dont save over an existing design doc

lib/couchrest/core/model.rb

@@ -1,3 +1,5 @@
+require 'digest/md5'
+
 # = CouchRest::Model - ORM, the CouchDB way
 module CouchRest
   # = CouchRest::Model - ORM, the CouchDB way
@@ -270,7 +272,7 @@ module CouchRest
               refresh_design_doc
             end
             raw = query.delete(:raw)
-            view_name = "#{type}/#{method_name}"
+            view_name = "#{design_doc_slug}/#{method_name}"
 
             view = fetch_view(view_name, query)
             if raw
@@ -283,6 +285,11 @@ module CouchRest
         end
       end
 
+      # Fetch the generated design doc. Could raise an error if the generated views have not been queried yet.
+      def design_doc
+        database.get("_design/#{design_doc_slug}")
+      end
+
       private
 
       def fetch_view view_name, opts
@@ -301,26 +308,33 @@ module CouchRest
         end
       end
 
-      def design_doc_id
+      def design_doc_slug
-        "_design/#{self.to_s}"
+        return @design_doc_slug if @design_doc_slug && @@design_doc_fresh
+        funcs = []
+        @@design_doc['views'].each do |name, view|
+          funcs << "#{name}/#{view}"
+        end
+        md5 = Digest::MD5.hexdigest(funcs.sort.join(''))
+        @design_doc_slug = "#{self.to_s}-#{md5}"
       end
 
       def default_design_doc
         {
-          "_id" => design_doc_id,
           "language" => "javascript",
           "views" => {}
         }
       end
 
       def refresh_design_doc
-        saved = database.get(design_doc_id) rescue nil
+        did = "_design/#{design_doc_slug}"
+        saved = database.get(did) rescue nil
         if saved
           @@design_doc['views'].each do |name, view|
             saved['views'][name] = view
           end
           database.save(saved)
         else
+          @@design_doc['_id'] = did
           database.save(@@design_doc)
         end
         @@design_doc_fresh = true
@@ -408,6 +422,7 @@ module CouchRest
 
     def cast_keys
       return unless self.class.casts
+      # TODO move the argument checking to the cast method for early crashes
       self.class.casts.each do |k,v|
         next unless self[k]
         target = v[:as]

spec/couchrest/core/model_spec.rb

@@ -336,7 +336,7 @@ describe CouchRest::Model do
     
     it "should create the design doc" do
       Article.by_date rescue nil
-      doc = Article.database.get("_design/Article")
+      doc = Article.design_doc
       doc['views']['by_date'].should_not be_nil
     end
     
@@ -371,7 +371,7 @@ describe CouchRest::Model do
     end
     it "should create the design doc" do
       Article.by_user_id_and_date rescue nil
-      doc = Article.database.get("_design/Article")
+      doc = Article.design_doc
       doc['views']['by_date'].should_not be_nil
     end
     it "should sort correctly" do
@@ -412,6 +412,24 @@ describe CouchRest::Model do
     end
   end
 
+  describe "adding a view" do
+    before(:each) do
+      Article.by_date
+      @design_docs = Article.database.documents :startkey => "_design/", :endkey => "_design/\u9999"
+    end
+    it "should not create a design doc on view definition" do
+      Article.view_by :created_at
+      newdocs = Article.database.documents :startkey => "_design/", :endkey => "_design/\u9999"
+      newdocs["rows"].length.should == @design_docs["rows"].length
+    end
+    it "should create a new design document on view access" do
+      Article.view_by :created_at
+      Article.by_created_at
+      newdocs = Article.database.documents :startkey => "_design/", :endkey => "_design/\u9999"
+      newdocs["rows"].length.should == @design_docs["rows"].length + 1
+    end
+  end
+
   describe "destroying an instance" do
     before(:each) do
       @obj = Basic.new