send(load_method)
    else
      controller.send(:load_controller_object, options[:context] || controller_name)
    end
  end
  filter_access_to :all, :attribute_check => true, :context => options[:context]

  members.merge(new_actions).merge(collections).each do |action, privilege|
    if action != privilege or (options[:no_attribute_check] and options[:no_attribute_check].include?(action))
      filter_options = {
        :context          => options[:context],
        :attribute_check  => !options[:no_attribute_check] || !options[:no_attribute_check].include?(action)
      }
      filter_options[:require] = privilege if action != privilege
      filter_access_to(action, filter_options)
    end
  end
end