DynamicHttpErrorHandler Class

Namespace
Kampute.HttpClient.ErrorHandlers
Assembly
  • Kampute.HttpClient.dll

Definition

Handles error responses with a function, without defining a handler class.
public class DynamicHttpErrorHandler : IHttpErrorHandler
Inheritance
Implements

Remarks

The handler accepts every status code, so it is asked about every error response that the handlers added before it do not retry. The function decides, for example by checking HttpResponseErrorContext.Response, whether to return a request to retry.

Examples

This handler retries a request up to three times, one second apart, while the server answers '409 Conflict'. The policy object is the source of the retries, so they are counted separately from the retries of other handlers.
var conflictRetries = RetryStrategies.Constant(TimeSpan.FromSeconds(1)).WithMaxRetries(3).ToHttpRetryPolicy();

client.ErrorHandlers.Add(new DynamicHttpErrorHandler((ctx, cancellationToken) =>
    ctx.Response.StatusCode == HttpStatusCode.Conflict
        ? ctx.ScheduleRetryAsync(conflictRetries, errorContext => conflictRetries.CreateSession(errorContext), cancellationToken)
        : Task.FromResult(HttpErrorHandlerResult.NoRetry)));

Constructors

DynamicHttpErrorHandler(Func<HttpResponseErrorContext, CancellationToken, Task<HttpErrorHandlerResult>>)

Initializes a new instance of the DynamicHttpErrorHandler class.
public DynamicHttpErrorHandler(Func<HttpResponseErrorContext, CancellationToken, Task<HttpErrorHandlerResult>> asyncHandler)

Parameters

asyncHandler Func<HttpResponseErrorContext, CancellationToken, Task<HttpErrorHandlerResult>>
The function that decides. It receives the context of the error response and a cancellation token, and returns the decision.

Exceptions

ArgumentNullException
Thrown if asyncHandler is null.

Methods

CanHandle(HttpStatusCode)

Determines whether the handler is capable of handling the provided HTTP status code.
public bool CanHandle(HttpStatusCode statusCode)

Parameters

statusCode HttpStatusCode
The HTTP status code to evaluate.

Returns

bool
Always true.

DecideOnRetryAsync(HttpResponseErrorContext, CancellationToken)

Calls the function of this handler to decide whether to retry a request after an error response.
protected virtual Task<HttpErrorHandlerResult> DecideOnRetryAsync(HttpResponseErrorContext ctx, CancellationToken cancellationToken)

Parameters

ctx HttpResponseErrorContext
The context containing information about the HTTP response that indicates a failure.
cancellationToken CancellationToken
A token for canceling the operation.

Returns

Task<HttpErrorHandlerResult>
A task that resolves to an HttpErrorHandlerResult, indicating whether the request should be retried.

Explicit Interface Implementations

IHttpErrorHandler.DecideOnRetryAsync(HttpResponseErrorContext, CancellationToken)

Decides whether to retry a request after an error response.
Task<HttpErrorHandlerResult> IHttpErrorHandler.DecideOnRetryAsync(HttpResponseErrorContext ctx, CancellationToken cancellationToken)

Parameters

ctx HttpResponseErrorContext
The context containing information about the HTTP response that indicates a failure.
cancellationToken CancellationToken
A token for canceling the operation.

Returns

Task<HttpErrorHandlerResult>
A task that resolves to HttpErrorHandlerResult.Retry(HttpRequestMessage) with the request to send, or to HttpErrorHandlerResult.NoRetry to let the next handler decide.

Exceptions

ArgumentNullException
Thrown if ctx is null.