public async Task <string> DownloadFileAsync(GridFSFileInfo file)
{
var gridFsBucket = new GridFSBucket(GetDatabase());
string filename = file.Metadata["fileName"].AsString;
string targetDir = Path.Combine(ProgramUI.GetWorkspaceDirectory(), MongoConfig.MongoConfigName);
if (!Directory.Exists(targetDir))
{
Directory.CreateDirectory(targetDir);
}
string extension = ".bin";
if (file.ContentType.Equals("plain/text", StringComparison.CurrentCultureIgnoreCase))
{
extension = ".txt";
}
string targetFilename = Path.Combine(targetDir, filename + "_" + file.Id.ToString() + extension);
Logger.Log($"Saving file to {targetFilename}");
// using (GridFSDownloadStream<ObjectId> sourceStream = await gridFsBucket.OpenDownloadStreamByNameAsync(filename))
using (GridFSDownloadStream sourceStream = await gridFsBucket.OpenDownloadStreamAsync(file.Id))
{
using (FileStream destinationStream = File.Open(targetFilename, FileMode.Create))
{
await sourceStream.CopyToAsync(destinationStream);
}
}
return(targetFilename);
}
public async Task DemoDownloadFileAsync(IMongoDatabase database, string filePath, string fileName)
{
var gridFsBucket = new GridFSBucket(database);
using (
GridFSDownloadStream <ObjectId> sourceStream = await gridFsBucket.OpenDownloadStreamByNameAsync(fileName)
)
{
using (FileStream destinationStream = File.Open(filePath, FileMode.Create))
{
await sourceStream.CopyToAsync(destinationStream);
}
}
}
public Task <bool> CopyTo(Stream stream, CancellationToken cancellationToken)
{
if (stream is null)
{
throw new ArgumentNullException(nameof(stream));
}
const int MinBufferSize = 81920;
const int MaxBufferSize = 1 << 20;
var bufferSize = Math.Min(Math.Max(_stream.FileInfo.ChunkSizeBytes, MinBufferSize), MaxBufferSize);
return(_errorHandler.HandleErrors(
Copy,
Filename,
() => (stream.CanSeek && _stream.CanSeek) || _stream.Position == 0,
cancellationToken));
async Task <bool> Copy()
{
var position = stream.CanSeek ? stream.Position : 0;
try
{
if (_stream.Position != 0)
{
_stream.Position = 0;
}
await _stream.CopyToAsync(stream, bufferSize, cancellationToken);
}
catch (GridFSChunkException) when(position == 0 && _stream.Position == 0)
{
return(false);
}
catch (GridFSChunkException) when(stream.CanSeek)
{
stream.SetLength(position);
return(false);
}
catch when(stream.CanSeek)
{
stream.SetLength(position);
throw;
}
return(true);
}
}
private async Task <bool> CopyToImpl(Stream stream, CancellationToken cancellationToken)
{
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
if (_stream.Position != 0)
{
var newStream = await _bucket.OpenDownloadStreamAsync(_stream.FileInfo.Id, null, cancellationToken);
if (newStream == null)
{
return(false);
}
using (_stream)
{
_stream = newStream;
}
}
const int MinBufferSize = 81920;
const int MaxBufferSize = 1 << 20;
var bufferSize = Math.Min(Math.Max(_stream.FileInfo.ChunkSizeBytes, MinBufferSize), MaxBufferSize);
var position = stream.CanSeek ? stream.Position : 0;
try
{
await _stream.CopyToAsync(stream, bufferSize, cancellationToken);
}
catch (GridFSChunkException) when(_stream.Position == 0 && position == 0)
{
return(false);
}
catch (GridFSChunkException) when(stream.CanSeek)
{
stream.SetLength(position);
return(false);
}
catch when(stream.CanSeek)
{
stream.SetLength(position);
throw;
}
return(true);
}
