Add a Sitemap rake task to detect and fix issues

It is possible that, due to exceptions or other unexpected errors, the lft/rgt values and/or the page depth on the pages are not correct. In that case these tasks can help to detect and fix issues in the page sitemap.

lib/tasks/alchemy/sitemap.rake

@@ -0,0 +1,97 @@
+class SiteMapIssueFinder
+  attr_reader :save
+  attr_accessor :depth_issue_page_ids, :lft_rgt_issue_page_ids
+
+  def initialize(save: false)
+    @save = save
+    @depth_issue_page_ids = Set.new
+    @lft_rgt_issue_page_ids = Set.new
+  end
+
+  def depth_issues
+    puts "\nFind Page Depth Issues"
+    puts "======================\n"
+
+    Alchemy::Page.each_with_level(Alchemy::Page.root.self_and_descendants) do |page, level|
+      not_the_same_level = level != page.depth
+      print not_the_same_level ? "F" : "."
+      if not_the_same_level
+        depth_issue_page_ids << page.id
+        page.update_column(:depth, level) if save
+      end
+    end
+
+    print_conclusion(depth_issue_page_ids, "depth")
+  end
+
+  def lft_rgt_issues
+    puts "\nFind Page Left/Right Value Issues"
+    puts "=================================\n"
+
+    Alchemy::Page.roots.each do |root_page|
+      traverse_children(root_page, root_page.lft)
+    end
+
+    print_conclusion(lft_rgt_issue_page_ids, "left/right value")
+  end
+
+  private
+
+  def print_conclusion(page_ids, field_description)
+    puts "\n\n"
+    if page_ids.length > 0
+      if save
+        puts "Found and corrected #{field_description} for #{page_ids.length} page(s)!"
+      else
+        puts "Following Pages have an incorrect #{field_description}: #{page_ids.join(", ")}"
+      end
+    else
+      puts "All pages have the correct #{field_description}!\n"
+    end
+    puts "\n"
+  end
+
+  def fix_page_field(page, field, counter)
+    wrong_counter = page[field] != counter
+    print wrong_counter ? "F" : "."
+    if wrong_counter
+      lft_rgt_issue_page_ids << page.id
+      page.update_column(field, counter) if save
+    end
+  end
+
+  ##
+  # @param [Alchemy::Page] page
+  # @param [Integer] counter
+  # @return [Integer]
+  def traverse_children(page, counter)
+    page.children.order(lft: :asc).each do |child_page|
+      counter += 1
+      fix_page_field(child_page, :lft, counter)
+      counter = traverse_children(child_page, counter) unless child_page.leaf?
+
+      counter += 1
+      fix_page_field(child_page, :rgt, counter)
+    end
+
+    counter
+  end
+end
+
+namespace :alchemy do
+  namespace :sitemap do
+    desc "Get an overview over all sitemap issues"
+    task anomalies: [:environment] do
+      finder = SiteMapIssueFinder.new
+      finder.lft_rgt_issues
+      finder.depth_issues
+    end
+
+    desc "Fix nested set sitemap issues"
+    task fix: [:environment] do
+      finder = SiteMapIssueFinder.new(save: true)
+      finder.lft_rgt_issues
+      finder.depth_issues
+    end
+  end
+end