Quickstart: Create a chat room with SignalR Service

Microsoft Azure SignalR Service is currently in Public Preview.

Azure SignalR Service is an Azure service that helps developers easily build web applications with real-time features. This service is based on SignalR for ASP.NET Core 2.0.

This article shows you how to get started with the Azure SignalR Service. In this quickstart, you will create a chat application using an ASP.NET Core MVC Web App web app. This app will make a connection with your Azure SignalR Service resource to enable real-time content updates. You will host the web application locally and connect with multiple browser clients. Each client will be able to push content updates to all other clients.

You can use any code editor to complete the steps in this quickstart. However, Visual Studio Code is an excellent option available on the Windows, macOS, and Linux platforms.

The code for this tutorial is available for download in the AzureSignalR-samples GitHub repository. Also, the creation of the Azure resources used in this quickstart can be accomplished with the Create a SignalR Service script.

Quickstart Complete local

If you don't have an Azure subscription, create a free account before you begin.

Prerequisites

Create an Azure SignalR resource

  1. To create a new Azure SignalR Service resource, first sign in to the Azure portal. In the upper left side of the page, click + Create a resource. In the Search the Marketplace textbox, type SignalR Service and press enter.

  2. Click SignalR Service in the results and click Create.

  3. In the new SignalR settings page, add the following settings for your new SignalR resource:

    Name Recommended value Description
    Resource Name testsignalr Enter a unique resource name to use for the SignalR resource. The name must be a string between 1 and 63 characters and contain only numbers, letters, and the - character. The name cannot start or end with the - character, and consecutive - characters are not valid.
    Subscription Choose your subscription Select the Azure subscription that you want to use to test SignalR. If your account has only one subscription, it is automatically selected and the Subscription drop-down isn't displayed.
    Resource group Create a new resource group named SignalRTestResources Select or create a resource group for your SignalR resource. This group is useful for organizing multiple resources that you may want to delete at the same time by deleting the resource group. For more information, see Using Resource groups to manage your Azure resources.
    Location East US Use Location to specify the geographic location in which your SignalR resource is hosted. For the best performance, we recommend that you create the resource in the same region as other components of your application.
    Pricing tier Free Currently there are Free and Standard options available.
    Pin to dashboard Check this box to have the resource pinned to your dashboard making it easier to find.
  4. Click Create. The deployment may take a few minutes to complete.

  5. Once the deployment is complete, click Keys under SETTINGS. Copy your primary key connection string. You will use this later to configure your app to use the Azure SignalR Service resource.

    The connection string will have the following form:

     Endpoint=<service_endpoint>;AccessKey=<access_key>;
    

Create an ASP.NET Core web app

In this section, you use the .NET Core command-line interface (CLI) to create a new ASP.NET Core MVC Web App project. The advantage of using the .NET Core CLI over Visual Studio is that it is available across the Windows, macOS, and Linux platforms.

  1. Create a new folder for your project. In this quickstart, the E:\Testing\chattest folder is used.

  2. In the new folder, execute the following command to create a new ASP.NET Core MVC Web App project:

     dotnet new mvc
    

Add Secret Manager to the project

In this section, you will add the Secret Manager tool to your project. The Secret Manager tool stores sensitive data for development work outside of your project tree. This approach helps prevent the accidental sharing of app secrets within source code.

  1. Open your .csproj file. Add a DotNetCliToolReference element to include Microsoft.Extensions.SecretManager.Tools. Also add a UserSecretsId element as shown below, and save the file.

    chattest.csproj:

    <Project Sdk="Microsoft.NET.Sdk.Web">
    <PropertyGroup>
        <TargetFramework>netcoreapp2.0</TargetFramework>
        <UserSecretsId>SignalRChatRoomEx</UserSecretsId>
    </PropertyGroup>
    <ItemGroup>
        <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
    </ItemGroup>
    <ItemGroup>
        <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0" />
        <DotNetCliToolReference Include="Microsoft.Extensions.SecretManager.Tools" Version="2.0.0" />
    </ItemGroup>
    </Project>    
    

Add Azure SignalR to the web app

  1. Add a reference to the Microsoft.Azure.SignalR NuGet package by executing the following command:

     dotnet add package Microsoft.Azure.SignalR -v 1.0.0-*
    
  2. Execute the following command to restore packages for your project.

     dotnet restore
    
  3. Add a secret named Azure__SignalR__ConnectionString to Secret Manager. This secret is a hierarchical config value, and a colon (:) may not work on all platforms. Double underscore (__), as used by this secret, is supported by all platforms. This secret will contain the connection string to access your SignalR Service resource. Azure__SignalR__ConnectionString is the default configuration key that SignalR looks for in order to establish a connection. Replace the value in the command below with the connection string for your SignalR Service resource.

    This command must be executed in the same directory as the .csproj file.

    dotnet user-secrets set Azure__SignalR__ConnectionString "Endpoint=<Your endpoint>;AccessKey=<Your access key>;"    
    

    Secret Manager will only be used for testing the web app while it is hosted locally. In a later tutorial, you will deploy the chat web app to Azure. Once the web app is deployed to Azure, you will use an application setting instead of storing the connection string with Secret Manager.

  4. Open Startup.cs and update the ConfigureServices method to use Azure SignalR Service by calling the services.AddSignalR().AddAzureSignalR() method:

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc();
        services.AddSignalR().AddAzureSignalR();
    }
    

    By not passing a parameter to AddAzureSignalR(), this code uses the default configuration key, Azure__SignalR__ConnectionString, for the SignalR Service resource connection string.

  5. Also in Startup.cs, update the Configure method by replacing the call to app.UseStaticFiles() with the following code and save the file.

    app.UseFileServer();
    app.UseAzureSignalR(routes =>
    {
        routes.MapHub<Chat>("/chat");
    });
    

Add a hub class

In SignalR, a hub is a core component that exposes a set of methods that can be called from client. In this section, you define a hub class with two methods:

  • Broadcast: This method broadcasts a message to all clients.
  • Echo: This method sends a message back to the caller.

Both methods use the Clients interface provided by the ASP.NET Core SignalR SDK. This interface gives you access to all connected clients enabling you to push content to your clients.

  1. In your project directory, add a new folder named Hub. Add a new hub code file named Chat.cs to the new folder.

  2. Add the following code to Chat.cs to define you hub class and save the file.

    Update the namespace for this class if you used a project name that differs from chattest.

    using Microsoft.AspNetCore.SignalR;
    
    namespace chattest
    {
    
        public class Chat : Hub
        {
            public void BroadcastMessage(string name, string message)
            {
                Clients.All.SendAsync("broadcastMessage", name, message);
            }
    
            public void Echo(string name, string message)
            {
                Clients.Client(Context.ConnectionId).SendAsync("echo", name, message + " (echo from server)");
            }
        }
    }
    

Add the web app client interface

The client user interface for this chat room app will be composed of HTML and JavaScript in a file named index.html in the wwwroot directory.

Copy the index.html file, and the css, and scripts folders from the wwwroot folder of the samples repository into your project's wwwroot folder.

The main code of index.html:

var connection = new signalR.HubConnectionBuilder()
                            .withUrl('/chat')
                            .build();
bindConnectionMessage(connection);
connection.start()
    .then(function () {
        onConnected(connection);
    })
    .catch(function (error) {
        console.error(error.message);
    });

The code in index.html, calls HubConnectionBuilder.build() to make an HTTP connection to the Azure SignalR resource.

If the connection is successful, that connection is passed to bindConnectionMessage, which adds event handlers for incoming content pushes to the client.

HubConnection.start() starts communication with the hub. Once communication is started, onConnected() adds the button event handlers. These handlers use the connection to allow this client to push content updates to all connected clients.

Add a development runtime profile

In this section, you will add a development runtime environment for ASP.NET Core. For more information on runtime environment for ASP.NET Core, see Work with multiple environments in ASP.NET Core.

  1. Create a new folder in your project named Properties.

  2. Add a new file named launchSettings.json to the folder, with the following content and save the file.

    {
        "profiles" : 
        {
            "ChatRoom": 
            {
                "commandName": "Project",
                "launchBrowser": true,
                "environmentVariables": 
                {
                    "ASPNETCORE_ENVIRONMENT": "Development"
                },
                "applicationUrl": "http://localhost:5000/"
            }
        }
    }
    

Build and Run the app locally

  1. To build the app using the .NET Core CLI, execute the following command in the command shell:

     dotnet build
    
  2. Once the build successfully completes, execute the following command to run the web app locally:

     dotnet run
    

    The app will be hosted locally on port 5000 as configured in our development runtime profile:

     E:\Testing\chattest>dotnet run
     Hosting environment: Development
     Content root path: E:\Testing\chattest
     Now listening on: http://localhost:5000
     Application started. Press Ctrl+C to shut down.    
    
  3. Launch two browser windows and navigate each browser to http://localhost:5000. You will be prompted to enter your name. Enter a client name for both clients and test pushing message content between both clients using the Send button.

    Quickstart Complete local

Clean up resources

If you will be continuing to the next tutorial, you can keep the resources created in this quickstart and reuse them with the next tutorial.

Otherwise, if you are finished with the quickstart sample application, you can delete the Azure resources created in this quickstart to avoid charges.

Important

Deleting a resource group is irreversible and that the resource group and all the resources in it are permanently deleted. Make sure that you do not accidentally delete the wrong resource group or resources. If you created the resources for hosting this sample inside an existing resource group that contains resources you want to keep, you can delete each resource individually from their respective blades instead of deleting the resource group.

Sign in to the Azure portal and click Resource groups.

In the Filter by name... textbox, type the name of your resource group. The instructions for this quickstart used a resource group named SignalRTestResources. On your resource group in the result list, click ... then Delete resource group.

Delete

You will be asked to confirm the deletion of the resource group. Type the name of your resource group to confirm, and click Delete.

After a few moments, the resource group and all of its contained resources are deleted.

Next steps

In this quickstart, you've created a new Azure SignalR Service resource and used it with an ASP.NET Core Web app to push content updates in real time to multiple connected clients. To learn more about using Azure SignalR Service, continue to the next tutorial that demonstrates authentication.