树莓派python，tornado，返回json数据代码，初级网络编程。

import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web
import tornado.escape

from tornado.options import define, options
define("port", default=8002, help="run on the given port", type=int)

class IndexHandler(tornado.web.RequestHandler):
def get(self):
greeting = self.get_argument('greeting', 'Hello')
respon = {'issuccess':greeting}
respon_json = tornado.escape.json_encode(respon)
self.write(respon_json)
#self.write(greeting + ', friendly user!')

if __name__ == "__main__":
tornado.options.parse_command_line()
app = tornado.web.Application(handlers=[(r"/", IndexHandler)])
http_server = tornado.httpserver.HTTPServer(app)
http_server.listen(options.port)
tornado.ioloop.IOLoop.instance().start()