public async Task <Tuple <string, MemoryStream> > DownloadFileAsync(string id, string bucketName = "")
{
var gridFsBucket = string.IsNullOrEmpty(bucketName)? new GridFSBucket(this.database): new GridFSBucket(this.database, new GridFSBucketOptions
{
BucketName = bucketName
});
MemoryStream destinationStream = new MemoryStream();
//await gridFsBucket.DownloadToStreamAsync(id, destinationStream);
using (GridFSDownloadStream sourceStream = await gridFsBucket.OpenDownloadStreamAsync(new ObjectId(id)))
{
long filezise = sourceStream.Length;
//缓冲区大小
int maxlenth = 4096;
byte[] buffer = new byte[maxlenth];
while (filezise > 0)
{
if (filezise < maxlenth)
{
maxlenth = (int)filezise;
}
await sourceStream.ReadAsync(buffer, 0, maxlenth);
await destinationStream.WriteAsync(buffer, 0, maxlenth);
filezise -= maxlenth;
}
return(new Tuple <string, MemoryStream>(sourceStream.FileInfo.Filename, destinationStream));
}
}
public async Task <GridFSFileInfo> DownloadFileAsync(ObjectId id, GridFSDownloadOptions options = null)
{
var gridFsBucket = new GridFSBucket(this.database);
using (GridFSDownloadStream sourceStream = await gridFsBucket.OpenDownloadStreamAsync(id))
{
long filezise = sourceStream.Length;
//缓冲区大小
int maxlenth = 4096;
byte[] buffer = new byte[maxlenth];
using (FileStream destinationStream = File.Open(_confg + "/" + sourceStream.FileInfo.Filename, FileMode.Create))
{
while (filezise > 0)
{
if (filezise < maxlenth)
{
maxlenth = (int)filezise;
}
await sourceStream.ReadAsync(buffer, 0, maxlenth);
await destinationStream.WriteAsync(buffer, 0, maxlenth);
filezise -= maxlenth;
}
}
return(sourceStream.FileInfo);
}
}
