如何“独立”使用PolicyHttpMessageHandler？

我只是想创建一个简单的测试，我使用DelegateHandlers实例化一个HttpClient无需带Asp.net Core包。 我有 2 个删除处理程序

• ThrottlingDelegatingHandler
• PolicyHttpMessageHandler（来自波莉包）

我怎样才能将两者结合起来并传递给HttpClient?

var policy = HttpPolicyExtensions.HandleTransientHttpError().CircuitBreakerAsync(5, TimeSpan.FromSeconds(30));
var pollyHandler = new PolicyHttpMessageHandler(policy);
var http = new HttpClient(new ThrottlingDelegatingHandler(MaxParallelism, pollyHandler));

上面给了我一个错误：System.InvalidOperationException : The inner handler has not been assigned.

The PolicyHttpMessageHandler没有可以传递的构造函数innerHandler.

我怎样才能做到这一点？

你必须设置InnerHandler在你最内心的处理者中HttpClientHandler像这样：

var policy = HttpPolicyExtensions.HandleTransientHttpError().CircuitBreakerAsync(5, TimeSpan.FromSeconds(30));
var pollyHandler = new PolicyHttpMessageHandler(policy);

//New line
pollyHandler.InnerHandler = new HttpClientHandler();

var http = new HttpClient(new ThrottlingDelegatingHandler(MaxParallelism, pollyHandler));

您基本上必须设置管道中的下一个处理程序。

以供参考：如果未指定处理程序，这就是 HttpClient 的构造方式

#region Constructors

public HttpClient() : this(new HttpClientHandler())
{
}

public HttpClient(HttpMessageHandler handler) : this(handler, true)
{
}

public HttpClient(HttpMessageHandler handler, bool disposeHandler) : base(handler, disposeHandler)
{
    _timeout = s_defaultTimeout;
    _maxResponseContentBufferSize = HttpContent.MaxBufferSize;
    _pendingRequestsCts = new CancellationTokenSource();
}

#endregion Constructors

哪里的base is the HttpMessageInvoker class