AngularFire扩展了服务问题 [英] AngularFire extending the service issue

问题描述

我一直在寻找Synchronized Arrays的文档 https://www.firebase.com/docs/web/libraries/angular/api.html#angularfire-extending-the-services 和 https://www.firebase.com/docs/web/libraries/angular/guide/ extensions-services.html＃section-firebasearray

我使用的是Firebase 2.2.7版本和AngularFire 1.1.2版本。 b

使用下面的代码，我很难识别$$已移除的事件。

  .factory （ExtendedCourseList，[$ firebaseArray，function（$ firebaseArray）{
 //创建一个基于$ firebaseArray的新服务
 ExtendedCourseList = $ firebaseArray。$ extend（{
 $ $ added：function（dataSnapshot，prevChild）{
 var course = d ataSnapshot.val（）; 
 var course_key = dataSnapshot.key（）; 
 console.log（new course）; 
回报当然; 
}，
 $$ removed：function（snap）{
 console.log（removed）; 
返回true; 
} 
}）; 
返回函数（listRef）{
 return new ExtendedCourseList（listRef）; （CompanyRefObj，function（CompanyRef）{
 // CompanyRef是一个包含url字符串的常量
 var ref = new Firebase（CompanyRef）; 
 return ref; 
}）
 $ b $ .factory（'CourseList'，function（localstorage，$ rootScope，ExtendedCourseList，CompanyRefObj）{
 var companyID = localstorage.get（company）; 
 $ rootScope.courseList = ExtendedCourseList（CompanyRefObj.child（companyID）.child（courses））; 
）
  

如果我运行这个代码，只会触发$$添加的事件。为了模拟移除事件，我使用Firebase中的Web界面来显示数据，在那里我按下删除按钮并接受永久删除的数据。

另外，如果我删除$$去掉的函数，当记录被删除时，扩展服务仍然不会同步。如果我修改我的代码使用$ firebaseArray而不是扩展服务（如上所示），添加和删除事件将被识别。

$ b $

  .factory（'CourseList'，function（localstorage，$ rootScope，$ firebaseArray，CompanyRefObj）{
 var companyID = localstorage.get（company）; 
 $ rootScope.courseList = $ firebaseArray（CompanyRefObj.child（companyID）.child（courses））; 
）
  

最后，有没有错误的做法会导致某些扩展函数无法工作？

已解决

  $$新增：function（dataSnapshot，prevChild） {
 var course = dataSnapshot.val（）; 
 var course_key = dataSnapshot.key（）; 
 //在
课程下修改$ id = course_key; 
 //修改结束
 console.log（new course）; 
回报当然; 
 
  

解决方案

=https://github.com/firebase/angularfire/issues/638 =nofollow> firebase / angularfire github上的问题我收到了一个答案，解决了我的问题。当 $$ added 被提供的代码覆盖时， $ firebaseArray 也失去了内部记录 $ ID 。

添加以下代码行： course。$ id = course_key; 在返回课程之前，使AngularFire识别出该记录已从服务器中删除。

I've been looking at the documentation for Synchronized Arrays https://www.firebase.com/docs/web/libraries/angular/api.html#angularfire-extending-the-services and https://www.firebase.com/docs/web/libraries/angular/guide/extending-services.html#section-firebasearray

I'm using Firebase version 2.2.7 and AngularFire version 1.1.2

Using the code below, I'm having trouble recognizing $$removed events.

.factory("ExtendedCourseList", ["$firebaseArray",  function($firebaseArray) {
  // create a new service based on $firebaseArray
  var ExtendedCourseList= $firebaseArray.$extend({
    $$added: function(dataSnapshot, prevChild){
        var course = dataSnapshot.val();
        var course_key = dataSnapshot.key();
        console.log("new course");
        return course;
    },
    $$removed: function(snap){
        console.log("removed");
        return true;
    }
  });
  return function(listRef) {      
    return new ExtendedCourseList(listRef);
  } 
}]) 

.factory("CompanyRefObj", function(CompanyRef) {
  //CompanyRef is a constant containing the url string  
  var ref = new Firebase(CompanyRef);
  return ref;
})

.factory('CourseList', function (localstorage,$rootScope,ExtendedCourseList,CompanyRefObj) {
    var companyID = localstorage.get("company");   
    $rootScope.courseList = ExtendedCourseList(CompanyRefObj.child(companyID).child("courses")); 
)

If I run this code, only the $$added events will be triggered. To simulate the remove events I use the web-interface at Firebase to display data, where I press the remove button and accept the data being deleted permanently.

Additionally, if I delete the $$removed function, the extended service still won't synchronize when a record is deleted.

If I modify my code to use the $firebaseArray instead of extending the service (as seen above) both add and remove events will be recognized.

 .factory('CourseList', function (localstorage,$rootScope,$firebaseArray,CompanyRefObj) {
    var companyID = localstorage.get("company");   
    $rootScope.courseList = $firebaseArray(CompanyRefObj.child(companyID).child("courses")); 
)

Finally, are there any bad practices I've missed that can cause some of the extended functions to not work?

Solved

$$added: function(dataSnapshot, prevChild){
    var course = dataSnapshot.val();
    var course_key = dataSnapshot.key();
    //Modified below
    course.$id = course_key;
    //End of modification
    console.log("new course");
    return course;
}

解决方案

After posting about the issue at firebase/angularfire github I received an answer that solved my issue. When $$added got overridden by the code provided, the $firebaseArray also lost its internal record $id.

Adding this line of code: course.$id = course_key; before returning the course, made AngularFire recognize when the record was removed from the server.

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