App Engine Blobstore - What can I do to limit the size of a file that a user can upload?

Question

What can I do to limit the size of a file that can be uploaded? I know I can limit it client side with SWFUpload, but how can I limit it server side?

How do I protect against someone uploading a 1GB file and eating up my quota?

Whaley

Answer 1

App Engine 1.5.4 SDK introduced an option to specify a limit on your blob upload size.

See maxUploadSizeBytes and maxUploadSizeBytesPerBlob of the UploadOptions class.

Hunk

Answer 2

You can't prohibit people from uploading files that are too large (though this would make a good feature request). What you can do is check the size of the uploaded blob, and immediately delete it if it's too big.

Jornada

I filed a feature request - code.google.com/p/googleappengine/issues/detail?id=3554 – Whaley

Answer 3

Put the code below in serlet where you are recieving data, before calling datastore API.

// Determine the HTTP method
long maxSize = 1024*1024 * 50; //Limit 50 MB
boolean isPostMethod = request.getMethod().equals("POST");

// Verify the content length
int contentLength = request.getContentLength();
if (isPostMethod && (contentLength < 0 || contentLength > maxSize))
  //posted data size is not in acceptable range
else {
    // Process Data
}

Babism

As the OP said, this is using the App Engine blobstore API, so this doesn't apply. – Jornada

And from where he'll call blobstore API? from within a servlet? Do you tell me which line of code is not applicable in App Engine? – Babism

if you read the docs on the blobstore (which is different than the datastore) you'll see that none of the lines above are applicable - your servlet doesn't accept the data from the user, the blobstore does. the form the user submits goes directly to the blobstore, not your servlet. code.google.com/appengine/docs/java/blobstore/overview.html – Regional