Python 3.4 stream readline uses bytes instead of string

[Dutchy-]

In my previous pull request, I only fix the obvious crash. However, there was more. I'm not 100% sure of the problem and the solution, but the current code works for me.

In python 3.4, the readline used for streams seems to return an empty byte array instead of an empty string. Without this, it keeps looping for streams.

My fix simply replaces '' with bytes(), however I'm not convinced this works for python versions other than 3.4. We'll have the build bot check it out first. If this doesn't work for the other versions, I'm not sure I can fix it, I might need some help.

My theory is that this was never caught because all the test cases run from files instead of from an actual nmap process.

My context and use case was https://groups.google.com/forum/#!msg/home-assistant-dev/hKcH32MzQvs/kF98gmFCIUQJ and I'm hoping for a new libnmap release soon :)

[Dutchy-]

Never mind, this is wrong. Consider this a bug report, but my fix is not correct...

[coveralls]

Coverage remained the same at 69.47% when pulling f537836 on Dutchy-:master into 496b547 on savon-noir:master.

[coveralls]

Coverage remained the same at 69.47% when pulling f537836 on Dutchy-:master into 496b547 on savon-noir:master.

[Dutchy-]

Ok, I've really fixed this now. This is 100% confirmed working in python 3.4, but I have no idea about other versions. Please realise that your build bot seems to be not working, because it accepted both my previous 'fixes'.

[coveralls]

Coverage remained the same at 69.47% when pulling 8b70bc7 on Dutchy-:master into 496b547 on savon-noir:master.

[Dutchy-]

I've made a gist to illustrate the problem:

https://gist.github.com/Dutchy-/c87b1c27b9c08fb0323c

There are several solutions:

1. Always open files using byte mode, ie. open('file.txt', 'rb')
2. Supply a temporary file to subprocess.Popen as described in http://stackoverflow.com/a/10134899

One of those may help in keeping things more compatible than they are now.

[savon-noir]

i'll check this out asap.

[savon-noir]

Hello, this fix gives error in py3.8:

Traceback (most recent call last):
File "proc_nmap_like.py", line 53, in
report = do_scan("127.0.0.1", "-sV")
File "proc_nmap_like.py", line 12, in do_scan
rc = nmproc.run()
File "/home/ronald/pydev/lib/python3.8/site-packages/libnmap/process.py", line 315, in run
self.__stdout += streamline.decode('utf-8')
AttributeError: 'str' object has no attribute 'decode'

[savon-noir]

but the issue got fixed in: https://github.com/savon-noir/python-libnmap/pull/68/files thanks to both of you @Dutchy- @rcarrillo (sorry guys for that late update, i'm in a full review/clean-up process of this lib :)