File upload. Huge files

[Oleg Slyusarchuk]

Hi,
This is topic that has been discussed thousand times, however.
Classic approach is to use HttpPostedFile object, check if it's not null,
and save it.

Something like:

// Check to see if file was uploaded
if( filMyFile.PostedFile != null ){
// Get a reference to PostedFile object
HttpPostedFile myFile = filMyFile.PostedFile;
// Get size of uploaded file
int nFileLen = myFile.ContentLength;
// make sure the size of the file is > 0
if( nFileLen > 0 ){
// Allocate a buffer for reading of the file
byte[] myData = new byte[nFileLen];
// Read uploaded file from the Stream
myFile.InputStream.Read(myData, 0, nFileLen);
// Create a name for the file to store
string strFilename = Path.GetFileName(myFile.FileName);
// Write data into a file
WriteToFile(Server.MapPath(strFilename), ref myData);
}

or even easier:

if (File1.PostedFile !=null)
//Checking for valid file { // PostedFile.FileName gives the entire
path.Use Substring function to rip of the filename.
string StrFileName =
File1.PostedFile.FileName.Substring(File1.PostedFile.FileName.LastIndexOf("\
\") + 1) ;
string StrFileType = File1.PostedFile.ContentType ;
int IntFileSize =File1.PostedFile.ContentLength; //Checking for the file
length
if (IntFileSize <=0) Response.Write(" Uploading of file " + StrFileName + "
failed ");
else { File1.PostedFile.SaveAs(Server.MapPath(".\\" + StrFileName));
Response.Write( "Your file " + StrFileName + " of type " + StrFileType + "
and size " + IntFileSize.ToString() + " was uploaded successfully"); } }

Everything works fine for relatively small files (say, a couple megs).

Hoverver, if files becomes big (say, 100Mb), and a couple files are being
uploded at the same time,
required memory grows, and finelly system may crash.


QUESTION.

Is there any way to read file in parts (similar to DB-based ReadChunk)
methods?
What an appropriate aproach can be used in this situation?
May I get a reference to response stream before all the file is uploaded?

Thanks,

Oleg

 

[Matt Sollars]

Hi, Oleg:

To my knowledge, there is no easy solution to this problem. You will
have to write a custom HttpHandler and perform the I/O manually in chunks.

However, some folks have already done the work for you. I recommend one
of the following:

- ABCUpload .NET by Web Super Goo
(http://www.websupergoo.com/abcupload.net-1.htm)
- FileUp by SoftArtisans (http://fileup.softartisans.com/fileup-147.aspx)

I can vouche for the first one on a production server with large
uploads. It runs great. It isn't the cheapest component, but it's under
a grand and saves a lot of headache and custom code that would've cost
me more in time than the cost. I played with a demo of the second one
and it seemed competent enough to handle large files as well. They both
offer a pure HTML progress indicator solution as well.

I hope this helps,

Matt