add client invocation for management sdk

src/Microsoft.Azure.SignalR.Common/Utilities/Rest/BinaryPayloadContentBuilder.cs

@@ -4,7 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Net.Http;
-
+using Azure.Core.Serialization;
 using Microsoft.AspNetCore.SignalR.Protocol;
 
 #nullable enable
@@ -20,6 +20,8 @@ public BinaryPayloadContentBuilder(IReadOnlyList<IHubProtocol> hubProtocols)
         _hubProtocols = hubProtocols;
     }
 
+    public ObjectSerializer? ObjectSerializer => null;
+
     public HttpContent? Build(HubMessage? payload, Type? typeHint)
     {
         return payload == null ? null : (HttpContent)new BinaryPayloadMessageContent(payload, _hubProtocols);

src/Microsoft.Azure.SignalR.Common/Utilities/Rest/IPayloadContentBuilder.cs

@@ -3,7 +3,7 @@
 
 using System;
 using System.Net.Http;
-
+using Azure.Core.Serialization;
 using Microsoft.AspNetCore.SignalR.Protocol;
 
 #nullable enable
@@ -13,4 +13,6 @@ namespace Microsoft.Azure.SignalR.Common;
 internal interface IPayloadContentBuilder
 {
     HttpContent? Build(HubMessage? payload, Type? typeHint);
+
+    ObjectSerializer? ObjectSerializer { get; }
 }

src/Microsoft.Azure.SignalR.Common/Utilities/Rest/JsonPayloadContentBuilder.cs

@@ -24,4 +24,6 @@ public JsonPayloadContentBuilder(ObjectSerializer jsonObjectSerializer)
     {
         return payload == null ? null : new JsonPayloadMessageContent(payload, _jsonObjectSerializer, typeHint);
     }
+
+    public ObjectSerializer? ObjectSerializer => _jsonObjectSerializer;
 }

src/Microsoft.Azure.SignalR.Common/Utilities/RestClient.cs

@@ -25,6 +25,8 @@ internal class RestClient
 
     private readonly IPayloadContentBuilder _payloadContentBuilder;
 
+    private static readonly ObjectSerializer DefaultObjectSerializer = new JsonObjectSerializer();
+
     public RestClient(IHttpClientFactory httpClientFactory, IPayloadContentBuilder contentBuilder)
     {
         _httpClientFactory = httpClientFactory;
@@ -81,10 +83,10 @@ public Task SendMessageWithRetryAsync(
         HttpMethod httpMethod,
         string methodName,
         object?[] args,
-        Func<HttpResponseMessage, bool>? handleExpectedResponse = null,
+        Func<HttpResponseMessage, Task<bool>>? handleExpectedResponse = null,
         CancellationToken cancellationToken = default)
     {
-        return SendAsyncCore(Constants.HttpClientNames.MessageResilient, api, httpMethod, new InvocationMessage(methodName, args), null, AsAsync(handleExpectedResponse), cancellationToken);
+        return SendAsyncCore(Constants.HttpClientNames.MessageResilient, api, httpMethod, new InvocationMessage(methodName, args), null, handleExpectedResponse, cancellationToken);
     }
 
     public Task SendStreamMessageWithRetryAsync(
@@ -99,6 +101,8 @@ public Task SendStreamMessageWithRetryAsync(
         return SendAsyncCore(Constants.HttpClientNames.MessageResilient, api, httpMethod, new StreamItemMessage(streamId, arg), typeHint, AsAsync(handleExpectedResponse), cancellationToken);
     }
 
+    public ObjectSerializer ObjectSerializer => _payloadContentBuilder.ObjectSerializer ?? DefaultObjectSerializer;
+
     private static Uri GetUri(string url, IDictionary<string, StringValues>? query)
     {
         if (query == null || query.Count == 0)

src/Microsoft.Azure.SignalR.Management/ClientInvocation/InvocationResponse.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Text.Json.Serialization;
+
+namespace Microsoft.Azure.SignalR.Management.ClientInvocation;
+
+sealed class InvocationResponse<T>
+{
+    [JsonPropertyName("result")]
+    public T Result { get; set; }
+}

src/Microsoft.Azure.SignalR.Management/HubInstanceFactories/ServiceHubLifetimeManagerFactory.cs

@@ -40,7 +40,8 @@ public IServiceHubLifetimeManager<THub> Create<THub>(string hubName) where THub
                         var httpClientFactory = _serviceProvider.GetRequiredService<IHttpClientFactory>();
                         var serviceEndpoint = _serviceProvider.GetRequiredService<IServiceEndpointManager>().Endpoints.First().Key;
                         var restClient = new RestClient(httpClientFactory, payloadBuilderResolver.GetPayloadContentBuilder());
-                        return new RestHubLifetimeManager<THub>(hubName, serviceEndpoint, _options.ApplicationName, restClient);
+                        var protocolResolver = _serviceProvider.GetRequiredService<IHubProtocolResolver>();
+                        return new RestHubLifetimeManager<THub>(hubName, serviceEndpoint, _options.ApplicationName, restClient, protocolResolver);
                     }
                 default: throw new InvalidEnumArgumentException(nameof(ServiceManagerOptions.ServiceTransportType), (int)_options.ServiceTransportType, typeof(ServiceTransportType));
             }

src/Microsoft.Azure.SignalR.Management/RestApiProvider.cs

@@ -105,6 +105,11 @@ public RestApiEndpoint GetListConnectionsInGroupEndpoint(string appName, string
         return GenerateRestApiEndpoint(appName, hubName, $"/groups/{Uri.EscapeDataString(groupName)}/connections");
     }
 
+    public RestApiEndpoint GetClientInvocationEndpoint(string appName, string hubName, string connectionId)
+    {
+        return GenerateRestApiEndpoint(appName, hubName, $"/connections/{Uri.EscapeDataString(connectionId)}/:invoke");
+    }
+
     private RestApiEndpoint GenerateRestApiEndpoint(string appName, string hubName, string pathAfterHub, IDictionary<string, StringValues> queries = null)
     {
         var requestPrefixWithHub = $"{_serverEndpoint}api/hubs/{Uri.EscapeDataString(hubName.ToLowerInvariant())}";

src/Microsoft.Azure.SignalR.Management/RestHubLifetimeManager.cs

@@ -14,6 +14,10 @@
 using Azure;
 
 using Microsoft.AspNetCore.SignalR;
+#if NET7_0_OR_GREATER
+using System.IO;
+using Microsoft.AspNetCore.SignalR.Protocol;
+#endif
 using Microsoft.Extensions.Primitives;
 
 using static Microsoft.Azure.SignalR.Constants;
@@ -31,13 +35,15 @@ internal class RestHubLifetimeManager<THub> : HubLifetimeManager<THub>, IService
     private readonly RestApiProvider _restApiProvider;
     private readonly string _hubName;
     private readonly string _appName;
+    private readonly IHubProtocolResolver _protocolResolver;
 
-    public RestHubLifetimeManager(string hubName, ServiceEndpoint endpoint, string appName, RestClient restClient)
+    public RestHubLifetimeManager(string hubName, ServiceEndpoint endpoint, string appName, RestClient restClient, IHubProtocolResolver protocolResolver)
     {
         _restApiProvider = new RestApiProvider(endpoint);
         _appName = appName;
         _hubName = hubName;
         _restClient = restClient;
+        _protocolResolver = protocolResolver;
     }
 
     public override async Task AddToGroupAsync(string connectionId, string groupName, CancellationToken cancellationToken = default)
@@ -353,6 +359,103 @@ public async Task SendStreamCompletionAsync(string connectionId, string streamId
         await _restClient.SendWithRetryAsync(api, HttpMethod.Post, handleExpectedResponse: null, cancellationToken: cancellationToken);
     }
 
+#if NET7_0_OR_GREATER
+    public override async Task<T> InvokeConnectionAsync<T>(string connectionId, string methodName, object?[] args, CancellationToken cancellationToken = default)
+    {
+        if (string.IsNullOrEmpty(methodName))
+        {
+            throw new ArgumentException(NullOrEmptyStringErrorMessage, nameof(methodName));
+        }
+        if (string.IsNullOrEmpty(connectionId))
+        {
+            throw new ArgumentException(NullOrEmptyStringErrorMessage, nameof(connectionId));
+        }
+        if (!_protocolResolver.AllProtocols.All(IsInvocationSupported))
+        {
+            throw new NotSupportedException("Non supported protocol for client invocation.");
+        }
+
+        var api = _restApiProvider.GetClientInvocationEndpoint(_appName, _hubName, connectionId);
+        string? errorContent = null;
+        var isSuccess = false;
+        T? resultValue = default;
+
+        await _restClient.SendMessageWithRetryAsync(
+            api,
+            HttpMethod.Post,
+            methodName,
+            args,
+            async response =>
+            {
+                isSuccess = response.IsSuccessStatusCode;
+
+                if (isSuccess)
+                {
+                    await using var contentStream = await response.Content.ReadAsStreamAsync(cancellationToken);
+
+                    // Deserialize whole response into JsonDocument (InvocationResponse "shell")
+                    using var doc = await JsonDocument.ParseAsync(contentStream, cancellationToken: cancellationToken);
+                    var root = doc.RootElement;
+
+                    if (!root.TryGetProperty("result", out var resultProperty))
+                    {
+                        throw new HubException("Response cannot be null or empty.");
+                    }
+
+                    using var resultStream = new MemoryStream();
+                    await using (var utf8Writer = new Utf8JsonWriter(resultStream))
+                    {
+                        resultProperty.WriteTo(utf8Writer);
+                        await utf8Writer.FlushAsync(cancellationToken);
+                    }
+
+                    resultStream.Position = 0;
+
+                    var deserialized = await _restClient.ObjectSerializer.DeserializeAsync(
+                                            resultStream,
+                                            typeof(T),
+                                            cancellationToken);
+                    resultValue = (T)deserialized!;
+                }
+                else
+                {
+                    errorContent = await response.Content.ReadAsStringAsync(cancellationToken);
+                }
+
+                return isSuccess || response.StatusCode == HttpStatusCode.InternalServerError;
+            },
+            cancellationToken);
+
+        if (!isSuccess)
+        {
+            throw new HubException(errorContent ?? "Unknown error in response");
+        }
+
+        return resultValue!;
+    }
+
+    public override Task SetConnectionResultAsync(string connectionId, CompletionMessage result)
+    {
+        // This method won't get trigger because in transient we will wait for the returned completion message.
+        // this is to honor the interface
+        throw new NotImplementedException();
+    }
+
+    private static bool IsInvocationSupported(IHubProtocol protocol)
+    {
+        // Use protocol.Name to check for supported protocols
+        switch (protocol.Name)
+        {
+            case "json":
+            //case "messagepack":
+                return true;
+            default:
+                return false;
+        }
+    }
+
+#endif
+
     private static bool FilterExpectedResponse(HttpResponseMessage response, string expectedErrorCode) =>
         response.IsSuccessStatusCode
         || (response.StatusCode == HttpStatusCode.NotFound && response.Headers.TryGetValues(Headers.MicrosoftErrorCode, out var errorCodes) && errorCodes.First().Equals(expectedErrorCode, StringComparison.OrdinalIgnoreCase));