q = []
q.push('page=' + params['page'].to_s) if params['page']
q.push('page_size=' + params['page_size'].to_s) if params['page_size']
+ q.push('offset=' + params['offset'].to_s) if params['offset']
+ q.push('count=' + params['count'].to_s) if params['count']
if q.length > 0
'?' + q.join('&')
else