          url = "%s?page=%d" % (self.request.path, page_number)
  
          limit = self.get_limit()
          if limit != self.limit:
              url = "%s&limit=%d" % (url, limit)
  
          return url
  
      def next(self, page):
          """ Returns a url to the next page of results (if any) """
 
</s> remove         url = "%s?page=%d" % (self.request.path, page_number)
 </s> add         url = URLObject.parse(self.request.get_full_path())
        url = url.add_query_param('page', page_number)
            url = url.add_query_param('limit', limit)
          url = "%s?page=%d" % (self.request.path, page_number)
  
          limit = self.get_limit()
          if limit != self.limit:
            url = url.add_query_param('limit', limit)
  
          return url
  
      def next(self, page):
          """ Returns a url to the next page of results (if any) """
keep keep keep keep replace keep keep keep keep keep
 Preserve existing query params in PaginatorMixin

Previously, generation of next/previous links would discard any existing
query parameters. This commit introduces a dependency on URLObject, which
is used to intelligently parse and modify URLs to ensure existing params
are preserved.

Addresses issues #107 
djangorestframework/mixins.py