Question

我正在尝试拍摄照片对象列表，并根据拍摄日期将它们分配到图库。诀窍在于，在流程执行之前，可能根本没有画廊（即 - 代码需要为当天拍摄当天拍摄的照片时没有画廊的一天创建新画廊。）

这是我的代码：

var Photo = Parse.Object.extend("Photo");
var Gallery = Parse.Object.extend("Gallery");

var query = new Parse.Query(Photo);
query.equalTo("owner", Parse.User.current());

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

    // Create a trivial resolved promise as a base case.
    var promise = Parse.Promise.as();

    for (photo in results)
    {
       var photoObject = results[photo];

       //Closure to encapsulate the photo object represented by this loop iteration
       //(function(photo) {
       promise = promise.then((function(photo) {
            console.log('iterator: ' + photo.id);
            var takenAt = photo.get("takenAt");

            var dd = takenAt.getDate();
            var mm = takenAt.getMonth()+1; //January is 0!`

            var yyyy = takenAt.getFullYear();

            var dateOf = new Date(yyyy+"-"+mm+"-"+dd);

            var query = new Parse.Query(Gallery);
            query.equalTo("owner", Parse.User.current());
            query.equalTo("dateOf", dateOf);

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

              console.log("Galleries:"+galleries.length);

              if (galleries.length > 0)
              {
                 photo.addUnique("galleries",galleries[0]);
                 photo.save();
              }
              else
              {
                 var gallery = new Gallery();
                 gallery.set("owner",Parse.User.current());
                 gallery.set("dateOf",dateOf);

                 return gallery.save();
              }

            }).then(function(gallery) {
              //Finished new gallery save!
              photo.addUnique("galleries",gallery);
              photo.save();

            });

       })(photoObject));
    }

    return promise;

    //console.log(photo.get("takenAt"));
}).then(function() {
// Every photo was added to the proper gallery.
});

问题是当它运行时，我得到以下输出（在后端运行Express / Node.js服务器，这是控制台输出）：

I2014-10-03T19:08:24.934Z]iterator: bZJ1Ke0QXO
I2014-10-03T19:08:24.936Z]iterator: 6li2Ztxhrd
I2014-10-03T19:08:24.937Z]iterator: FfUCwgNsts
I2014-10-03T19:08:24.937Z]iterator: fJdAeqCwYW
I2014-10-03T19:08:24.939Z]iterator: ChUmgipm7d
I2014-10-03T19:08:24.942Z]iterator: 9MiTFHxLzh
I2014-10-03T19:08:24.942Z]iterator: bWZAbNiNB2
I2014-10-03T19:08:24.943Z]iterator: RQqe3NyAxK
I2014-10-03T19:08:24.991Z]Galleries:0
I2014-10-03T19:08:25.043Z]Galleries:0
I2014-10-03T19:08:25.045Z]Galleries:0
I2014-10-03T19:08:25.095Z]Galleries:0
I2014-10-03T19:08:25.146Z]Galleries:0
I2014-10-03T19:08:25.147Z]Galleries:0
I2014-10-03T19:08:25.253Z]Galleries:0
I2014-10-03T19:08:25.305Z]Galleries:0

因此，您可以看到正在创建的第一个图库在检查完所有照片后发生，问题是它在同一天创建了8个图库（样本集中的所有照片都是在同一天拍摄的）。 / p>

看起来承诺没有按照我的预期连续执行。如何强制这些调用按顺序发生，以便第二次照片查找在第一次完成创建图库后才会发生（如果需要）？

Parse.com系列链接承诺

0 个答案: