Allow a GPX to be fetched in XML format by fetching data.xml instead

of data (the data method returns it in the format it is stored in).

Closes #534.

config/initializers/streaming.rb

@@ -0,0 +1,31 @@
+# Hack ActionController::Streaming to allow streaming from a file handle
+module ActionController
+  module Streaming
+    alias_method :old_send_file, :send_file
+
+    def send_file(file, options = {})
+      if file.is_a? File or file.is_a? Tempfile
+        options[:length] ||= file.stat.size
+        options[:filename] ||= File.basename(file.path) unless options[:url_based_filename]
+        send_file_headers! options
+
+        @performed_render = false
+
+        if options[:stream]
+          render :status => options[:status], :text => Proc.new { |response, output|
+            logger.info "Streaming file #{file.path}" unless logger.nil?
+            len = options[:buffer_size] || 4096
+            while buf = file.read(len)
+              output.write(buf)
+            end
+          }
+        else
+          logger.info "Sending file #{file.path}" unless logger.nil?
+          render :status => options[:status], :text => file.read
+        end
+      else
+        old_send_file(file, options)
+      end
+    end
+  end
+end