In implementing Tutorial 15, there is a URL error for downloading vgg16 model, about tensorflow-tutorials

[leedqin]

URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749)>

This error to be exact when calling the maybe_download() function, can you help me fix it please

[johndpope]

are you on a mac? make sure you run system updates. I found this shell code useful.
https://github.com/albinekcom/updater-for-macos

[leedqin]

Yes. I can try that but my inception5h and inception models load perfectly fine..

[johndpope]

are they all hosted on same server? you may find one specific server has an out of date certificate. actually the script above - probably won't help - unless you need to update the root cert/ which may help. try hitting url in browser and see if you get ssl error.

[leedqin]

I tried that too and the url doesn't give me an error then but starts to download the model. I have tried to find some other url from where I can download the model. But I can't..

How do I update the root cert?

[leedqin]

---

SSLError Traceback (most recent call last)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py in do_open(self, http_class, req, **http_conn_args)
1317 h.request(req.get_method(), req.selector, req.data, headers,
-> 1318 encode_chunked=req.has_header('Transfer-encoding'))
1319 except OSError as err: # timeout error

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py in request(self, method, url, body, headers, encode_chunked)
1238 """Send a complete request to the server."""
-> 1239 self._send_request(method, url, body, headers, encode_chunked)
1240

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py in _send_request(self, method, url, body, headers, encode_chunked)
1284 body = _encode(body, 'body')
-> 1285 self.endheaders(body, encode_chunked=encode_chunked)
1286

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py in endheaders(self, message_body, encode_chunked)
1233 raise CannotSendHeader()
-> 1234 self._send_output(message_body, encode_chunked=encode_chunked)
1235

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py in _send_output(self, message_body, encode_chunked)
1025 del self._buffer[:]
-> 1026 self.send(msg)
1027

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py in send(self, data)
963 if self.auto_open:
--> 964 self.connect()
965 else:

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py in connect(self)
1399 self.sock = self._context.wrap_socket(self.sock,
-> 1400 server_hostname=server_hostname)
1401 if not self._context.check_hostname and self._check_hostname:

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py in wrap_socket(self, sock, server_side, do_handshake_on_connect, suppress_ragged_eofs, server_hostname, session)
400 server_hostname=server_hostname,
--> 401 _context=self, _session=session)
402

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py in init(self, sock, keyfile, certfile, server_side, cert_reqs, ssl_version, ca_certs, do_handshake_on_connect, family, type, proto, fileno, suppress_ragged_eofs, npn_protocols, ciphers, server_hostname, _context, _session)
807 raise ValueError("do_handshake_on_connect should not be specified for non-blocking sockets")
--> 808 self.do_handshake()
809

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py in do_handshake(self, block)
1060 self.settimeout(None)
-> 1061 self._sslobj.do_handshake()
1062 finally:

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py in do_handshake(self)
682 """Start the SSL/TLS handshake."""
--> 683 self._sslobj.do_handshake()
684 if self.context.check_hostname:

SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749)

During handling of the above exception, another exception occurred:

URLError Traceback (most recent call last)
in ()
----> 1 vgg16.maybe_download()

/Users/qindeelishtiaq1/vgg16.py in maybe_download()
60 # This function should not extract the file when it does not have
61 # a relevant filename-extensions such as .zip or .tar.gz
---> 62 download.maybe_download_and_extract(url=data_url, download_dir=data_dir)
63
64

/Users/qindeelishtiaq1/download.py in maybe_download_and_extract(url, download_dir)
77 file_path, _ = urllib.request.urlretrieve(url=url,
78 filename=file_path,
---> 79 reporthook=_print_download_progress)
80
81 print()

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py in urlretrieve(url, filename, reporthook, data)
246 url_type, path = splittype(url)
247
--> 248 with contextlib.closing(urlopen(url, data)) as fp:
249 headers = fp.info()
250

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py in urlopen(url, data, timeout, cafile, capath, cadefault, context)
221 else:
222 opener = _opener
--> 223 return opener.open(url, data, timeout)
224
225 def install_opener(opener):

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py in open(self, fullurl, data, timeout)
524 req = meth(req)
525
--> 526 response = self._open(req, data)
527
528 # post-process response

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py in _open(self, req, data)
542 protocol = req.type
543 result = self._call_chain(self.handle_open, protocol, protocol +
--> 544 '_open', req)
545 if result:
546 return result

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py in _call_chain(self, chain, kind, meth_name, *args)
502 for handler in handlers:
503 func = getattr(handler, meth_name)
--> 504 result = func(*args)
505 if result is not None:
506 return result

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py in https_open(self, req)
1359 def https_open(self, req):
1360 return self.do_open(http.client.HTTPSConnection, req,
-> 1361 context=self._context, check_hostname=self.check_hostname)
1362
1363 https_request = AbstractHTTPHandler.do_request

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py in do_open(self, http_class, req, **http_conn_args)
1318 encode_chunked=req.has_header('Transfer-encoding'))
1319 except OSError as err: # timeout error
-> 1320 raise URLError(err)
1321 r = h.getresponse()
1322 except:

URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749)>

In [ ]:

​

That's the whole error.I don't really understand how to fix it.

[Hvass-Labs]

I just checked and the URL with the pre-trained VGG16 model still works:

https://s3.amazonaws.com/cadl/models/vgg16.tfmodel

Unfortunately I don't know what the problem is. If you find the solution then please write it here.

@johndpope very nice of you to help with this!

[Hvass-Labs]

As a quick hack, maybe you could download the pre-trained model manually and place it in the right dir?

[Hvass-Labs]

I'll assume you solved this problem. Please leave a comment on how you solved it, so it may help others in the future.