Implement the cancan filters for diary entries

Access logic is not _entirely_ exported from the controller,
unfortunately.  For interface reasons, some actions which require admin
have to be listed within the controller's deny_access method.

This is required because, being a default-deny system, cancancan
_cannot_ tell you the reason you were denied access; and so
the "nice" feedback presenting next steps can't be gleaned from
the exception

app/controllers/diary_entry_controller.rb

@@ -3,13 +3,15 @@ class DiaryEntryController < ApplicationController
 
   before_action :authorize_web
   before_action :set_locale
-  before_action :require_user, :only => [:new, :edit, :comment, :hide, :hidecomment, :subscribe, :unsubscribe]
+
+  authorize_resource
+
   before_action :lookup_user, :only => [:view, :comments]
   before_action :check_database_readable
   before_action :check_database_writable, :only => [:new, :edit, :comment, :hide, :hidecomment, :subscribe, :unsubscribe]
-  before_action :require_administrator, :only => [:hide, :hidecomment]
   before_action :allow_thirdparty_images, :only => [:new, :edit, :list, :view, :comments]
 
+
   def new
     @title = t "diary_entry.new.title"
 
@@ -215,6 +217,22 @@ class DiaryEntryController < ApplicationController
 
   private
 
+  # This is required because, being a default-deny system, cancancan
+  # _cannot_ tell you the reason you were denied access; and so
+  # the "nice" feedback presenting next steps can't be gleaned from
+  # the exception
+  ##
+  # for the hide actions, require that the user is a administrator, or fill out
+  # a helpful error message and return them to the user page.
+  def deny_access(exception)
+    if current_user && exception.action.in?([:hide, :hidecomment])
+      flash[:error] = t("user.filter.not_an_administrator")
+      redirect_to :action => "view"
+    else
+      super
+    end
+  end
+
   ##
   # return permitted diary entry parameters
   def entry_params
@@ -229,15 +247,6 @@ class DiaryEntryController < ApplicationController
     params.require(:diary_comment).permit(:body)
   end
 
-  ##
-  # require that the user is a administrator, or fill out a helpful error message
-  # and return them to the user page.
-  def require_administrator
-    unless current_user.administrator?
-      flash[:error] = t("user.filter.not_an_administrator")
-      redirect_to :action => "view"
-    end
-  end
 
   ##
   # decide on a location for the diary entry map

app/models/ability.rb

@@ -7,8 +7,16 @@ class Ability
     can :index, :site
     can [:permalink, :edit, :help, :fixthemap, :offline, :export, :about, :preview, :copyright, :key, :id, :welcome], :site
 
+    can [:list, :rss, :view, :comments], DiaryEntry
+
     if user
       can :weclome, :site
+
+      can [:create, :edit, :comment, :subscribe, :unsubscribe], DiaryEntry
+
+      if user.administrator?
+        can [:hide, :hidecomment], [DiaryEntry, DiaryComment]
+      end
     end
     # Define abilities for the passed in user here. For example:
     #

test/models/abilities_test.rb

@@ -4,4 +4,40 @@ require "test_helper"
 
 class AbilityTest < ActiveSupport::TestCase
 
+  test "diary permissions for a guest" do
+    ability = Ability.new(nil, [])
+    [:list, :rss, :view, :comments].each do |action|
+      assert ability.can?(action, DiaryEntry), "should be able to #{action} DiaryEntries"
+    end
+
+    [:create, :edit, :comment, :subscribe, :unsubscribe, :hide, :hidecomment].each do |action|
+      assert ability.cannot?(action, DiaryEntry), "should be able to #{action} DiaryEntries"
+      assert ability.cannot?(action, DiaryComment), "should be able to #{action} DiaryEntries"
+    end
+  end
+
+
+  test "Diary permissions for a normal user" do
+    ability = Ability.new(create(:user), [])
+
+    [:list, :rss, :view, :comments, :create, :edit, :comment, :subscribe, :unsubscribe].each do |action|
+      assert ability.can?(action, DiaryEntry), "should be able to #{action} DiaryEntries"
+    end
+
+    [:hide, :hidecomment].each do |action|
+      assert ability.cannot?(action, DiaryEntry), "should be able to #{action} DiaryEntries"
+      assert ability.cannot?(action, DiaryComment), "should be able to #{action} DiaryEntries"
+    end
+  end
+
+  test "Diary for an administrator" do
+    ability = Ability.new(create(:administrator_user), [])
+    [:list, :rss, :view, :comments, :create, :edit, :comment, :subscribe, :unsubscribe, :hide, :hidecomment].each do |action|
+      assert ability.can?(action, DiaryEntry), "should be able to #{action} DiaryEntries"
+    end
+
+    [:hide, :hidecomment].each do |action|
+      assert ability.can?(action, DiaryComment), "should be able to #{action} DiaryComment"
+    end
+  end
 end