如何安全地从委派处理程序中引发异常

Question

我有一个委托处理程序，它根据从服务器收到的错误消息引发特定异常。这允许客户端重试(使用 polly，但如您所见，机制无关紧要(两次尝试失败后，第三次尝试将挂起。没有数据到达服务器，也没有进一步的事情发生。这似乎是因为 HttpClient 最多有两个连接，这表明这些连接没有正确关闭。我可以做些什么来关闭连接，或者我应该更改设计以使委派处理程序不会引发异常？

请参阅下面的简单示例以重现

private class Test : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var response = await base.SendAsync(request, cancellationToken);
        throw new Exception("afesaf");
    }
}
[HttpGet]
[Route("B")]
public async Task B()
{
    var handler = new HttpClientHandler();
    var pipeline = HttpClientFactory.CreatePipeline(handler, new[] { new Test() });
    var http = new HttpClient(pipeline);
    http.BaseAddress = new Uri("http://google.com");
    var count = 0;
    while (count++ < 5)
    try
    {
        Log.Info("A");
        var request = new HttpRequestMessage(HttpMethod.Get, "");
        await http.SendAsync(request, HttpCompletionOption.ResponseContentRead, CancellationToken.None).ConfigureAwait(false);
    }
    catch
    {
    }
}

Answer 1

释放

响应对象。

我在委派处理程序中使用了以下内容，因为我有多个点可以在实际代码中抛出异常

protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
    HttpResponseMessage response = null;
    try
    {         
        response = await base.SendAsync(request, cancellationToken);
        throw new Exception("afesaf");
    } 
    catch
    {
        response?.Dispose();
        throw 
    }
}