I am doing my first tests with SignalR. I am toying with chat messages, but that's only a first step to replace all the polling from client to server which I have today on my site.
I have a lot of scenarios where I want to notify certain users either by their login or by their ID. The idea is that I am adding each user to two groups as soon as he connects. I do this in OnConnected and that event is called.
When I send a chat message, I have two modes: either public or personal. If it is personal the sender is notified and the recipient should be notified. The sender gets a message but the group never does. It seems to be impossible to found out how many members a group has.
Any ideas what's going wrong here?
public class GlobalHub:Hub
{
private Users user;
private void AuthenticateUser()
{
var ydc = new MyDataContext();
user = ydc.Users.First(u => u.Login == HttpContext.Current.User.Identity.Name);
}
public override Task OnConnected()
{
var ydc = new MyDataContext();
user = ydc.Users.First(u => u.Login == HttpContext.Current.User.Identity.Name);
Groups.Add(Context.ConnectionId, user.Login);
Groups.Add(Context.ConnectionId, user.ID.ToString());
return base.OnConnected();
}
public void SendChatMessage(string message, string recipient)
{
AuthenticateUser();
var cm = ChatController.AddChatMessage(user.Login, user.ID, recipient, tmessage);
if (recipient != "")
{
Clients.Caller.NewMessage(cm);
Clients.Group(recipient).NewMessage(cm);
}
else
{
Clients.All.NewMessage(cm);
}
}
}
It looks like that Groups.Add does not immediately join the connection to the group, but instead returns a Task, that needs to be started. Try returning the result of Groups.Add as result of OnConnectedMethod.
See also more detailed explanation at: https://stackoverflow.com/a/15469038/174638
Related
I'm new to signalr and created a project with this sample to get the number of users on a specific website: Tutorial
This is running fine. My goal is to access the website only by one user, if a second user want to open the page he should be redirected. How can I do this?
If I check the users on the page and redirect if there are more than one then all users get redirected. Ok that what signalr should do.
userActivity.client.updateUsersOnlineCount = function (count) {
// Add the message to the page.
$('#usersCount').text(count);
if (count > 1) { window.document.location.href = "OPL.aspx"; }
};
How can I store the count in a datatype which I can access from code behind in the .cs? Thanks
For this, you need two client methods. The updateUsersOnlineCount have one job, which is to update users online for all to see. Then you need a second client side method called something like redirectTheUser to redirect the user.
In your SignalR hub, you would implement the OnConnected, OnReconnected, OnDisconnected events, to store (keep track of) the connection Ids, and when the count reaches a certain threshold, send the updateUsersOnlineCount to all clients with Clients.All.updateUsersOnlineCount(msg), but send the message withClients.Client(connectionId).redirectTheUser()` for all users above the threshold.
To illustrate:
public override Task OnConnected()
{
string name = Context.User.Identity.Name;
_connections.Add(name, Context.ConnectionId);
// send to all above threshold
if(_connections.Count > threshold)
SendRedirect(_connections.Skip(threshold));
return base.OnConnected();
}
public override Task OnDisconnected(bool stopCalled)
{
string name = Context.User.Identity.Name;
_connections.Remove(name, Context.ConnectionId);
return base.OnDisconnected(stopCalled);
}
public override Task OnReconnected()
{
string name = Context.User.Identity.Name;
if (!_connections.GetConnections(name).Contains(Context.ConnectionId))
{
_connections.Add(name, Context.ConnectionId);
// send to all above threshold
if(_connections.Count > threshold)
SendRedirect(_connections.Skip(threshold));
}
return base.OnReconnected();
}
private void SendRedirect(IEnumerable<string> connectionIds)
{
foreach (var connectionId in connectionIds)
{
Clients.Client(connectionId).redirectTheUser();
}
}
I need to implement chat on my web project. How to implement it on one page - there are many articles about it. But I need to have ability :
1. Notify other users, that somebody logged to site (on any page, not only on chat page)
2. Notify other users, that somebody logout
So, I have the following code of hub:
public void Connect()
{
try
{
var id = Context.ConnectionId;
string username = Context.User.Identity.Name;
var currentUser = connectedUsers.Where(p => p.Username == username).FirstOrDefault();
if (currentUser == null)
{
AddNewUserToCollection();
}
else
{
// update ConnectionId for sure (connection id is changed sometimes (probably if user is logged out and login again))
if (currentUser.ConnectionId != id)
{
var companyId = _chatRepository.GetCompanyIdOfUser(username); // throws exception if companyId is null
Groups.Remove(currentUser.ConnectionId, companyId.ToString());
Groups.Add(id, companyId.ToString());
currentUser.ConnectionId = id;
//Clients.Group(companyId.ToString()).onNewUserConnected(username);
}
}
}
catch(InvalidCompanyException c_ex)
{
Clients.Client(Context.ConnectionId).onErrorMessage($"User '{c_ex.Username}' does not exist");
}
}
public void Disconnect()
{
string username = Context.User.Identity.Name;
var item = connectedUsers.Where(p => p.Username == username).FirstOrDefault();
if (item != null)
{
connectedUsers.Remove(item);
Groups.Remove(item.ConnectionId, item.CompanyID.ToString());
Clients.Group(item.CompanyID.ToString()).onUserDisconnected(item.Username);
}
}
public override Task OnDisconnected(bool stopCalled)
{
var item = connectedUsers.Where(p => p.ConnectionId == Context.ConnectionId).FirstOrDefault();
if (item != null)
{
connectedUsers.Remove(item);
Groups.Remove(item.ConnectionId, item.CompanyID.ToString());
Clients.Group(item.CompanyID.ToString()).onUserDisconnected(item.Username);
}
return base.OnDisconnected(stopCalled);
}
and I added the following code to _layout.cshtml:
<script>
$(document).ready(function () {
var chat = $.connection.chatHub;
$.connection.hub.start().done(function () {
chat.server.connect();
});
});
</script>
to notify other users, that the current user is logged. But debugger says, that pair OnDisconnected/Connect is called every time, when user reload page (go thru pages) with different connectionId. When I remove this client code - that pair is not called. How to implement it correctly, to notify other users, that somebody is online, but without reconnect each time?
Since you have the connect() call in a razor (_layout.cshtml) page, you will effectively be disconnecting/connecting on every post back (page load).
The scenario you're trying to use is best in a SPA (or AJAX) scenario where navigation is handled asynchronously by client side JavaScript. Your current setup is refreshing the screen, reloading the JavaScript, re-running the document ready() function with each server rendered navigation.
Another alternative is to use the client's actual user Id, and pass that to the server.connect(id) method. Then use this user Id to track the user activity instead of the hub ConnectionId.
Is it possible to use the IUserIDProvider instead of ConnectionID when working with Groups? I have already found an answer here, but that concerns the SignalR 1.0 version. I wonder, whether things have changed in 2.0.
So far, I was using the conventional
Groups.Add(Context.ConnectionId, "groupName");
However, it was difficult to keep track of the connected users when their connectionID was changed (the client is a Xamarin Android app and somehow, reconnection always resulted in creation of a new ConnectionID). Thus, when the client is connecting, I have added a header:
public async Task<bool> Login(int waitMilis, string name)
{
var cts = new CancellationTokenSource();
try
{
cts.CancelAfter(waitMilis);
_connection.Headers.Add("userName", name);
await _connection.Start();
return true;
}
catch(Exception ex)
{
CallFailure(ex);
return false;
}
}
And on server side, implemented the IUserIdProvider:
public class MyUserProvider : IUserIdProvider
{
public string GetUserId(IRequest request)
{
if (request == null)
throw new ArgumentNullException("request");
else if (request.Headers != null && request.Headers["userName"] != null)
return request.Headers["userName"].ToString();
else return null;
}
}
Now, I would like to do something like
Groups.Add("userName", "groupName");
but the Add method does not have an overload for IUserIdProvider. So, is there a possibility to combine the IUserIdProvider and working with Groups, or am I stuck to creating a ConcurrentDictionary and then calling this?
foreach(User user in group.Users)
{
Clients.User(user.Name).SendMessage(message,
group.LastUpdateIndex
);
}
It ruins the whole beauty and simplicity of the SignalR code :-/
Unfortunately, there isn't currently a method like Groups.Add("userName", "groupName"); in SignalR.
I suggest adding users to their appropriate group(s) in OnConnected:
public class MyHub : Hub
{
public override async Task OnConnected()
{
var userName = MyUserHelper.GetUserId(Context.Request);
foreach (var groupName in GroupManager.GetJoinedGroups(userName))
{
await Groups.Add(Context.ConnectionId, groupName);
}
}
// ...
}
If you need to add an already connected user to a group, then you will likely need to send a message to the user using something like Clients.User(userName).joinGroup(groupName). Each client with userName could then call the appropriate hub method to join groupName.
I’m trying to build a chat apps whereby users id are represented by their auto generated signalR connection id. On page refresh, the connection id changes when a new connection is instantiated. Is there a way to persist the state of the connection id of a user until the browser session is ended (i.e until he ends his session on client).
Any guide or documentation? It really would help.
i am new in signalr. so trying to know many things searching Google. from this url i got a similar snippet http://kevgriffin.com/maintaining-signalr-connectionids-across-page-instances/
they are saying it is possible. the problem is signalr often create a new connection id if we referesh the page. i want to prevent this but how.......
this code snippet.
public class MyConnectionFactory : IConnectionIdFactory
{
public string CreateConnectionId(IRequest request)
{
if (request.Cookies["srconnectionid"] != null)
{
return request.Cookies["srconnectionid"];
}
return Guid.NewGuid().ToString();
}
}
$.connection.hub.start().done(function () {
alert("Connected!");
var myClientId = $.connection.hub.id;
setCookie("srconnectionid", myClientId);
});
function setCookie(cName, value, exdays) {
var exdate = new Date();
exdate.setDate(exdate.getDate() + exdays);
var c_value = escape(value) + ((exdays == null) ? "" : "; expires=" + exdate.toUTCString());
document.cookie = cName + "=" + c_value;
}
my doubt is does it work in all signalr version? if not then how to handle it in new version specially for not generate a new connection id if page gets refreshed. looking for suggestion.
if we work with Persistent connection class instead of hub then what happen.....in this case connection id will persist if we refresh the page at client side? please guide.
thanks
SignalR allows you to send messages to a user via their IPrincipal.Identity.Name. Just use Clients.User(userName) instead of Clients.Client(connectionId).
If you for some reason cannot address a user using their IPrincipal.Identity.Name you could create your own IUserIdProvider. This is the replacement for IConnectionIdFactory which no longer exists in SignalR >= 1.0.0.
The equivalent IUserIdProvider would look like this:
public class MyConnectionFactory : IUserIdProvider
{
public string GetUserId(IRequest request)
{
if (request.Cookies["srconnectionid"] != null)
{
return request.Cookies["srconnectionid"];
}
return Guid.NewGuid().ToString();
}
}
public class Startup
{
public void Configuration(IAppBuilder app)
{
var idProvider = new MyConnectionFactory();
GlobalHost.DependencyResolver.Register(typeof(IUserIdProvider), () => idProvider);
app.MapSignalR();
}
}
public class MyHub : Hub
{
public Task Send(string userName, string message)
{
return Clients.User(userName).receive(message);
}
}
It would be really trivial to spoof a user given this MyConnectionFactory. You could make it more secure by using an HMAC.
Ideally you would just use the default IUserIdProvider which retrieves the user ID from IRequest.User.Identity.Name.
The user id provider doesn't work, because the connection id doesn't come from it. I implemented a solution (https://weblogs.asp.net/ricardoperes/persisting-signalr-connections-across-page-reloads) that uses a pseudo-session id stored in session storage. Every SignalR connection id is then mapped to this pseudo-session id.
In the latest version of Asp.Net SignalR, was added a new way of sending a message to a specific user, using the interface "IUserIdProvider".
public interface IUserIdProvider
{
string GetUserId(IRequest request);
}
public class MyHub : Hub
{
public void Send(string userId, string message)
{
Clients.User(userId).send(message);
}
}
My question is: How do I know to whom I am sending my message? The explanation of this new method is very superficial. And the draft Statement of SignalR 2.0.0 with this bug and does not compile. Has anyone implemented this feature?
More Info : http://www.asp.net/signalr/overview/signalr-20/hubs-api/mapping-users-to-connections#IUserIdProvider
Hugs.
SignalR provides ConnectionId for each connection. To find which connection belongs to whom (the user), we need to create a mapping between the connection and the user. This depends on how you identify a user in your application.
In SignalR 2.0, this is done by using the inbuilt IPrincipal.Identity.Name, which is the logged in user identifier as set during the ASP.NET authentication.
However, you may need to map the connection with the user using a different identifier instead of using the Identity.Name. For this purpose this new provider can be used with your custom implementation for mapping user with the connection.
Example of Mapping SignalR Users to Connections using IUserIdProvider
Lets assume our application uses a userId to identify each user. Now, we need to send message to a specific user. We have userId and message, but SignalR must also know the mapping between our userId and the connection.
To achieve this, first we need to create a new class which implements IUserIdProvider:
public class CustomUserIdProvider : IUserIdProvider
{
public string GetUserId(IRequest request)
{
// your logic to fetch a user identifier goes here.
// for example:
var userId = MyCustomUserClass.FindUserId(request.User.Identity.Name);
return userId.ToString();
}
}
The second step is to tell SignalR to use our CustomUserIdProvider instead of the default implementation. This can be done in the Startup.cs while initializing the hub configuration:
public class Startup
{
public void Configuration(IAppBuilder app)
{
var idProvider = new CustomUserIdProvider();
GlobalHost.DependencyResolver.Register(typeof(IUserIdProvider), () => idProvider);
// Any connection or hub wire up and configuration should go here
app.MapSignalR();
}
}
Now, you can send message to a specific user using his userId as mentioned in the documentation, like:
public class MyHub : Hub
{
public void Send(string userId, string message)
{
Clients.User(userId).send(message);
}
}
Here's a start.. Open to suggestions/improvements.
Server
public class ChatHub : Hub
{
public void SendChatMessage(string who, string message)
{
string name = Context.User.Identity.Name;
Clients.Group(name).addChatMessage(name, message);
Clients.Group("2#2.com").addChatMessage(name, message);
}
public override Task OnConnected()
{
string name = Context.User.Identity.Name;
Groups.Add(Context.ConnectionId, name);
return base.OnConnected();
}
}
JavaScript
(Notice how addChatMessage and sendChatMessage are also methods in the server code above)
$(function () {
// Declare a proxy to reference the hub.
var chat = $.connection.chatHub;
// Create a function that the hub can call to broadcast messages.
chat.client.addChatMessage = function (who, message) {
// Html encode display name and message.
var encodedName = $('<div />').text(who).html();
var encodedMsg = $('<div />').text(message).html();
// Add the message to the page.
$('#chat').append('<li><strong>' + encodedName
+ '</strong>: ' + encodedMsg + '</li>');
};
// Start the connection.
$.connection.hub.start().done(function () {
$('#sendmessage').click(function () {
// Call the Send method on the hub.
chat.server.sendChatMessage($('#displayname').val(), $('#message').val());
// Clear text box and reset focus for next comment.
$('#message').val('').focus();
});
});
});
Testing
This is how use SignarR in order to target a specific user (without using any provider):
private static ConcurrentDictionary<string, string> clients = new ConcurrentDictionary<string, string>();
public string Login(string username)
{
clients.TryAdd(Context.ConnectionId, username);
return username;
}
// The variable 'contextIdClient' is equal to Context.ConnectionId of the user,
// once logged in. You have to store that 'id' inside a dictionaty for example.
Clients.Client(contextIdClient).send("Hello!");
Look at SignalR Tests for the feature.
Test "SendToUser" takes automatically the user identity passed by using a regular owin authentication library.
The scenario is you have a user who has connected from multiple devices/browsers and you want to push a message to all his active connections.
Old thread, but just came across this in a sample:
services.AddSignalR()
.AddAzureSignalR(options =>
{
options.ClaimsProvider = context => new[]
{
new Claim(ClaimTypes.NameIdentifier, context.Request.Query["username"])
};
});
For anyone trying to do this in asp.net core. You can use claims.
public class CustomEmailProvider : IUserIdProvider
{
public virtual string GetUserId(HubConnectionContext connection)
{
return connection.User?.FindFirst(ClaimTypes.Email)?.Value;
}
}
Any identifier can be used, but it must be unique. If you use a name identifier for example, it means if there are multiple users with the same name as the recipient, the message would be delivered to them as well. I have chosen email because it is unique to every user.
Then register the service in the startup class.
services.AddSingleton<IUserIdProvider, CustomEmailProvider>();
Next. Add the claims during user registration.
var result = await _userManager.CreateAsync(user, Model.Password);
if (result.Succeeded)
{
await _userManager.AddClaimAsync(user, new Claim(ClaimTypes.Email, Model.Email));
}
To send message to the specific user.
public class ChatHub : Hub
{
public async Task SendMessage(string receiver, string message)
{
await Clients.User(receiver).SendAsync("ReceiveMessage", message);
}
}
Note: The message sender won't be notified the message is sent. If you want a notification on the sender's end. Change the SendMessage method to this.
public async Task SendMessage(string sender, string receiver, string message)
{
await Clients.Users(sender, receiver).SendAsync("ReceiveMessage", message);
}
These steps are only necessary if you need to change the default identifier. Otherwise, skip to the last step where you can simply send messages by passing userIds or connectionIds to SendMessage. For more