downloading cgi advice

[Ian Bicking]

On Thu, 2002-05-09 at 17:38, Jeff Shipman wrote:
> I've got a cgi which handles downloading
> files to a person's computer. Files of
> type .tar.gz and .exe go through this CGI.
> These are some snippets I have from the
> program:
> 
>     # Determine size of file
>     try:
>        s = os.stat(BASEDIR+'/'+loc)
>
>        size = int(s[6])
>     except OSError:
>        errmsg('Couldn\'t stat() file!')
>     except:
>        errmsg('Unexpected error while calling stat()!')

In case of errors, you should send proper error messages to the client. 
Something like:

print 'Status: 404 Not Found'

or in the case of unknown errors:

print 'Status: 500 Internal Server Error'

Otherwise it looks fine.  Though when you do
sys.stdout.write(file.read(size)), you'll have the entire file in memory
for a short time -- if you have the memory, and a low number of users,
it doesn't really matter.  If not you should chunk it like:

while 1:
    t = file.read(4096) # 4096 = random number
    if not t: break
    sys.stdout.write(t)

  Ian