Let's say, I have an enterprise application runs on Azure Web App Service. Among 100+ pages, I have 3-5 pages needs to be served real-time. to benefit from real-time capabilities of Azure SignalR Service, I want to make clients land on my SignalR application (which runs on RignalR Service). But I couldn't find any related example-article about it. How can I invoke a Hub method outside of the code? Any other approach to solve my problem is more than welcome. My main concern here is the performance of real-time pages.
If you have an ASP.NET Core SignalR Server (i.e. you have classes deriving from Hub in your application), you can't directly send messages to clients via the Azure SignalR Service. You'd have to provide an API in your ASP.NET Core application that does that.
Azure SignalR does also support a "serverless" mode in which you don't have a Hub on the server at all. In that model, clients connect directly to the service (instead of first connecting to your app) and then you can send messages to those clients using the REST API. This is a relatively new scenario so there isn't a lot of documentation. There are some blog posts and videos online on the subject, but not a lot of documentation.
If you already have an ASP.NET Core app, I'd suggest doing this by adding a REST API to your own application that allows other services in your application to send messages by calling this API. In the implementation of this API, you can use IHubContext<T> to send the messages.