Cannot set the ContentType of a blob in Azure Data Lake Gen2 in csharp - azure

Question

I'm using the Azure.Storage.Files.DataLake nuget package to write and append file on my Azure Storage account that is enabled for Data Lake Gen2 (including hierarchy).
However, I need to set the Content Type of a new file I create and I don't succeed in it, although I thought I had things written correctly. Here's my code:
public async Task<bool> WriteBytes(string fileName, byte[] recordContent, string contentType)
{
var directory = await CreateDirectoryIfNotExists();
var fileClient = await directory.CreateFileAsync(fileName,
new PathHttpHeaders
{
ContentType = contentType
})).Value;
long recordSize = recordContent.Length;
var recordStream = new MemoryStream(recordContent);
await fileClient.AppendAsync(recordStream, offset: 0);
await fileClient.FlushAsync(position: recordSize);
return true;
}
The result after the execution of the above code looks like this (the default content-type is kept):
Thanks for any insights

Answer 1

I am able to reproduce the behavior you're seeing. Basically the issue is with fileClient.FlushAsync() method. Before calling this method, I checked the content type of the file and it was set properly. However after execution of this method, the content type was changed to application/octet-stream (which is the default).
Looking at the documentation for this method here, you can also set the headers in this method. I tried doing the same and the content type changed to the desired one.
var headers = new PathHttpHeaders()
{
ContentType = "text/plain"
};
await fileClient.FlushAsync(position: recordSize, httpHeaders: headers);