Stream video in chunks to client. Server controller in a Kestrel hosted Blazor WASM ASP.NET Core 6 preview 1 / C# 9 project

StreamController.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.FileProviders;
using Microsoft.Extensions.Logging;
using System;
using System.IO;
using System.Threading.Tasks;

namespace Media.Server.Controllers
{
	[Route("[controller]")]
	public class StreamController : ControllerBase
	{
		private readonly IWebHostEnvironment env;
		private readonly ILogger<StreamController> logger;
		public StreamController(ILogger<StreamController> logger, IWebHostEnvironment env)
		{
			this.logger = logger;
			this.env = env;
		}

		[HttpGet("{file}")]
		public async Task GetStream(string file)
		{
			var provider = new PhysicalFileProvider(env.ContentRootPath);
			string videoPathFile = Path.Combine(provider.Root, "Files", "Videos", $"{file}");
			byte[] buffer = new byte[1024 * 1024 * 4]; // 'Chunks' of 4MB
			long startPosition = 0;

			if (!string.IsNullOrEmpty(Request.Headers["Range"]))
			{
				string[] range = Request.Headers["Range"].ToString().Split(new char[] { '=', '-' });
				startPosition = long.Parse(range[1]);
			}

			using FileStream inputStream = new(videoPathFile, FileMode.Open, FileAccess.Read, FileShare.Read)
			{
				Position = startPosition
			};
			//using FileStream inputStream = fileStream;
			int chunkSize = await inputStream.ReadAsync(buffer.AsMemory(0, buffer.Length));
			long fileSize = inputStream.Length;

			if (chunkSize > 0)
			{
				Response.StatusCode = 206;
				Response.Headers["Accept-Ranges"] = "bytes";
				Response.Headers["Content-Range"] = string.Format($" bytes {startPosition}-{fileSize - 1}/{fileSize}");
				Response.ContentType = "application/octet-stream";

				using Stream outputStream = Response.Body;
				await outputStream.WriteAsync(buffer.AsMemory(0, chunkSize));
			};
		}
	}
}