DownloadFeedTrasientErrorDetectionStrategy.cs

/// <summary> 
/// Provides the transient error detection logic that can recognize transient faults when dealing with reading online feed. 
/// </summary> 
internal class DownloadFeedTrasientErrorDetectionStrategy : ITransientErrorDetectionStrategy
{
    /// <summary> 
    /// Determines whether the specified exception represents a transient failure that can be compensated by a retry. 
    /// </summary> 
    /// <param name="ex">The exception object to be verified.</param> 
    /// <returns>True if the specified exception is considered as transient, otherwise false.</returns> 
    public bool IsTransient(Exception ex)
    {
        return CheckIsTransientInternal(ex);
    }
 
    /// <summary>
    /// Allows you to override the call to change or extend the behavior by extending this class.
    /// </summary>
    /// <param name="ex">The error to check.</param>
    /// <returns></returns>
    protected virtual bool CheckIsTransientInternal(Exception ex)
    {
        return CheckIsTransient(ex);
    }
 
    private static bool CheckIsTransient(Exception ex)
    {
        if (ex is TimeoutException)
        {
            return true;
        }
        else if (ex is WebException)
        {
            return true;
        }
        else if (ex is UnauthorizedAccessException)
        {
            return false;
        }
 
        return false;
    }
}