Up:: CSharp

Uploading files in CSharp using .net core

found links:

• Upload files in ASP.NET Core | Microsoft Learn

Code snippet:

 
/// Source
/// https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/mvc/models/file-uploads/samples/5.x/LargeFilesSample/Controllers/FileUploadController.cs
///
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.WebUtilities;
using Microsoft.Extensions.Logging;
using Microsoft.Net.Http.Headers;
using System.IO;
using System.Threading.Tasks;
 
namespace LargeFilesSample.Controllers
{
    /// <summary>
    /// controller for upload large file
    /// </summary>
    [ApiController]
    [Route("[controller]")]
    public class FileUploadController : ControllerBase
    {
        private readonly ILogger<FileUploadController> _logger;
 
        public FileUploadController(ILogger<FileUploadController> logger)
        {
            _logger = logger;
        }
 
        /// <summary>
        /// Action for upload large file
        /// </summary>
        /// <remarks>
        /// Request to this action will not trigger any model binding or model validation,
        /// because this is a no-argument action
        /// </remarks>
        /// <returns></returns>
        [HttpPost]
        [Route(nameof(UploadLargeFile))]
        public async Task<IActionResult> UploadLargeFile()
        {
            var request = HttpContext.Request;
 
            // validation of Content-Type
            // 1. first, it must be a form-data request
            // 2. a boundary should be found in the Content-Type
            if (!request.HasFormContentType ||
                !MediaTypeHeaderValue.TryParse(request.ContentType, out var mediaTypeHeader) ||
                string.IsNullOrEmpty(mediaTypeHeader.Boundary.Value))
            {
                return new UnsupportedMediaTypeResult();
            }
 
            var reader = new MultipartReader(mediaTypeHeader.Boundary.Value, request.Body);
            var section = await reader.ReadNextSectionAsync();
 
            // This sample try to get the first file from request and save it
            // Make changes according to your needs in actual use
            while (section != null)
            {
                var hasContentDispositionHeader = ContentDispositionHeaderValue.TryParse(section.ContentDisposition,
                    out var contentDisposition);
 
                if (hasContentDispositionHeader && contentDisposition.DispositionType.Equals("form-data") &&
                    !string.IsNullOrEmpty(contentDisposition.FileName.Value))
                {
                    // Don't trust any file name, file extension, and file data from the request unless you trust them completely
                    // Otherwise, it is very likely to cause problems such as virus uploading, disk filling, etc
                    // In short, it is necessary to restrict and verify the upload
                    // Here, we just use the temporary folder and a random file name
 
                    // Get the temporary folder, and combine a random file name with it
                    var fileName = Path.GetRandomFileName();
                    var saveToPath = Path.Combine(Path.GetTempPath(), fileName);
 
                    using (var targetStream = System.IO.File.Create(saveToPath))
                    {
                        await section.Body.CopyToAsync(targetStream);
                    }
 
                    return Ok();
                }
 
                section = await reader.ReadNextSectionAsync();
            }
 
            // If the code runs to this location, it means that no files have been saved
            return BadRequest("No files data in the request.");
        }
    }
}

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📇 Additional Metadata

• 🗂 Type::#type/note
• 🏷️ Tags:: CSharp
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