title: Flask JSON request is None
body: <p>I'm working on my first Flask app (version 0.10.1), and also my first Python (version 3.5) app. One of its pieces needs to work like this:</p>
  
  <ol>
  <li>Submit a form</li>
  <li>Run a Celery task (which makes some third-party API calls)</li>
  <li>When the Celery task's API calls complete, send a JSON post to another URL in the app</li>
  <li>Get that JSON data and update a database record with it</li>
  </ol>
  
  <p>Here's the relevant part of the Celery task:</p>
  
  <pre><code>if not response['errors']: # response comes from the Salesforce API call
      # do something to notify that the task was finished successfully
      message = {'flask_id' : flask_id, 'sf_id' : response['id']}
      message = json.dumps(message)
      print('call endpoint now and update it')
      res = requests.post('http://0.0.0.0:5000/transaction_result/', json=message)
  </code></pre>
  
  <p>And here's the endpoint it calls:</p>
  
  <pre><code>@app.route('/transaction_result/', methods=['POST'])
  def transaction_result():
      result = jsonify(request.get_json(force=True))
      print(result.flask_id)
      return result.flask_id
  </code></pre>
  
  <p>So far I'm just trying to get the data and print the ID, and I'll worry about the database after that.</p>
  
  <p>The error I get though is this: <code>requests.exceptions.ConnectionError: None: Max retries exceeded with url: /transaction_result/ (Caused by None)</code></p>
  
  <p>My reading indicates that my data might not be coming over as JSON, hence the Force=True on the result, but even this doesn't seem to work. I've also tried doing the same request in CocoaRestClient, with a Content-Type header of application/json, and I get the same result.</p>
  
  <p>Because both of these attempts break, I can't tell if my issue is in the request or in the attempt to parse the response.</p>