ASP.NET C# OutofMemoryException On Large File Upload
asp.net, c#, ihttphandler, large-files, out-of-memory
Solution
There is no need to load a file into memory to write it to somewhere. You should be using a small buffer (maybe 8k), and looping over the streams. Or, with 4.0, the `CopyTo` method. For example:
using(var newFile = File.Create(tempPath)) {
request.InputStream.CopyTo(newFile);
}
(which does the small-buffer/loop for you, using a 4k buffer by default, or allowing a custom buffer-size to be passed via an overload)
Problem
I have the following file upload handler: ``` public class FileUploader : IHttpHandler { public void ProcessRequest(HttpContext context) { HttpRequest request = context.Request; context.Response.ContentType = "text/html"; context.Response.ContentEncoding = System.Text.Encoding.UTF8; context.Response.Cache.SetCacheability(HttpCacheability.NoCache); var tempPath = request.PhysicalApplicationPath + "\\Files\\TempFiles\\"; byte[] buffer = new byte[request.ContentLength]; using (BinaryReader br = new BinaryReader(request.InputStream)) { br.Read(buffer, 0, buffer.Length); } var tempName = WriteTempFile(buffer, tempPath); context.Response.Write("{\"success\":true}"); context.Response.End(); } public bool IsReusable { get { return true; } } private string WriteTempFile(byte[] buffer, string tempPath) { var fileName = GetUniqueFileName(tempPath); File.WriteAllBytes(tempPath + fileName, buffer); return fileName; } private string GetUniqueFileName(string tempPath) { var guid = Guid.NewGuid().ToString().ToUpper(); while (File.Exists(tempPath + guid)) { guid = Guid.NewGuid().ToString().ToUpper(); } return guid; } } ``` When I upload large files, this is causing OutOfMemoryException. Could someone tell what's right way to upload large files using such a handler?