修改对象

Question

我正在尝试通过Parse Cloud Code在修改某个对象时发送推送通知 - ＆＃34;脏＆＃34;

我想我差不多了，但收到错误，因为我相信我正在创建一个新用户，而不是查询一个用户。

Parse.Cloud.beforeSave("Fact", function(request, response) {
  var dirtyKeys = request.object.dirtyKeys();
  for (var i = 0; i < dirtyKeys.length; ++i) {
    var dirtyKey = dirtyKeys[i];
    if (dirtyKey === "isValid") {

      //send push
      // Creates a pointer to _User with object id of userId

      var targetUser = new Parse.User();
      // targetUser.id = userId;
      targetUser.id = request.object.userID;

      var query = new Parse.Query(Parse.Installation);
      query.equalTo('user', targetUser);

      Parse.Push.send({
        where: query,
        data: {
          alert: "Your Fact was approved :)"
        }
      });

      return;
    }
  }
  response.success();
});

我发现this post与我的问题有关。我现在的问题是如何在我的beforeSave块中集成用户查询。理想情况下，我会为用户查询创建另一个函数，并将其放在我的beforeSave块中。

** 5/14更新 我接受了@ toddg的建议并修复了之前的保存。以下是我正在尝试做的事情和新错误的更清晰的图片。

Answer 1

在我进入代码之前，有几点（正如@Subash在评论中指出的那样）：

1. Parse.Push.send是异步操作，因此您需要确保在推送完成后调用response.success()。我将使用Promises处理这个问题，因为我认为它们比回调更灵活。如果您不熟悉，请阅读here
2. if语句中的返回可能会阻止调用response.success()。

这是我推荐的做法：

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

  // Keep track of whether we need to send the push notification
  var shouldPushBeSent = false;

  var dirtyKeys = request.object.dirtyKeys();
  for (var i = 0; i < dirtyKeys.length; ++i) {
    var dirtyKey = dirtyKeys[i];

    if (dirtyKey === "isValid") {
      shouldPushBeSent = true;
    }
  }

  if (shouldPushBeSent) {

      //send push
      // Creates a pointer to _User with object id of userId

      var targetUser = new Parse.User();
      // targetUser.id = userId;
      targetUser.id = request.object.userId;

      var query = new Parse.Query(Parse.Installation);

      // We want to pass the User object to the query rather than the UserId
      query.equalTo('user', targetUser);
      Parse.Push.send({
        where: query, // Set our Installation query
        data: {
          alert: "Your fact was approved"
        }
      }).then(function(){

        // Now we know the push notification was successfully sent
        response.success();
      }, function(error){

        // There was an error sending the push notification
        response.error("We had an error sending push: " + error);
      });
  } else {
    // We don't need to send the push notification.
    response.success();
  }
});

顺便说一句，我假设您的Installation类上有一列用于跟踪与每个安装相关联的用户。