How to send unsigned characters over TCP in this communication protocol format in Python?
Question
So, I'm working on a project with a proprietary communication protocol. I need to send data in given format and Up, Down, Left & Right co-ordinates to particular IP address. Communication happens over TCP and I need to program TCP client in python to send data in following format:
IP address/Handshake address: 192.166.166.166
This is the Data format .
Data type is unsigned char 0-255 (8-bit binary) and data length is 6-64 bit.
Data length of each frame is 10-64 bit.
So, If I want to move object at 1.0.0.1 to (23, 45, 67, 89), this is the given instruction:
Send 255 255 10 3 1 0 0 1 23 45 67 89 to specified IP address. I imagine specified IP address is 192.166.166.166. You can refer to data format to understand this data that I'm supposed to send. It's quite simple.
The question is, how am I supposed to send this series of unsigned chars over TCP in python?
I've tried following:
import socket
host = '192.166.166.166'
port = 80 # 80 Because TCP
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))
data = '255 255 10 3 1 0 0 1 23 45 67 89'
s.sendall(data)
result = s.recv(1024)
s.close()
print('Received', repr(result))
Obviously this is not working. I've not specified unsigned char and I'm just sending raw data and spaces.
This is what I get in return from server:
('Received', '\'HTTP/1.0 400 Bad Request\\r\\nServer: Mini-IoT-314\\r\\nDate: , 31 1969 23:59:59 GMT\\r\\nPragma: no-
cache\\r\\nCache-Control: no-cache\\r\\nContent-Type:
text/html\\r\\nConnection: close\\r\\n\\r\\n<HTML><HEAD><TITLE>400 Bad
Request</TITLE></HEAD>\\n<BODY BGCOLOR="#cc9999"><H4>400 Bad
Request</H4>\\nCan\\\'t parse request.\\n</BODY></HTML>\\n\'')
Now, I'm not sure what to do and how to send this data so server can process this data appropriately. I would really appreciate a help here.
2 answers
solution1
0 2018-05-24 09:18:51
Not really my area of expertise, just an idea: You might need to send the data as a Structure.
Have a look at python's ctypes: https://docs.python.org/3/library/ctypes.html#structured-data-types
from ctypes import *
class payload(Structure):
_fields_ = [("data_sign1", c_ubyte),
...]
solution2
0 2018-05-24 10:03:04
1) I tested your code in python 3.5 with slight modifications rather than sending string,i sent bytes by converting string into bytes
bytes(data,'utf-8')
2) Do not use Port 80,might be your http server is running on that port, Try to use some other port. it will work
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