标签:dependency-injection asp-net c asp-net-mvc
我有一个完整的引擎,该引擎依赖于基于用户交互的抽象.这对WPF / Xamarin应用程序非常有效,因为我可以使用window / form来实现这种抽象.
将此引擎移植到ASP MVC时遇到一些问题.
这样可以显示一个简单的示例.
抽象接口(简体)
public interface IQuestionBox
{
Task<bool> ShowYesNoQuestionBox(string message);
}
对于WPF,这确实非常简单,我通过调用ShowDialog()将此接口实现为返回窗口的结果.
在一个简单的业务类中,我可以进行这种调用(简化):
public async Task<string> GetValue(IQuestionBox qbox)
{
if(await qbox.ShowYesNoQuestionBox("Question ?"))
{
return "Ok";
}
return "NOk";
}
由于HTTP处于无状态状态,我真的看不到如何在ASP中实现这种行为,因为我知道这种调用可以随域/业务需求的变化而变化.我认为应该这样做是通过返回PartialView注入弹出窗口来实现的,但是在不中断所有过程的情况下,我不知道如何做到这一点.
有人做过吗?
解决方法:
您可以创建从客户端到服务器端的Web套接字连接.并通过Web套接字请求处理前端内容.它可以实现如下:
客户端:
$app = {
uiEventsSocket : null,
initUIEventsConnection : function(url) {
//create a web socket connection
if (typeof (WebSocket) !== 'undefined') {
this.uiEventsSocket = new WebSocket(url);
} else if (typeof (MozWebSocket) !== 'undefined') {
this.uiEventsSocket = new MozWebSocket(url);
} else {
console.error('WebSockets unavailable.');
}
//notify if there is an web socket error
this.uiEventsSocket.onerror = function () {
console.error('WebSocket raised error.');
}
this.uiEventsSocket.onopen = function () {
console.log("Connection to " + url + " established");
}
//handling message from server side
this.uiEventsSocket.onmessage = function (msg) {
this._handleMessage(msg.data);
};
},
_handleMessage : function(data){
//the message should be in json format
//the next line fails if it is not
var command = JSON.parse(data);
//here is handling the request to show prompt
if (command.CommandType == 'yesNo') {
var message = command.Message;
var result = confirm(message);
//not sure that bool value will be successfully converted
this.uiEventsSocket.send(result ? "true" : "false");
}
}
}
并从ready或load事件初始化它:
window.onload = function() { $app.initUIEventsConnection(yourUrl); }
请注意,您的url应该以ws://而不是http://和wss://而不是https://开头(Web套接字和Web套接字安全).
服务器端.
Here是一篇有关如何在asp.net核心应用程序上设置Web套接字的好文章,或者您可以找到另一个.请注意,您应该将单个用户的Web套接字连接分组,如果要向具体用户发送消息,则应该为该用户的每个连接发送消息.
您应该通过AcceptWebSocketAsync()方法调用接受的每个Web套接字,然后将此Web套接字的实例添加到singleton,其中包含一组按用户分组的Web套接字连接.
以下类将用于操作命令:
public class UICommand
{
public string CommandType { get; set; }
public string Message { get; set; }
public Type ReturnType { get; set; }
}
以及用于处理套接字的完整单例代码
public class WebSocketsSingleton
{
private static WebSocketsSingleton _instance = null;
//here stored web sockets groupped by user
//you could use user Id or another marker to exactly determine the user
private Dictionary<string, List<WebSocket>> _connectedSockets;
//for a thread-safety usage
private static readonly ReaderWriterLockSlim Locker = new ReaderWriterLockSlim();
public static WebSocketsSingleton Instance {
get {
if (this._instance == null)
{
this._instance = new WebSocketsSingleton();
}
return this._instance;
}
}
private WebSocketsSingleton()
{
this._connectedSockets = new Dictionary<string, List<WebSocket>>();
}
/// <summary>
/// Adds a socket into the required collection
/// </summary>
public void AddSocket(string userName, WebSocket ws)
{
if (!this._connectedSockets.ContainsKey(userName))
{
Locker.EnterWriteLock();
try
{
this._connectedSockets.Add(userName, new List<WebSocket>());
}
finally
{
Locker.ExitWriteLock();
}
}
Locker.EnterWriteLock();
try
{
this._connectedSockets[userName].Add(ws);
}
finally
{
Locker.ExitWriteLock();
}
}
/// <summary>
/// Sends a UI command to required user
/// </summary>
public async Task<string> SendAsync(string userName, UICommand command)
{
if (this._connectedSockets.ContainsKey(userName))
{
var sendData = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(command));
foreach(var item in this._connectedSockets[userName])
{
try
{
await item.SendAsync(new ArraySegment<byte>(sendData), WebSocketMessageType.Text, true, CancellationToken.None);
}
catch (ObjectDisposedException)
{
//socket removed from front end side
}
}
var buffer = new ArraySegment<byte>(new byte[1024]);
var token = CancellationToken.None;
foreach(var item in this._connectedSockets[userName])
{
await Task.Run(async () => {
var tempResult = await item.ReceiveAsync(buffer, token);
//result received
token = new CancellationToken(true);
});
}
var resultStr = Encoding.Utf8.GetString(buffer.Array);
if (command.ReturnType == typeof(bool))
{
return resultStr.ToLower() == "true";
}
//other methods to convert result into required type
return resultStr;
}
return null;
}
}
说明:
>在通过Web套接字建立连接时,将添加
AddSocket方法
>在发送请求以显示消息时,所需的命令将传递到SendAsync方法中
>该命令将被序列化为JSON(使用Json.Net,但是您可以以您的方式进行序列化)并发送到与所需用户相关的所有套接字
>发送命令后,应用程序将等待前端方的响应
>结果将转换为所需的类型,并发送回您的IQuestionBox
在处理Web套接字时,应添加以下代码:
app.Use(async (http, next) =>
{
if (http.WebSockets.IsWebSocketRequest)
{
var webSocket = await http.WebSockets.AcceptWebSocketAsync();
var userName = HttpContext.Current.User.Identity.Name;
WebSocketsSingleton.Instance.AddSocket(userName, webSocket);
while(webSocket.State == WebSocketState.Open)
{
//waiting till it is not closed
}
//removing this web socket from the collection
}
});
而且,ShowYesNoQuestionBox的方法实现应如下所示:
public async Task<bool> ShowYesNoQuestionBox(string userName, string text)
{
var command = new UICommand
{
CommandType = "yesNo",
Message = text,
ReturnType = typeof(bool)
};
return await WebSocketsSingleton.Instance.SendAsync(string userName, command);
}
请注意,应该添加userName以防止向所有连接的用户发送相同的消息.
WebSocket应该在服务器和客户端之间创建持久连接,因此您可以简单地以两种方式发送命令.
我是Asp.Net Core的新手,所以最终的实现可能与此有所不同.
标签:dependency-injection,asp-net,c,asp-net-mvc 来源: https://codeday.me/bug/20191111/2021402.html
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