Javascript 跨域ajax post中回调函数未定义

我试图向我的flask应用程序发出ajax post请求，并在回调函数中得到答案。不幸的是，我得到了未定义的值，而不是json

非常感谢您的帮助

我的服务器端代码：

application = Flask(__name__)
CORS(application)

...

@application.route('/get_forecast', methods=['POST', 'GET'])
def get_forecast():
    if request.method == 'POST':
        print('in post')
        predictions = {} 
        predictions['data'] = calc_forecast(request.get_json()["data"])
        print(predictions)
        return jsonify(predictions)

  $.ajax({
            type: "POST", 
            url: "http://localhost:5000/get_forecast",
            data: JSON.stringify(markers),
            dataType: 'json',
            crossDomain: true,
            contentType: "application/json",
            done: function(resp, status){
                console.log('done')
                console.log(resp)
                console.log(status)
                console.log('=====')
                }(),
            fail: function(xhr, ajaxOptions, thrownError){
                console.log('fail');
                console.log(thrownError)
                }()

        });

我的客户端代码：

application = Flask(__name__)
CORS(application)

...

@application.route('/get_forecast', methods=['POST', 'GET'])
def get_forecast():
    if request.method == 'POST':
        print('in post')
        predictions = {} 
        predictions['data'] = calc_forecast(request.get_json()["data"])
        print(predictions)
        return jsonify(predictions)

  $.ajax({
            type: "POST", 
            url: "http://localhost:5000/get_forecast",
            data: JSON.stringify(markers),
            dataType: 'json',
            crossDomain: true,
            contentType: "application/json",
            done: function(resp, status){
                console.log('done')
                console.log(resp)
                console.log(status)
                console.log('=====')
                }(),
            fail: function(xhr, ajaxOptions, thrownError){
                console.log('fail');
                console.log(thrownError)
                }()

        });

这是我在烧瓶终端得到的：

 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
127.0.0.1 - - [02/Dec/2018 12:59:53] "OPTIONS /get_forecast HTTP/1.1" 200 -
in post
{'data': [10.15451836569513, 56.578480707072714, 12.435548873275337]}
127.0.0.1 - - [02/Dec/2018 12:59:53] "POST /get_forecast HTTP/1.1" 200 -

以下是我在chrome控制台中得到的信息：

demo.html:228 done
demo.html:229 undefined
demo.html:230 undefined
demo.html:231 =====
demo.html:234 fail
demo.html:235 undefined

---

如果您仔细查看这些示例，它们看起来与您对

$.ajax

的调用有很大不同。我调整了您的代码以更好地类似于示例。也许这有帮助

$.ajax({
    type: "POST", 
    url: "http://localhost:5000/get_forecast",
    data: JSON.stringify(markers),
    dataType: 'json',
    crossDomain: true,
    contentType: "application/json"
    })
    .done(function (data, textStatus, jqXHR) {
        console.log('done');
        console.log(data);
        console.log(textStatus);
        console.log('=====');
    })
    .fail(function (jqXHR, textStatus, errorThrown) {
        console.log('fail');
        console.log(textStatus);
    });

我想，您正在寻找

成功

和

错误

设置

---

更新：是的，我很确定，您的设置

完成

和

失败

是错误的。您想使用

成功

和

错误

还有，看看

这意味着，如果要将所有内容都放入

$的设置中，代码也可以是这样。ajax

调用：

$.ajax({
    type: "POST", 
    url: "http://localhost:5000/get_forecast",
    data: JSON.stringify(markers),
    dataType: 'json',
    crossDomain: true,
    contentType: "application/json",
    success: function (data, textStatus, jqXHR) {
        console.log('done');
        console.log(data);
        console.log(textStatus);
        console.log('=====');
    },
    error: function (jqXHR, textStatus, errorThrown ) {
        console.log('fail');
        console.log(errorThrown);
    }
});