解析 - 在Cloud Code中检查BeforeSave内部的更新

Question

我想检查一下,我没有为事件的参与状态保存重复条目 - 所以在BeforeSave上我正在检查事件rsvp是否尚未输入 - 如果有,我想知道是否需要更新.如果是,我想进行更新而不是创建新的RSVP条目.

这是我的代码 - 即使使用BeforeSave中的简单更新,我似乎也无法使其工作.

Parse.Cloud.beforeSave("Rsvps", function(request, response) {

var eventid = request.object.get("eventid");
var userid = request.object.get("userid");
var rsvp_status = request.object.get("rsvp_status");

var Rsvps = Parse.Object.extend("Rsvps");
var query = new Parse.Query(Rsvps);
query.equalTo("eventid", eventid);
query.equalTo("userid", userid);
query.first({
  success: function(object) {
    if (object) {
        // response.error("An RSVP for this event already exists.");
        request.object.id = object.id;
        request.object.set('rsvp_status', "attending");
        request.object.save();
    } else {
      response.success();
    }
  },
  error: function(error) {
    response.error("Error: " + error.code + " " + error.message);
  }
});

});

我已经尝试了很多变化而没有任何喜悦 - 这是我最近的尝试.

Answer 1

更新。我添加了一项检查，如果“参加”值正确，则不更新现有对象。尝试一下。如果有任何您无法解决的问题，请将错误添加为对此答案的评论。

Parse.Cloud.beforeSave("Rsvps", function (request, response) {

    var eventid = request.object.get("eventid");
    var userid = request.object.get("userid");
    var rsvp_status = request.object.get("rsvp_status");

    //Do not re-declare the class
    //var Rsvps = Parse.Object.extend("Rsvps");
    var query = new Parse.Query("Rsvps");

    //Check for existing RSVP
    query.equalTo("eventid", eventid);
    query.equalTo("userid", userid);

    query.first().then(function (object) {

            if (object && object.get('rsvp_status') != "attending") {
                //RSVP exists and needs updating.
                // Do not save the object attached to the request.
                //Instead, update existing object.

                object.set('rsvp_status', "attending");
                object.save().then(function () {
                        response.error('Updated existing RSVP to "attending"');
                    },

                    function (error) {

                        response.error("Error: " + error.code + " " + error.message);
                    });

            } else {

                //Continuing and save the new RSVP object because it is not a duplicate.
                response.success();
            }
        },
        function (error) {

            response.error("Error: " + error.code + " " + error.message);

        });
});