[mod_python] file upload very slow in fieldStorage

Jim Gallacher jg.lists at sympatico.ca
Tue Oct 25 08:38:34 EDT 2005

Hi Mike,

I believe this has been fixed in 3.2. See


Mike Looijmans wrote:
> I was looking at Barry's fix in util.py, but I had already done some 
> work into the same direction, in order to upload huge files (to a TAPE 
> streamer, go figure...).
> http://www.modpython.org/pipermail/mod_python/2005-March/017773.html
> My idea is that the "read_to_boundary" function is unnessary complex. 
> the following code does basically the same thing, but it skips a lot of 
> memcpy calls (based on the 3.1.4 code but should work for 3.2.x too):
>     def read_to_boundary(self, req, boundary, file):
>         delim = ""
>         line = req.readline(10240)
>         while line and not line.startswith(boundary):
>             odelim = delim
>             if line[-2:] == "\r\n":
>                 delim = "\r\n"
>                 line = line[:-2]
>             elif line[-1:] == "\n":
>                 delim = "\n"
>                 line = line[:-1]
>             else:
>                 delim = ""
>             file.write(odelim + line)
>             line = req.readline(10240)
> Consider:
> - If the last char is a #13 (\r) then it's just sent to the file. The 
> next readline will return the \n by itself. Since most callback handlers 
> will just write to a disk file, they don't care about line ends anyway. 
> They must be prepared to receive partial lines anyway.
> - line.startswith(boundary)
> Now you may argue that it is only a boundary if it appears on a line by 
> itself. Well, I say, the odds that your file contains a boundary string 
> followed by a newline are not _significantly_ smaller than without that 
> one character.
> I tested this implementation with various binary (100MB), DOS and UNIX 
> text files, without problems. The uploaded files were bitwise equal.
> I also implemented the callback by allowing subclasses to override 
> make_file. That should go into another thread, I guess.

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