Retrying HttpClient Unsuccessful Requests

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Instead of implementing retry functionality that wraps the HttpClient, consider constructing the HttpClient with a HttpMessageHandler that performs the retry logic internally. For example:

public class RetryHandler : DelegatingHandler
{
    // Strongly consider limiting the number of retries - "retry forever" is
    // probably not the most user friendly way you could respond to "the
    // network cable got pulled out."
    private const int MaxRetries = 3;

    public RetryHandler(HttpMessageHandler innerHandler)
        : base(innerHandler)
    { }

    protected override async Task<HttpResponseMessage> SendAsync(
        HttpRequestMessage request,
        CancellationToken cancellationToken)
    {
        HttpResponseMessage response = null;
        for (int i = 0; i < MaxRetries; i++)
        {
            response = await base.SendAsync(request, cancellationToken);
            if (response.IsSuccessStatusCode) {
                return response;
            }
        }

        return response;
    }
}

public class BusinessLogic
{
    public void FetchSomeThingsSynchronously()
    {
        // ...

        // Consider abstracting this construction to a factory or IoC container
        using (var client = new HttpClient(new RetryHandler(new HttpClientHandler())))
        {
            myResult = client.PostAsync(yourUri, yourHttpContent).Result;
        }

        // ...
    }
}

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