Forge chunk upload .NET Core - autodesk-forge

Question

I have question about uploading large objects in forge bucket. I know that I need to use /resumable api, but how can I get the file( when I have only filename). In this code what is exactly FILE_PATH? Generally, should I save file on server first and then do the upload on bucket?
private static dynamic resumableUploadFile()
{
Console.WriteLine("*****begin uploading large file");
string path = FILE_PATH;
if (!File.Exists(path))`enter code here`
path = #"..\..\..\" + FILE_PATH;
//total size of file
long fileSize = new System.IO.FileInfo(path).Length;
//size of piece, say 2M
long chunkSize = 2 * 1024 * 1024 ;
//pieces count
long nbChunks = (long)Math.Round(0.5 + (double)fileSize / (double)chunkSize);
//record a global response for next function.
ApiResponse<dynamic> finalRes = null ;
using (FileStream streamReader = new FileStream(path, FileMode.Open))
{
//unique id of this session
string sessionId = RandomString(12);
for (int i = 0; i < nbChunks; i++)
{
//start binary position of one certain piece
long start = i * chunkSize;
//end binary position of one certain piece
//if the size of last piece is bigger than total size of the file, end binary
// position will be the end binary position of the file
long end = Math.Min(fileSize, (i + 1) * chunkSize) - 1;
//tell Forge about the info of this piece
string range = "bytes " + start + "-" + end + "/" + fileSize;
// length of this piece
long length = end - start + 1;
//read the file stream of this piece
byte[] buffer = new byte[length];
MemoryStream memoryStream = new MemoryStream(buffer);
int nb = streamReader.Read(buffer, 0, (int)length);
memoryStream.Write(buffer, 0, nb);
memoryStream.Position = 0;
//upload the piece to Forge bucket
ApiResponse<dynamic> response = objectsApi.UploadChunkWithHttpInfo(BUCKET_KEY,
FILE_NAME, (int)length, range, sessionId, memoryStream,
"application/octet-stream");
finalRes = response;
if (response.StatusCode == 202){
Console.WriteLine("one certain piece has been uploaded");
continue;
}
else if(response.StatusCode == 200){
Console.WriteLine("the last piece has been uploaded");
}
else{
//any error
Console.WriteLine(response.StatusCode);
break;
}
}
}
return (finalRes);
}

Answer 1

FILE_PATH: is the path where you stored file on your server.
You should upload your file to server first. Why? Because when you upload your file to Autodesk Forge Server you need internal token, which should be kept secret (that why you keep it in your server), you dont want someone take that token and mess up your Forge Account.

Answer 2

The code you pasted from this article is more about uploading from a server when the file is already stored there - either for caching purposes or the server is using/modifying those files.
As Paxton.Huynh said, FILE_PATH there contains the location on the server where the file is stored.
If you just want to upload the chunks to Forge through your server (to keep credentials and internal access token secret), like a proxy, then it's probably better to just pass on those chunks to Forge instead of storing the file on the server first and then passing it on to Forge - what the sample code you referred to is doing.
See e.g. this, though it's in NodeJS: https://github.com/Autodesk-Forge/forge-buckets-tools/blob/master/server/data.management.js#L171