title: Http post request in Angular2 does not pass parameters
body: <p>I am trying to send a parameter using Angular2 POST to my Python/Tornado back-end which returns a JSON object. The parameters are being sent properly but at the Python side, it is returning 400 POST missing arguments error. I am using Ionic 2/Angular2 in the front-end and Python/Tornado server.</p>
  
  <p>Angular2 code is as follows: 
  Here content is a variable containing HTML table</p>
  
  <pre><code>let body = JSON.stringify({content: content});
  let headers = new Headers({ 'Content-Type': 'application/json' });
  let options = new RequestOptions({ headers: headers });
  this.http.post(url, body, options).map(res =&gt; res.json()).subscribe(data =&gt; {
        console.log(data)
  }, error =&gt; {
        console.log(JSON.stringify(error));
  });
  </code></pre>
  
  <p>Python code is as follows:</p>
  
  <pre><code>def post(self):
      print self.request.arguments
      print self.get_argument('content')
      self.finish(dict(result="ok", data=content))
  </code></pre>
  
  <p>Here is the error:</p>
  
  <pre><code>[W 160824 06:04:30 web:1493] 400 POST /test (182.69.5.99): Missing argument content
  [W 160824 06:04:30 web:1908] 400 POST /test (182.69.5.99) 1.67ms
  </code></pre>