Practical ASP.NET Core SignalR: HubContext

HubContext

In this section, I’m going to cover how you can use SignalR outside of a Hub. In most asp.net core applications, you will likely want to communicate with the connect clients from within your application but outside of a Hub. You can accomplish this by using the HubContext.

For example, an ASP.NET Core MVC Controller or any other class that is instantiated by ASP.NET Core’s Dependency Injection.

This blog post is apart of a course that is a complete step-by-setup guide on how to build real-time web applications using ASP.NET Core SignalR. By the end of this course, you’ll be able to build real-world, scalable, production applications using the tools and techniques provided in this course.

If you haven’t already, check out the prior sections of this course.

  1. Course Overview
  2. ASP.NET Core SignalR Overview
  3. Basics
  4. Server Hubs

HubContext

The HubContext allows you to send messages to your connected clients. It has many of the same features to communicate with clients as when you are inside of a Hub.

In order to get an instance of the HubContext, you need to be using dependency injection by specifying you want an IHubContext<T> in the constructor. Where T is your Hub.

In the example below I’m creating an ASP.NET Core MVC Controller that is taking the IHubContext<MessageHub> injected via the constructor.

Once you have the IHubContext<T> in your controller or any class that was created by the DI container, you can access almost all of the similar methods that are on a Hub.

In this example, I’ve created a HttpPost route that will accept a string and then I’m using the Clients.All.SendAsync() to send a message to all connected clients.

Get The Course!

You’ve got several options:

  1. Check out my Practical ASP.NET Core SignalR playlist on my CodeOpinion YouTube channel.
  2. Access the full course now by enrolling for free on Teachable.
  3. Follow along with the blog post series here on CodeOpinion.com
    1. Course Overview
    2. ASP.NET Core SignalR Overview
    3. Basics
    4. Server Hubs
    5. HubContext
    6. Authorization
    7. Scaling with Redis
    8. Scaling with Azure SignalR Service

Source Code

All of the source code for this blog post and this course is available the Practical.AspNetCore.SignalR repo on GitHub.

Roundup #33: Securing SPAs, Razor Pages First Impressions, .NET OSS, Networker

Here are the things that caught my eye this week in .NET.  I’d love to hear what you found most interesting this week.  Let me know in the comments or on Twitter.

An alternative way to secure SPAs (with ASP.NET Core, OpenID Connect, OAuth 2.0 and ProxyKit)

You might have noticed the recent public discussions around how to securely build SPAs – and especially about the “weak security properties” of the OAuth 2.0 Implicit Flow. Brock has written up a good summary here.
The whole implicit vs code flow discussion isn’t particularly new – and my stance was always that, yes – getting rid of the tokens on the URL is nice – but the main problem isn’t how the tokens are transported to the browser, but rather how they are stored in the browser afterwards.

Link: https://leastprivilege.com/2019/01/18/an-alternative-way-to-secure-spas-with-asp-net-core-openid-connect-oauth-2-0-and-proxykit/

My ASP.NET Core Razor Pages First Impressions

Recently, I’ve been given the opportunity to rebuild an existing web site that is important, but not technically complex. The website has a few content-focused pages, some forms, and a single funnel. The goal with the redesign is to simplify the backend code and leverage more frontend technologies. Given the requirements, I thought it would be a perfect chance to try Razor Pages. In this post, I’ll give my first impressions, what I love about Razor Pages, and what I think could use improvement.

Link: https://www.khalidabuhakmeh.com/my-asp-net-core-razor-pages-first-impressions

Open Source .NET – 4 years later

A little over 4 years ago Microsoft announced that they were open sourcing large parts of the .NET framework and as this slide from New Features in .NET Core and ASP.NET Core 2.1 shows, the community has been contributing in a significant way

Link: https://mattwarren.org/2018/12/04/Open-Source-.Net-4-years-later

Networker

A simple to use TCP and UDP networking library for .NET, designed to be flexible, scalable and FAST.

Link: https://github.com/MarkioE/Networker

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Roundup #32: System.IO.Pipelines, Libraries vs Frameworks, Performance Profiling in Rider, Cyclomatic Complexity, Lessons from the Birth of Microservices

Here are the things that caught my eye this week in .NET.  I’d love to hear what you found most interesting this week.  Let me know in the comments or on Twitter.

High Performance IO with System.IO.Pipelines

Pipelines was born from the work the .NET Core team was doing to make it easier to do high performance IO in .NET.

In this episode, Pavel Krymets (@pakrym) and David Fowler (@davidfowl) come on the show to give us an overview of how the Pipelines programming model works, as well as give show us a few demos on how to use the API.

Link: https://www.youtube.com/watch?v=1koWtKkKb_o

Libraries vs Frameworks w/ Dennis Doomen

Dennis Doomen is on an everlasting quest for better solutions that will significantly improve the efficiency, the quality and the productivity of your software development teams.

And among other things he is the author of Fluent Assertions, an API for asserting the results of unit tests in .NET.

Link: https://6figuredev.com/podcast/episode-074-libraries-vs-frameworks-w-dennis-doomen/

Performance Profiling in Rider

If you’re an active Rider 2018.3 user or just follow our blog, you probably know that Rider just got an integrated performance profiler based on JetBrains dotTrace. Though we’ve already reviewed the profiler features on the EAP stage, the release version brings some important changes, especially concerning profiling session configuration. Read this post to learn more about the changes.

Link: https://blog.jetbrains.com/dotnet/2019/01/17/performance-profiling-rider-2018-3-whats-new/

Rider Cyclomatic Complexity Plugin

Link: https://plugins.jetbrains.com/plugin/10395-cyclomaticcomplexity

What We Got Wrong: Lessons from the Birth of Microservices

Ben Sigelman talks about what Google got wrong about microservices, the lessons learned along the way and how to apply those lessons today.

Link: https://www.youtube.com/watch?v=-pDyNsB9Zr0

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