/// <summary> Watch a file for changes.
public IChangeToken Watch(string filter)
{
if (_pollingInterval == null)
{
return(null);
}
_logger.LogDebug("Watching {0}", filter);
var path = SplitObjectPath(filter);
var token = new CloudStorageChangeToken();
var obj = GetObject(path);
Task.Run(() => PollAsync(path, token, obj?.Generation));
return(token);
}
async Task PollAsync(ObjectPath path, CloudStorageChangeToken token,
long?generation)
{
while (true)
{
await Task.Delay(_pollingInterval.Value);
try
{
var obj = GetObject(path);
if (generation != obj?.Generation)
{
token.NotifyChanged();
return;
}
}
catch (Exception e)
{
_logger.LogError(0, e, "Exception while watching {0}/{1}",
path.BucketName, path.ObjectName);
}
}
}