AppEngine BlobStore upload failing with a request that works in the Development Environment

Question

I have an AppEngine application that uses the blobstore to store user-provided image data. When I upload images to that application from a form in Chrome it works fine. When

Answer 1

Turns out the problem was this line:

Content-Disposition: form-data; name="img";filename="PhotoHunt.jpg"

It should read like this:

Content-Disposition: form-data; name="img"; filename="PhotoHunt.jpg"

The parser for form-data on the production servers is more strict than the one in the development environment and requires a space between the semicolon and "filename="

Answer 2

Another option could be because you added URL parameters, which works normally, but doesn't with the way Blobstore uploader redirect to your servlet.