private async Task MessageHandler(Message message, CancellationToken cancellationToken)
{
if (await _subscriptionClient.WaitForPause(message, cancellationToken))
{
return;
}
// Note: About exception handling
// Any exception leaving this method will cause the message to be retried later.
// If you consider the exception to be permanent, complete the message.
// This is just examples of error handling
AvailableBlobEvent metadata;
try
{
metadata = message.DeserializeJsonBody <AvailableBlobEvent>();
}
catch (Exception ex)
{
Console.WriteLine($"Permanent error: {ex.Message}");
await _subscriptionClient.CompleteMessage(message);
return;
}
Console.WriteLine(
$"Got message of type '{metadata.BlobType}' and with correlation-id '{metadata.CorrelationId}', uri '{metadata.Uri}'. Content had format '{metadata.ContentType}'");
// Save incoming blob to a temporary file. This could of course be done in memory, or to some database
var blobLocalStorage = LocalStorageUtility.GetNewWorkingFile();
await _blobDownloader.DownloadBlobAsync(metadata, blobLocalStorage, cancellationToken);
await ProcessFile(message.MessageId, metadata, blobLocalStorage);
await _subscriptionClient.CompleteMessage(message);
LocalStorageUtility.RemoveWorkingFile(blobLocalStorage);
}
private async Task MessageHandler(Message message, CancellationToken cancellationToken)
{
if (await _subscriptionClient.WaitForPause(message, cancellationToken))
{
return;
}
// Note: If anything in this method throws an exception, the message-handling will be retried later.
// To prevent this, catch the exception here, figure out if it is transient or permanent and complete the message depending on that.
// This is just examples of error handling
AvailableBlobEvent metadata;
try
{
metadata = message.DeserializeJsonBody <AvailableBlobEvent>();
}
catch (Exception ex)
{
Console.WriteLine($"Permanent error: {ex.Message}");
await _subscriptionClient.CompleteMessage(message);
return;
}
LogMessage(metadata);
var blobLocalStorage = LocalStorageUtility.GetNewWorkingFile();
await _blobDownloader.DownloadBlobAsync(metadata, blobLocalStorage);
await ProcessFile(message.MessageId, metadata, blobLocalStorage);
await _subscriptionClient.CompleteMessage(message);
LocalStorageUtility.RemoveWorkingFile(blobLocalStorage);
}