Error decoding chunked response in _update_chunk_length: ValueError: invalid literal for int() with base 16: b'HTTP/1.1 200 OK\r\n'

[danc86]

Decoding a response with chunked encoding fails because it seems to be reading from the HTTP status line instead of the start of the body.

Expected Result

Successfully return a 200 response object.

Actual Result

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 535, in _update_chunk_length
    self.chunk_left = int(line, 16)
ValueError: invalid literal for int() with base 16: b'HTTP/1.1 200 OK\r\n'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 298, in _error_catcher
    yield
  File "/usr/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 590, in read_chunked
    self._update_chunk_length()
  File "/usr/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 539, in _update_chunk_length
    raise httplib.IncompleteRead(line)
http.client.IncompleteRead: IncompleteRead(17 bytes read)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/requests/models.py", line 719, in generate
    for chunk in self.raw.stream(chunk_size, decode_content=True):
  File "/usr/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 428, in stream
    for line in self.read_chunked(amt, decode_content=decode_content):
  File "/usr/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 618, in read_chunked
    self._original_response.close()
  File "/usr/lib64/python3.6/contextlib.py", line 99, in __exit__
    self.gen.throw(type, value, traceback)
  File "/usr/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 316, in _error_catcher
    raise ProtocolError('Connection broken: %r' % e, e)
requests.packages.urllib3.exceptions.ProtocolError: ('Connection broken: IncompleteRead(17 bytes read)', IncompleteRead(17 bytes read))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3.6/site-packages/requests/api.py", line 70, in get
    return request('get', url, params=params, **kwargs)
  File "/usr/lib/python3.6/site-packages/requests/api.py", line 56, in request
    return session.request(method=method, url=url, **kwargs)
  File "/usr/lib/python3.6/site-packages/requests/sessions.py", line 488, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/lib/python3.6/site-packages/requests/sessions.py", line 641, in send
    r.content
  File "/usr/lib/python3.6/site-packages/requests/models.py", line 797, in content
    self._content = bytes().join(self.iter_content(CONTENT_CHUNK_SIZE)) or bytes()
  File "/usr/lib/python3.6/site-packages/requests/models.py", line 722, in generate
    raise ChunkedEncodingError(e)
requests.exceptions.ChunkedEncodingError: ('Connection broken: IncompleteRead(17 bytes read)', IncompleteRead(17 bytes read))

Reproduction Steps

import requests
requests.get('https://my.virginmoney.com.au/AUVMA/JSO/signon/DisplayUsernameSignon.do')

System Information

requests 2.13.0
urllib3 1.20
Python 3.6.2
Fedora 26

[danc86]

This works fine with requests 2.10.0 so something regressed between then and 2.13.0. Also tested with 2.18.4 and the bug exists as above.

[danc86]

I can't spot anything defective or invalid in the response from that server when I look at it manually.

One thing I do notice is that it is using both Content-Encoding: gzip and Transfer-Encoding: chunked which might be a little unusual. Could this bug be caused by some bad interaction between the gzip decoding and chunk decoding?

[Lukasa]

I can't reproduce this with Requests 2.18.4 on either Python 3 or Python 2. Have you tried updating urllib3 to check if this resolves the problem?

[danc86]

Okay sorry, my comment above about 2.10.0 vs. 2.13.0 was incorrect. I did not thoroughly test all the combinations. It turns out this works fine with all versions/combinations of requests and urllib3 that I tested on Fedora 25 but fails with all versions/combinations of requests and urllib3 that I tested on Fedora 26.

Which most likely means: it's something specific to Python 3.6?

[Lukasa]

Or at least Fedora 36, as it works fine for me with my Python 3.6.2 on macOS. I recommend reporting a bug with Fedora.

[siddhi]

I get this error on Windows with the latest Python 3.7 alpha and latest requests / urllib3. When I use Python 3.5 then it works fine with the same requests / urllib3. I'm suspecting a python version issue as well.

[danc86]

I haven't dug into this in a while. Back when I was looking at it, I could not find any substantial differences between Fedora 25 and 26 in Python land at all (same Python version, same version of all the relevant Python libraries I could see, same code for urllib3 and requests) but one big difference did stand out: Fedora 25 has openssl 1.0.2 whereas Fedora 26+ has openssl 1.1.0. Not sure if that is related.

[cedric05]

i'm facing same kind of issue. any idea how to bypass this?

<Response [200]>
Traceback (most recent call last):
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 539, in _update_chunk_length
    self.chunk_left = int(line, 16)
ValueError: invalid literal for int() with base 16: b''

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 302, in _error_catcher
    yield
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 594, in read_chunked
    self._update_chunk_length()
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 543, in _update_chunk_length
    raise httplib.IncompleteRead(line)
http.client.IncompleteRead: IncompleteRead(0 bytes read)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/models.py", line 738, in generate
    for chunk in self.raw.stream(chunk_size, decode_content=True):
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 432, in stream
    for line in self.read_chunked(amt, decode_content=decode_content):
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 622, in read_chunked
    self._original_response.close()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/contextlib.py", line 100, in __exit__
    self.gen.throw(type, value, traceback)
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/packages/urllib3/response.py", line 320, in _error_catcher
    raise ProtocolError('Connection broken: %r' % e, e)
requests.packages.urllib3.exceptions.ProtocolError: ('Connection broken: IncompleteRead(0 bytes read)', IncompleteRead(0 bytes read))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "loginscheck.py", line 49, in <module>
    f.write(req.text)
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/models.py", line 840, in text
    if not self.content:
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/models.py", line 816, in content
    self._content = bytes().join(self.iter_content(CONTENT_CHUNK_SIZE)) or bytes()
  File "/Users/officeuse/environs/py_elt_service/lib/python3.6/site-packages/requests/models.py", line 741, in generate
    raise ChunkedEncodingError(e)
requests.exceptions.ChunkedEncodingError: ('Connection broken: IncompleteRead(0 bytes read)', IncompleteRead(0 bytes read))

[odboy]

I solved this problem by adding one line code.

python3 on Mac
urllib3 == 1.23
requests == 2.19.1

Traceback (most recent call last):
File "/usr/local/Cellar/python3/3.6.4/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/urllib3/response.py", line 574, in _update_chunk_length
self.chunk_left = int(line, 16)
ValueError: invalid literal for int() with base 16: b''

so, I open the file "......./urllib3/response.py", add line = (len(line)>0 and line or "0") in 571, like below:

    def _update_chunk_length(self):
        # First, we'll figure out length of a chunk and then
        # we'll try to read it from socket.
        if self.chunk_left is not None:
            return
        line = self._fp.fp.readline()
        line = line.split(b';', 1)[0]
        line = (len(line)>0 and line or "0")     # added this line
        try:
            self.chunk_left = int(line, 16)
        except ValueError:
            # Invalid chunked protocol response, abort.
            self.close()
            raise httplib.IncompleteRead(line)

[cosminnastasie]

I solved this problem by adding one line code.

python3 on Mac
urllib3 == 1.23
requests == 2.19.1

Traceback (most recent call last):
File "/usr/local/Cellar/python3/3.6.4/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/urllib3/response.py", line 574, in _update_chunk_length
self.chunk_left = int(line, 16)
ValueError: invalid literal for int() with base 16: b''

so, I open the file "......./urllib3/response.py", add line = (len(line)>0 and line or "0") in 571, like below:

    def _update_chunk_length(self):
        # First, we'll figure out length of a chunk and then
        # we'll try to read it from socket.
        if self.chunk_left is not None:
            return
        line = self._fp.fp.readline()
        line = line.split(b';', 1)[0]
        line = (len(line)>0 and line or "0")     # added this line
        try:
            self.chunk_left = int(line, 16)
        except ValueError:
            # Invalid chunked protocol response, abort.
            self.close()
            raise httplib.IncompleteRead(line)

It looks that ths line fixes the problem for me. Can you please explain what this line do?

[KonMann]

Shouldn't this then be fixed in urllib3? @Lukasa

[sigmavirus24]

@KonMann yes it should.

[odboy]

@cosminnastasie I am a little forgotten. It seems like that without this line, there should be occur problem at the last chunk data. when the value of 'line' is Null, the error arise.

[odboy]

@cosminnastasie

>>> line = b''
>>> line = line.split(b';', 1)[0]
>>> int(line,16)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 16: b''

but if we add that line:

>>> line = b''
>>> line = line.split(b';', 1)[0]
>>> line = (len(line)>0 and line or "0")     # added this line
>>> int(line,16)
0

problem solved!!!

[KonMann]

@sigmavirus24 ok, as far as I can see there is no open issue about this in the Urllib3 Issue Tracker at the moment => Let's open an issue there?

[sigmavirus24]

@KonMann you seem to have more time than me. Go for it.

[KonMann]

@odboy Do you have some code to reproduce?

[hixss]

We temporarily repaired it in this way. I wonder if there will be any problem.

def _update_chunk_length(self):
    # First, we'll figure out length of a chunk and then
    # we'll try to read it from socket.
    if self.chunk_left is not None:
        return
    line = self._fp.fp.readline()
    line = line.split(b';', 1)[0]
    try:
        if len(line) == 0:
            self.chunk_left = 0
        else:
            self.chunk_left = int(line, 16)
    except ValueError:
        # Invalid chunked protocol response, abort.
        self.close()
        raise httplib.IncompleteRead(line)

[fildred13]

I'm running into this exact issue as well, with an identical traceback as #4248 (comment). I've tried reverting requests as far back as 2.9.1, and as far forward as the current release (2.20.1), with a few different combinations of urllib3 versions in each case - they all give the exact same traceback.

Is there a release which we can use until this is fixed, or do we have to patch our requests with the above corrected def?

[dulitz]

I am having this issue as well, and I agree the problem is at the urllib3 level.

[pheanex]

Can we agree on where we want this issue to be fixed? Here in requests or in urllib3?

[sigmavirus24]

The underlying exception comes from urllib3, but as @dulitz explained in urllib3/urllib3#1516, this isn't necessarily always a "bug" in requests or urllib3. So "fixing" it might not be easy or possible. Regardless, I'm closing this issue here.

[mbatle]

I am able to reproduce the same bug by using this code

import requests
requests.get('https://www.telecreditobcp.com/tlcnp/index.do')

I think this is a bug in the server side, but maybe urllib3 could do a better job workarounding this bug in the server, as other libraries / applications do for example (same URL works ok in a web browser like chrome or firefox ...)

[mbatle]

As far as I could see, the server (in the example above) sends chunked transfer, but it does not send properly the last 0-length chunk and returns the response code. That's where urllib3 raises exception when trying to decode the length of the chunk from the response status code line. Some insights I could find so far:

• the same request works in a browser without complain (I have tried sending same headers than the browser but didn't see a different for the sample code reproducing the bug)

• sometimes the request works perfectly with the sample code for a while, and then stops working again. So as our local side has not changed really, I assume there is some load balancing or something and we are served by another server maybe with possibly a slightly different version of software.

• the following code makes it deliver part of the content but still not the full content:

r = requests.get('https://www.telecreditobcp.com/tlcnp/index.do', stream=True)
for line in r.iter_lines():
print(line)

• the bug in my local environment happens with python 3.6.8, 3.7.3 and 2.7.16 versions in Linux. Have tried same kernel though (5.1.16-300.fc30.x86_64).

• Have tried with Ubuntu and Fedora, both seem to fail same way.

• I have a server in AWS running Linux with python 3.5.2, and it works always, no bugs

• I've been told the bug seems not reproducible in Windows environment with any version.

• I've been told enabling traffic through a VPN makes it work in a Linux environment that used to fail.

• same bug seems to happen with curl
  curl -X GET https://www.telecreditobcp.com/tlcnp/index.do

curl: (56) Illegal or missing hexadecimal sequence in chunked-encoding

[aswath-kumar]

line = (len(line)>0 and line or "0") # added this line

Solved my problem. Man is a LEGEND.