title: Meteor + React - Session Variable not behaving reactively
body: <p>I'm new to the community but I kept searching for one week on it to see if my question was answered before but apparently not much is relating to meteor 1.4 with react.</p>
  
  <p>So I'm building an app (I'm new to Meteor + React) that reads a huge XML file stored on the server and then needs to extract some data from it, display it and then launch some other functions with that acquired data on different pages so I thought it was a good idea to store this XML parsed into a JSON Object into a session variable but then immediately the problems started as the first simple data extraction doesn't behave reactively.</p>
  
  <p>This is the code:</p>
  
  <pre><code>import React, { Component, PropTypes } from 'react';
  import ReactDOM from 'react-dom';
  import { Meteor } from 'meteor/meteor';
  import { createContainer } from 'meteor/react-meteor-data';
  
  FlightPlan = new Mongo.Collection("flightPlan");
  
  export default class FlightPlanWrapper extends Component { 
    constructor(props) {
      super(props);
    }
  
    xmlDemo(){
      Meteor.call('xmlDemo',function(error,flightPlanXML){
        let tempXML = flightPlanXML;
        Session.set({
          'flightPlanXML': flightPlanXML
        });
      });
    }
  
    render() {
      const flightNumber = Session.get('flightPlanXML') ? (
        &lt;span className="flightNumber"&gt;{Session.get('flightPlanXML').FlightPlan.FlightInfo.aTCCallsign}&lt;/span&gt;
      ) : '';
  
      return (
        &lt;div id='flightPlan' className='contentWrapper'&gt;
          &lt;h2&gt;
            Flight Plan
          &lt;/h2&gt;
  
          {
            Session.get('flightPlanXML') ? flightNumber :
              &lt;div&gt;
                &lt;button onClick={this.xmlDemo.bind(this)}&gt;click me&lt;/button&gt;
              &lt;/div&gt;
          }
        &lt;/div&gt;
      );
    }
  }
  
  export default createContainer (() =&gt; {
    Meteor.subscribe('flightPlan');
    return {
      'resolutions': FlightPlan.find().fetch()
    };
  }, FlightPlanWrapper);
  </code></pre>
  
  <p>So I'm not sure if my understanding of the system is correct at all but what I would like to do in this simplified version of the code is to either display the button or the content of that session variable.</p>
  
  <p>Please note that when I change page after having clicked the button and then I come back to the same page the content is updated properly.</p>