Can i use putblock as append blob? - asp.net-core-webapi

Question

So I am trying to upload file chunk by chunk...
Can PutBlock be used to append to an existing BlockBlob in Azure from this example...
I am uploading a 20mb file but finally, when I see it on the container it is 7mb and when I download blob it is broken... What am I doing wrong?
public async Task AppendBlobOnAsset(Stream stream, MediaServiceRequest request)
{
var cloudBlobContainer = new CloudBlobContainer(request.InputAssetStorageUri);
var blockBlob = cloudBlobContainer.GetBlockBlobReference(request.BlobName);
var blockList = new List<ListBlockItem>();
var blockListItems = new List<string>();
if (true)
{
var blocks = await blockBlob.DownloadBlockListAsync();
blockList = blocks.ToList();
blockListItems = blockList.Select(x => x.Name).ToList();
}
//string blockId = Guid.NewGuid().ToString("m");
string blockId = Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes("0000005"));
blockBlob.PutBlock(blockId, stream, null);
blockListItems.Add(blockId);
blockBlob.PutBlockList(blockListItems);
}
using var file = File.OpenRead("C:\\Projects\\file.mp4");
int bytesRead;
var appendBlobMaxAppendBlockBytes = 4000000;
var buffer = new byte[appendBlobMaxAppendBlockBytes];
while ((bytesRead = await file.ReadAsync(buffer, 0, buffer.Length)) > 0)
{
var newArray = new Span<byte>(buffer, 0, bytesRead).ToArray();
Stream stream = new MemoryStream(newArray);
stream.Position = 0;
await AppendBlobOnAsset(stream, request);
}

Answer 1

public async Task AppendBlobOnAssetAsync(int blockId, Stream stream, MediaServiceRequest request)
{
var cloudBlobContainer = new CloudBlobContainer(request.InputAssetStorageUri);
var blockBlob = cloudBlobContainer.GetBlockBlobReference(request.BlobName);
var blockItems = new List<ListBlockItem>();
var blockItemIds = new List<string>();
if (blockId > 0)
{
var blocks = await blockBlob.DownloadBlockListAsync();
blockItems = blocks.ToList();
blockItemIds = blockItems.Select(x => x.Name).ToList();
}
var Id = Convert.ToBase64String(Encoding.UTF8.GetBytes(blockId.ToString(CultureInfo.InvariantCulture).PadLeft(30, '0')));
blockBlob.PutBlock(Id, stream, null);
blockItemIds.Add(Id);
blockBlob.PutBlockList(blockItemIds);
}