DRY up csv/xls rendering, put it into model

app/models/map.rb

@@ -84,39 +84,46 @@ class Map < ActiveRecord::Base
     json
   end
 
+  def to_spreadsheet
+    spreadsheet = []
+    spreadsheet << ["Topics"]
+    spreadsheet << ["Id", "Name", "Metacode", "X", "Y", "Description", "Link", "User", "Permission"]
+    self.topicmappings.each do |mapping|
+      topic = mapping.mappable
+      next if topic.nil?
+      spreadsheet << [
+        topic.id,
+        topic.name,
+        topic.metacode.name,
+        mapping.xloc,
+        mapping.yloc,
+        topic.desc,
+        topic.link,
+        topic.user.name,
+        topic.permission
+      ]
+    end
+    spreadsheet << []
+    spreadsheet << ["Synapses"]
+    spreadsheet << ["Id", "Description", "Category", "Topic1", "Topic2", "User", "Permission"]
+    self.synapses.each do |synapse|
+      spreadsheet << [
+        synapse.id,
+        synapse.desc,
+        synapse.category,
+        synapse.node1_id,
+        synapse.node2_id,
+        synapse.user.name,
+        synapse.permission
+      ]
+    end
+    spreadsheet
+  end
+
   def to_csv(options = {})
     CSV.generate(options) do |csv|
-      csv << ["topics"]
-      csv << ["id", "name", "metacode", "x", "y", "desc", "link", "user.name", "permission"]
-      self.topicmappings.each do |mapping|
-        topic = mapping.mappable
-        next if topic.nil?
-        csv << [
-          topic.id,
-          topic.name,
-          topic.metacode.name,
-          mapping.x,
-          mapping.y,
-          topic.desc,
-          topic.link,
-          topic.user.name,
-          topic.permission,
-          topic.synapses_csv("text")
-        ]
-      end
-      csv << []
-      csv << ["synapses"]
-      csv << ["id", "description", "category", "topic1", "topic2", "username", "permission"]
-      self.synapses.each do |synapse|
-        csv << [
-          synapse.id,
-          synapse.desc,
-          synapse.category,
-          synapse.node1_id,
-          synapse.node2_id,
-          synapse.user.name,
-          synapse.permission
-        ]
+      to_spreadsheet.each do |line|
+        csv << line
       end
     end
   end

app/views/maps/show.xls.erb

@@ -1,51 +1,9 @@
 <table>
-  <tr><th>Topics</th></tr>
-  <tr>
-    <th>ID</th>
-    <th>Name</th>
-    <th>Metacode</th>
-    <th>X</th>
-    <th>Y</th>
-    <th>Description</th>
-    <th>Link</th>
-    <th>Username</th>
-    <th>Permission</th>
-  </tr>
-  <% @map.topicmappings.each do |mapping| %>
-  <% topic = mapping.mappable %>
-  <% next if topic.nil? %>
-  <tr>
-    <td><%= topic.id %></td>
-    <td><%= topic.name %></td>
-    <td><%= topic.metacode.name %></td>
-    <td><%= mapping.xloc %></td>
-    <td><%= mapping.yloc %></td>
-    <td><%= topic.desc %></td>
-    <td><%= topic.link %></td>
-    <td><%= topic.user.name %></td>
-    <td><%= topic.permission %></td>
-  </tr>
-  <% end %>
-  <tr></tr>
-  <tr><th>Synapses</th></tr>
-  <tr>
-    <th>ID</th>
-    <th>Description</th>
-    <th>Category</th>
-    <th>Topic1</th>
-    <th>Topic2</th>
-    <th>Username</th>
-    <th>Permission</th>
-  </tr>
-  <% @map.synapses.each do |synapse| %>
-  <tr>
-    <td><%= synapse.id %></td>
-    <td><%= synapse.desc %></td>
-    <td><%= synapse.category %></td>
-    <td><%= synapse.node1_id %></td>
-    <td><%= synapse.node2_id %></td>
-    <td><%= synapse.user.name %></td>
-    <td><%= synapse.permission %></td>
-  </tr>
+  <% @map.to_spreadsheet.each do |line| %>
+    <tr>
+      <% line.each do |field| %>
+        <td><%= field %></td>
+      <% end %>
+    </tr>
   <% end %>
 </table>