asp.net core signalR identity

Question

I have a uwp client application which needs to do following 3 scenarios for chat feature.

1. chat with everyone connected to the signal R hub ( public )
2. chat with MyGroup only : each user will be part of a group.
3. private chat ( 1v1 chat with other users )

I have following hub code where I somehow manage to do public and group feature.

public class ChatHub : Hub
{
    public Task SendPrivateTweet(string user, string message)
    {
        return Clients.User(user).SendAsync("ReceiveTweet", user, message);
    }

    public async Task SendTweet(string user, string message)
    {
        await Clients.All.SendAsync("ReceiveTweet", user, message);
    }


    public async Task SendTweetGroup(string groupName, string user, string message)
    {
        await Clients.Group(groupName).SendAsync("ReceiveTweet", user, message);
    }

    public async Task AddToGroup(string user, string groupName)
    {
        await Groups.AddToGroupAsync(Context.ConnectionId, groupName);

        await Clients.Group(groupName).SendAsync("EnteredOrLeft", $"{user} has joined the group {groupName}.");
    }

    public async Task RemoveFromGroup(string user, string groupName)
    {
        await Groups.RemoveFromGroupAsync(Context.ConnectionId, groupName);

        await Clients.Group(groupName).SendAsync("EnteredOrLeft", $"{user} has left the group {groupName}.");
    }
}

I have a db with users info in it and each user has a group name linked to it based on that I add each connection to their respective group.

await hubConnection.InvokeAsync("AddToGroup", user.Name, user.GroupName);

I have to do this because I do not have users logged into signalR so I cannot match their userIds with the one in my db, and that is exactly why I cannot send private message to a specific user because for that the context must have user info which it doesn't at the moment, according to docs there is some complex token bearer stuff going on and I don't know the api to popup Microsoft login for the user ( which would be ideal ).

Is there any other way how I can retain the user ids in the hub so that I can easily send a private message from client by sending the receiver user id?

I mean, can I assign a user Id from each connection at the time of connecting to the hub? which can be later on used for querying within the hub?

I can see how to do identity in a web app but can't find tutorial for doing the same in a native app like uwp: https://docs.microsoft.com/en-us/aspnet/core/security/authentication/identity?view=aspnetcore-2.2&tabs=visual-studio

Answer 1

You need to store the ConnectionId with your custom usernames. It's found as Context.ConnectionId . You'll have to handle connecting and disconnecting because the id will change between sessions.

There's an example here. Don't worry about the Identity . You can use your custom ids stored in the database. I assume since no one is logging in, you're not worried about people pretending to be someone else.

https://docs.microsoft.com/en-us/aspnet/signalr/overview/guide-to-the-api/mapping-users-to-connections#inmemory

To be honest, your question is confusing. I'm assuming you're making users type their name into a dialog box every time they connect, right? Then, just store the ConnectionId.