opencv/samples/dnn/face_detector/download_weights.py

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#!/usr/bin/env python
from __future__ import print_function
import hashlib
import time
import sys
import xml.etree.ElementTree as ET
if sys.version_info[0] < 3:
from urllib2 import urlopen
else:
from urllib.request import urlopen
class HashMismatchException(Exception):
def __init__(self, expected, actual):
Exception.__init__(self)
self.expected = expected
self.actual = actual
def __str__(self):
return 'Hash mismatch: {} vs {}'.format(self.expected, self.actual)
class MetalinkDownloader(object):
BUFSIZE = 10*1024*1024
NS = {'ml': 'urn:ietf:params:xml:ns:metalink'}
tick = 0
def download(self, metalink_file):
status = True
for file_elem in ET.parse(metalink_file).getroot().findall('ml:file', self.NS):
url = file_elem.find('ml:url', self.NS).text
fname = file_elem.attrib['name']
hash_sum = file_elem.find('ml:hash', self.NS).text
print('*** {}'.format(fname))
try:
self.verify(hash_sum, fname)
except Exception as ex:
print(' {}'.format(ex))
try:
print(' {}'.format(url))
with open(fname, 'wb') as file_stream:
self.buffered_read(urlopen(url), file_stream.write)
self.verify(hash_sum, fname)
except Exception as ex:
print(' {}'.format(ex))
print(' FAILURE')
status = False
continue
print(' SUCCESS')
return status
def print_progress(self, msg, timeout = 0):
if time.time() - self.tick > timeout:
print(msg, end='')
sys.stdout.flush()
self.tick = time.time()
def buffered_read(self, in_stream, processing):
self.print_progress(' >')
while True:
buf = in_stream.read(self.BUFSIZE)
if not buf:
break
processing(buf)
self.print_progress('>', 5)
print(' done')
def verify(self, hash_sum, fname):
sha = hashlib.sha1()
with open(fname, 'rb') as file_stream:
self.buffered_read(file_stream, sha.update)
if hash_sum != sha.hexdigest():
raise HashMismatchException(hash_sum, sha.hexdigest())
if __name__ == '__main__':
sys.exit(0 if MetalinkDownloader().download('weights.meta4') else 1)