close #411 segments should not be allowed where node_a == node_b

app/controllers/segment_controller.rb

@@ -14,9 +14,14 @@ class SegmentController < ApplicationController
 
         segment.from_node = Node.find(segment.node_a.to_i)
         segment.to_node = Node.find(segment.node_b.to_i)
+          
+        if segment.from_node == segment.to_node
+          render :nothing => true, :status => HTTP_EXPECTATION_FAILED
+          return
+        end
         
         unless segment.preconditions_ok? # are the nodes visible?
-          render :nothing => true, :status => 412
+          render :nothing => true, :status => HTTP_PRECONDITION_FAILED
         end
 
         if segment.save_with_history
@@ -65,13 +70,19 @@ class SegmentController < ApplicationController
       segment.timestamp = Time.now
       segment.user_id = @user.id
 
+      if new_segment.node_a == new_segment.node_b
+        render :nothing => true, :status => HTTP_EXPECTATION_FAILED
+        return
+      end
+
       segment.node_a = new_segment.node_a
       segment.node_b = new_segment.node_b
+      
       segment.tags = new_segment.tags
       segment.visible = new_segment.visible
 
       if segment.id == new_segment.id and segment.save_with_history
-        render :nothing => true, :status => 200
+        render :nothing => true, :status => HTTP_OK
       else
         render :nothing => true, :status => 500
       end

config/environment.rb

@@ -61,3 +61,18 @@ ActionMailer::Base.server_settings = {
   :port  => 25, 
   :domain  => 'localhost',
 } 
+
+
+# HTTP CODES
+
+# 200's
+
+HTTP_OK = 200
+
+# 400's
+
+HTTP_PRECONDITION_FAILED = 412
+HTTP_EXPECTATION_FAILED = 417
+
+
+