我在Parse.com上有一个游戏,用户进行提交,其他玩家对此进行投票。
我正在尝试编写Cloud后台作业,以用投票总数更新我的所有用户帐户,该投票总数是每个用户提交的投票总数之和。
我已经尝试了大约5种不同的方法,但无法运行嵌套查询(更不用说更新和保存了)。
这是文档和有用的博客文章...
https://parse.com/docs/js_guide#promises-creation
http://blog.parse.com/2013/01/29/whats-so-great-about-javascript-promises/
这是我的最新消息,非常感谢您的帮助...
编辑:感谢@axymous使我清楚地看到,我需要显式创建并立即返回promise,然后在回调中解决它。
Parse.Cloud.job("calculateUserTotals", function(request, status) {
Parse.Cloud.useMasterKey();
var query = new Parse.Query(Parse.User);
query.find().then(function(users) {
var promises = [];
_.each(users, function(user) {
promises.push((function(user){
var promise = new Parse.Promise();
console.log(user.toJSON().objectId); // user objectId is correct here
var submissionQuery = new Parse.Query('submission');
submissionQuery.equalTo('user', user.toJSON().objectId);
submissionQuery.find({ // this doesnt seem to ever run, i have tried .each as well
success: function(submissions) {
var votes = 0;
for (var i=0; i<submissions.length; i++) {
var submission = submissions[i];
votes = votes + submission.get('votes').length;
}
user.set('submission_count', submissions.length);
user.set('vote_count', votes);
user.save({
success: function(user) {
promise.resolve();
}
});
},
error: function(error) {
status.error(error);
}
});
return promise;
})(user));
});
return Parse.Promise.when(promises);
})
.then(function() {
status.success('leaderboard updated.');
});
});
最佳答案
我需要显式创建并立即返回promise,然后在回调中解决它。谢谢@axymous。
Parse.Cloud.job("calculateUserTotals", function(request, status) {
Parse.Cloud.useMasterKey();
var query = new Parse.Query(Parse.User);
query.find().then(function(users) {
var promises = [];
_.each(users, function(user) {
promises.push((function(user){
var promise = new Parse.Promise();
console.log(user.toJSON().objectId); // user objectId is correct here
var submissionQuery = new Parse.Query('submission');
submissionQuery.equalTo('user', user.toJSON().objectId);
submissionQuery.find({ // this doesnt seem to ever run, i have tried .each as well
success: function(submissions) {
var votes = 0;
for (var i=0; i<submissions.length; i++) {
var submission = submissions[i];
votes = votes + submission.get('votes').length;
}
user.set('submission_count', submissions.length);
user.set('vote_count', votes);
user.save({
success: function(user) {
promise.resolve();
}
});
},
error: function(error) {
status.error(error);
}
});
return promise;
})(user));
});
return Parse.Promise.when(promises);
})
.then(function() {
status.success('leaderboard updated.');
});
});