这是一个完全有效的示例(复制/粘贴它并尝试一下,只需获取 Polly Nuget)
我有以下控制台应用程序代码,它向 ' 上的 HTTP 客户端沙箱发出 POST 请求http://ptsv2.com/t/v98pb-1521637251/post'(您可以访问此链接“http://ptsv2.com/t/v98pb-1521637251”查看配置或让自己成为一个“厕所”):
class Program
{
private static readonly HttpClient _httpClient = new HttpClient()
; //WHY? BECAUSE - https://aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/
static void Main(string[] args)
{
_httpClient.BaseAddress = new Uri(@"http://ptsv2.com/t/v98pb-1521637251/post");
_httpClient.DefaultRequestHeaders.Accept.Clear();
_httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("text/xml"));
var result = ExecuteAsync("Test").Result;
Console.WriteLine(result);
Console.ReadLine();
}
private static async Task<string> ExecuteAsync(string request)
{
var response = await Policies.PolicyWrap.ExecuteAsync(async () => await _httpClient.PostAsync("", new StringContent(request)).ConfigureAwait(false));
if (!response.IsSuccessStatusCode)
return "Unsuccessful";
return await response.Content.ReadAsStringAsync().ConfigureAwait(false);
}
}
Http 客户端等待 4 秒,然后返回响应。
我已经制定了这样的政策(超时策略设置为等待1秒响应):
public static class Policies
{
public static TimeoutPolicy<HttpResponseMessage> TimeoutPolicy
{
get
{
return Policy.TimeoutAsync<HttpResponseMessage>(1, onTimeoutAsync: (context, timeSpan, task) =>
{
Console.WriteLine("Timeout delegate fired after " + timeSpan.TotalMilliseconds);
return Task.CompletedTask;
});
}
}
public static RetryPolicy<HttpResponseMessage> RetryPolicy
{
get
{
return Policy.HandleResult<HttpResponseMessage>(r => !r.IsSuccessStatusCode)
.Or<TimeoutRejectedException>()
.RetryAsync(3, onRetryAsync: (delegateResult, i) =>
{
Console.WriteLine("Retry delegate fired for time No. " + i);
return Task.CompletedTask;
});
}
}
public static FallbackPolicy<HttpResponseMessage> FallbackPolicy
{
get
{
return Policy.HandleResult<HttpResponseMessage>(r => !r.IsSuccessStatusCode)
.Or<TimeoutRejectedException>()
.FallbackAsync(new HttpResponseMessage(HttpStatusCode.InternalServerError), onFallbackAsync: (delegateResult, context) =>
{
Console.WriteLine("Fallback delegate fired");
return Task.CompletedTask;
});
}
}
public static PolicyWrap<HttpResponseMessage> PolicyWrap
{
get
{
return Policy.WrapAsync(FallbackPolicy, RetryPolicy, TimeoutPolicy);
}
}
}
但是, onTimeoutAsync 委托根本没有被命中,控制台打印出以下内容:
Retry delegate fired for time No. 1 //Hit after 4 seconds
Retry delegate fired for time No. 2 //Hit after 4 more seconds
Retry delegate fired for time No. 3 //Hit after 4 more seconds
Fallback delegate fired
Unsuccessful
它包含在 PolicyWrap 中并且是异步的,我不知道为什么它没有被命中。
任何信息都受到高度赞赏。