Automatically resume a download w/ urllib?

Chris Moffitt chris_moffitt at yahoo.com
Wed Oct 24 04:29:02 CEST 2001


After Oleg pointed me in the right direction, I managed to put something
together too.  Too bad someone else beat me to the punch!  Still, the
solution I came up with is a little different.  It just needs to override an
error handler in urllib.FancyURLopener..  Let me know what you think.

import urllib, os

class myURLOpener(urllib.FancyURLopener):
    """Create sub-class in order to overide error 206.  This error means a
partial file is being sent,
       which is ok in this case.  Do nothing with this error.
    """
    def http_error_206(self, url, fp, errcode, errmsg, headers, data=None):
        pass
loop = 1
dlFile = "testfile"
existSize = 0
myUrlclass = myURLOpener()
if os.path.exists(dlFile):
    outputFile = open(dlFile,"ab")
    existSize = os.path.getsize(dlFile)
    #If the file exists, then only download the remainder
    myUrlclass.addheader("range","bytes=%s-" % (existSize))
else:
    outputFile = open(dlFile,"wb")

webPage = myUrlclass.open("http://192.168.1.4/%s" % dlFile)

#If the file exists, but we already have the whole thing, don't download
again
if int(webPage.headers['content-length']) == existSize:
    loop = 0
    print "File already downloaded"

numBytes = 0
while loop:
    data = webPage.read(8192)
    if not data:
        break
    outputFile.write(data)
    numBytes = numBytes + len(data)

webPage.close()
outputFile.close()

for k,v in webPage.headers.items():
    print k, "=",v
print "copied", numBytes, "bytes from", webPage.url


"Oleg Broytmann" <phd at phd.pp.ru> wrote in message
news:mailman.1003831763.10689.python-list at python.org...
> On Tue, Oct 23, 2001 at 05:31:54PM +1300, Mark Rowe wrote:
> > After reading some RFC's and tweaking some Apache settings, I managed to
get
> > this working.  I was only able to test it on my local server and it
appears
> > to work fine.  Any comments or improvements, feel free :)
>
>    Thank you.
>
> [skip]
> >     if existSize > 0:
> >         h.putheader('Range', 'bytes=%d-' % (existSize, ))
>
>    Looks good.
>
> [skip]
> >         ## HTTP error 416 = Request Range not Satisiable
>                                                     ^
>    Typo (-:                                        _|
>
> Oleg.
> --
>      Oleg Broytmann            http://phd.pp.ru/            phd at phd.pp.ru
>            Programmers don't die, they just GOSUB without RETURN.
>





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