使用 Angular 在 Firebase 中保存结构化数据

我了解储蓄的概念和最佳实践结构化数据 https://www.firebase.com/docs/web/guide/structuring-data.html在 firebase 中，但我不清楚如何将数据实际保存到多个位置并提供所需的交叉引用。

{
  articles: {
    -KBX5TurV9uJTeiR26-N: {
       title: 'post title 1',
       body: 'post body goes here',
       imagesRef: {
          -KBX5XOYASP7h2ZPOKmg: true
       }
    },
    -KCe7cy6QC29WRYap0D1: {
       title: 'post title 2',
       body: 'post body goes here',
       imagesRef: {
          -KBX5XOYASP7h2ZPOKmg: true
       }
    }
  }
  images: {
    -KBX5XOYASP7h2ZPOKmg: {
       image: 'data:image/gif;base64,R0lGODlhZABkAOYAAPj4...',
       articlesRef: {
          -KBX5TurV9uJTeiR26-N: true,
          -KCe7cy6QC29WRYap0D1: true
       }
    }
  }
}

上面的模式是我想要的一个例子。在提交由标题、正文和图像字段组成的表单时，我需要将标题和正文发布到articles对象，然后将图像发布到images对象，然后使用交叉引用更新imagesRef和articlesRef对象。在 Angular 中解决这个问题的最佳方法是什么？我也有 Angularfire 作为项目的一部分。

我是 Angular 和 Firebase 的新手，但我认为我需要写两篇文章，一篇文章，一篇图片，以保存它们并生成唯一的 id。然后，我需要知道如何等待两者都成功，获取唯一的 id，并对两个对象进行更新以保存交叉引用。这是我到目前为止所拥有的，但不知道如何进一步......

     $scope.AddPost = function(){

        var ref = new Firebase(FIREBASE_URI);
        var newArticleRef = ref.child('articles').push();
        var newArticleKey = newArticleRef.key();

        // Create the data we want to update
        var addNewPost = {};
        addNewPost["articles/" + newArticleKey] = {
            title:   $scope.article.title,
            post:    $scope.article.post
        };

        if ($scope.image) {

            var newImageRef = ref.child('images').push();
            var newImageKey = newImageRef.key();

            // Add image...
            addNewPost['images/' + newImageKey] = {
                image: $scope.image
            };

            //Add article ref...
            addNewPost['images/' + newImageKey + '/articles/' + newArticleKey] = true;

            //Add cross ref to article...
            addNewPost['articles/' + newArticleKey + '/image/' + newImageKey] = true;

        }


        // Do a deep-path update
        ref.update(addNewPost, function(error) {
                if (error) {
                    console.log("Error:", error);
                }
        });

    });

UPDATE:我更新了代码示例以利用多地点更新 https://www.firebase.com/blog/2015-09-24-atomic-writes-and-more.html和扇出方法 https://www.firebase.com/blog/2015-10-07-how-to-keep-your-data-consistent.html，但我在保存时遇到错误...

Error: Firebase.update failed: First argument contains a path /images/-KCpx-Pj9oMM-EWN9irS that is ancestor of another path /images/-KCpx-Pj9oMM-EWN9irS/articles/-KCpx-Pj9oMM-EWN9irR
at Error (native)
at ig (http://localhost:8000/app/assets/js/plugins.js:430:390)
at jg (http://localhost:8000/app/assets/js/plugins.js:431:383)
at X.update (http://localhost:8000/app/assets/js/plugins.js:564:369)
at r.$scope.AddPost (http://localhost:8000/app/assets/js/app.js:171:17)
at fn (eval at <anonymous> (http://localhost:8000/app/assets/js/plugins.js:216:110), <anonymous>:4:212)
at e (http://localhost:8000/app/assets/js/plugins.js:257:177)
at r.$eval (http://localhost:8000/app/assets/js/plugins.js:133:446)
at r.$apply (http://localhost:8000/app/assets/js/plugins.js:134:175)
at r.scopePrototype.$apply (chrome-extension://ighdmehidhipcmcojjgiloacoafjmpfk/dist/hint.js:1427:22)

WARNING:我尝试了以下方法。它创建了一个对象，并且没有触发 JS 错误，但它清除了我的数据库，只留下新创建的对象。没有损失太多，因为我现在只是在运行一些测试，但我认为我应该警告其他人。不要这样做...

        addNewPost.Articles = {};
        addNewPost.Articles[newArticleKey] = {};
        addNewPost.Articles[newArticleKey].title = $scope.article.title;
        addNewPost.Articles[newArticleKey].post = $scope.article.post;

        var newImageRef = ref.child('images').push();
        var newImageKey = newImageRef.key();

        addNewPost.images = {};
        addNewPost.images[newImageKey] = {};
        addNewPost.images[newImageKey].image = $scope.image;
        addNewPost.images[newImageKey].articles = {};
        addNewPost.images[newImageKey].articles[newArticleKey] = true;

        addNewPost.Articles[newArticleKey].image = {};
        addNewPost.Articles[newArticleKey].image[newImageKey] = true;

不确定这是最好的答案，但我发现以下内容对我有用。它利用了 Frank van Puffelen 的建议，即使用多位置更新。以下代码设置为支持添加新图像、使用现有图像或根本不使用图像。我认为这同样适用于类别、标签或用户中的任何元数据。

    .controller('AddPostController', ['$scope','$firebaseArray','FIREBASE_URI',
    function($scope,$firebaseArray,FIREBASE_URI) {

        var ref = new Firebase(FIREBASE_URI);

        $scope.AddPost = function(){

            var newArticleRef = ref.child('articles').push();
            var newArticleKey = newArticleRef.key();

            var newImageRef = ref.child('images').push();
            var newImageKey = newImageRef.key();

            // Create the data we want to update
            var addNewPost = {};

            // Add new article...
            addNewPost["articles/" + newArticleKey] = {
                title:   $scope.article.title,
                post:    $scope.article.post,
                emailId: user,
                '.priority': user
            };

            if ($scope.image) {

                // Add new image reference to new article...
                addNewPost["articles/" + newArticleKey].image = {};
                addNewPost["articles/" + newArticleKey].image[newImageKey] = true;

                // Add new image...
                addNewPost['images/' + newImageKey] = {
                    image: $scope.image,
                    emailId: user,
                    '.priority': user
                };

                // Add article reference to new image...
                addNewPost['images/' + newImageKey].articles = {};
                addNewPost['images/' + newImageKey].articles[newArticleKey] = true;

            } else if ($scope.article.image) {

                // Add existing image reference to article...
                addNewPost["articles/" + newArticleKey].image = {};
                addNewPost["articles/" + newArticleKey].image[$scope.article.image] = true;

                // Add new article reference to existing image...
                addNewPost['images/' + $scope.article.image + '/articles/' + newArticleKey] = true;

            }

            // Do a deep-path update
            ref.update(addNewPost, function(error) {
                if (error) {
                    console.log("Error:", error);
                }
            });

        };

    }]);