Skip to content

Latest commit

 

History

History
362 lines (277 loc) · 16.8 KB

signalr-quickstart-dotnet-core.md

File metadata and controls

362 lines (277 loc) · 16.8 KB
titledescriptionauthorms.servicems.devlangms.customms.topicms.datems.author
Quickstart to learn how to use Azure SignalR Service
A quickstart for using Azure SignalR Service to create a chat room with ASP.NET Core web apps.
vicancy
azure-signalr-service
csharp
devx-track-dotnet
quickstart
11/11/2023
lianwei

Quickstart: Create a chat room by using SignalR Service

Azure SignalR Service is an Azure service that helps developers easily build web applications with real-time features.

This article shows you how to get started with the Azure SignalR Service. In this quickstart, you'll create a chat application by using an ASP.NET Core web app. This app will make a connection with your Azure SignalR Service resource to enable real-time content updates. You'll 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. One option is Visual Studio Code, which is available on the Windows, macOS, and Linux platforms.

The code for this tutorial is available for download in the AzureSignalR-samples GitHub repository. You can create the Azure resources used in this quickstart by following Create a SignalR Service script.

[!INCLUDE quickstarts-free-trial-note]

[!INCLUDE Connection string security]

Ready to start?

[!div class="nextstepaction"] Step by step build

[!div class="nextstepaction"] Try chat demo now

Prerequisites

Having issues? Try the troubleshooting guide or let us know.

Create an Azure SignalR resource

[!INCLUDE azure-signalr-create]

Create an ASP.NET Core web app

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

  1. Create a folder for your project. This quickstart uses the chattest folder.

  2. In the new folder, run the following command to create the project:

    dotnet new web

Add Secret Manager to the project

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

  1. In the folder, init UserSecretsId by running the following command:

    dotnet user-secrets init

  2. Add a secret named Azure:SignalR:ConnectionString to Secret Manager.

    [!INCLUDE Connection string security comment]

    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 to establish a connection. Replace the value in the following command with the connection string for your SignalR Service resource.

    You must run this command in the same directory as the csproj file.

    dotnet user-secrets set Azure:SignalR:ConnectionString "<Your connection string>"

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

    This secret is accessed with the Configuration API. A colon (:) works in the configuration name with the Configuration API on all supported platforms. See Configuration by environment.

Add Azure SignalR to the web app

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

    dotnet add package Microsoft.Azure.SignalR

  2. Open Program.cs and update the code to the following, it calls the AddSignalR() and AddAzureSignalR() methods to use Azure SignalR Service:

    varbuilder=WebApplication.CreateBuilder(args);builder.Services.AddSignalR().AddAzureSignalR();varapp=builder.Build();app.UseDefaultFiles();app.UseRouting();app.UseStaticFiles();app.MapHub<ChatSampleHub>("/chat");app.Run();

    Not passing a parameter to AddAzureSignalR() means it uses the default configuration key for the SignalR Service resource connection string. The default configuration key is Azure:SignalR:ConnectionString. It also uses ChatSampleHub which we will create in the below section.

Add a hub class

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

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

Both methods use the Clients interface that the ASP.NET Core SignalR SDK provides. This interface gives you access to all connected clients, so you can push content to your clients.

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

  2. Add the following code to ChatSampleHub.cs to define your hub class and save the file.

    usingMicrosoft.AspNetCore.SignalR;publicclassChatSampleHub:Hub{publicTaskBroadcastMessage(stringname,stringmessage)=>Clients.All.SendAsync("broadcastMessage",name,message);publicTaskEcho(stringname,stringmessage)=>Clients.Client(Context.ConnectionId).SendAsync("echo",name,$"{message} (echo from server)");}

Add the client interface for the web app

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

Copy the css/site.css file from the wwwroot folder of the samples repository. Replace your project's css/site.css with the one you copied.

Create a new file in the wwwroot directory named index.html, copy and paste the following HTML into the newly created file.

<!DOCTYPE html><html><head><metahttp-equiv="Cache-Control" content="no-cache, no-store, must-revalidate" /><metaname="viewport" content="width=device-width"><metahttp-equiv="Pragma" content="no-cache" /><metahttp-equiv="Expires" content="0" /><linkhref="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" rel="stylesheet" /><linkhref="css/site.css" rel="stylesheet" /><title>Azure SignalR Group Chat</title></head><body><h2class="text-center" style="margin-top: 0; padding-top: 30px; padding-bottom: 30px;">Azure SignalR Group Chat</h2><divclass="container" style="height: calc(100% - 110px);"><divid="messages" style="background-color: whitesmoke; "></div><divstyle="width: 100%; border-left-style: ridge; border-right-style: ridge;"><textareaid="message" style="width: 100%; padding: 5px 10px; border-style: hidden;" placeholder="Type message and press Enter to send..."></textarea></div><divstyle="overflow: auto; border-style: ridge; border-top-style: hidden;"><buttonclass="btn-warning pull-right" id="echo">Echo</button><buttonclass="btn-success pull-right" id="sendmessage">Send</button></div></div><divclass="modal alert alert-danger fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel"><divclass="modal-dialog" role="document"><divclass="modal-content"><divclass="modal-header"><div>Connection Error...</div><div><strongstyle="font-size: 1.5em;">Hit Refresh/F5</strong> to rejoin. ;)</div></div></div></div></div><!--Reference the SignalR library. --><scriptsrc="https://cdnjs.cloudflare.com/ajax/libs/microsoft-signalr/6.0.1/signalr.js"></script><!--Add script to update the page and send messages.--><scripttype="text/javascript">document.addEventListener("DOMContentLoaded",function(){functiongetUserName(){functiongenerateRandomName(){returnMath.random().toString(36).substring(2,10);}// Get the user name and store it to prepend to messages.varusername=generateRandomName();varpromptMessage="Enter your name:";do{username=prompt(promptMessage,username);if(!username||username.startsWith("_")||username.indexOf("<")>-1||username.indexOf(">")>-1){username="";promptMessage="Invalid input. Enter your name:";}}while(!username)returnusername;}username=getUserName();// Set initial focus to message input box.varmessageInput=document.getElementById("message");messageInput.focus();functioncreateMessageEntry(encodedName,encodedMsg){varentry=document.createElement("div");entry.classList.add("message-entry");if(encodedName==="_SYSTEM_"){entry.innerHTML=encodedMsg;entry.classList.add("text-center");entry.classList.add("system-message");}elseif(encodedName==="_BROADCAST_"){entry.classList.add("text-center");entry.innerHTML=`<div class="text-center broadcast-message">${encodedMsg}</div>`;}elseif(encodedName===username){entry.innerHTML=`<div class="message-avatar pull-right">${encodedName}</div>`+`<div class="message-content pull-right">${encodedMsg}<div>`;}else{entry.innerHTML=`<div class="message-avatar pull-left">${encodedName}</div>`+`<div class="message-content pull-left">${encodedMsg}<div>`;}returnentry;}functionappendMessage(encodedName,encodedMsg){varmessageEntry=createMessageEntry(encodedName,encodedMsg);varmessageBox=document.getElementById("messages");messageBox.appendChild(messageEntry);messageBox.scrollTop=messageBox.scrollHeight;}functionbindConnectionMessage(connection){varmessageCallback=function(name,message){if(!message)return;// Html encode display name and message.varencodedName=name;varencodedMsg=message.replace(/&/g,"&amp;").replace(/</g,"&lt;").replace(/>/g,"&gt;");appendMessage(encodedName,encodedMsg);};// Create a function that the hub can call to broadcast messages.connection.on("broadcastMessage",messageCallback);connection.on("echo",messageCallback);connection.onclose(onConnectionError);}functiononConnected(connection){console.log("connection started");connection.send("broadcastMessage","_SYSTEM_",username+" JOINED");document.getElementById("sendmessage").addEventListener("click",function(event){// Call the broadcastMessage method on the hub.if(messageInput.value){connection.send("broadcastMessage",username,messageInput.value).catch((e)=>appendMessage("_BROADCAST_",e.message));}// Clear text box and reset focus for next comment.messageInput.value="";messageInput.focus();event.preventDefault();});document.getElementById("message").addEventListener("keypress",function(event){if(event.keyCode===13){event.preventDefault();document.getElementById("sendmessage").click();returnfalse;}});document.getElementById("echo").addEventListener("click",function(event){// Call the echo method on the hub.connection.send("echo",username,messageInput.value);// Clear text box and reset focus for next comment.messageInput.value="";messageInput.focus();event.preventDefault();});}functiononConnectionError(error){if(error&&error.message){console.error(error.message);}varmodal=document.getElementById("myModal");modal.classList.add("in");modal.style="display: block;";}varconnection=newsignalR.HubConnectionBuilder().withUrl("/chat").build();bindConnectionMessage(connection);connection.start().then(function(){onConnected(connection);}).catch(function(error){console.error(error.message);});});</script></body></html>

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. Then, onConnected() adds the button event handlers. These handlers use the connection to allow this client to push content updates to all connected clients.

Build and run the app locally

  1. Run the following command to run the web app locally:

    dotnet run

    The app will be hosted locally with output containing the localhost URL, for example, as the following:

    Building... info: Microsoft.Hosting.Lifetime[14] Now listening on: http://localhost:5000 info: Microsoft.Hosting.Lifetime[0] Application started. Press Ctrl+C to shut down. info: Microsoft.Hosting.Lifetime[0] Hosting environment: Development

  2. Open two browser windows. In each browser, go to the localhost URL shown in the output window, for example, http://localhost:5000/ as the above output window shows. You're prompted to enter your name. Enter a client name for both clients and test pushing message content between both clients by using the Send button.

    Example of an Azure SignalR group chat

Clean up resources

If you'll continue to the next tutorial, you can keep the resources created in this quickstart and reuse them.

If you're 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 includes all the resources in that group. Make sure that you don't accidentally delete the wrong resource group or resources. If you created the resources in this sample in an existing resource group that contains resources you want to keep, you can delete each resource individually from its blade instead of deleting the resource group.

Sign in to the Azure portal and select Resource groups.

In the Filter by name text box, 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, select the ellipsis (...) > Delete resource group.

Selections for deleting a resource group

You're asked to confirm the deletion of the resource group. Enter the name of your resource group to confirm, and select Delete.

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

Having issues? Try the troubleshooting guide or let us know.

Next steps

In this quickstart, you created a new Azure SignalR Service resource. You then 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 tutorial that demonstrates authentication.

[!div class="nextstepaction"] Azure SignalR Service authentication

close