Added optimistic locking to wiki pages.

app/controllers/pages_controller.rb

@@ -56,16 +56,16 @@ class PagesController < ApplicationController
   def update
     @page = Page.find(params[:id])
 
-    respond_to do |format|
     if @page.update_attributes(params[:page])
       flash[:notice] = 'Seite wurde aktualisiert.'
-        format.html { redirect_to(wiki_page_path(@page.permalink)) }
-        format.xml  { head :ok }
+      redirect_to wiki_page_path(@page.permalink)
     else
-        format.html { render :action => "edit" }
-        format.xml  { render :xml => @page.errors, :status => :unprocessable_entity }
-      end
+      render :action => "edit"
     end
+
+  rescue ActiveRecord::StaleObjectError
+    flash[:error] = "Achtung, die Seite wurde gerade von jemand anderes bearbeitet. Bitte versuche es erneut."
+    redirect_to wiki_page_path(@page.permalink)
   end
 
   # DELETE /pages/1

app/views/pages/_form.html.haml

@@ -15,7 +15,7 @@
 
 - form_for @page do |f|
   = f.error_messages
-
+  = f.hidden_field :lock_version
   %p
     %b Title
     %br/

db/migrate/20090325175756_create_pages.rb

@@ -4,6 +4,7 @@ class CreatePages < ActiveRecord::Migration
       t.string :title
       t.text :body
       t.string :permalink
+      t.integer :lock_version, :default => 0
 
       t.timestamps
     end

db/schema.rb

@@ -215,6 +215,7 @@ ActiveRecord::Schema.define(:version => 20090325175756) do
     t.string   "title"
     t.text     "body"
     t.string   "permalink"
+    t.integer  "lock_version", :default => 0
     t.datetime "created_at"
     t.datetime "updated_at"
   end