Error assembling blockwise response, passing on error NotImplemented()

[gcerar]

Reading from /.well-known/core on contiki (v2.7) device raises error.NotImplemented(). My guess is that something around block2 is not implemented.

Error assembling blockwise response, passing on error NotImplemented()

Traceback (most recent call last):
File "aiocoap_examples.py", line 31, in <module>
    asyncio.get_event_loop().run_until_complete(main())
File "/usr/lib64/python3.5/asyncio/base_events.py", line 387, in run_until_complete
    return future.result()
File "/usr/lib64/python3.5/asyncio/futures.py", line 274, in result
    raise self._exception
File "/usr/lib64/python3.5/asyncio/tasks.py", line 241, in _step
    result = coro.throw(exc)
File "aiocoap_examples.py", line 21, in main
    response = await protocol.request(request).response
File "/usr/lib64/python3.5/asyncio/futures.py", line 361, in __iter__
    yield self  # This tells Task to wait for completion.
File "/usr/lib64/python3.5/asyncio/tasks.py", line 296, in _wakeup
    future.result()
File "/usr/lib64/python3.5/asyncio/futures.py", line 274, in result
    raise self._exception
File "/home/gcerar/workspace/logatec2-tools/env35/lib64/python3.5/site-packages/aiocoap/protocol.py", line 742, in process_block2_in_response
    self._assembled_response._append_response_block(response)
File "/home/gcerar/workspace/logatec2-tools/env35/lib64/python3.5/site-packages/aiocoap/message.py", line 257, in _append_response_block
    raise error.NotImplemented()
aiocoap.error.NotImplemented

Code where this raises:

import aiocoap as coap
import asyncio

# skipped config of address and port
async def main():
    uri = 'coap://[{}]:{}/.well-known/core'.format(address, port)

    protocol = await coap.Context.create_client_context()
    request = coap.Message(code=coap.GET, uri=uri)

    try:
        response = await protocol.request(request).response
    except Exception as e:
        print(e)
        raise
    else:
        print('Result: %s\n%r' % (response.code, response.payload))

if __name__ == '__main__':
    asyncio.get_event_loop().run_until_complete(main())

[chrysn]

thanks for reporting this. the easiest way to reproduce this would be having such a contiki node mapped somewhere in the internet for me to quickly test that, would that be possible? (you can send the address to chrysn@fsfe.org if you don't want it to be public). if that's not an option, could you send network dumps of of the request/response messages?

[gcerar]

Nodes are not in public network. Inside institute I don't have permissions to change that. Security is very tight here. I have sent you on an email tcpdumps of working comm (Firefox's Copper) and non working comm (aiocoap) right before it enters contiki sensor network. Hope it helps.

[chrysn]

The problem occurred because one of the early responses in the blockwise transfer (that had Block2.M=1 set) but did had a payload size different from the size advertised in Block2. aiocoap should handle this earlier (when receiving the odd message, not when receiving the next one), and give a clear error message.

[gcerar]

After few exchanged emails with @chrysn, we figured out that issue is on server side. There is a bug at advertising Block2 as @chrysn mentioned. He even gratefully suggested workaround in aiocoap. Until this is fixed, workaround will be kept at my fork, "contiki27-workaround" branch.

Issue can now be closed.

[chrysn]

Re-opening because aiocoap did not properly report the issue at the first corrupt message but gave a mislieading error description at a later message.