I have a requirement to show email notification to receivers using SignalR. I am developing my application using MVC 4. I am a beginner and do not have much knowledge for SignalR. So far I have followed the posts below and tried to prepare a sample that can fulfill my requirement.
http://www.codeproject.com/Articles/732190/Real-Time-Web-Solution-for-Chat-by-MVC-SignalR-H
http://techbrij.com/realtime-post-comment-notifications-signalr-knockout
One of above is using knockout.js and other is not. I have followed both and am not able to meet my requirement.
Here is the code from SignalR Hub class:
public void SendEmail(Email email)
{
email.SentBy = WebSecurity.CurrentUserId;
using (NotifyEntities db = new NotifyEntities())
{
UsersContext uc = new UsersContext();
db.Emails.Add(email);
db.SaveChanges();
var ret = new
{
Message = post.Message,
SentBy = post.SentBy,
};
Clients.Caller.sendEmail(ret);
#region add to table which contain user id and email_post_id (I am sending the email to 2 users/receivers)
UsersMessage msgRel = new UsersMessage();
msgRel.EID = email.Id;
msgRel.UID = 2; //user 1
db.UsersMessages.Add(msgRel);
db.SaveChanges();
msgRel = new UsersMessage();
msgRel.EID = email.Id;
msgRel.UID = 5;//user 2
db.UsersMessages.Add(msgRel);
db.SaveChanges();
#endregion
var unread = (from ure in db.Emails.ToList()
join um in db.UsersMessages on ure.Id equals um.EID
where um.UID == WebSecurity.CurrentUserId && um.IsReaded == false
orderby ure.Id descending
select new
{
Message = pst.Message,
SentBy = pst.SentBy,
}).ToArray();
Clients.All.loadUnreadPosts(unread); //this returns unread emails of currently logged in user
Clients.All.loadPosts(ret); // this returns all emails of currently logged in user
}
}
When I do not use knockout.js then I am not able to show instant notification, it only appears on page refresh and it display to all users instead of the receivers.
When I use knockout.js the notification is showing instantly but the same issue exists that message/notification is displaying to all users.
Please help me with this. I don't know how to create group for receivers of particular email.
In order to send the notification to specific users only, you would want to use the Group functionality of SignalR. Here is some documentation on how to set it up: link
You would probably end up creating a group per user on user login or some similar action.
public async Task UserOnline(string emailAddress)
{
await Groups.Add(this.Context.ConnectionId, emailAddress);
}
Then you would want to use something like this in your signalr SendEmail hub class.
Clients.Group(emailAddress).loadUnreadPosts(unread);
Clients.Group(emailAddress).loadPosts(ret);
As a side note, I recommend going through the documentation at the link I provided. There should be no reason that you need to use knockout to get signalR to work appropriately.
EDIT
I have gotten something similar to the above working before (although I have lost that code); but I just came across this article that may actually provide a more elegant solution.
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