Stream handlers with Tornado

gistfile1.py

class StreamHandler(AMSHandler): 
    @tornado.web.asynchronous 
    def get(self):
        self.post()
        
    @tornado.web.asynchronous 
    def post(self):
        self.write("<pre>")
        self.ioloop = tornado.ioloop.IOLoop.instance() 
        self.pipe = self.get_pipe()        
        self.ioloop.add_handler( self.pipe.fileno(), self.async_callback (self.on_read), self.ioloop.READ)
        
    def on_read(self, fd, events): 
        buffer = self.pipe.read(1024) 
        try: 
            assert buffer 
            self.write(buffer) 
            self.flush() 
        except: 
            self.pipe.close() 
            self.ioloop.remove_handler(fd) 
            self.finish()
            
    def _get_pipe(self, commandline):
        return subprocess.Popen(
            commandline, 
            shell=True, 
            stdout=subprocess.PIPE, 
            stdin=subprocess.PIPE, 
            stderr=subprocess.PIPE).stdout
            
    def get_pipe(self):
        return self._get_pipe('cat /dev/urandom')

class TCPDumpHandler(StreamHandler):
    def get_pipe(self):
        iface = self.get_argument('iface', 'any')
        verbose = self.get_argument('verbose', None) and ' -vvvXX ' or ''
        return self._get_pipe("tcpdump %s -nli %s 'not port 22'" % (verbose, iface))
            
class LogFileHandler(StreamHandler):
    def get_pipe(self):
        return self._get_pipe("tail -f /var/log.syslog")