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aspnetcore/tutorials/signalr/includes/signalr3-5.md

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:::moniker range=">= aspnetcore-3.1 < aspnetcore-6.0"

This tutorial teaches the basics of building a real-time app using SignalR. You learn how to:

[!div class="checklist"]

  • Create a web project.
  • Add the SignalR client library.
  • Create a SignalR hub.
  • Configure the project to use SignalR.
  • Add code that sends messages from any client to all connected clients.

At the end, you'll have a working chat app:

Prerequisites

Visual Studio

[!INCLUDE]

Visual Studio Code

[!INCLUDE]

Visual Studio for Mac

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Create a web app project

Visual Studio

  • From the menu, select File > New Project.
  • In the Create a new project dialog, select ASP.NET Core Web Application, and then select Next.
  • In the Configure your new project dialog, name the project SignalRChat, and then select Create.
  • In the Create a new ASP.NET Core web Application dialog, select .NET Core and ASP.NET Core 3.1.
  • Select Web Application to create a project that uses Razor Pages, and then select Create.

Visual Studio Code

  • Open the integrated terminal to the folder in which the new project folder will be created.
  • Run the following commands:
dotnetcli
dotnet new webapp -o SignalRChat
cd SignalRChat
code -r .

Visual Studio for Mac

  • From the menu, select File > New Solution.
  • Select .NET Core > App > Web Application (Don't select Web Application (Model-View-Controller)), and then select Next.
  • Make sure the Target Framework is set to .NET Core 3.1, and then select Next.
  • Name the project SignalRChat, and then select Create.

Add the SignalR client library

The SignalR server library is included in the ASP.NET Core 3.1 shared framework. The JavaScript client library isn't automatically included in the project. For this tutorial, you use Library Manager (LibMan) to get the client library from unpkg. unpkg is a content delivery network (CDN) that can deliver anything found in npm, the Node.js package manager.

Visual Studio

  • In Solution Explorer, right-click the project, and select Add > Client-Side Library.
  • In the Add Client-Side Library dialog, for Provider select unpkg.
  • For Library, enter @microsoft/signalr@latest.
  • Select Choose specific files, expand the dist/browser folder, and select signalr.js and signalr.min.js.
  • Set Target Location to wwwroot/js/signalr/
  • Select Install

LibMan creates a wwwroot/js/signalr folder and copies the selected files to it.

Visual Studio Code

  • In the integrated terminal, run the following command to install LibMan.
dotnetcli
dotnet tool install -g Microsoft.Web.LibraryManager.Cli

[!INCLUDE]

  • Run the following command to get the SignalR client library by using LibMan. You might have to wait a few seconds before seeing output.
console
libman install @microsoft/signalr@latest -p unpkg -d wwwroot/js/signalr --files dist/browser/signalr.js --files dist/browser/signalr.js

The parameters specify the following options:

  • Use the unpkg provider.
  • Copy files to the wwwroot/js/signalr destination.
  • Copy only the specified files.

The output looks like the following example:

console
wwwroot/js/signalr/dist/browser/signalr.js written to disk
wwwroot/js/signalr/dist/browser/signalr.js written to disk
Installed library "@microsoft/signalr@latest" to "wwwroot/js/signalr"

Visual Studio for Mac

  • In the Terminal, run the following command to install LibMan.
dotnetcli
dotnet tool install -g Microsoft.Web.LibraryManager.Cli

[!INCLUDE]

  • Navigate to the project folder (the one that contains the SignalRChat.csproj file).

  • Run the following command to get the SignalR client library by using LibMan.

console
libman install @microsoft/signalr@latest -p unpkg -d wwwroot/js/signalr --files dist/browser/signalr.js --files dist/browser/signalr.js

The parameters specify the following options:

  • Use the unpkg provider.
  • Copy files to the wwwroot/js/signalr destination.
  • Copy only the specified files.

The output looks like the following example:

console
wwwroot/js/signalr/dist/browser/signalr.js written to disk
wwwroot/js/signalr/dist/browser/signalr.js written to disk
Installed library "@microsoft/signalr@latest" to "wwwroot/js/signalr"

Create a SignalR hub

A hub is a class that serves as a high-level pipeline that handles client-server communication.

  • In the SignalRChat project folder, create a Hubs folder.
  • In the Hubs folder, create a ChatHub.cs file with the following code:

[!code-csharpChatHub]

The ChatHub class inherits from the SignalR Hub class. The Hub class manages connections, groups, and messaging.

The SendMessage method can be called by a connected client to send a message to all clients. JavaScript client code that calls the method is shown later in the tutorial. SignalR code is asynchronous to provide maximum scalability.

Configure SignalR

The SignalR server must be configured to pass SignalR requests to SignalR.

  • Add the following highlighted code to the Startup.cs file.

    [!code-csharpStartup]

    These changes add SignalR to the ASP.NET Core dependency injection and routing systems.

Add SignalR client code

  • Replace the content in Pages/Index.cshtml with the following code:

    [!code-cshtmlIndex]

    The preceding code:

    • Creates text boxes for name and message text, and a submit button.
    • Creates a list with id="messagesList" for displaying messages that are received from the SignalR hub.
    • Includes script references to SignalR and the chat.js application code that you create in the next step.

  • In the wwwroot/js folder, create a chat.js file with the following code:

    [!code-javascriptchat]

    The preceding code:

    • Creates and starts a connection.
    • Adds to the submit button a handler that sends messages to the hub.
    • Adds to the connection object a handler that receives messages from the hub and adds them to the list.

Run the app

Visual Studio

  • Press CTRL+F5 to run the app without debugging.

Visual Studio Code

  • In the integrated terminal, run the following command:

    dotnetcli
    dotnet watch run -p SignalRChat.csproj

Visual Studio for Mac

  • From the menu, select Run > Start Without Debugging.
  • Copy the URL from the address bar, open another browser instance or tab, and paste the URL in the address bar.
  • Choose either browser, enter a name and message, and select the Send Message button. The name and message are displayed on both pages instantly.

[!TIP]

  • If the app doesn't work, open your browser developer tools (F12) and go to the console. You might see errors related to your HTML and JavaScript code. For example, suppose you put signalr.js in a different folder than directed. In that case the reference to that file won't work and you'll see a 404 error in the console.

  • If you get the error ERR_SPDY_INADEQUATE_TRANSPORT_SECURITY in Chrome, run these commands to update your development certificate:

    dotnetcli
    dotnet dev-certs https --clean
dotnet dev-certs https --trust

Publish to Azure

For information on deploying to Azure, see Quickstart: Deploy an ASP.NET web app.

Next steps

:::moniker-end