Azure WebJobs Web PubSub for Socket.IO client library for .NET - version 1.0.0-beta.2

Article
09/02/2024

This extension provides functionality for receiving Web PubSub for Socket.IO webhook calls in Azure Functions, allowing you to easily write functions that respond to any event published to Web PubSub for Socket.IO in serverless mode.

Source code | Package | API reference documentation | Product documentation | Samples

Getting started

Install the package

Install the Web PubSub for Socket.IO extension with NuGet:

dotnet add package Microsoft.Azure.WebJobs.Extensions.WebPubSubForSocketIO --prerelease

Prerequisites

You must have an Azure subscription and an Azure resource group with a Web PubSub for Socket.IO resource. Follow this Quickstart to create an Web PubSub for Socket.IO instance.

Authenticate the client

In order to let the extension work with Web PubSub for Socket.IO, you will need to provide either access keys or identity based configuration to authenticate with the service.

Access key based configuration

The AzureWebJobsStorage connection string is used to preserve the processing checkpoint information as required refer to Storage considerations

You can find the Keys for you Azure Web PubSub service in the Azure Portal.

For the local development, use the local.settings.json file to store the connection string. Set WebPubSubForSocketIOConnectionString to the connection string copied from the previous step:

{
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "WebPubSubForSocketIOConnectionString": "Endpoint=https://<webpubsub-name>.webpubsub.azure.com;AccessKey=<access-key>;Version=1.0;"
  }
}

When deployed use the application settings to set the connection string.

Identity based configuration

For the local development, use the local.settings.json file to store the connection string. Set WebPubSubForSocketIOConnectionString to the connection string copied from the previous step:

{
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "WebPubSubForSocketIOConnectionString__endpoint": "https://<webpubsub-name>.webpubsub.azure.com",
    "WebPubSubForSocketIOConnectionString__tenant": "<tenant id you're in>",
  }
}

For using online, the AzureWebJobsStorage should refer to Connecting to host storage with an identity

Key concepts

Using SocketIO input binding

Please follow the input binding tutorial to learn about using this extension for building SocketIONegotiationResult to create Socket.IO client connection negotiation result.

Using SocketIO output binding

Please follow the output binding tutorial to learn about using this extension for publishing Socket.IO messages.

Using SocketIO trigger

Please follow the trigger binding tutorial to learn about triggering an Azure Function when an event is sent from service.

For connect and all user defined events, function will return values send back service. Then service will depend on the response to proceed the request or else. The responses and events are paired. For example, Connect will only respect SocketIOConnectResponse, and ignore other returns. If the status code is not a success code, the service will reject this socket. And user defined events response is only useful when client is requesting an event and wait for the acknowledgement. Please follow the trigger binding return value tutorial to learn about using the trigger return value.

Examples

Functions that uses SocketIO input binding

public static class SocketIOBindingFunction
{
    [FunctionName("SocketIOInputBinding")]
    public static IActionResult SocketInputBinding(
        [HttpTrigger(AuthorizationLevel.Anonymous, "get")] HttpRequest req,
        [SocketIONegotiation(Hub = "hub", UserId = "uid")] SocketIONegotiationResult result)
    {
        return new OkObjectResult(result);
    }
}

Functions that uses SocketIO output binding

public static class SocketIOOutputBindingFunction
{
    [FunctionName("SocketIOOutputBinding")]
    public static async Task<IActionResult> OutboundBinding(
        [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
        [SocketIO(Hub = "hub")] IAsyncCollector<SocketIOAction> operation,
        ILogger log)
    {
        string userName = Guid.NewGuid().ToString();
        await operation.AddAsync(SocketIOAction.CreateSendToNamespaceAction("new message", new[] { new { username = userName, message = "Hello" } }));
        log.LogInformation("Send to namespace finished.");
        return new OkObjectResult("ok");
    }
}

Functions that uses SocketIO trigger

public static class SocketIOTriggerFunction
{
    [FunctionName("TriggerBindingForConnect")]
    public static SocketIOEventHandlerResponse TriggerBindingForConnect(
        [SocketIOTrigger("hub", "connect")] SocketIOConnectRequest request,
        ILogger log)
    {
        log.LogInformation("Running trigger for: connect");
        return new SocketIOConnectResponse();
    }

    [FunctionName("TriggerBindingForConnected")]
    public static void TriggerBindingForConnected(
        [SocketIOTrigger("hub", "connected")] SocketIOConnectedRequest request,
        [SocketIO(Hub = "hub")] IAsyncCollector<SocketIOAction> collector,
        ILogger log)
    {
        log.LogInformation("Running trigger for: connected");
    }

    [FunctionName("TriggerBindingForDisconnected")]
    public static void TriggerBindingForDisconnected(
        [SocketIOTrigger("hub", "disconnected")] SocketIODisconnectedRequest request,
        [SocketIO(Hub = "hub")] IAsyncCollector<SocketIOAction> collector,
        ILogger log)
    {
        log.LogInformation("Running trigger for: disconnected");
    }

    [FunctionName("TriggerBindingForNewMessage")]
    public static async Task TriggerBindingForNewMessage(
        [SocketIOTrigger("hub", "new message")] SocketIOMessageRequest request,
        [SocketIO(Hub = "hub")] IAsyncCollector<SocketIOAction> collector,
        ILogger log)
    {
        log.LogInformation("Running trigger for: new message");
        await collector.AddAsync(SocketIOAction.CreateSendToNamespaceAction("new message", new[] { new { message = request.Parameters } }, new[] { request.SocketId }));
    }
}

Functions that uses SocketIO trigger return value as Acknowledgement

public static class SocketIOTriggerReturnValueFunction
{
    [FunctionName("TriggerBindingForNewMessageAndAck")]
    public static async Task<SocketIOMessageResponse> TriggerBindingForNewMessageAndAck(
        [SocketIOTrigger("hub", "new message")] SocketIOMessageRequest request,
        [SocketIO(Hub = "hub")] IAsyncCollector<SocketIOAction> collector,
        ILogger log)
    {
        log.LogInformation("Running trigger for: new message");
        await collector.AddAsync(SocketIOAction.CreateSendToNamespaceAction("new message", new[] { new { message = request.Parameters } }, new[] { request.SocketId }));
        return new SocketIOMessageResponse(new[] {"ackValue"});
    }
}

Troubleshooting

Please refer to Monitor Azure Functions for troubleshooting guidance.

Next steps

Read the introduction to Azure Function or creating an Azure Function guide.

Contributing

See our CONTRIBUTING.md for details on building, testing, and contributing to this library.

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit cla.microsoft.com.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

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