javascript - 解析 Javascript API Cloud 代码 afterSave 并访问 beforeSave 值

Question

我正在使用 Parse Cloud Code 进行保存前/保存后处理。我会检查 afterSave Hook 中属性的 beforeSave 值 - 例如，当 parseObj.get('status') 从 processing => Complete 转换时执行某些操作。我可以访问 oldVal/newVal 以获取 beforeSave 处理程序中更改的属性，但我找不到传递 oldVal 的方法到 afterSave 处理程序，而不保存为数据库字段。

我尝试将这些值作为属性传递给 response 和 response.object 对象，但都没有传递到 afterSave

Parse.Cloud.beforeSave('ParseObj', function(request, response) {
  var checkDirty, isDirty, parseObj, prevQ;
  // request keys=["object","installationId","user","master"]
  if (request.object.isNew()) {
    return response.success();
  } else {
    parseObj = request.object;
    checkDirty = ['status']; // array of all attrs to check
    isDirty = [];
    _.each(checkDirty, function(attr) {
      if (parseObj.dirty(attr)) {
        isDirty.push(attr);
      }
    });
    console.log("isDirty=" + JSON.stringify(isDirty));
    if (isDirty.length) {
      prevQ = new Parse.Query('ParseObj');
      return prevQ.get(parseObj.id).then(function(prevParseObj) {
        var newVal, oldVal;
        console.log("prevParseObj, id=" + prevParseObj.id);
        oldVal = _.pick(prevParseObj.toJSON(), isDirty);
        _beforeSave(parseObj, oldVal);  // do something here
        request.previousValues = oldVal
        request.object.previousValues = oldVal
        return response.success();
      }, function(err) {
        return response.error("parsObj NOT FOUND, parseObj.id=" + parseObj.id);
      });
    } else {
      return response.success();
    }
  }
});

Parse.Cloud.afterSave('ParseObj', function(request) {
  var parseObj;
  // request keys=["object","installationId","user","master"], 
  oldVal = request.previousValues  // undefined
  oldVal = request.object.previousValues // also, undefined
  parseObj = request.object;
  _afterSave(parseObj, oldVal)  // do something else here
  return; 
});

有什么想法吗？

Answer 1

我对此进行了更多研究，最终暂时保存到 Parse 对象，然后将其删除，如下所示:

//Add the value you need to the object prior to saving using an "oldValue" key
yourPFObject["oldValue"] = value (this is in your SDK somewhere where the save happens)

//Get that value in afterSave in Cloud Code
var old = object.get("oldValue")

//Do whatever you need to do with "old"...

//Remove the temporary old value so it doesn't stay in the database
object.unset("oldValue") 
object.save()

我希望这会有所帮助。祝你好运!