My SignalR client is Console Application
I want to set the ConnectionId for my console application (SignalRClient)
My thought is, in my console application config file, I set the ConnectionId, say, in app.config, I set a property "MyConnectionId" with value "123-123-123-123" and that ID ("123-123-123-123") should be used as SignalRClientConnectionId instead of auto-generated GUID.
Is this possible? If so, how?
The intention behind it is, I want to identify all the clients connected to my hubs, so that, I can send the data to respective SignalRClient/ConsoleApp
Hope, I'm clear.
Thank you.
Unfortunately you cannot provide a custom ConnectionId. This ConnectionId is always generated by SignalR itself.
For your intention what you can do is store the information of your console apps with along the ConnectionID. (ex:- in a database table where columns will be console app name and ConnectionID). By doing that you can identify which ConnectionID belongs to which console application so you can identify and send them separately as you want.
Related
I have following scenario:
User request for certain resource on server, This request is long running task and very like 2~3 seconds to 10 seconds. We issue a JobTicket to user, As our user want to wait.
On receiving request we store that request in persistence storage and issue a token to user as JobTicket (GUID).
User make connection with Hub to get information about that GUID.
In Background:
We have WAS Hosted as well as Windows Service to perform some operation on that request.
On complete, WAS Hosted/Windows Service call our Web Application that job has been completed.
From there based on job Ticket we identify which user and on its connection we let user know its job has been completed.
Now we have farm of servers, we are using Windows Server On Prem ServiceBus 1.1 which is working fine, But challenge we have is that we are not able to intercept ServiceBus based backplane message broadcast and message is going to all the client. As we have farm, user intermediately may have drop connection and connected to other server based on load balancer so we need to have scale out using Service Bus as its kind of seamless to integrate and we are also using for our internal purpose in our application so we don't want to user any other mix in complex solution.
I have tried using IHubPipelineModule but still Scale out message broadcast not passing thru that, I tried to hookup SignalR code directly and debug thru it but its taking long. I don't want to mess-up something arbitrary in actual code. As I can see that in OnReceive I can see message are coming, but not able to follow further. I just need small mechanism that I can intercept broadcast message and make sure that it goes to client it intended and not all the client by wasting resources, and security concern as well.
Please help me on this issue, it's kind of stuck from last 4 days and not able to come to any solution and same time I want to go with establish pattern and don't want to fork any special build for this kind of small issues which I am sure one of you expert knows how I can do that seamlessly.
Thanks,
Shrenik
After lots of struggling and not finding straight forward way, I have found the way as below for someone else in future it might help.
Scenario:
1. Web Farm: Host External User facing Web Pages
2. Backend Process: Which is mix of WebApi, SharePoint, Windows Service etc.
User from Web Page submit some request and get a unique id as return back. Internally on receiving request, we queue that request to Service Bus using TopicClient for processing.
There are pool of Windows Service watching on Message on Service Bus using SubscriptionClient and process that message. On completion of process which can run from 5 seconds to 30 seconds and some cases even more. We need to inform client that its job done if its waiting on web page or waiting for completion notification.
In this story, We are using SignalR to push job completion notification to client.
Now my earlier problem is How I let know from windows service to web application that job is done so send notification to client who submitted request.
One way is we hosted another hub internally in web application, Windows service act as client and call web application hosted hub, and in that hub method it will call external facing hub method to propagate message to specific client who submitted request, for which we are using Single user Group.
And as we have register service bus as backplane it will propagate to other servers and then appropriate client will get notification. So this is ideal solution and should work in most cases.
In above approach we have one limitation that, how Windows Service connect to Web Client, as we donot have windows auth, but we have openid based auth with ADFS. Now in such case Web Application required special code in which provide separate userid or password for windows service to communicate or have windows authentication also allowed for that hub for service account of windows service.
I was trying and trying how to remove all this hopes between interserver communication and again management of extra security.
So I did below with simplicity, though it tooks me whole night to find our internal of SignalR. But it works:
Approach is to send message directly to ServiceBus Backplane, and as all Web Server already hooked-up with ServiceBus backplane then they will get message.
Unfortunately SignalR doesn't provide such mechanism to send message directly to Backplane. I think its on pub/sub model so they don't want somebody to hack in their system :). or its violation of their pattern, but its make sense, in my case because of different roles and security, I have simplify code as below:
Create a ServiceBusMessageBus instance in my code, Same way as Below: Though I have created separate instance and store till lifetime of Windows Service, so I don't create instance every time:
ServiceBusMessageBus serviceBusBackplane = new ServiceBusMessageBus(new DefaultDependencyResolver(), new ServiceBusScaleoutConfiguration(connectionString, appName));
Create a ClientHubInvocation Object: This is a message which actually get created in SignalR infrastructure when Backplane based message broadcast:
ClientHubInvocation hubData = new ClientHubInvocation
{
Args = new object[] { msg },
Hub = "JobStatusHub",
Method = "onJobStatus",
State = null,
};
Create a Message object which accept by ServiceBusMessageBus.Publish, Yes, so this is a method which actually get called on base class ScaleoutMessageBus.Publish. This class is actually responsible for sending message to topic and other subscribers on other server nodes. Why not use that directly. Now to create Message Object, You need following code:
Message backplaneMessage = new Message(
sourceId,
"hg-JobStatusHub." + name,
new ArraySegment(Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(hubData))));
In above second parameter is something interesting,
In case if you want to publish to all the client then syntax is "h-", in my case specific group user, so syntax is "hg-.. You can check the code here: https://github.com/SignalR/SignalR/blob/bc9412bcab0f5ef097c7dc919e3ea1b37fc8718c/src/Microsoft.AspNet.SignalR.Core/Infrastructure/PrefixHelper.cs
Publish your message to backplane directly as below:
await serviceBusBackplane.Publish(backplaneMessage);
I wish this PrefixHelper class have been public.
Remember: This is not recommended way and doent insulate from future upgrade for SignalR, as its internal they may change so any upgrade might come with small hazale to change this code. But in summary this works. Hope SignalR Team provide some mechanisam out of box to send message directly to backplane instead.
Thanks
I'm writing a Single Page Application with Durandal and I'm planning on using SignalR for some functionality. First of all, I have a top bar that listens for notifications that the server may send. The site start a connection to the "TopBarNotificationHub".
On one of the pages I want to connection to another hub as two users might edit the data on this page simultaneous and I want to notify if someone updated the data. No problem, this works fine.
But, when leaving that page I want to disconnect from ONLY the second hub, but I can't find a way to accomplish this. If I just say hub.connection.stop(); the connection to th eTopBarNotificationHub also stops (as it's shared).
Is there a way to just leave one hubproxy and let the other exist?
As this is a SPA the "shell" is never reloaded so it doesn't connect to the hub again... I might be able to force this to reconnect everytime another page disconnects from a hub, but there might be a cleaner solution...
Thanks in advance.
//J
If you use multiple hubs on a single page that's fine, but they share the same connection, so it isn't taking up more resources on the client other than receiving the updates.
Therefore to "connect and disconnect to/from a hub" you need to slightly rearchitect. If you use Groups instead of Clients on the server side you can "register" with a Hub by calling a (for example) Hub1.Register method and sticking the client in the relevant group in that method. To "deregister" you call a (for example) Hub1.DeRegister and remove the client's ConnectionId from the group in that method. Then, when you push updates to clients, you can just use the Group instead of Clients.All.
(C# assumed for server language as you didn't specify in your tag)
To add a client to the hub group: Groups.Add(Context.ConnectionId, groupNameForHub);
To remove a client from the hub group: Groups.Remove(Context.ConnectionId, id.ToString());
To broadcast to that Hub's clients: Clients.Group(groupNameForHub).clientMethodName(param1, param2);
Just to make it confusing, though, note that the group named "myGroup" in Hub1 is separate to the group named "myGroup" in Hub2.
This is the exact approach recommended in the documents (copied here in case they move/change in later versions):
Multiple Hubs
You can define multiple Hub classes in an application. When you do that, the connection is shared but groups are separate:
• All clients will use the same URL to establish a SignalR connection with your service ("/signalr" or your custom URL if you specified one), and that connection is used for all Hubs defined by the service.
There is no performance difference for multiple Hubs compared to defining all Hub functionality in a single class.
• All Hubs get the same HTTP request information.
Since all Hubs share the same connection, the only HTTP request information that the server gets is what comes in the original HTTP request that establishes the SignalR connection. If you use the connection request to pass information from the client to the server by specifying a query string, you can't provide different query strings to different Hubs. All Hubs will receive the same information.
• The generated JavaScript proxies file will contain proxies for all Hubs in one file.
For information about JavaScript proxies, see SignalR Hubs API Guide - JavaScript Client - The generated proxy and what it does for you.
• Groups are defined within Hubs.
In SignalR you can define named groups to broadcast to subsets of connected clients. Groups are maintained separately for each Hub. For example, a group named "Administrators" would include one set of clients for your ContosoChatHub class, and the same group name would refer to a different set of clients for your StockTickerHub class.
I have created a really basic hub that I get the IHubContext and call the my javascript client side method via a group so I can always push the data to the same user no matter how many diffrent connections they are on, which i pass some text to and that text is appended in a multiline textbox in the browser.
It all works really nicely. The thread will typically run long operations, often appending text reporting on the status of the operation using the hub context to call the client.
However, I wish to cater for the situation where someone would close their browser then return later the page with the textbox.
Now at the moment they would just start reciving the text from the point in the operation they connect on. How can I send a request from the client to the server to retrive all the text back from the begining of the operation?
My idea was to have a StringBuilder object that i append each line identically as the text I send to the client hub.
Then on connect of the hub call a server side function from the client which asks for the full text which can be taken from the StringBuilder object ToString();
But how can the hub know where to get the StringBuilder object from in the still executing thread?
OR
If there is a way to push it to the client instead, how can I know in the executing thread that the user has connected and send the StringBuilder ToString() to the user?
NB. I do not want to resend the full string appened every time! Only when the user has just connected and needs to catch up.
I think understanding how to do this would help understand how to deal with signalR and state on the server outside of the hub. Thank you.
Well, for starters, you should probably store this data in some kind of persistent storage (not just in an in-memory StringBuilder). Regardless of that though, what you really need to do is store the individual strings with timestamps. Then just remember the last time you saw the logical user and dump all entries since that time when they are first connecting to your Hub.
JabbR, the flagship, test bed application for SignalR, does something just like this except it just does it using message ids and asks for all message ids since the last message id the client received. Check out the Chat Hub's GetPreviousMessages for details.
I have an "enevelope" schema and a body schema and I have setup the correct properties on the "envelope" to point to the body.
I also have a property schema for promoting a value in the body message so that i can route on it.
I set up a File drop receive location and two send ports. Each send port subscribing on a different value of the promoted property. The receive location uses XmlReceive and the send ports both use XmlTransmit.
When i drop one envelope message at the Rcv location, Bts picks it up, splits it, promotes the property and my send ports pick up the relevant messages and do their thing.
File drop was fine for testing, but the real scenario is slightly different.
I want clients to submit "envelope" schemas containing multiple document elements via Wcf
So i published the envelope schema as a Wcf endpoint using the publishing wizard. Let it create the new Receive location. Wired up a Wcf client to talk to this endpoint and submitted a message.
Without changing anything on the Send ports in BizTalk I expected the same result;
However I now get a routing failure.
If i remove the extra filter in the Send port that filters on the promoted property it works, no routing failure.
So ... it would appear that the promoting of my property is not happening on the Wcf receive location.
I have checked; the Wcf receive location is using XmlReceive.
What gives?
How do i fix this?
I would guess that the namespace of your incoming message has changed as a result of changing it to use WCF.
This can cause the property promotion to no longer match the incoming message.
You can view the property promotions in the tracked messages in the BizTalk server admin tools.
I know that Session is for a single user , and application is for multi user purpose.The Data in the application object is shared. Right? Then how can access the application data from an another client.
if My concept is wrong then what's right?
A client cannot access directly from the Application object. The server will need to send data to the client (the way to do this will depend entirely on your scenario). The Application is the same as a static dictionary only that it is thread safe.
for fist one answer application object means not only for single user .the enter in application is just like a data base it will store the data we are given and new user will access on not is only user option.