/// <summary>Subtest that back-off handler works as expected when exception is or isn't thrown.</summary>
private void SubtestSendAsync_BackOffExceptionHandler(bool throwException,
BackOffHandler.Initializer initializer, Exception exceptionToThrow = null)
{
var handler = new ExceptionMessageHandler { ThrowException = throwException };
if (exceptionToThrow != null)
{
handler.Exception = exceptionToThrow;
}
var configurableHanlder = new ConfigurableMessageHandler(handler);
var boHandler = new MockBackOffHandler(initializer);
configurableHanlder.AddExceptionHandler(boHandler);
int boHandleCount = 0;
// if an exception should be thrown and the handler can handle it then calculate the handle count by the
// lg(MaxTimeSpan)
if (throwException && initializer.HandleExceptionFunc(exceptionToThrow))
{
boHandleCount = Math.Min((int)Math.Floor(Math.Log(boHandler.MaxTimeSpan.TotalSeconds, 2)) + 1,
configurableHanlder.NumTries - 1);
boHandleCount = boHandleCount >= 0 ? boHandleCount : 0;
}
using (var client = new HttpClient(configurableHanlder))
{
var request = new HttpRequestMessage(HttpMethod.Get, "https://test-exception-handler");
try
{
HttpResponseMessage response = client.SendAsync(request).Result;
Assert.False(throwException);
}
catch (AggregateException ae)
{
Assert.True(throwException);
// Don't compare exception messages because for TaskCanceledException the message
// on Mono is different if there is a task associated with the exception.
Assert.AreEqual(handler.Exception.GetType(), ae.InnerException.GetType());
}
Assert.That(boHandler.Waits.Count, Is.EqualTo(boHandleCount));
// check the exponential behavior - wait 1, 2, 4, 8, ... seconds.
if (throwException)
{
for (int i = 0; i < boHandler.Waits.Count; ++i)
{
Assert.That(boHandler.Waits[i].TotalSeconds, Is.EqualTo((int)Math.Pow(2, i)));
}
}
Assert.That(handler.Calls, Is.EqualTo(boHandleCount + 1));
}
}
/// <summary>
/// Subtest that back-off handler works as expected when a successful or abnormal response is returned.
/// For testing the back-off handler in case of a canceled request, set the <code>cancelRequestNum</code>
/// parameter to the index of the request you want to cancel.
/// </summary>
private void SubtestSendAsync_BackOffUnsuccessfulResponseHandler(HttpStatusCode statusCode,
BackOffHandler.Initializer initializer, int cancelRequestNum = 0, int numTries = 10)
{
var handler = new UnsuccessfulResponseMessageHandler { ResponseStatusCode = statusCode };
CancellationToken cancellationToken = CancellationToken.None;
bool cancel = cancelRequestNum > 0;
if (cancel)
{
CancellationTokenSource tcs = new CancellationTokenSource();
handler.CancellationTokenSource = tcs;
handler.CancelRequestNum = cancelRequestNum;
cancellationToken = tcs.Token;
}
var configurableHanlder = new ConfigurableMessageHandler(handler)
{
NumTries = numTries
};
var boHandler = new MockBackOffHandler(initializer);
configurableHanlder.AddUnsuccessfulResponseHandler(boHandler);
int boHandleCount = 0;
if (initializer.HandleUnsuccessfulResponseFunc != null &&
initializer.HandleUnsuccessfulResponseFunc(new HttpResponseMessage { StatusCode = statusCode }))
{
boHandleCount = Math.Min((int)Math.Floor(Math.Log(boHandler.MaxTimeSpan.TotalSeconds, 2)) + 1,
configurableHanlder.NumTries - 1);
boHandleCount = boHandleCount >= 0 ? boHandleCount : 0;
if (cancel)
{
boHandleCount = Math.Min(boHandleCount, cancelRequestNum);
}
}
using (var client = new HttpClient(configurableHanlder))
{
var request = new HttpRequestMessage(HttpMethod.Get, "https://test-exception-handler");
try
{
HttpResponseMessage response = client.SendAsync(request, cancellationToken).Result;
Assert.False(cancel);
}
catch (AggregateException ae)
{
// a canceled request should throw an exception
Assert.IsInstanceOf<TaskCanceledException>(ae.InnerException);
Assert.True(cancel);
}
Assert.That(boHandler.Waits.Count, Is.EqualTo(boHandleCount));
// check the exponential behavior - wait 1, 2, 4, 8, ... seconds.
for (int i = 0; i < boHandler.Waits.Count; ++i)
{
Assert.That(boHandler.Waits[i].TotalSeconds, Is.EqualTo((int)Math.Pow(2, i)));
}
// if the request was canceled the number of calls to the message handler is equal to the number of
// calls to back-off handler
Assert.That(handler.Calls, Is.EqualTo(boHandleCount + (cancel ? 0 : 1)));
}
}
/// <summary>Constructs a new back-off handler by the given initializer.</summary>
public MockBackOffHandler(BackOffHandler.Initializer initializer)
: base(initializer)
{
Waits = new List<TimeSpan>();
}