3

我的 AngularJS CRUD 应用程序通过 WebSocket 服务器处理它的信息。（这主要是为了让一个用户的更新自动推送给所有用户，而不需要大量的 HTTP 轮询）

我很早就意识到，我必须以不同于通常使用 HTTP 服务的方式设置我的服务。通常，对于我正在使用的每个模型，我都会为他们提供自己的服务来填充该特定模型。但是，这对于 Websocket 连接是不可行的，因为我不希望每个服务都有单独的连接。因此，有几个解决方案。

1）设置一个建立连接的服务，然后与将使用该服务进行特定查询的其他服务共享该连接

2）创建一个单一的、类型不可知的服务，所有需要访问连接和数据的控制器都将使用该服务。

选项 2 似乎更容易管理，并且可以跨应用程序重用，所以我开始了。那时我意识到这实际上是一个机会。我可以创建一个主对象，并在数据从请求流入时根据需要data动态创建子对象，而不是为客户端可以接收的每种类型的数据显式创建模型。myService.data因此，如果我需要更新我的模型，我只需在服务器级别更新模型，客户端已经知道如何接收它；它只需要一个知道如何使用它的控制器。

然而，这个机会带来了一个缺点。显然，因为myService.Data在创建时是一个空的、无子对象，任何想要引用其未来子对象的 Scope 都必须简单地引用对象本身。

例如，$scope.user = myService.data.user 抛出一个错误，因为该对象在声明时不存在。看来我唯一的选择是让每个控制器简单地拥有$scope.data = myservice.data，并且每个控制器的视图都必须使用 < ng-model='data'>，声明类似于{{data.user.username}}。我已经测试过了，这确实有效。

我的问题是这个；有什么方法可以让我两全其美？我可以让我的服务动态更新它的数据模型，但仍然让我的控制器只访问他们需要的部分吗？一世？直到我意识到我的所有控制器都可以访问整个数据模型之前，我感觉自己很聪明……但老实说，我无法确定这是否是一个大问题。

这是我的服务：

app.factory('WebSocketService', ['$rootScope', function ($rootScope) {
    var factory = {
        socket: null,
        data: {},
        startConnection: function () {
            //initialize Websocket
            socket = new WebSocket('ws://localhost:2012/')
            socket.onopen = function () {
              //todo: Does anything need to happen OnOpen?
            }
            socket.onclose = function () {
              //todo: Does anything need to happen OnClose?
            }
            socket.onmessage = function (event) {
                var packet = JSON.parse(event.data);
                ////Model of Packet:
                ////packet.Data: A serialised Object that contains the needed data
                ////packet.Operation: What to do with the Data
                ////packet.Model: which child object of Factory.data to use
                ////packet.Property: used by Update and Delete to find a specific object with a property who's name matches this string, and who's value matches Packet.data
                //Deserialize Data
                packet.Data = JSON.parse(packet.Data);
                //"Refresh" is used to completely reload the array 
                // of objects being stored in factory.data[packet.Model]
                // Used for GetAll commands and manual user refreshes
                if (packet.Operation == "Refresh") {
                    factory.data[packet.Model] = packet.Data
                }
                //Push is used to Add an object to an existing array of objects.  
                //The server will send this after somebody sends a successful POST command to the WebSocket Server
                if (packet.Operation == "Push") {
                    factory.data[packet.Model].push(packet.Data)
                }
                if (packet.Operation == "Splice") {
                    for (var i = 0; i < factory.data[packet.Model].length; i++) {
                        for (var j = 0; j < packet.Data.length; j++){
                            if (factory.data[packet.Model][i][packet.Property] == packet.Data[j][packet.Property]) {
                                factory.data[packet.Model].splice(i, 1);
                                i--;
                            }
                        }
                    }          
                }
                // Used to update existing objects within the Array.  Packet.Data will be an array, although in most cases it will usually only have one value.  
                if (packet.Operation == "Update") {
                    for (var i = 0; i < factory.data[packet.Model].length; i++) {
                        for (var j = 0; j < packet.Data.length; j++) {
                            if (factory.data[packet.Model][i][packet.Property] == packet.Data[j][packet.Property]) {
                                factory.data[packet.Model][i] = packet.Data[j]
                                i--;
                            }
                        }
                    }
                }
                //Sent by WebSocket Server after it has properly authenticated the user, sending the user information that it has found.  
                if (packet.Operation == "Authentication") {
                    if (packet.Data == null) {
                        //todo: Authentication Failed.  Alert User Somehow
                    }
                    else {
                        factory.data.user = packet.Data;
                        factory.data.isAuthenticated = true;
                    }

                }
                $rootScope.$digest();
            }  
        },
        stopConnection: function () {
            if (socket) {
                socket.close();
            }
        },
        //sends a serialised command to the Websocket Server according to it's API.
        //The DataObject must be serialised as a string before it can be placed into Packet object,which will also be serialised.  
        //This is because the Backend Framework is C#, which must see what Controller and Operation to use before it knows how to properly Deserialise the DataObject.
        sendPacket: function (Controller, Operation, DataObject) {
            if (typeof Controller == "string" && typeof Operation == "string") {
                var Data = JSON.stringify(DataObject);
                var Packet = { Controller: Controller, Operation: Operation, Data: Data };
                var PacketString = JSON.stringify(Packet);
                socket.send(PacketString);
            }
        }
    }
    return factory
}]);

这是一个访问用户信息的简单控制器。它实际上用在<div>Index.html 中的永久标题中，在动态之外<ng-view>。它负责启动 Websocket 连接。

App.controller("AuthenticationController", function ($scope, WebSocketService) {
    init();

    function init() {
        WebSocketService.startConnection();
    }
    //this is the ONLY way that I have found to access the Service Data.
    //$scope.user = WebSocketService.data.user doesn't work
    //$scope.user = $scope.data.user doesn't even work
    $scope.data = WebSocketService.data
});

这是使用该控制器的 HTML

    <div data-ng-controller="AuthenticationController">
        <span data-ng-model="data">{{data.user.userName}}</span>
    </div>
4

1 回答 1

1

您可以做的一件事是将data对象存储在根范围内，并在各种控制器上设置监视以监视它们需要的任何特定于控制器的键：

// The modules `run` function is called once the 
// injector is finished loading all its modules.
App.run(function($rootScope, WebSocketService) {
  WebSocketService.startConnection();
  $rootScope.socketData = WebSocketService.data;
});

// Set up a $watch in your controller
App.controller("AuthenticationController", function($scope) {
  $scope.$watch('socketData.user', function(newUser, oldUser) {
    // Assign the user when it becomes available.
    $scope.user = newUser;
  });
});
于 2013-05-21T17:21:53.293 回答