why undefined?

index.js

var Person = require('./person')
  , bob = new Person('bob')
  , express = require('express')
  , app = express()
  ;


  bob.sayName();

  app.get('/person', bob.getName)
  app.listen(3000, function() { console.log('listening...') });

person.js

module.exports = person 

function person(name) { this.name = name; } 

person.prototype.sayName = function() { 
  console.log('my name is ' + this.name);
};

person.prototype.getName = function(req, res) {
  console.log('request has arrived'); 
  res.send('my name is ' + this.name);
};

stdout

//////////////
// tty1
/////////////
$ node index.js
my name is bob
listening...
request has arrived

//////////////
// tty2
/////////////
 $ curl 'localhost:3000/person'
   my name is undefined