Added -c option (--continue)

interrupted downloads will properly resume and append to the previously downloaded data, instead of overwriting the file.

There's some error checking - if the length of the file to be download matches the length of the previously downloaded data, we report that this file has already been downloaded and do nothing.

If there is some other HTTP 416 'Requested range not satisfiable' error, we simply re-download the whole file (reverting to the original functionality)

All other HTTP errors are simply raised.

Resuming does not override -w (--nooverwrite), since it is not clear what should happen if file on disk is larger than file to be downloaded.

Thus, -c does nothing if -w is present.
This commit is contained in:
Paul Ivanov 2009-05-26 14:06:21 -07:00 committed by Ricardo Garcia
parent daa88ccc2e
commit f76c2df64e

View File

@ -306,7 +306,7 @@ class FileDownloader(object):
return
try:
outstream = open(filename, 'wb')
outstream = open(filename, 'ab')
except (OSError, IOError), err:
self.trouble('ERROR: unable to open for writing: %s' % str(err))
return
@ -368,7 +368,27 @@ class FileDownloader(object):
def _do_download(self, stream, url):
request = urllib2.Request(url, None, std_headers)
data = urllib2.urlopen(request)
# Resume transfer if filesize is non-zero
resume_len = stream.tell()
if self.params["continue"] and resume_len != 0:
print "[download] Resuming download at byte %d" % resume_len
request.add_header("Range","bytes=%d-" % resume_len)
else:
stream.close()
stream = open(stream.name,'wb')
try:
data = urllib2.urlopen(request)
except urllib2.HTTPError, e:
if not e.code == 416: # 416 is 'Requested range not satisfiable'
raise
data = urllib2.urlopen(url)
if int(data.info()['Content-Length']) == resume_len:
print '[download] %s has already been downloaded' % stream.name
return
else:
print "[download] Unable to resume, restarting download from the beginning"
stream.close()
stream = open(stream.name,'wb')
data_len = data.info().get('Content-length', None)
data_len_str = self.format_bytes(data_len)
byte_counter = 0
@ -1084,6 +1104,8 @@ if __name__ == '__main__':
dest='batchfile', metavar='F', help='file containing URLs to download')
filesystem.add_option('-w', '--no-overwrites',
action='store_true', dest='nooverwrites', help='do not overwrite files', default=False)
filesystem.add_option('-c', '--continue',
action='store_true', dest='continue_dl', help='resume partially downloaded files', default=False)
parser.add_option_group(filesystem)
(opts, args) = parser.parse_args()
@ -1141,6 +1163,7 @@ if __name__ == '__main__':
'ignoreerrors': opts.ignoreerrors,
'ratelimit': opts.ratelimit,
'nooverwrites': opts.nooverwrites,
'continue': opts.continue_dl,
})
fd.add_info_extractor(youtube_search_ie)
fd.add_info_extractor(youtube_pl_ie)