title: Flask JSON post request not working
body: <p>I am using react to submit a form to a flask backend. The data is submitted in json this is an example.</p>
  
  <pre><code>add_new_user(e){
    e.preventDefault()
    var user_details = {}
    user_details['fname'] = this.state.first_name
    user_details['last_name'] = this.state.last_name
  
  var post_request = new Request('http://127.0.0.1:5000/add_new_user', {
      method: 'post',
      body: JSON.stringify(user_details)
  })
  
  fetch(post_request).then(function(response){
      console.log(response)
  })
  </code></pre>
  
  <p>On my backend the code looks like this,</p>
  
  <pre><code>@app.route('/add_new_user', methods=['POST'])
  def add_user():
      content = request.json()
      print content
      return 'user added'
  </code></pre>
  
  <p>However the content variable is null and therefore the printed data on the screen is None. How can I fix this? What am I doing wrong. Thanks</p>