我在解析User（默认情况下）和UserData中创建了两个类。 BeforeSave触发如下：
Parse.Cloud.beforeSave(Parse.User, function(request, response) {
var userDataObject = new Parse.Object("UserData");
var fromUserPointer = {"__type":"Pointer","className":"_User","objectId":request.object.id};
return userDataObject.save({score: 0, ideasCount: 0, followersCount:0, return:0}).then(function (userData) {
var userDataPointer = {"__type":"Pointer","className":"UserData","objectId":userData.id};
request.object.set("userData", userDataPointer);
response.success();
}, function(error) {
response.error(error.message);
});
}）;
它保存用户的UserData并获取其UserData指针字段并保存在UserData类中。
Parse.Cloud.afterSave(Parse.User, function(request) {
Parse.Cloud.useMasterKey();
var userPointer = {"__type":"Pointer","className":"_User","objectId":request.object.id};
var userData = request.object.get("userData");
if (userData) {
var userDataPointer = {"__type":"Pointer","className":"UserData","objectId":userData.id};
var userDataQuery = new Parse.Query("UserData");
userData.set("user", userPointer);
return userData.save().then (function (userData) {
var activityObject = new Parse.Object("Activity");
return activityObject.save({fromUserData: userDataPointer, from:userPointer,
toUserData:userDataPointer, to:userPointer, type:"follow"});
}).then (function (success) {
}, function (error) {
console.error("Error in afterSave(user) : " + request.object.id + ":" + error.message);
});
}
}）;
问题是，在保存User类之前，它有时不会创建它应该创建的UserData。因此，这两个触发器必须以原子方式运行，而它们则不是。