I don't know how to send data in xml format using an api.
http_post "https://crm.zoho.com/crm/private/xml/Notes/insertRecords?newFormat=1&authtoken=#{settings.api_token}&scope=crmapi&xmlData" do |req|
req.headers['Content-Type'] = 'application/xml'
req.body = {xmlData:{note:generate_note_content(ticket)}}.to_xml
end
You should try using Net/http lib.
http://ruby-doc.org/stdlib-2.0.0/libdoc/net/http/rdoc/Net/HTTP/Post.html