SignalR | SignalR Core support for Microsoft ASP.NET Core Blazor | Frontend Framework library

Well I had only half of the solution implemented.

What fixed it for me was adding this to BOTH the common AND iOS projects. Not only the common project.

Browsers do not support headers for websockets, therefore the bearer token has to be added as query string parameter. We hit the maximum length for URLs due to the length of our bearer token. We could shorten our token or use a reference token, see also: https://github.com/aspnet/SignalR/issues/1266

Hope this helps others as well.

If any one looking for the solution. I think the error happens when multiple threads are working together we solved it in a way instead of returning Task Process we changed the method to.

Here is the solution described again, maybe a little bit more convenient:

To fix this problem, I changed in the site-configuration (/etc/nginx/sites-available) of nginx the following variables:

You can send the ID down to the clients using context.Clients.User(...) or context.Clients.All(). Then in JavaScript, read the ID and compare it to what's on the page. If it's a match, carry out some action; else ignore.

As an example, let's say your app's processing a specific record on an edit screen. The record ID is on the page as a form field. You send a SignalR message down from C# with the ID. You do a comparison in JavaScript between the ID and the form field value; if they match, you display a toaster message, perform other processing, etc.

Using a stream as described in the Stream from JavaScript to .NET solved my problem.

From Microsoft docs:

In JavaScript:

You have to use Reflection here as HubEndpointRouteBuilderExtensions class doesn't provide a none-generic version of MapHub method. Below code should work for your scenario.

The bug was reported and fixed here in library repository: https://github.com/reactiveui/ReactiveUI/issues/3091

SignalR for Flutter uses web sockets and SSE to receive messages from the SignalR service. If the app was terminated because the user restarted their phone or the OS shut down the app to save battery, these push notifications would not be received by the app.

To overcome this, app developers (and SignalR) have to use FCM on Android, and APNs on iOS (or FCM which will also use APNs on iOS). All other approaches will be more limited because the operating systems do not allow users to keep background processes running the entire time. This was actually allowed years ago, but the operating systems have made these changes to save the user battery - they enforce that all apps go through the same push notification medium - FCM on Android, APNs on iOS.

SignalR for Flutter uses neither FCM nor APNs. At it's current state, SignalR is not well suited for Android or iOS - take a look at the comments with people struggling with similar problems to you on How to use signalr in Android.

The simplest / easiest way to get started is to use Firebase Cloud Messaging.

• On Android, it will be used directly to send messages to devices, and
• on iOS, FCM will use APNs to reach devices reliably

Caveat: On Android, there is a more complicated alternative called unifiedpush, but the limitations include showing a notification to the user at all times to handle background notifications.

My analysis: This is all done based on my quick investigation by reading the pubspec.yaml, the GitHub issues on the original repo, the SignalR documentation, and some experience implementing Push Notifications for Flutter.

Disclosure: I just released a push notification library 2 days ago called push which would be well suited to these types of Push Notification packages making the transformation to using FCM on Android and APNs on iOS. However, as an app developer, in most cases, you should use firebase_messaging, not push.