Question

我在Parse上运行云代码。我正在运行查询，对于每个查询，我正在执行子查询。我将修改子查询的结果。但是修改了我的子查询对象后，我想修改我的查询结果对象以反映我已经处理过它们。

使用promises，我可以进行初始查询，遍历每个结果，使用该结果执行子查询并修改新的子查询结果。但是，一旦我成功保存了子查询结果，就不会调用保存回调，也无法更新我的初始查询对象。

Parse.Cloud.job("processEvents", function(request, status){

    Parse.Cloud.useMasterKey();

        var query = new Parse.Query("events");
        query.equalTo("processed", false);
        query.limit(10);

        query.find().then(function(results) {

        var promise = Parse.Promise.as();

        _.each(results, function(eventsRecord) { //EACH

            var eventData = eventsRecord.get("eventData");
            var eventsObject = JSON.parse(eventData);
            var events = eventsObject["events"];

            for (var i = 0; i < events.length; i++) {   //FOR

                var currentEvent = events[i];
                if(currentEvent["type"] === "vote"){

                    var votes = currentEvent["entity"]["votes"];
                    for (var i = 0; i < votes.length; i++) {

                        var currentVote = votes[i];

                        promise = promise.then(function() {

                            var EventAssociationObject = Parse.Object.extend("eventAssociation");
                            var query = new Parse.Query(EventAssociationObject);
                            query.equalTo("voteID", currentVote["id"]);

                            return query.first({ 
                                success:function(object){

                                    var partyEntity = currentEvent["entity"]; 

                                    object.set("entityJSONInformation", JSON.stringify(partyEntity));   

                                    //object in the response callback must be the object saved
                                    return object.save(object, {

                                        success:function(object){
                                            eventsRecord.set("processed", true);
                                            return eventsRecord.save();
                                        },
                                        error: function(error){
                                            console.log(error);
                                        }
                                    });

                                    }, 
                                    error:function(error){
                                        console.log(error);
                                    }
                                }); 
                            });
                    };

                }


            };  //FOR

        });  //EACH

        return promise;

    }).then(function() {
        status.success("Finished");
    });

});

Answer 1

当您使用Parse的回调机制success:执行此类操作时，您正在逃避承诺代码。当你从成功中返回时：它不会返回任何有意义的东西，也不会像承诺那样异步地等待它。

相反，你应该返回承诺并链接它们。

query.first({...

应该成为

query.first().then(function(result){
     // ...
     return result.save();
}).then(function(result){
     eventRecords.set(...
     return eventsRecord.save();
});

祝你好运，编码愉快:)。

Answer 2

这是回应Benjamin Gruenbaum评论的正确代码。

Parse.Cloud.job("processEvents", function(request, status){

Parse.Cloud.useMasterKey();

    var query = new Parse.Query("events");
    query.equalTo("processed", false);
    query.limit(10);

    query.find().then(function(results) {

    var promise = Parse.Promise.as();

    _.each(results, function(eventsRecord) { //EACH

        var eventData = eventsRecord.get("eventData");
        var eventsObject = JSON.parse(eventData);
        var events = eventsObject["events"];

        for (var i = 0; i < events.length; i++) {   //FOR

            var currentEvent = events[i];
            if(currentEvent["type"] === "vote"){

                var votes = currentEvent["entity"]["votes"];
                for (var i = 0; i < votes.length; i++) {

                    var currentVote = votes[i];

                    promise = promise.then(function() {

                    var EventAssociationObject = Parse.Object.extend("eventAssociation");
                    var query = new Parse.Query(EventAssociationObject);
                    query.equalTo("voteID", currentVote["id"]);

                    return query.first().then(function(object){}){ 
                            var partyEntity = currentEvent["entity"]; 
                            object.set("entityJSONInformation", JSON.stringify(partyEntity));   

                            //object in the response callback must be the object saved
                            return object.save().then(function(object){
                                eventsRecord.set("processed", true);
                                return eventsRecord.save();
                            });
                        });
                };

            }


        };  //FOR

    });  //EACH

    return promise;

}).then(function() {
    status.success("Finished");
});

});

解析没有调用对象保存的回调

2 个答案: