Automatic Versioning

gistfile1.rb

#Current key is always the most current version of the document. Everytime it gets modified, we increase the count of versions and save current couchbase version of document #as a version with current_version - 1 appended.

#So:

#create_doc
#mydoc = { "txt" => "my first text" }

#replace_doc
#mydoc::version = 2
#mydoc::version::1 = { "txt" => "my_first_text", "auto_version" => 1, "auto_version_stamp" => "6/28/2012 20:35" }
#mydoc = { "txt" => "my_second_text", "auto_version" => 2  }

#replace_doc
#mydoc::version = 3
#mydoc::version::1 = { "txt" => "my_first_text", "auto_version" => 1, "auto_version_stamp" => "6/28/2012 20:35" }
#mydoc::version::2 = { "txt" => "my_second_text", "auto_version" => 2, "auto_version_stamp" => "6/28/2012 20:40" }
#mydoc = { "txt" => "my third text", "auto_version" => 3 }


#replace_doc
#mydoc::version = 4
#mydoc::version::1 = { "txt" => "my_first_text", "auto_version" => 1, "auto_version_stamp" => "6/28/2012 20:35" }
#mydoc::version::2 = { "txt" => "my_second_text", "auto_version" => 2, "auto_version_stamp" => "6/28/2012 20:40" }
#mydoc::version::3 = { "txt" => "my_third_text", "auto_version" => 3, "auto_version_stamp" => "6/28/2012 20:45" }
#mydoc = { "txt" => "my fourth text", "auto_version" => 4 }


def replace_document ( key, value, args = {} )

   if args.has_key_and_value?(:auto_version)

     version_tracker_key = key + "::version"
     initialize_document ( version_tracker_key, 1 )
     
     current_version = increment_atomic_count(version_tracker_key)

     # if the value is a Map then add the version to the doc
     if value.is_a? Map
          value[:auto_version] = current_version
     end

     # if there are previous versions, save current existing doc as a version, and straight key will be current                               version
     if current_version > 1
          doc = get_document(key)
          doc[:version_stamp] = Time.now.getUtc
          doc[:auto_version] = current_version - 1
          add_document(key + "::version::#{current_version - 1}", doc)
     end

   end
   
   COUCH.replace(key, value)

end