发出正确的 POST 请求并获取响应数据

Question

I have an application hosted on pythonanywhere.com . It throws a 400 error if sended data does not contain data property, otherwise it returns a response data. This is Flask code of the server:

@app.route('/api', methods=['POST'])
def get_post():
    if not request.json or not 'data' in request.json:
        abort(400)
    data = request.json['data']
    # do something with the data...
    return jsonify({'response': str(data)}), 200

And my front-end part of application should send a POST request with a data and get a response. I am trying to use fetch but it gets a 400 error though I send a JSON object with a data object:

function sendData(value) {
  data = { 'data': value };
  fetch('http://' + appUrl, {
      method: 'POST',
      headers: {
        'content-type': 'application/json',
      },
      mode: 'no-cors',
      body: JSON.stringify(data),
  })
  .then(data => { return data.json() })
}

Also I tried to use XMLHttpRequest :

var xhr = new XMLHttpRequest();
xhr.open("POST", 'http://' + appUrl, true);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.send(data);

But I can't find out how to disable CORS and get a response data.

Answer 1

if you are having CORS issue, always check if the server accept your origin of request (other than pythonanywhere.com ) if not, you should allow it from your server.

you mentioned that you are using Flask as your backend, you might want to check out this library:

https://flask-cors.readthedocs.io/en/latest/

if you follow the docs from the link, you can allow, accept http request depends on the parameter you provided.

Happy Coding