Ledger.prototype.server = undefined;
Ledger.prototype.halt_service = function() {
 this.server.removeAllListeners('request');
 this.server.removeAllListeners('listening');
 this.server.close();
};
Ledger.prototype.service = function() {
  var self = this;
  var http = require('http');
  var sys = require('sys');
  self.server = http.createServer(function(request,response) {
    var resp = response;
    self.find_all(function(err,items){
      var body = JSON.stringify(items);
      resp.writeHead(200, {
        'Content-Length': body.length,
        'Content-Type': 'text/json'
      });
      resp.write(body,'utf8')
      resp.end();
    });
  });
  self.server.addListener('close',function(errno) {
    sys.puts('close ' + errno);
  });
  self.server.listen(8001);
};