/* This Handler must be configured as the PrimaryHttpMessageHandler to be able to
* be invoked during the Polly retry attempts and also swapout the
* OperationCanceledException when a request timeout occurs
* This Handler has a dual purpose for the above reason
*/
protected async override Task <HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
using (var cts = GetCancellationTokenSource(request, cancellationToken))
{
try
{
// If the Polly WaitAndRetryAsync handler has ran we will have the Retry Info
Polly.Context context = request.GetPolicyExecutionContext();
RetryInfo retryInfo = context.GetRetryInfo();
if (retryInfo != null)
{
// Log the fact that this request is due to a retry
_logger.LogWarning($"{DateTime.Now.ToString()} : Retrying {request.Method.ToString()} Request to Resource: {context["Resource"]}");
}
var response = await base.SendAsync(request, cts?.Token ?? cancellationToken);
return(response);
}
catch (OperationCanceledException ex) when(!cancellationToken.IsCancellationRequested)
{
// Throw a TimeoutException with useful message and pass along the InnerException
var tex = new TimeoutException($"Request timed out, did not receive response within {(request.GetTimeout() ?? DefaultTimeout).TotalSeconds} seconds", ex.InnerException);
// Set the source of the exception
tex.Source = "TimeoutHandler";
throw tex;
}
catch (Exception ex)
{
throw ex;
}
}
}
static async Task PollyTest()
{
var atr = new CRL.Core.Remoting.PollyAttribute();
//atr.TimeOutTime = TimeSpan.FromMilliseconds(100);
atr.CircuitBreakerCount = 2;
atr.RetryCount = 1;
var pollyCtx = new Polly.Context();
var response = await PollyExtension.InvokeAsync <string>(atr, async() =>
{
//await Task.Delay(200);
throw new Exception("has error");
return(await Task.FromResult(new CRL.Core.Remoting.PollyExtension.PollyData <string>()
{
Data = "ok"
}));
}, "");
if (pollyCtx.ContainsKey("msg"))
{
Console.WriteLine(pollyCtx["msg"]);
}
//var str = PollyExtension.Invoke(atr, () =>
// {
// throw new Exception("has error");
// //System.Threading.Thread.Sleep(200);
// return new PollyExtension.PollyData<string>() { Error = "ok" };
// }, "test");
Console.WriteLine(response.ToJson());
}
/* This Handler must be configured as the PrimaryHttpMessageHandler so that it
* gets invoked during the Polly retry attempts and is able to detect the original url and method
* This handler swaps out OperationCanceledException when a request timeout occurs
* This Handler adds info about the request into the Request Properties and Exception Data
* This Handler has 3 purposes but can't be split out as the above functions rely on it being the primary handler.
*/
protected async override Task <HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
using (var cts = GetCancellationTokenSource(request, cancellationToken))
{
try
{
// If the Polly WaitAndRetryAsync handler has ran we will have the Retry Info
Polly.Context context = request.GetPolicyExecutionContext();
RetryInfo retryInfo = context.GetRetryInfo();
// The RequestUri and Method will always be the original ones as this code will not be hit
// if a redirection occurs as it is handles further down the chain.
if (retryInfo == null)
{
AugmentRequest(request);
}
else
{
// It's possible to detect a redirect here during a retry as the new request uses the redirected url
string requestUrl = request?.RequestUri?.AbsoluteUri?.ToString();
string resourcePath = (string)request.GetResourcePath();
string originalRequestUrl = (string)request.GetOriginalRequestUrl();
bool isRedirected = false;
if (!String.IsNullOrEmpty(requestUrl) && requestUrl != originalRequestUrl)
{
isRedirected = true;
}
string redirected = isRedirected ? " Redirected" : "";
string originalRequestMethod = (string)request.GetOriginalRequestMethod();
// Log the fact that this request is due to a retry
_logger.LogWarning($"{DateTime.Now.ToString()} SendAsync: Retrying a Failed{redirected} {originalRequestMethod} Request to Resource: {resourcePath} {redirected}Url: {requestUrl}");
}
var response = await base.SendAsync(request, cts?.Token ?? cancellationToken);
return(response);
}
catch (OperationCanceledException ex) when(!cancellationToken.IsCancellationRequested)
{
// Also catches TaskCanceledException as it is a subclass of OperationCanceledException
// Throw a TimeoutException with useful message and pass along the InnerException
var tex = new TimeoutException($"Request timed out, did not receive response within {(request.GetTimeout() ?? DefaultTimeout).TotalSeconds} seconds", ex.InnerException);
// Set the source of the exception
tex.Source = "TimeoutHandler";
AugmentException(tex, request);
throw tex;
}
catch (Exception ex)
{
_logger.LogError($"{DateTime.Now.ToString()} SendAsync: Exception occurred in SendAsync() method, Request Url: {request?.RequestUri?.AbsoluteUri?.ToString()} Exception:\n{ex.ToString()}");
AugmentException(ex, request);
throw ex;
}
}
}
public static void SetRetryInfo(this Polly.Context context, RetryInfo retryInfo)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
context[PropertyKeys.RetryInfoKey] = retryInfo;
}
public static Task <HttpResponseMessage> FallbackValueFactory(Polly.Context context, CancellationToken cancellationToken)
{
var items = Enumerable.Empty <WeatherForecast>();
var json = System.Text.Json.JsonSerializer.Serialize(items);
var response = new HttpResponseMessage(System.Net.HttpStatusCode.OK)
{
Content = new StringContent(json, Encoding.UTF8, "application/json")
};
return(Task.FromResult(response));
}
public static RetryInfo GetRetryInfo(this Polly.Context context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
object retryInfo = null;
context.TryGetValue(PropertyKeys.RetryInfoKey, out retryInfo);
if (retryInfo != null && retryInfo is RetryInfo)
{
return((RetryInfo)retryInfo);
}
return(null);
}
protected async Task <T> SendRequestAsync <T>(PollyAttribute pollyAttr, Request.ImitateWebRequest request, string url, string httpMethod, string postArgs, string pollyKey, Func <string, T> dataCall)
{
var pollyCtx = new Polly.Context();
//var response = await request.SendDataAsync(url, httpMethod.ToString(), postArgs);
var pollyData = await PollyExtension.InvokeAsync(pollyAttr, async() =>
{
var res = await request.SendDataAsync(url, httpMethod.ToString(), postArgs);
return(new PollyExtension.PollyData <string>()
{
Data = res
});
}, pollyKey);
if (!string.IsNullOrEmpty(pollyData.Error))
{
ThrowError(pollyData.Error, "500");
}
//转换为指定的类型
return(dataCall(pollyData.Data));
}
public static void SetPolicyExecutionContext(this System.Net.Http.HttpRequestMessage request, Polly.Context context)
{
}
protected virtual System.Threading.Tasks.Task <System.Net.Http.HttpResponseMessage> SendCoreAsync(System.Net.Http.HttpRequestMessage request, Polly.Context context, System.Threading.CancellationToken cancellationToken)
{
throw null;
}
