Fix socket receive issues related to message buffer size

[flavio-fernandes]

This change addresses a few issues in the handling of the MQTT
messages that caused the library to become unstable:

• Add wapper for socket.recv() so that an exact number of bytes
  are read into the buffer before attempting to parse the MQTT
  message;

• Fix handling of ping response packets via _wait_for_msg();

• Fix disconnect so it can gracefully handle cases when socket writes
  are not possible. Also re-init _subscribed_topics as an empty list
  instead of None.

Related-to adafruit/Adafruit_CircuitPython_ESP32SPI#102
Fixes adafruit/Adafruit_CircuitPython_PyPortal#98
Fixes #54
Signed-off-by: Flavio Fernandes [email protected]

[flavio-fernandes]

Hi @tannewt . I could use some much needed help on the CI failure, as well as code review from you on this PR.
I believe this addresses the issue we were talking about in adafruit/Adafruit_CircuitPython_ESP32SPI#102

[ladyada]

https://learn.adafruit.com/contribute-to-circuitpython-with-git-and-github has some info about running black/pylint
@dherrada can you help with CI passing Q's

[flavio-fernandes]

https://learn.adafruit.com/contribute-to-circuitpython-with-git-and-github has some info about running black/pylint
@dherrada can you help with CI passing Q's

Thank you for the link. It seems that Travis is no longer used and https://learn.adafruit.com/contribute-to-circuitpython-with-git-and-github/open-pull-request needs an update, agree? It would be nice to add more info on running black tool
on that page too.

@dherrada : The ci issues are not related to my changes so I will definitely need some help. I managed to get past the
lint, but have no idea on how to tackle this one:

Unfortunately, your project is not compliant with version 3.0 of the REUSE Specification :-(

Best,

-- flaviof

[flavio-fernandes]

Hi @brentru ! Based on your involvement with https://learn.adafruit.com/pyportal-weather-station , I would like very
much if you tried / reviewed the changes I'm proposing on this PR. Could you, pretty please? ;)

[evaherrada]

@flavio-fernandes I'll get the REUSE thing fixed right away.

[evaherrada]

@flavio-fernandes master is now passing, but there are a few conflicts. I would recommend running pre-commit locally to make the conflicts smaller and then resolving the remaining ones manually

[flavio-fernandes]

@flavio-fernandes master is now passing, but there are a few conflicts. I would recommend running pre-commit locally to make the conflicts smaller and then resolving the remaining ones manually

Sounds good. How do you run the pre-commit locally? All I got so far is "pip install black ; black file.py" ;)

[evaherrada]

How do you run the pre-commit locally?

@flavio-fernandes Install pre-commit with pip, and then just run it with pre-commit run --all-files. Note that you should copy this (https://github.com/adafruit/Adafruit_CircuitPython_MiniMQTT/blob/master/.pre-commit-config.yaml) file over to your fork to get it to run right.

[brentru]

@flavio-fernandes This is passing, do you want me to re-review on hardware?

[flavio-fernandes]

@flavio-fernandes This is passing, do you want me to re-review on hardware?

Sure thing @brentru ! I have 2 pyportals running this code for over a week w/out any problems. If you or anyone would be interested on using that code.py, here is a link:
https://github.com/flavio-fernandes/pyportal_station

Thanks,

-- flaviof

[brentru]

@flavio-fernandes Thanks for making the requested changes! Tested simpletest and adafruit io on Adafruit CircuitPython 6.1.0-rc.1 on 2021-01-15; Adafruit PyPortal with samd51j20