code: def download_file_from_url(self, source_app, url):
          
          if source_app:
              source_name = source_app
          else:
              source_name = urlparse.urlparse(url).netloc.replace('.', '_')
  
          filename = self.create_file_name(source_name)
          self.download_file(url, filename)
          return filename
docs: Download file from source app or url, and return local filename.