/// <summary>
/// Attempts to get an image from the catalog for the specified url.
/// </summary>
/// <param name="imageUrl">The url for the image.</param>
/// <param name="options">The image options.</param>
/// <returns>The image if one is currently stored in the catalog or null if one does not exist.</returns>
public byte[] TryGetImage(string imageUrl, ImageOptions options)
{
return(this.imageCache.TryGet(this.GetRequestKey(imageUrl, options)));
}
private RemoteImageRequest AttemptRetry(RemoteImageRequest failedRequest, string imageUrl, ImageOptions options)
{
if (!failedRequest.IsRequestCompleted)
{
throw new ArgumentException("The request has not completed.", nameof(failedRequest));
}
if (failedRequest.Task.Result.ResultCode == ServiceResultCode.Success)
{
throw new ArgumentException("The request was successful, no retry needed.", nameof(failedRequest));
}
if (failedRequest.Task.Result.ResultCode == ServiceResultCode.ResourceNotFound ||
failedRequest.RetryCounter == this.maxRetryAttempts)
{
return(failedRequest);
}
int retryCounter = failedRequest.RetryCounter;
if (failedRequest.Task.Result.ResultCode != ServiceResultCode.NetworkUnavailable)
{
// If the network is unavailable we will keep retrying until it becomes available.
// It is assumed that the underlying remote client is optimized to handle network status
// so that a call to make repeated remote request is cheap.
retryCounter++;
}
string requestKey = this.GetRequestKey(imageUrl, options);
this.TryRemoveRequest(requestKey);
return(this.TryStartImageRequest(imageUrl, options, retryCounter));
}
/// <summary>
/// Removes the specified image from the cache if it exists.
/// </summary>
/// <param name="imageUrl">The url for the image.</param>
/// <param name="options">The image options for the image.</param>
public void RemoveCachedImage(string imageUrl, ImageOptions options)
{
string key = this.GetRequestKey(imageUrl, options);
this.imageCache.Remove(key);
}
/// <summary>
/// Gets whether or not an image for the specified url is currently stored in cache.
/// </summary>
/// <param name="imageUrl">The url for the image.</param>
/// <param name="options">The options for the image.</param>
/// <returns>True if the image for the url is currently stored in cache, otherwise false.</returns>
public bool IsInCache(string imageUrl, ImageOptions options)
{
string requestKey = this.GetRequestKey(imageUrl, options);
return(this.imageCache.Exists(requestKey));
}
/// <summary>
/// Adds the specified image into the cache if it does not exist or updates it if one already exists.
/// </summary>
/// <param name="imageUrl">The url for the image.</param>
/// <param name="options">The image options for the image.</param>
/// <param name="imageData">The image as bytes.</param>
public void AddOrUpdateCachedImage(string imageUrl, ImageOptions options, byte[] imageData)
{
string key = this.GetRequestKey(imageUrl, options);
this.imageCache.Put(key, imageData);
}