.NET Core 反向代理中间件和 signalR

Question

我需要在 ASP.NET Core 中做一个反向代理中间件。我有这样的东西。但它不适用于 SignalR。

反向代理的地址为 192.168.187.72:5000； SignalR 192.168.187.62:5000。客户端连接到代理，代理将 url 更改为 SignalR hub url，但在客户端中我总是收到此错误：

The server disconnected before the handshake could be started

代码：

public ReverseProxyMiddleware(RequestDelegate nextMiddleware,ILogger<ReverseProxyMiddleware> logger)
{
    _nextMiddleware = nextMiddleware;
    _logger = logger;
}

public async Task Invoke(HttpContext context)
{
     var targetUri = BuildTargetUri(context.Request);
       
     if (targetUri != null)
     {
         var targetRequestMessage = CreateTargetMessage(context, targetUri);
           
         using (var responseMessage = await _httpClient.SendAsync(targetRequestMessage, HttpCompletionOption.ResponseHeadersRead, context.RequestAborted))
         {
             context.Response.StatusCode = (int)responseMessage.StatusCode;
                
             CopyFromTargetResponseHeaders(context, responseMessage);
             await responseMessage.Content.CopyToAsync(context.Response.Body);
         }

         return;
    }

    await _nextMiddleware(context);
}

private HttpRequestMessage CreateTargetMessage(HttpContext context, Uri targetUri)
{
    var requestMessage = new HttpRequestMessage();

    CopyFromOriginalRequestContentAndHeaders(context, requestMessage);

    requestMessage.RequestUri = targetUri;
    requestMessage.Headers.Host = targetUri.Host;
    requestMessage.Method = GetMethod(context.Request.Method);

    return requestMessage;
}

private void CopyFromOriginalRequestContentAndHeaders(HttpContext context, HttpRequestMessage requestMessage)
{
    var requestMethod = context.Request.Method;
       
    var streamContent = new StreamContent(context.Request.Body);
    requestMessage.Content = streamContent;

    foreach (var header in context.Request.Headers)
    {
        requestMessage.Content?.Headers.TryAddWithoutValidation(header.Key, header.Value.ToArray());
    }
}

private void CopyFromTargetResponseHeaders(HttpContext context, HttpResponseMessage responseMessage)
{
    foreach (var header in responseMessage.Headers)
    {
        context.Response.Headers[header.Key] = header.Value.ToArray();
    }

    foreach (var header in responseMessage.Content.Headers)
    {
        context.Response.Headers[header.Key] = header.Value.ToArray();
    }

    context.Response.Headers.Remove("transfer-encoding");
}

private static HttpMethod GetMethod(string method)
{
    if (HttpMethods.IsDelete(method)) return HttpMethod.Delete;
    if (HttpMethods.IsGet(method)) return HttpMethod.Get;
    if (HttpMethods.IsHead(method)) return HttpMethod.Head;
    if (HttpMethods.IsOptions(method)) return HttpMethod.Options;
    if (HttpMethods.IsPost(method)) return HttpMethod.Post;
    if (HttpMethods.IsPut(method)) return HttpMethod.Put;
    if (HttpMethods.IsTrace(method)) return HttpMethod.Trace;

    return new HttpMethod(method);
}

private Uri BuildTargetUri(HttpRequest request)
{
    Uri targetUri = null;
    StringValues clientId = string.Empty;

    targetUri = new Uri($"http://192.168.187.62:5000{request.Path}{request.QueryString}");

    _logger.LogInformation($"Request URL {request.Host + request.Path + request.QueryString} Target URL {targetUri.ToString()}");

    return targetUri;
}

Answer 1

您确定要手动创建此类功能吗？

有很多很棒的反向代理库，Microsoft 有一个名为 YARP (https://microsoft.github.io/reverse-proxy/) 的新项目，它是一个开源反向代理，据说具有高性能和高度可定制性。

如果您愿意，我可以向您展示如何在 ASP.NET 核心应用程序中使用 yarp 的示例。

.NET Core 反向代理中间件和 signalR

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