SignalR is an ASP.NET library for real-time applications. It uses the WebSockets API:

The WebSocket API is an advanced technology that makes it possible to open a two-way interactive communication session between the user’s browser and a server. With this API, you can send messages to a server and receive event-driven responses without having to poll the server for a reply. The WebSocket API (WebSockets) - MDN

SignalR comes pre instal with ASP.NET Core 2.1. If you don’t have .NET core SDK on your machine, you can instal this one from the microsoft website

I build a small demo using SignalR with Vue.js:

SignalR-Vuejs–Demo - Github

demo

Create a new .NET core MVC project

Create a new .NET core MVC project.

If you are using the terminal run:

dotnet new mvc

Set up our hub

First, we need to create a hub. The hub is a class used for persistent connections between the client and the server.

At the root of our project lets create a ChatHub.cs:

using Microsoft.AspNetCore.SignalR;
using System.Threading.Tasks;

namespace signalrChatApp
{
  public class ChatHub : Hub
  {
    public async Task SendMessage(string user, string message)
    {
      await Clients.All.SendAsync("ReceiveMessage", user, message);
    }
  }
}

In Startup.cs

//...
using signalrChatApp;

//...

namespace MyApp
{
  public class Startup
  {
    //...
    public void ConfigureServices(IServiceCollection services)
    {
      //...
      services.AddSignalR();
    }

    //...

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
      //...
      app.UseSignalR(routes =>
      {
        routes.MapHub<ChatHub>("/chatHub");
      });
    }
  }
}

Set up our front end with vue.js

We are going to use the Views/Home/Index.cshtml file to make our demo, I got rid of all the unused markup in this file and the _lautout.cshtml as well

Add our dependencies

First, we need the @aspnet/signalr package. You can download it from npm

npm install @aspnet/signalr

Copy the file in node_modules/@sapnet/signalr/dist/browser/signalr.js into the wwwroot folder.

Now we need the reference this file in our view

<script src="~/signalr.js"></script>

We are going to add vue.js with a CDN as well:

<!-- (Developer version) -->
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

Front End

Now that our dependencies have been added, let’s work on the Front End.

Above our script let’s add our app markup:

<div id="chatApp">
    <div class="form-group">
        <form>
            <div>
                <label for="userName">Your Name</label>
                <input type="text" name="Name" id="userName" v-model="userName">
            </div>
            <div>
                <label for="userMessage">Message</label>
                <input type="text" name="Message" id="userMessage" v-model="userMessage">
            </div>
            <button v-on:click="submitCard" type="button">Submit</button>
        </form>
        <ul v-for="(item, index) in messages" v-bind:key="index + 'itemMessage'">
            <li><b>Name: </b></li>
            <li><b>Message: </b></li>
        </ul>
    </div>
</div>

Now lets set up our script:

document.addEventListener("DOMContentLoaded", function(event) {
  var app = new Vue({
    el: "#chatApp",
    data: {
      userName: "",
      userMessage: "",
      connection: "",
      messages: []
    },
    methods: {
      submitCard: function() {
        if (this.userName && this.userMessage) {
          // ---------
          //  Call hub methods from client
          // ---------
          this.connection
            .invoke("SendMessage", this.userName, this.userMessage)
            .catch(function(err) {
              return console.error(err.toSting());
            });

          this.userName = "";
          this.userMessage = "";
        }
      }
    },
    created: function() {
      // ---------
      // Connect to our hub
      // ---------
      this.connection = new signalR.HubConnectionBuilder()
        .withUrl("/chatHub")
        .configureLogging(signalR.LogLevel.Information)
        .build();
      this.connection.start().catch(function(err) {
        return console.error(err.toSting());
      });
    },
    mounted: function() {
      // ---------
      // Call client methods from hub
      // ---------
      var thisVue = this;
      thisVue.connection.start();
      thisVue.connection.on("ReceiveMessage", function(user, message) {
        thisVue.messages.push({ user, message });
      });
    }
  });
});

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