http file post

[Dave]

Greetings.

Ive been trying to figure out how I can write to a file from an HTTP 
post while it is being uploaded.  So far ive realized that my script 
isn't getting the data until the browser is done uploading.  What I want 
to accomplish is a way to track the progress of a file upload.  I'm 
guessing that if I can get it to write to a file as it is uploaded I can 
load another browser to check the progress of the transfer (by refreshing).

Here is the general idea I have tried:

if item.file:
    filen   =   item.filename
    filen1  =   filen.split('\\')
    filen2  =   filen1[len(filen1)-1]
    outfile =   open(path + filen2 + '.tmp','wb')
    buff    =   item.file.read(40000)
    while buff != "":
        outfile.write(buff)
        buff    =   item.file.read(40000)
        if not buff:
            break

Works, but I recieve the data all at once rather then while..

Perhaps it is my ignorance about how http works and that there is no 
other way?

Thanks in advance.
-Dave