private static async Task Main(string[] args)
{
if (!ParseParameters(args))
{
Logger.WriteWarning(ContentId, 0, "Aspose preview generator process arguments are not correct.");
return;
}
if (!await InitializeAsync())
{
return;
}
try
{
//TODO: use the cancellation token to stop image generation manually
var tokenSource = new CancellationTokenSource();
await GenerateImagesAsync(tokenSource.Token);
}
catch (Exception ex)
{
if (AsposeTools.ContentNotFound(ex))
{
return;
}
Logger.WriteError(ContentId, 0, ex: ex, startIndex: StartIndex, version: Version);
await SetPreviewStatusAsync(-3); // PreviewStatus.Error
}
}
private static Task <int> UploadImageAsync(Stream imageStream, int previewsFolderId, string imageName,
CancellationToken cancellationToken)
{
return(Retrier.RetryAsync(REQUEST_RETRY_COUNT, 50, async() =>
{
imageStream.Seek(0, SeekOrigin.Begin);
var image = await Content.UploadAsync(previewsFolderId, imageName,
imageStream, "PreviewImage").ConfigureAwait(false);
return image.Id;
}, (result, count, ex) =>
{
if (ex == null)
{
return true;
}
if (count == 1 || AsposeTools.ContentNotFound(ex))
{
throw ex;
}
cancellationToken.ThrowIfCancellationRequested();
return false;
}));
}
private static async Task <Stream> GetBinaryAsync()
{
var documentStream = new MemoryStream();
try
{
// download the whole file from the server
await RESTCaller.GetStreamResponseAsync(ContentId, Version, async response =>
{
if (response == null)
{
throw new ClientException($"Content {ContentId} {Version} not found.",
HttpStatusCode.NotFound);
}
await response.Content.CopyToAsync(documentStream).ConfigureAwait(false);
documentStream.Seek(0, SeekOrigin.Begin);
}, CancellationToken.None).ConfigureAwait(false);
}
catch (ClientException ex)
{
if (AsposeTools.ContentNotFound(ex))
{
return(null);
}
Logger.WriteError(ContentId, 0, "Error during remote file access.", ex, StartIndex, Version);
// We need to throw the error further to let the main catch block
// log the error and set the preview status to 'Error'.
throw;
}
return(documentStream);
}
private static Task <dynamic> GetResponseJsonAsync(ODataRequest request, HttpMethod method = null, object body = null)
{
return(Retrier.RetryAsync(REQUEST_RETRY_COUNT, 50,
async() => await RESTCaller.GetResponseJsonAsync(request, method: method ?? HttpMethod.Get, postData: body),
(result, count, ex) =>
{
if (ex == null)
{
return true;
}
// last try: throw the exception
if (count == 1 || AsposeTools.ContentNotFound(ex))
{
throw ex;
}
// failed, but give them a new chance
return false;
}));
}
private static async Task SaveImageStreamAsync(Stream imageStream, string previewName, int page, int previewsFolderId,
CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
imageStream.Seek(0, SeekOrigin.Begin);
try
{
var imageId = await UploadImageAsync(imageStream, previewsFolderId, previewName, cancellationToken);
cancellationToken.ThrowIfCancellationRequested();
// set initial preview image properties (CreatedBy, Index, etc.)
await PostAsync(imageId, "SetInitialPreviewProperties");
}
catch (ClientException ex)
{
// a 404 must be handled by the caller
if (AsposeTools.ContentNotFound(ex))
{
throw;
}
// node is out of date is not an error
if (ex.ErrorData?.ExceptionType?.Contains("NodeIsOutOfDateException") ?? false)
{
return;
}
Logger.WriteError(ContentId, page, ex.Message, ex, StartIndex, Version);
// in case of status 500, we still have to terminate the process after logging the error
if (AsposeTools.IsTerminatorError(ex))
{
throw;
}
}
}