Node.js and protocol buffers - How to parse a PB from a post

I load by PB schema as follows:

var Schema = require('protobuf').Schema;
var schema = new Schema(fs.readFileSync('/home/ubuntu/workspace/test.desc'));

Then for a post I expect a pb, I have the following.

   app.post('/mypost', function(req, res){

        var Feed = schema['MyRequest'];
        var aFeed = Feed.parse(req.body);
        var serialized = Feed.serialize(aFeed);

   });

I am rather new to node.js and also getting post data. is the req.body the buffer from the post data?

TypeError: Argument should be a buffer
    at Function.parse (unknown source)
    at /home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/bidder.js:71:22
    at callbacks (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/node_modules/express/lib/router/index.js:272:11)
    at param (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/node_modules/express/lib/router/index.js:246:11)
    at pass (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/node_modules/express/lib/router/index.js:253:5)
    at Router._dispatch (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/node_modules/express/lib/router/index.js:280:4)
    at Object.handle (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/node_modules/express/lib/router/index.js:45:10)
    at next (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/node_modules/express/node_modules/connect/lib/http.js:204:15)
    at Object.methodOverride [as handle] (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/node_modules/express/node_modules/connect/lib/middleware/methodOverride.js:35:5)
    at next (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/node_modules/express/node_modules/connect/lib/http.js:204:15)

Looking for specific examples for simple request response handling in http with nodejs. This should help you get to the parsing step. http://nodejs.org/api/all.html#all_class_http_serverrequest http://nodejs.org/api/http.html#http_event_data

example:

var options = {
  host: 'www.google.com',
  port: 80,
  path: '/upload',
  method: 'POST'
};

var req = http.request(options, function(res) {
  console.log('STATUS: ' + res.statusCode);
  console.log('HEADERS: ' + JSON.stringify(res.headers));
  res.setEncoding('utf8');
  res.on('data', function (chunk) {
    console.log('BODY: ' + chunk);
  });
});

req.on('error', function(e) {
  console.log('problem with request: ' + e.message);
});

// write data to request body
req.write('data\n');
req.write('data\n');
req.end();

example see explanation of request and response in this answer http://stackoverflow.com/a/4696338/51700

another example with cookies http://stackoverflow.com/a/4581610/51700