private async Task <Stream> GetStreamAsync(string path, ImageSource source)
{
Stream stream = null;
if (string.IsNullOrWhiteSpace(path))
{
return(null);
}
try
{
switch (source)
{
case ImageSource.ApplicationBundle:
stream = Context.Assets.Open(path, Access.Streaming);
break;
case ImageSource.Filepath:
stream = FileStore.GetInputStream(path);
break;
case ImageSource.Url:
stream = await DownloadCache.GetStreamAsync(path, Parameters.CacheDuration).ConfigureAwait(false);
break;
}
}
catch (Exception ex)
{
Logger.Error("Unable to retrieve image data", ex);
return(null);
}
return(stream);
}
protected async virtual Task <GenerateResult> TryDownloadImageAsync()
{
try
{
if (Parameters.Source != ImageSource.Url)
{
throw new InvalidOperationException("DownloadOnly: Only Url ImageSource is supported.");
}
var data = await DownloadCache.GetStreamAsync(Parameters.Path, CancellationToken.Token, Parameters.OnDownloadStarted, Parameters.CacheDuration, Parameters.CustomCacheKey, Parameters.CacheType).ConfigureAwait(false);
using (var imageStream = data.ImageStream)
{
if (!data.RetrievedFromDiskCache)
{
Logger?.Debug(string.Format("DownloadOnly: {0} successfully downloaded.", Parameters.Path));
}
}
return(GenerateResult.Success);
}
catch (Exception ex)
{
if (ex is OperationCanceledException)
{
return(GenerateResult.Canceled);
}
Logger?.Error(string.Format("DownloadOnly: {0} downloaded failed.", Parameters.Path), ex);
return(GenerateResult.Failed);
}
}