向特定用户问题发送 SignalR 消息。我做错了什么？

Question

首先，当我向所有客户端发送 SignalR 消息时，一切工作正常，其中：

public async Task SendMessage(GameStateModel game)
{
    UpdateExistingGame(game);

    await Clients.All.SendAsync("ReceiveMessage", game); //todo: send only to users in current game
}

在我的客户中：

public addGameStateListener = (): void => {
  this.hubConnection.on('ReceiveMessage', (message: GameState) => {
    if (message.gameId == this.game.gameState.gameId) {
      this.game.setGame(message);
    }
  });
};

现在，当我尝试将其发送给特定客户时，我正在做这样的事情：

public async Task SendMessage(GameStateModel game) //todo: SendMessageAndUpdateCachedGame(GameStateModel game)
{
    UpdateExistingGame(game);

    await SendToUsersInGame(game);
}

private async Task SendToUsersInGame(GameStateModel game)
{
    foreach (string user in game.PlayersNames)
    {
        if (!string.IsNullOrEmpty(user))
        {
            string id = await GetUserId(user);
            await Clients.User(id).SendAsync("ReceiveMessage", game);
        }
    }
}

private async Task<string> GetUserId(string user) //from auth DB
{
    return await _userService.GetUserId(user);
}

客户端代码仍然相同：

public addGameStateListener = (): void => {
  this.hubConnection.on('ReceiveMessage', (message: GameState) => {
    if (message.gameId == this.game.gameState.gameId) {
      this.game.setGame(message);
    }
  });
};

注意请注意，GetUserId 正在从数据库中检索用户 ID，但它与 Context.User.Identity.Name 相同。

而且我没有收到客户的任何通知。问题是，在documentation 中写的是，在集线器中它应该是：

public class MyHub : Hub
{
    public void Send(string userId, string message)
    {
        Clients.User(userId).send(message);
    }
}

这很令人困惑，因为没有像Send(string message) 这样的方法。我做错了什么？

更新基于on this GitHub answer，在发送个人消息时我尝试过：

foreach (string user in game.PlayersNames)
{
    if (!string.IsNullOrEmpty(user))
    {
        string id = await GetUserId(user);
        await Clients.Client(Context.ConnectionId).SendAsync("ReceiveMessage", game);
    }
}

那么现在的问题是，如何获取每个用户的个人Context.ConnectionId？

Answer 1

之前我试图解决同样的问题，所以我的客户有他的 id（在 db 和客户端相同），我添加了 if 语句，如 if(this.client.id == received.id) => do smth .它工作正常。

Answer 2

好的，我解决了这个问题。根据问题更新，Context.ConnectionId 与 Context.User.Identity.Name 不同，您只能使用 Context.ConnectionId 进行单独的消息呼叫。

所以我创建了缓存 Dictionary<string, string> 保存用户名和连接 ID：

public Dictionary<string, string> GetUserConnectionIdList()
{
    if (!_cache.TryGetValue(CacheKeys.ConnectionIdList, out Dictionary<string, string> result))
    {
        result = new Dictionary<string, string>();
        _cache.Set(CacheKeys.ConnectionIdList, result);
    }

    return result;
}

public void SetConnectionIdList(Dictionary<string, string> list)
{
    _cache.Set(CacheKeys.ConnectionIdList, list);
}

public static class CacheKeys
{
    public static string ConnectionIdList { get { return "_ConnectionIdList"; } }
}

接下来，在我的 hub 类中，OnConnectedAsync 我正在向字典中添加新用户，OnDisconnectedAsync 我从字典中删除用户：

public override async Task OnConnectedAsync()
{
    string userName = await GetUserName(Context.User.Identity.Name);
    string connectionId = Context.ConnectionId;

    Dictionary<string, string> ids = _memoryAccess.GetUserConnectionIdList();
    ids.Add(userName, connectionId);

    _memoryAccess.SetConnectionIdList(ids);
}

public override async Task OnDisconnectedAsync(Exception ex)
{
    string userName = await GetUserName(Context.User.Identity.Name);
    string userDisplay = await GetUserDisplay(Context.User.Identity.Name);
    Dictionary<string, string> ids = _memoryAccess.GetUserConnectionIdList();
    ids.Remove(userName);
    _memoryAccess.SetConnectionIdList(ids);
}

就是这样。现在我可以拨打个人电话了：

public async Task SendMessage(GameStateModel game)
{
    UpdateExistingGame(game);

    await SendToUsersInGame(game);
}

private async Task SendToUsersInGame(GameStateModel game)
{
    foreach (string user in game.PlayersNames)
    {
        if (!string.IsNullOrEmpty(user))
        {
            string id = GetConnectionId(user);
            await Clients.Client(id).SendAsync("ReceiveMessage", game);
        }
    }
}

private string GetConnectionId(string user)
{
    Dictionary<string, string> ids = _memoryAccess.GetUserConnectionIdList();
    return ids[user];
}