ASP. Net core signalr tutorial

This tutorial introduces the use of SignalR The basics of generating real-time applications . You will learn ：
1.     establish Web project .
2.     add to SignalR Client library .
3.     establish SignalR center .
4.     Configure items to use SignalR.
5.     Add code to send messages from any client to all connected clients .
Last , You will have a work chat app ：

establish Web project

1. Select from the menu “ file ”>“ New projects ” .

2. stay “ New projects ” In the dialog box , choice “ already installed ”>“Visual C#”>“Web”>“ASP.NET Core Web application ” .  Name the project “SignalRChat” .

 

3． choice “Web application ”, To create and use Razor Pages Project .

4. choice “.NET Core” The target framework , choice “ASP.NET Core 2.1”, And then click “ determine ” .

add to SignalR Client library

Microsoft.AspNetCore.App The meta package includes SignalR Server Library . JavaScript Client libraries are not automatically included in the project . For this tutorial , Using the library manager (LibMan) from unpkg Get the client library . unpkg It's a content distribution network (CDN), Can be distributed in npm（ namely Node.js Package manager ） Anything found in .

1. stay “ Solution explorer ” in , Right click on the item , And then choose “ add to ” >“ Client library ” .

2.     stay “ Add Client Library ” In the dialog box , about “ Provider ” , choice “unpkg” .
3.     about “ library ” , Input @aspnet/[email protected], Then select the latest version that is not a preview version .
4.     choice “ Select a specific file ” , an “dist/browser” Folder , And then choose “signalr.js” and “signalr.min.js” .
5.     take “ Target location ” Set to wwwroot/lib/signalr/ , And then choose “ install ” .

establish SignalR center
The center is a class , Used as a processing client - Advanced pipeline for server communication .
?     stay SignalRChat In the project folder , establish Hubs Folder .
?     stay Hubs In the folder , Use the following code to create ChatHub.cs file ：
ChatHub Class inherits from SignalR Hub. Hub Class management connection 、 Groups and messages .
Can be called from a connected client SendMessage, To send messages to all clients . Later in this tutorial, you will see how to invoke this method JavaScript Client code . SignalR The code is asynchronous , Provides maximum scalability .
 

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

To configure SignalR
Must be SignalR The server is configured to SignalR Request passed to SignalR.
 1. Add the following highlighted code to Startup.cs file  
 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using SignalRChatTest.Hubs;

namespace SignalRChatTest
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });


            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
            services.AddSignalR();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();
            app.UseSignalR(routes =>
            {
                routes.MapHub<ChatHub>("/chatHub");
            });
            app.UseMvc();
        }
    }
}

add to SignalR Client code

@*@page
    @model IndexModel
    @{
        ViewData["Title"] = "Home page";
    }

    <div id="myCarousel" class="carousel slide" data-ride="carousel" data-interval="6000">
        <ol class="carousel-indicators">
            <li data-target="#myCarousel" data-slide-to="0" class="active"></li>
            <li data-target="#myCarousel" data-slide-to="1"></li>
            <li data-target="#myCarousel" data-slide-to="2"></li>
        </ol>
        <div class="carousel-inner" role="listbox">
            <div class="item active">
                <img src="~/images/banner1.svg" alt="ASP.NET" class="img-responsive" />
                <div class="carousel-caption" role="option">
                    <p>
                        Learn how to build ASP.NET apps that can run anywhere.
                        <a class="btn btn-default" href="https://go.microsoft.com/fwlink/?LinkID=525028&clcid=0x409">
                            Learn More
                        </a>
                    </p>
                </div>
            </div>
            <div class="item">
                <img src="~/images/banner2.svg" alt="Visual Studio" class="img-responsive" />
                <div class="carousel-caption" role="option">
                    <p>
                        There are powerful new features in Visual Studio for building modern web apps.
                        <a class="btn btn-default" href="https://go.microsoft.com/fwlink/?LinkID=525030&clcid=0x409">
                            Learn More
                        </a>
                    </p>
                </div>
            </div>
            <div class="item">
                <img src="~/images/banner3.svg" alt="Microsoft Azure" class="img-responsive" />
                <div class="carousel-caption" role="option">
                    <p>
                        Learn how Microsoft's Azure cloud platform allows you to build, deploy, and scale web apps.
                        <a class="btn btn-default" href="https://go.microsoft.com/fwlink/?LinkID=525027&clcid=0x409">
                            Learn More
                        </a>
                    </p>
                </div>
            </div>
        </div>
        <a class="left carousel-control" href="#myCarousel" role="button" data-slide="prev">
            <span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
            <span class="sr-only">Previous</span>
        </a>
        <a class="right carousel-control" href="#myCarousel" role="button" data-slide="next">
            <span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
            <span class="sr-only">Next</span>
        </a>
    </div>

    <div class="row">
        <div class="col-md-3">
            <h2>Application uses</h2>
            <ul>
                <li>Sample pages using ASP.NET Core Razor Pages</li>
                <li>Theming using <a href="https://go.microsoft.com/fwlink/?LinkID=398939">Bootstrap</a></li>
            </ul>
        </div>
        <div class="col-md-3">
            <h2>How to</h2>
            <ul>
                <li><a href="https://go.microsoft.com/fwlink/?linkid=852130">Working with Razor Pages.</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkId=699315">Manage User Secrets using Secret Manager.</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkId=699316">Use logging to log a message.</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkId=699317">Add packages using NuGet.</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkId=699319">Target development, staging or production environment.</a></li>
            </ul>
        </div>
        <div class="col-md-3">
            <h2>Overview</h2>
            <ul>
                <li><a href="https://go.microsoft.com/fwlink/?LinkId=518008">Conceptual overview of what is ASP.NET Core</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkId=699320">Fundamentals of ASP.NET Core such as Startup and middleware.</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkId=398602">Working with Data</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkId=398603">Security</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkID=699321">Client side development</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkID=699322">Develop on different platforms</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkID=699323">Read more on the documentation site</a></li>
            </ul>
        </div>
        <div class="col-md-3">
            <h2>Run &amp; Deploy</h2>
            <ul>
                <li><a href="https://go.microsoft.com/fwlink/?LinkID=517851">Run your app</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkID=517853">Run tools such as EF migrations and more</a></li>
                <li><a href="https://go.microsoft.com/fwlink/?LinkID=398609">Publish to Microsoft Azure App Service</a></li>
            </ul>
        </div>
    </div>*@
@page
<div class="container">
    <div class="row">&nbsp;</div>
    <div class="row">
        <div class="col-6">&nbsp;</div>
        <div class="col-6">
            User..........<input type="text" id="userInput" />
            <br />
            Message...<input type="text" id="messageInput" />
            <input type="button" id="sendButton" value="Send Message" />
        </div>
    </div>
    <div class="row">
        <div class="col-12">
            <hr />
        </div>
    </div>
    <div class="row">
        <div class="col-6">&nbsp;</div>
        <div class="col-6">
            <ul id="messagesList"></ul>
        </div>
    </div>
</div>
<script src="~/lib/signalr/dist/browser/signalr.js"></script>
<script src="~/js/chat.js"></script>

stay wwwroot/js In the folder , Use the following code to create chat.js file ：

"use strict";

var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();

//Disable send button until connection is established
document.getElementById("sendButton").disabled = true;

connection.on("ReceiveMessage", function (user, message) {
    var msg = message.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
    var encodedMsg = user + " says " + msg;
    var li = document.createElement("li");
    li.textContent = encodedMsg;
    document.getElementById("messagesList").appendChild(li);
});

connection.start().then(function () {
    document.getElementById("sendButton").disabled = false;
}).catch(function (err) {
    return console.error(err.toString());
});

document.getElementById("sendButton").addEventListener("click", function (event) {
    var user = document.getElementById("userInput").value;
    var message = document.getElementById("messageInput").value;
    connection.invoke("SendMessage", user, message).catch(function (err) {
        return console.error(err.toString());
    });
    event.preventDefault();
});

Run the application

1. Copy... From the address bar URL, Open another browser instance or tab , And paste this in the address bar URL.

2. Select any browser , Enter a name and message , And then choose “ Send a message ” Button .

3. The name and message are immediately displayed on both pages

Please pay attention to my WeChat official account , Let's make progress together ：

1.