我正在尝试与不安全的gRPC服务器建立连接。我正在使用gRPC在Docker容器内的两个进程之间进行通信，这就是为什么我不需要任何加密或强身份验证的原因。
服务器的行为符合预期，我可以像这样使用grpcurl进行呼叫：
grpcurl -plaintext localhost:42652 SomeService.DoSomething
现在，我正在尝试从.Net Core应用程序中调用相同的RPC方法：
// Registration of the DI service
services.AddGrpcClient<DaemonService.DaemonServiceClient>(options => {
// Enable support for unencrypted HTTP2
AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
options.Address = new Uri("http://localhost:42652");
// Just a test, doesn't change anything.
options.ChannelOptionsActions.Add(channelOptions => channelOptions.Credentials = ChannelCredentials.Insecure);
});
// Call
var reply = _someServiceClient.DoSomething(new Request());
但是最后一行的调用会导致异常：
fail: Grpc.Net.Client.Internal.GrpcCall[6]
Error starting gRPC call.
System.Net.Http.HttpRequestException: An error occurred while sending the request.
---> System.IO.IOException: The response ended prematurely.
at System.Net.Http.HttpConnection.FillAsync()
at System.Net.Http.HttpConnection.ReadNextResponseHeaderLineAsync(Boolean foldedHeadersAllowed)
at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithNtConnectionAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
at Grpc.Net.Client.Internal.GrpcCall`2.SendAsync(HttpRequestMessage request)
fail: Grpc.Net.Client.Internal.GrpcCall[3]
Call failed with gRPC error status. Status code: 'Cancelled', Message: 'Error starting gRPC call.'.
fail: SomeNamespace.Session.Program[0]
An error occured.
System.Net.Http.HttpRequestException: An error occurred while sending the request.
---> System.IO.IOException: The response ended prematurely.
at System.Net.Http.HttpConnection.FillAsync()
at System.Net.Http.HttpConnection.ReadNextResponseHeaderLineAsync(Boolean foldedHeadersAllowed)
at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithNtConnectionAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
at Grpc.Net.Client.Internal.GrpcCall`2.SendAsync(HttpRequestMessage request)
at Grpc.Net.Client.Internal.GrpcCall`2.GetResponseAsync()
at Grpc.Net.Client.Internal.HttpClientCallInvoker.BlockingUnaryCall[TRequest,TResponse](Method`2 method, String host, CallOptions options, TRequest request)
at Grpc.Core.Interceptors.InterceptingCallInvoker.<BlockingUnaryCall>b__3_0[TRequest,TResponse](TRequest req, ClientInterceptorContext`2 ctx)
at Grpc.Core.ClientBase.ClientBaseConfiguration.ClientBaseConfigurationInterceptor.BlockingUnaryCall[TRequest,TResponse](TRequest request, ClientInterceptorContext`2 context, BlockingUnaryCallContinuation`2 continuation)
at Grpc.Core.Interceptors.InterceptingCallInvoker.BlockingUnaryCall[TRequest,TResponse](Method`2 method, String host, CallOptions options, TRequest request)
at SomeNamespace.RpcServices.DaemonService.DaemonServiceClient.GetVncContainerEnvironment(EmptyRequest request, CallOptions options) in /src/SomeNamespace.RpcServices/obj/Release/netcoreapp3.0/Vnc-container-daemonGrpc.cs:line 98
at SomeNamespace.RpcServices.DaemonService.DaemonServiceClient.GetVncContainerEnvironment(EmptyRequest request, Metadata headers, Nullable`1 deadline, CancellationToken cancellationToken) in /src/SomeNamespace.RpcServices/obj/Release/netcoreapp3.0/Vnc-container-daemonGrpc.cs:line 94
at SomeNamespace.Rpc.RpcEventListener.StartListening() in /src/SomeNamespace/Rpc/RpcEventListener.cs:line 32
您知道我必须做些什么吗？我找不到很多有关建立不安全连接的文档。
答案 0 :(得分：4)
我自己找到了解决方法：
当我将AppContext.SetSwitch移到AddGrpcClient上方时，它起作用。
// Enable support for unencrypted HTTP2
AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
// Registration of the DI service
services.AddGrpcClient<DaemonService.DaemonServiceClient>(options => {
options.Address = new Uri("http://localhost:42652");
options.ChannelOptionsActions.Add(channelOptions => channelOptions.Credentials = ChannelCredentials.Insecure);
});