Copy varvet#443, allow define additional methods to the scope.

README.md

@@ -332,6 +332,45 @@ You can, and are encouraged to, use this method in views:
 <% end %>
 ```
 
+It is also possible to define additional methods the scope that you can use in
+different situations. We'll add an `unpublished` scope to the
+`PostPolicy::Scope`:
+
+``` ruby
+class PostPolicy < ApplicationPolicy
+  class Scope < Scope
+    def resolve
+      if user.admin?
+        scope.all
+      else
+        scope.where(published: true)
+      end
+    end
+
+    def unpublished
+      if user.admin?
+        scope.all
+      else
+        scope.where(published: false)
+      end
+    end
+  end
+
+  def update?
+    user.admin? or not post.published?
+  end
+end
+```
+
+To use the `unpublished` scope, simply pass the name of the method as the 2nd
+argument to `policy_scope`:
+
+``` ruby
+def index
+  @posts = policy_scope(Post, :unpublished)
+end
+```
+
 ## Ensuring policies and scopes are used
 
 When you are developing an application with Pundit it can be easy to forget to

lib/pundit.rb

@@ -91,9 +91,10 @@ def authorize(user, possibly_namespaced_record, query, policy_class: nil, cache:
     # @see https://github.com/varvet/pundit#scopes
     # @param user [Object] the user that initiated the action
     # @param scope [Object] the object we're retrieving the policy scope for
+    # @param method [Symbol] the method to call on the scope. Defaults to :resolve.
     # @raise [InvalidConstructorError] if the policy constructor called incorrectly
     # @return [Scope{#resolve}, nil] instance of scope class which can resolve to a scope
-    def policy_scope(user, scope)
+    def policy_scope(user, scope, method = :resolve)
       policy_scope_class = PolicyFinder.new(scope).scope
       return unless policy_scope_class
 
@@ -103,18 +104,19 @@ def policy_scope(user, scope)
         raise InvalidConstructorError, "Invalid #<#{policy_scope_class}> constructor is called"
       end
 
-      policy_scope.resolve
+      policy_scope.public_send(method)
     end
 
     # Retrieves the policy scope for the given record.
     #
     # @see https://github.com/varvet/pundit#scopes
     # @param user [Object] the user that initiated the action
     # @param scope [Object] the object we're retrieving the policy scope for
+    # @param method [Symbol] the method to call on the scope. Defaults to :resolve.
     # @raise [NotDefinedError] if the policy scope cannot be found
     # @raise [InvalidConstructorError] if the policy constructor called incorrectly
     # @return [Scope{#resolve}] instance of scope class which can resolve to a scope
-    def policy_scope!(user, scope)
+    def policy_scope!(user, scope, method = :resolve)
       policy_scope_class = PolicyFinder.new(scope).scope!
       return unless policy_scope_class
 
@@ -124,7 +126,7 @@ def policy_scope!(user, scope)
         raise InvalidConstructorError, "Invalid #<#{policy_scope_class}> constructor is called"
       end
 
-      policy_scope.resolve
+      policy_scope.public_send(method)
     end
 
     # Retrieves the policy for the given record.
@@ -165,8 +167,8 @@ def pundit_model(record)
 
   # @api private
   module Helper
-    def policy_scope(scope)
-      pundit_policy_scope(scope)
+    def policy_scope(scope, method = :resolve)
+      pundit_policy_scope(scope, method)
     end
   end
 end

lib/pundit/authorization.rb

@@ -87,11 +87,12 @@ def skip_policy_scope
     #
     # @see https://github.com/varvet/pundit#scopes
     # @param scope [Object] the object we're retrieving the policy scope for
+    # @param method [Symbol] the method to call on the scope. Defaults to :resolve.
     # @param policy_scope_class [Class] the policy scope class we want to force use of
     # @return [Scope{#resolve}, nil] instance of scope class which can resolve to a scope
-    def policy_scope(scope, policy_scope_class: nil)
+    def policy_scope(scope, method = :resolve, policy_scope_class: nil)
       @_pundit_policy_scoped = true
-      policy_scope_class ? policy_scope_class.new(pundit_user, scope).resolve : pundit_policy_scope(scope)
+      policy_scope_class ? policy_scope_class.new(pundit_user, scope).public_send(method) : pundit_policy_scope(scope, method)
     end
 
     # Retrieves the policy for the given record.
@@ -161,8 +162,11 @@ def pundit_user
 
     private
 
-    def pundit_policy_scope(scope)
-      policy_scopes[scope] ||= Pundit.policy_scope!(pundit_user, scope)
+    def pundit_policy_scope(scope, method = :resolve)
+      method = method.to_sym
+      key    = method == :resolve ? scope : [scope, method]
+
+      policy_scopes[key] ||= Pundit.policy_scope!(pundit_user, scope, method)
     end
   end
 end

spec/authorization_spec.rb

@@ -145,6 +145,10 @@
       expect(policy.post).to eq post
     end
 
+    it "returns an instantiated policy scope when a scope method is provided" do
+      expect(controller.policy_scope(Post, :unpublished)).to eq :unpublished
+    end
+
     it "throws an exception if the given policy can't be found" do
       expect { controller.policy(article) }.to raise_error(Pundit::NotDefinedError)
     end

spec/pundit_spec.rb

@@ -93,6 +93,10 @@
       expect(Pundit.policy_scope(user, Post)).to eq :published
     end
 
+    it "returns an instantiated policy scope given the method to call on the scope" do
+      expect(Pundit.policy_scope(user, Post, :unpublished)).to eq :unpublished
+    end
+
     it "returns an instantiated policy scope given an active model class" do
       expect(Pundit.policy_scope(user, Comment)).to eq CommentScope.new(Comment)
     end
@@ -139,6 +143,10 @@
       expect(Pundit.policy_scope!(user, Post)).to eq :published
     end
 
+    it "returns an instantiated policy scope given the method to call on the scope" do
+      expect(Pundit.policy_scope!(user, Post, :unpublished)).to eq :unpublished
+    end
+
     it "returns an instantiated policy scope given an active model class" do
       expect(Pundit.policy_scope!(user, Comment)).to eq CommentScope.new(Comment)
     end

spec/spec_helper.rb

@@ -21,6 +21,10 @@ class Scope < Struct.new(:user, :scope)
     def resolve
       scope.published
     end
+
+    def unpublished
+      scope.unpublished
+    end
   end
 
   def update?
@@ -53,6 +57,10 @@ def self.published
     :published
   end
 
+  def self.unpublished
+    :unpublished
+  end
+
   def self.read
     :read
   end