Talk to socket with str, to serial with bytes

[hroncok]

Apparently, the API of socket and serial is different.

Never tested. I have no printer at hand.

[hroncok]

Anyone for a review?

[rockstorm101]

Hi, I'm sorry but I'm currently unable to test anything. I'm working overseas so I have no printer nor my computer.

[Estragon2K17]

I tried this proposed fix but still cannot connect to my printer. The old Windows 1.6.0 release (Printrun-win-18Nov2017.zip) works fine (i.e. connects to the printer) and was used as the baseline for my testing.

3D Printer: FLSUN-QQ Delta
TCP IP+Port#: xxx.xxx.xxx.xxx:8080
OS: Windows 7 64-bit (Python 3.6 64-bit)

Before patch (Master branch ->2.0.0rc5 tag):
TypeError('write() argument must be str, not bytes',)

After #936 patch:
Can't write to printer (disconnected ?):
Traceback (most recent call last):
File "C:\source\Printrun\printrun\printcore.py", line 674, in _send self.printer.write(message)
io.UnsupportedOperation: not writable

I can help with further testing if someone can try to come up with a fix.

Thanks.

[Estragon2K17]

After passing the 'r' & 'w' as arguments for the socket makefile() method, the printer is able to connect now.

original:
self.printer = self.printer_tcp.makefile()

modified:
self.printer = self.printer_tcp.makefile('rw')

However, an exception with the following description was raised at the code below even though the printer appears to be working.

Description:
IndexError('tuple index out of range',)

Code:
else:
self.logError(_("SelectError ({0}): {1}").format(e.errno, decode_utf8(e.strerror)))
raise

[Estragon2K17]

Forgot to mention I had to make a change for the readline() method as well in order for the printer to connect.

Original:
try:
line = self.printer.readline().decode('ascii')

Modified:
try:
if self.printer_tcp:
line = self.printer.readline()
else:
line = self.printer.readline().decode('ascii')

I'm connecting to my printer via Wi-Fi connection. I have not tested serial connection so I'm not sure if any of these changes would break the serial connection mode. From code review, it doesn't appear so but I'll find time to test serial connection later.

[k3ns]

the default for makefile() is read, so make read & write:

self.printer = self.printer_tcp.makefile(mode='rw',buffering=None)

handle tcp and serial separately:

reading...

if (type(self.printer) is Serial):
    line = self.printer.readline().decode('ascii')
else:
    line = self.printer.readline()

writing...

if (type(self.printer) is Serial):
    self.printer.write((command + "\n").encode('ascii'))
else:
    self.printer.write((command + "\n")) 

I think this line:

if 'Bad file descriptor' in e.args[1]:

should be:

if 'Bad file descriptor' in e.args:

to fix tuple index out of range since e.args can be a list length 1

also need to increase timeout for self.printer_tcp.settimeout(self.timeout)

self.timeout = 4.25 

[rockstorm101]

Hi @k3ns, thanks a lot for your insight. This is really helpful. I just wanted to let you know that I've seen this and I'm working on a solution that not only fixes this but also liberates Printcore code from the "serial vs. tcp" thing. I'll let you know as soon as I have something for testing. Thanks again.

[rockstorm101]

I'm working on a solution that not only fixes this but also liberates Printcore code from the "serial vs. tcp" thing.

Well the bespoke solution (finally) arrived in the form of PR #1346.

Is this PR (talking about 936 now) still valid? I encountered no problems with the code as it is now so I would say we can cancel this. Thoughts?