Azure Functions 的 SignalR 服务触发器绑定

以下示例演示一个 C# 函数，该函数从客户端接收消息事件并记录消息内容。

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the MIT License. See License.txt in the project root for license information.


using Microsoft.Azure.Functions.Worker;
using Microsoft.Extensions.Logging;

namespace Extensions.SignalR
{
    public static class SignalRTriggerFunctions
    {
        // <snippet_on_connected>
        [Function(nameof(OnConnected))]
        public static void OnConnected(
            [SignalRTrigger("chat", "connections", "connected", ConnectionStringSetting = "SignalRConnection")]
                SignalRInvocationContext invocationContext, FunctionContext functionContext)
        {
            var logger = functionContext.GetLogger(nameof(OnConnected));
            logger.LogInformation("Connection {connectionId} is connected", invocationContext.ConnectionId);
        }
        // </snippet_on_connected>

        // <snippet_on_disconnected>
        [Function(nameof(OnDisconnected))]
        public static void OnDisconnected(
            [SignalRTrigger("chat", "connections", "disconnected", ConnectionStringSetting = "SignalRConnection")]
                SignalRInvocationContext invocationContext, FunctionContext functionContext)
        {
            var logger = functionContext.GetLogger(nameof(OnDisconnected));
            logger.LogInformation("Connection {connectionId} is disconnected. Error: {error}", invocationContext.ConnectionId, invocationContext.Error);
        }
        // </snippet_on_disconnected>

        // <snippet_on_message>
        [Function(nameof(OnClientMessage))]
        public static void OnClientMessage(
            [SignalRTrigger("Hub", "messages", "sendMessage", "content", ConnectionStringSetting = "SignalRConnection")]
                SignalRInvocationContext invocationContext, string content, FunctionContext functionContext)
        {
            var logger = functionContext.GetLogger(nameof(OnClientMessage));
            logger.LogInformation("Connection {connectionId} sent a message. Message content: {content}", invocationContext.ConnectionId, content);
        }
        // </snippet_on_message>
    }
}

C# 进程内模型的 SignalR 服务触发器绑定具有两种编程模型。 基于类的模型和传统模型。 基于类的模型提供一致的 SignalR 服务器端编程体验。 传统模型提供更大的灵活性，并与其他函数绑定类似。

有关详细信息，请参阅基于类的模型。

public class HubName1 : ServerlessHub
{
    [FunctionName("SignalRTest")]
    public Task SendMessage([SignalRTrigger]InvocationContext invocationContext, string message, ILogger logger)
    {
        logger.LogInformation($"Receive {message} from {invocationContext.ConnectionId}.");
    }
}

传统模型遵守使用 C# 开发的 Azure Function 的约定。 如果不熟悉该约定，可通过文档了解和学习。

[FunctionName("SignalRTest")]
public static Task Run([SignalRTrigger("SignalRTest", "messages", "SendMessage", parameterNames: new string[] {"message"})]InvocationContext invocationContext, string message, ILogger logger)
{
    logger.LogInformation($"Receive {message} from {invocationContext.ConnectionId}.");
}

因为在触发器中使用 ParameterNames 可能很困难，所以以下示例展示了如何使用 SignalRParameter 属性来定义 message 属性。

[FunctionName("SignalRTest")]
public static Task Run([SignalRTrigger("SignalRTest", "messages", "SendMessage")]InvocationContext invocationContext, [SignalRParameter]string message, ILogger logger)
{
    logger.LogInformation($"Receive {message} from {invocationContext.ConnectionId}.");
}

app.generic("function1",
    {
        trigger: { "type": "signalRTrigger", "name": "invocation", "direction": "in", "hubName": "hubName1", "event": "SendMessage", "category": "messages" },
        handler: (triggerInput, context) => {
            context.log(`Receive ${context.Arguments[0]} from ${triggerInput.ConnectionId}.`)
        }
    })

下面是 function.json 文件中的绑定数据：

{
    "type": "signalRTrigger",
    "name": "invocation",
    "hubName": "hubName1",
    "category": "messages",
    "event": "SendMessage",
    "parameterNames": [
        "message"
    ],
    "direction": "in"
}

JavaScript 代码如下所示：

module.exports = function (context, invocation) {
    context.log(`Receive ${context.bindingData.message} from ${invocation.ConnectionId}.`)
};

下表说明了 SignalRTrigger 特性的属性。

下表说明了 SignalRTrigger 特性的属性。