Move the changes api to its own controller

app/controllers/api/changes_controller.rb

@@ -0,0 +1,57 @@
+module Api
+  class ChangesController < ApplicationController
+    skip_before_action :verify_authenticity_token
+    before_action :api_deny_access_handler
+
+    authorize_resource :class => false
+
+    before_action :check_api_readable
+    around_action :api_call_handle_error, :api_call_timeout
+
+    # Get a list of the tiles that have changed within a specified time
+    # period
+    def index
+      zoom = (params[:zoom] || "12").to_i
+
+      if params.include?(:start) && params.include?(:end)
+        starttime = Time.parse(params[:start])
+        endtime = Time.parse(params[:end])
+      else
+        hours = (params[:hours] || "1").to_i.hours
+        endtime = Time.now.getutc
+        starttime = endtime - hours
+      end
+
+      if zoom >= 1 && zoom <= 16 &&
+         endtime > starttime && endtime - starttime <= 24.hours
+        mask = (1 << zoom) - 1
+
+        tiles = Node.where(:timestamp => starttime..endtime).group("maptile_for_point(latitude, longitude, #{zoom})").count
+
+        doc = OSM::API.new.get_xml_doc
+        changes = XML::Node.new "changes"
+        changes["starttime"] = starttime.xmlschema
+        changes["endtime"] = endtime.xmlschema
+
+        tiles.each do |tile, count|
+          x = (tile.to_i >> zoom) & mask
+          y = tile.to_i & mask
+
+          t = XML::Node.new "tile"
+          t["x"] = x.to_s
+          t["y"] = y.to_s
+          t["z"] = zoom.to_s
+          t["changes"] = count.to_s
+
+          changes << t
+        end
+
+        doc.root << changes
+
+        render :xml => doc.to_s
+      else
+        render :plain => "Requested zoom is invalid, or the supplied start is after the end time, or the start duration is more than 24 hours", :status => :bad_request
+      end
+    end
+  end
+end