Allow the client to request errors as an XML document

app/controllers/application_controller.rb

@@ -162,7 +162,18 @@ class ApplicationController < ActionController::Base
   def report_error(message, status = :bad_request)
     # Todo: some sort of escaping of problem characters in the message
     response.headers['Error'] = message
-    render :text => message, :status => status
+
+    if request.headers['X-Error-Format'] and
+       request.headers['X-Error-Format'].downcase == "xml"
+      result = OSM::API.new.get_xml_doc
+      result.root.name = "osmError"
+      result.root << (XML::Node.new("status") << interpret_status(status))
+      result.root << (XML::Node.new("message") << message)
+
+      render :text => result.to_s, :content_type => "text/xml"
+    else
+      render :text => message, :status => status
+    end
   end
   
   def set_locale