python - Sending what is received on one serial port to another serial port for logging

Question

I'm currently working on a python script that loggs a serial connection between two devices without interfering/interrupting the connection between the two parties for Logging and troubleshooting purposes.

Heres my Github Project: https://github.com/Oberfeldwedler/serial_logging.git

Heres my the relevant part of the Code:

    ser1 = serial.Serial(
        port='/dev/ttyUSB0',
        baudrate = 9600,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS,
        timeout=.1
    )

    ser2 = serial.Serial(
        port='/dev/ttyUSB1',
        baudrate = 9600,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS,
        timeout=.1
    )


print ('Start logging')
try:
    while counter==0:
        if(datestr != time.strftime("%Y_%m_%d")):
            logf.close()
            datestr = time.strftime("%Y_%m_%d")
            timestr = time.strftime("%H_%M")
            logf = open('/media/pi/log/' + datestr + '_' + timestr + "_tracelog.txt" , "w" )

        x=ser1.readline()
        y=ser2.readline()
        xx=x.decode('UTF-8')
        yy=y.decode('UTF-8')
        if(xx!=""):
            logf.write('
' + time.strftime("%Y_%m_%d %H:%M:%S ") + str(xx))
            ser2.write(x)
            print (xx)
            print (x)
        if(yy!=""):
            logf.write('
' + time.strftime("%Y_%m_%d %H:%M:%S ") + str(yy))
            ser1.write(y)
            print (yy)
            print (y)
        if(xx=="" and yy==""):
            print ('No Data received')
except KeyboardInterrupt:
    os.system('sudo umount ' + speicher)
    print("Speichermedium ausgeworfen.")
    print("Logging erfolgreich beendet.")
    pass

if (speicher !=0):
    logf.close()
    os.system('sudo umount -l ' + speicher)
#os.system('sudo poweroff')

Short Explanation: The script has two serial connections and relays what it receives on one port directly to the other. The whole thing is for logging purposes, so i also write to a file.

I got it working. The only thing I'm not sure about is the part where I'm not interfering in the connection between the two parties or in other words none of the parties noticing that I'm logging.

So my questions are:

• Do I have to worry about EOLs? I am using Putty to send and receive and it only replaces the current line, where the cursor is at. like_that.gif

• Can I circumvent the "maybe problem" by handling bare bits/bytes? Would that be the superior solution?

In the example I'm printing x and xx so and this is what I get:

test
b'test
'

• What does the b' do and how does it affect my Relay-Function?
• The means new line? That's kind of strange.

I would love to try it out before putting that thing to use, but I want to reduce the Downtime to a minimum. And I would like to advance my knowledge before having to troubleshoot.

question from:https://stackoverflow.com/questions/65546057/sending-what-is-received-on-one-serial-port-to-another-serial-port-for-logging

Answer 1

Waitting for answers