ASP.NET MVC 5调用无服务器Azure SignalR Hub方法的实现求助

问题背景 #

我有一个已集成ASP.NET SignalR V2的ASP.NET MVC 5应用，现在需要以无服务器模式集成Azure SignalR Service，但查阅文档后仍未找到正确的Hub方法调用或连接方式。尝试的代码中HubConnectionBuilder.WithUrl()报错，提示方法不存在，已引用Microsoft.AspNetCore.SignalR.Client。

尝试的MVC端代码 #

private static async void PushNotification(NotificationRequest notificationRequest, NotificationResponse notificationResponse, string signalRUrl, string authenticationType, Cookie cookie, ICredentials credentials, string accessToken, string userId, string cacheString)
{
    if (authenticationType == "AzureSignalR")
    {
        HubConnection _connection = new HubConnectionBuilder().WithUrl(signalRUrl).Build();
    }
    else
    {
        using (var hubConnection = new HubConnection(signalRUrl))
        {
            IHubProxy notificationHubProxy = hubConnection.CreateHubProxy("NotificationHub");
            if (authenticationType != "AzureSignalR")
            {
                ConfigureHubConnection(hubConnection, authenticationType, cookie, credentials);
            }

            try
            {
                await hubConnection.Start();
                await notificationHubProxy.Invoke("Send", notificationRequest, notificationResponse);
                hubConnection.Stop();
            }
            catch (Exception e)
            {
                if (hubConnection != null && !string.IsNullOrEmpty(hubConnection.ConnectionId))
                {
                    hubConnection.Stop();
                }
            }
        }
    }
    
}

Azure Function端Hub代码 #

public class NotificationHub : ServerlessHub
{
    [FunctionName("index")]
    public static IActionResult GetHomePage([HttpTrigger(AuthorizationLevel.Anonymous)] HttpRequest req, ExecutionContext context)
    {
        var path = Path.Combine(context.FunctionAppDirectory, "content", "index.html");
        return new ContentResult
        {
            Content = File.ReadAllText(path),
            ContentType = "text/html",
        };
    }

    [FunctionName("negotiate")]
    public static SignalRConnectionInfo Negotiate(
       [HttpTrigger(AuthorizationLevel.Anonymous)] HttpRequest req,
       [SignalRConnectionInfo(HubName = "NotificationHub")] SignalRConnectionInfo connectionInfo)
    {
        return connectionInfo;
    }
    [Authorize]
    [FunctionName(nameof(Send))]
    public async Task Send([SignalRTrigger] InvocationContext invocationContext, NotificationRequest notificationRequest, NotificationResponse notificationResponse)
    {
        try
        {
            await Clients.Clients(notificationResponse.ConnectionIds).SendAsync("SendNotification", notificationRequest);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }
    [FunctionName(nameof(OnDisconnected))]
    public async Task OnDisconnected([SignalRTrigger] InvocationContext invocationContext, ILogger logger)
    {
        var response = await APIService.CallDisconnectedTrigger(invocationContext.ConnectionId);
        if (response != null && response.ErrorMessages.Any())
        {
            string errorMessages = string.Join(", ", response.ErrorMessages);
            logger.LogInformation("Some error occured while disconnecting SignalR Connection. " + errorMessages);
        }
    }
}

解决方案 #

第一步：修正NuGet包引用 #

确保ASP.NET MVC 5项目安装兼容.NET Framework的Microsoft.AspNetCore.SignalR.Client版本（推荐3.1.x，高版本可能不支持.NET Framework）。

场景1：MVC作为SignalR客户端直接连接Azure SignalR Service #

修正PushNotification方法的Azure SignalR分支代码，需先调用negotiate端点获取连接凭证：

// 新增Negotiate响应模型
public class NegotiateResponse
{
    public string Url { get; set; }
    public string AccessToken { get; set; }
}

// 修正后的PushNotification方法（将async void改为async Task避免异步风险）
private static async Task PushNotification(NotificationRequest notificationRequest, NotificationResponse notificationResponse, string signalRNegotiateUrl, string authenticationType, Cookie cookie, ICredentials credentials, string accessToken, string userId, string cacheString)
{
    if (authenticationType == "AzureSignalR")
    {
        // 1. 调用Azure Function的negotiate端点获取连接信息
        var negotiateResponse = await new HttpClient().GetFromJsonAsync<NegotiateResponse>(signalRNegotiateUrl);
        
        // 2. 构建SignalR连接
        var connection = new HubConnectionBuilder()
            .WithUrl(negotiateResponse.Url, options =>
            {
                options.AccessTokenProvider = () => Task.FromResult(negotiateResponse.AccessToken);
                // 传入身份验证凭证（如果需要）
                if (cookie != null) options.Cookies.Add(cookie);
                options.Credentials = credentials;
            })
            .Build();

        try
        {
            await connection.StartAsync();
            // 调用Hub中的Send方法，参数需与Function端定义匹配
            await connection.InvokeAsync("Send", notificationRequest, notificationResponse);
        }
        catch (Exception e)
        {
            Console.WriteLine($"SignalR连接或调用失败：{e.Message}");
        }
        finally
        {
            await connection.StopAsync();
            await connection.DisposeAsync();
        }
    }
    else
    {
        // 保留原有的SignalR V2逻辑
        using (var hubConnection = new HubConnection(signalRUrl))
        {
            IHubProxy notificationHubProxy = hubConnection.CreateHubProxy("NotificationHub");
            ConfigureHubConnection(hubConnection, authenticationType, cookie, credentials);

            try
            {
                await hubConnection.Start();
                await notificationHubProxy.Invoke("Send", notificationRequest, notificationResponse);
                hubConnection.Stop();
            }
            catch (Exception e)
            {
                if (hubConnection != null && !string.IsNullOrEmpty(hubConnection.ConnectionId))
                {
                    hubConnection.Stop();
                }
            }
        }
    }
}

注意：signalRNegotiateUrl为Azure Function的negotiate端点地址，格式如https://你的函数应用名.azurewebsites.net/api/negotiate

场景2：MVC通过HTTP调用Azure Function推送消息（无服务器模式推荐方案） #

无需维护SignalR连接，直接调用Function的HTTP端点触发消息推送：

private static async Task PushNotificationViaFunction(NotificationRequest notificationRequest, NotificationResponse notificationResponse, string functionSendUrl, string accessToken)
{
    var client = new HttpClient();
    // 如果Function启用授权，添加Bearer令牌
    if (!string.IsNullOrEmpty(accessToken))
    {
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
    }

    // 构造请求体
    var requestBody = new
    {
        notificationRequest = notificationRequest,
        notificationResponse = notificationResponse
    };
    var content = new StringContent(JsonConvert.SerializeObject(requestBody), Encoding.UTF8, "application/json");
    
    var response = await client.PostAsync(functionSendUrl, content);
    if (!response.IsSuccessStatusCode)
    {
        var errorContent = await response.Content.ReadAsStringAsync();
        Console.WriteLine($"调用Function失败：{errorContent}");
    }
}

注意：functionSendUrl为Azure Function中Send方法的地址，格式如https://你的函数应用名.azurewebsites.net/api/Send，需安装Newtonsoft.Json包序列化请求体。

Azure Function端补充说明 #

1. 确保应用设置中已配置AzureSignalRConnectionString（指向你的Azure SignalR Service连接字符串）
2. 若无需授权，可移除Send方法上的[Authorize]特性；若需授权，需配置对应的身份验证规则
3. Send方法的参数需与客户端调用时的参数完全匹配，确保消息能正确路由到目标客户端

内容的提问来源于stack exchange，提问作者Mohd Anzal