Biometric push in Nodejs

In documentation of Biometric, initialization of information exchange. Telling

Step 1. A request message from client, and normal response the server is "OK".

GET /iclock/cdata?SN=${SerialNumber}$options=all....

so my code is.

var http = require('http');
http.createServer(function (req, res) {
   console.log(req.url);
   res.write('OK');
   res.end();
}).listen(5000); 

i got the the result /iclock/cdata?SN=aaa&options=all&pushver=2.32&language=69

Step 2.

 GET OPTION FROM: ${SerialNumber}${LF}${XXX}Stamp=${XXX}...

How could i return a time attendance. How should be my code look like. Please help.

Thank you in advance.