import tornado.ioloopimport tornado.iostreamimport socketclass WebRequest(object):    LINE_END = b‘\r\n‘    def __init__(self, host, port=80, callback=None):        self.host = host        self.port =port        self.headers = {}        self.data = ‘‘        self.callback = callback        self.transfer = ‘stream‘        self.http_ver_with_status = ‘‘        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)        self.stream = tornado.iostream.IOStream(s)        self.stream.connect((self.host, self.port), self.send_request)                        def send_request(self):        self.stream.write(b"GET / HTTP/1.0\r\nHost: %s\r\n\r\n" %self.host)        self.stream.read_until(self.LINE_END*2, self.on_headers)    def on_headers(self, data):        lines =  data.split(self.LINE_END)        self.http_ver_with_status = lines.pop(0)        for line in lines:            parts = line.split(b":", 1)            if len(parts) == 2:                self.headers[parts[0].strip()] = parts[1].strip()        if ‘Content-Length‘ in self.headers:            if int(self.headers[b"Content-Length"]) > 0:                self.transfer = ‘content_length‘                self.stream.read_bytes(int(self.headers[b"Content-Length"]), self.on_body)            else:                self.callback(self)                self.stream.close()        elif self.headers.get(b‘Transfer-Encoding‘) == ‘chunked‘:            self.transfer = ‘chunked‘            self.on_chunk()        else:            self.transfer = ‘stream‘            callback = lambda data: self.on_stream(data, True)            streaming_callback = lambda data: self.on_stream(data, False)            self.stream.read_until_close(callback, streaming_callback)    def on_body(self, data):        self.data += data        self.callback(self)        self.stream.close()    def on_chunk(self):        self.stream.read_until_regex(self.LINE_END, self.on_chunk_header)    def on_chunk_header(self, data):        data = data.strip(self.LINE_END)        length = int(data, 16)        if length > 0:            self.stream.read_bytes(length+len(self.LINE_END), self.on_chunk_data)        else:            self.stream.read_bytes(length+len(self.LINE_END), self.on_chunk_end)                def on_chunk_end(self, data):        self.callback(self)        self.stream.close()    def on_chunk_data(self, data):        self.data +=  data        self.on_chunk()            def on_stream(self, data, finish=False):        # do some thing        if finish:            self.data += data            self.callback(self)            self.stream.close()        else:            self.data += datadef callback(req):    print req.http_ver_with_status    print "Transfer :" , req.transfer    print "Headers: ", req.headers    #print "Data: ", req.data    req = WebRequest(‘cn.bing.com‘, 80, on_bing)def on_bing(req):    print req.http_ver_with_status    print "Transfer :" , req.transfer    print "Headers: ", req.headers    #print "Data: ", req.data    tornado.ioloop.IOLoop.instance().stop()if __name__ == ‘__main__‘:    req = WebRequest(‘valpha.gameloft.com‘, 20000, callback)    tornado.ioloop.IOLoop.instance().start()