Simple example for streamcallback usage in Tornado.

tornado_stream_callback_example.py

"""
Simple example for streamcallback usage in Tornado.
"""
import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web
import tornado.httpclient

from tornado.options import define, options

define("port", default=8889, help="run on the given port", type=int)


class MainHandler(tornado.web.RequestHandler):
    @tornado.web.asynchronous
    def get(self):
        url = 'http://speedtest.frankfurt.linode.com/100MB-frankfurt.bin'
        self.client = tornado.httpclient.AsyncHTTPClient()
        request = tornado.httpclient.HTTPRequest(
            url=url, streaming_callback=self._on_chunk,
            header_callback=self._on_header)
        self.client.fetch(request, self._on_download)

    def _on_chunk(self, chunk):
        self.write('some chunk')
        self.flush()

    def _on_download(self, response):
        self.write('finished')
        self.finish()

    def _on_header(self, header):
        k, v = self._parse_header_string(header)
        self.write(header)
        self.flush()
        self.set_header(k, v)

    def _parse_header_string(self, header_string):
        comma_index = header_string.find(':')
        k = header_string[:comma_index]
        v = header_string[comma_index + 1:].strip()
        return k, v


def main():
    tornado.options.parse_command_line()
    application = tornado.web.Application([
        (r"/", MainHandler),
    ])
    http_server = tornado.httpserver.HTTPServer(application)
    http_server.listen(options.port)
    tornado.ioloop.IOLoop.current().start()


if __name__ == "__main__":
    main()