Working on adding checksum support to design documents to handle updates

lib/couchrest/model/design_doc.rb

@@ -7,7 +7,7 @@ module CouchRest
       module ClassMethods
         
         def design_doc
-          @design_doc ||= Design.new(default_design_doc)
+          @design_doc ||= ::CouchRest::Design.new(default_design_doc)
         end
     
         # Use when something has been changed, like a view, so that on the next request
@@ -90,24 +90,17 @@ module CouchRest
         # Writes out a design_doc to a given database, returning the
         # updated design doc
         def update_design_doc(design_doc, db, force = false)
+          design_doc['couchrest-hash'] = design_doc.checksum
           saved = stored_design_doc(db)
           if saved
-            changes = force
-            design_doc['views'].each do |name, view|
-              if !compare_views(saved['views'][name], view)
-                changes = true
-                saved['views'][name] = view
-              end
-            end
-            if changes
+            if force || saved['couchrest-hash'] != design_doc['couchrest-hash']
+              saved.merge!(design_doc)
               db.save_doc(saved)
             end
-            design_doc
           else
-            design_doc.database = db
-            design_doc.save
-            design_doc
+            db.save_doc(design_doc)
           end
+          design_doc
         end
 
         # Return true if the two views match
@@ -117,7 +110,7 @@ module CouchRest
         end
 
       end # module ClassMethods
-      
+
     end
   end
 end

lib/couchrest/model/designs/view.rb

@@ -90,6 +90,13 @@ module CouchRest
           result ? all.last : limit(1).descending.all.last
         end
 
+        # Return the number of documents in the currently defined result set.
+        # Use <tt>#count</tt> for the total number of documents regardless
+        # of the current limit defined.
+        def length
+          docs.length
+        end
+
         # Perform a count operation based on the current view. If the view
         # can be reduced, the reduce will be performed and return the first
         # value. This is okay for most simple queries, but may provide
@@ -383,30 +390,24 @@ module CouchRest
         def execute
           return self.result if result
           raise "Database must be defined in model or view!" if use_database.nil?
-          retryable = true
+
           # Remove the reduce value if its not needed
           query.delete(:reduce) unless can_reduce?
-          begin
-            self.result = model.design_doc.view_on(use_database, name, query.reject{|k,v| v.nil?})
-          rescue RestClient::ResourceNotFound => e
-            if retryable
-              model.save_design_doc(use_database)
-              retryable = false
-              retry
-            else
-              raise e
-            end
-          end
+
+          # Save the design doc for the current database. This should be efficient
+          # and check for changes
+          model.save_design_doc(use_database)
+
+          self.result = model.design_doc.view_on(use_database, name, query.reject{|k,v| v.nil?})
         end
 
         # Class Methods
         class << self
-          
           # Simplified view creation. A new view will be added to the 
           # provided model's design document using the name and options.
           #
           # If the view name starts with "by_" and +:by+ is not provided in 
-          # the options, the new view's map method will be interpretted and
+          # the options, the new view's map method will be interpreted and
           # generated automatically. For example:
           #
           #   View.create(Meeting, "by_date_and_name")

lib/couchrest/model/support/couchrest_database.rb

@@ -0,0 +1,15 @@
+
+CouchRest::Database.class_eval do
+
+  alias :delete_orig! :delete!
+  def delete!
+    clear_model_fresh_cache
+    delete_orig!
+  end
+
+  # If the database is deleted, ensure that the design docs will be refreshed.
+  def clear_model_fresh_cache
+    ::CouchRest::Model::Base.subclasses.each{|klass| klass.req_design_doc_refresh if klass.respond_to?(:req_design_doc_refresh)}
+  end
+
+end

lib/couchrest/model/support/couchrest_design.rb

@@ -0,0 +1,24 @@
+
+CouchRest::Design.class_eval do
+
+  # Calculate a checksum of the Design document. Used for ensuring the latest
+  # version has been sent to the database.
+  #
+  # This will generate an flatterned, ordered array of all the elements of the
+  # design document, convert to string then generate an MD5 Hash. This should
+  # result in a consisitent Hash accross all platforms.
+  #
+  def checksum
+    # create a copy of basic elements
+    base = self.dup
+    base.delete('_id')
+    base.delete('_rev')
+    result = nil
+    flatten =
+      lambda{|v|
+        v.is_a?(Hash) ? v.flatten.map{|v| flatten.call(v)}.flatten : v
+      }
+    Digest::MD5.hexdigest(flatten.call(base).sort.join(''))
+  end
+
+end