SPFiles to .zip - file

Question

As the title sugests, I have a list of SPFiles (sharepoint attachments) and I need to compress it and push to user download it.
I`ve looked for some examples here and tryed to code something but yet no success.
Here follow my last try until now
using (var stream = new MemoryStream())
{
using (var archive = new ZipArchive(stream, ZipArchiveMode.Create, true))
{
foreach (SPFile item in lstFiles)
{
//string nomeEntrada = item.Substring(item.LastIndexOf("/") + 1);
var file = archive.CreateEntry(item.Name);
using (var entryStream = file.Open())
using (var streamWriter = new BinaryWriter(entryStream))
{
byte[] bytes = item.OpenBinary();
streamWriter.Write(bytes, 0, bytes.Length);
}
}
}
//For testing only, to check if the .zip is beeing correctly generated
using (FileStream file = new FileStream("C:\\teste\\file.zip", FileMode.Create, System.IO.FileAccess.Write))
{
stream.Seek(0, SeekOrigin.Begin);
stream.CopyTo(file);
}
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ContentType = "application/x-zip-compressed";
HttpContext.Current.Response.AddHeader("content-disposition", "attachment; filename=anexos.zip");
HttpContext.Current.Response.BinaryWrite(stream.ToArray());
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.Close();
HttpContext.Current.ApplicationInstance.CompleteRequest();
HttpContext.Current.Response.End();
}
PS: I do not want to save the file in server directory, that was just a test to check if the file was OK

Answer 1

I created an Application Page and redirected user to it. Since I can control the httpcontext by there, I coded the following and it worked just fine. The page quickly stream the file to client and them close itself. Hope it helps
using (var stream = new MemoryStream())
{
using (var archive = new ZipArchive(stream, ZipArchiveMode.Create, true))
{
foreach (SPFile item in lstFiles)
{
var file = archive.CreateEntry(item.Name);
using (var entryStream = file.Open())
using (var streamWriter = new BinaryWriter(entryStream))
{
byte[] bytes = item.OpenBinary();
streamWriter.Write(bytes, 0, bytes.Length);
}
}
}
stream.Seek(0, SeekOrigin.Begin);
Byte[] byteArray = stream.ToArray();
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.CacheControl = "public";
HttpContext.Current.Response.AddHeader("Pragma", "public");
HttpContext.Current.Response.AddHeader("Expires", "0");
HttpContext.Current.Response.AddHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");
HttpContext.Current.Response.AddHeader("Content-Description", "Report Export");
HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=\"Anexos.zip\"");
HttpContext.Current.Response.BinaryWrite(byteArray);
HttpContext.Current.Response.Flush(); // Sends all currently buffered output to the client.
HttpContext.Current.Response.SuppressContent = true; // Gets or sets a value indicating whether to send HTTP content to the client.
HttpContext.Current.ApplicationInstance.CompleteRequest(); // Causes ASP.NET to bypass all events and filtering in the HTTP pipeline chain of execution and directly execute the EndRequest event.
}