struct.error: argument for 's' must be a bytes object

[VijayalakshmiSundaravaradhan]

net.py is my sample application to set the ip address of my eth0 interface. I get the following error while running the application.

Traceback (most recent call last):
File "net.py", line 119, in
inf.set_ip("192.168.7.59");
File "/usr/lib/python3.5/site-packages/pynetlinux/ifconfig.py", line 210, in set_ip
ifreq = struct.pack('16sH2s4s8s', self.name, AF_INET, '\x00'*2, ipbytes, '\x00'*8)
struct.error: argument for 's' must be a bytes object

Please help me with the error.

[samyabdellatif]

Hello, there @VijayalakshmiSundaravaradhan , I know this an old thread but since the package developer is not responding for a while , Just want to point this for reference for anyone who faces the same problem in the future .

I have been trying to build a simple GUI tool for managing network interfaces and came across this same error you mentioned.. after a little research I found it's because of the struct format that is passed to the function struct.pack('16sH2s4s8s' ...), you can find how this format works in details here . This module performs conversions between Python values and C structs represented as Python bytes objects.

these are the most used in the project
s -----> char[] | bytes char array in C is string for python so make sure the self.name is in byte
H ----> unsigned short | integer

so whenever you get this error go to the ifconfig.py and edit the line in the error

for example line 210 becomes

ifreq = struct.pack('16sH2s4s8s', bytes(self.name,'utf-8'), AF_INET, b'\x00'*2, ipbytes, b'\x00'*8)

and it worked for me this way