So my project is that I need to send a jpg image from one computer to another computer in the same network. To send the data I split the data into chunks of at least 9999 bytes and then I create a length header that tells the length of the data and I attach it to the start of the massage. here is the code:
the protocol:
import os.path
LENGTH_FIELD_SIZE = 4
PORT = 8820
COMANDS_LIST = "TAKE_SCREENSHOT\nSEND_PHOTO\nDIR\nDELETE\nCOPY\nEXECUTE\nEXIT".split("\n")
def check_cmd(data):
"""
Check if the command is defined in the protocol, including all parameters
For example, DELETE c:\work\file.txt is good, but DELETE alone is not
"""
command = ""
file_location =""
splited_data = data.split(maxsplit=1)
if len(splited_data) == 2:
command, file_location = splited_data
return (command in COMANDS_LIST) and (file_location is not None)
elif len(splited_data) == 1:
command = splited_data[0]
return command in ["TAKE_SCREENSHOT","EXIT","SEND_PHOTO"]
return False
# (3)
def create_msg(data):
"""
Create a valid protocol message, with length field
"""
data_len = len(str(data))
if data_len > 9999 or data_len == 0:
print(f"data len is bigger then 9999 or is 0, data len = {data_len} ")
return False
len_field = str(data_len).zfill(4)
# (4)
print(len_field)
return True ,f"{len_field}{data}"
def get_msg(my_socket):
"""
Extract message from protocol, without the length field
If length field does not include a number, returns False, "Error"
"""
lenght_field = ""
data = ""
try:
while len(lenght_field) < 4:
lenght_field += my_socket.recv(4).decode()
except RuntimeError as exc_run:
return False, "header wasnt sent properly"
if not lenght_field.isdigit():
return False, "error, length header is not valid"
lenght_field = lenght_field.lstrip("0")
while len(data) < int(lenght_field):
data += my_socket.recv(int(lenght_field)).decode()
return True, data
now the protocol works fine when I use the same computer for both server and client and when I debug get_msg on the other computer. when I'm not, it seems that the problem is that the part that recv the header will recv something else after a few successful recv and return an error message.
here are the server parts:
import socket
import pyautogui as pyautogui
import protocol
import glob
import os.path
import shutil
import subprocess
import base64
IP = "0.0.0.0"
PORT = 8820
PHOTO_PATH = r"C:\Users\Innon\Pictures\Screenshots\screenShot.jpg"# The path + filename where the screenshot at the server should be saved
def check_client_request(cmd):
"""
Break cmd to command and parameters
Check if the command and params are good.
For example, the filename to be copied actually exists
Returns:
valid: True/False
command: The requested cmd (ex. "DIR")
params: List of the cmd params (ex. ["c:\\cyber"])
"""
# Use protocol.check_cmd first
cmd_arr = cmd.split(maxsplit=1)
command = cmd_arr[0]
file_location = None
if len(cmd_arr) == 2:
file_location = cmd_arr[1]
if file_location == None:
return protocol.check_cmd(cmd) ,command, file_location
else:
file_location = tuple(str(file_location).split())
if (os.path.exists(file_location[0])):
return protocol.check_cmd(cmd) , command , file_location
return False , command , file_location
# Then make sure the params are valid
# (6)
def handle_client_request(command,params):
"""Create the response to the client, given the command is legal and params are OK
For example, return the list of filenames in a directory
Note: in case of SEND_PHOTO, only the length of the file will be sent
Returns:
response: the requested data
"""
# (7)
response = "no server response"
if command == "DIR":
response = glob.glob(f"{params[0]}\\*.*" )
if command == "DELETE":
os.remove(params[0])
response = f"{params[0]} was deleted"
if command == "COPY":
try:
shutil.copy(params[0],params[1])
response = f"{params[0]} was copyed to {params[1]}"
except FileNotFoundError as ex1:
response = ex1
except IndexError as ex2:
response = ex2
if command == "EXECUTE":
subprocess.call(params[0])
response = f"{params[0]} was executed"
if command == "TAKE_SCREENSHOT":
#todo find a way to know and create the locatipn of screen shot to be saved
myScreenshot = pyautogui.screenshot()
myScreenshot.save(PHOTO_PATH)
response = f"screen shot have been taken and been saved at {PHOTO_PATH}"
if command == "SEND_PHOTO":
with open(PHOTO_PATH, "rb") as file:
file_data = base64.b64encode(file.read()).decode()
print(file_data)
is_vaild_response, img_length = protocol.create_msg(len(file_data))
print(img_length)
img_data = ""
if not is_vaild_response:
response = "img length data isnt valid"
return response
while len(file_data) > 0:
chunk_data = file_data[:9999]
is_vaild_response, data = protocol.create_msg(chunk_data)
if not is_vaild_response:
response = "img data isnt valid"
return response
img_data += data
file_data = file_data[9999:]
response = f"{img_length}{img_data}"
return response
def main():
# open socket with client
server_socket = socket.socket()
server_socket.bind((IP,PORT))
server_socket.listen(1)
# (1)
client_socket, addr = server_socket.accept()
# handle requests until user asks to exit
while True:
# Check if protocol is OK, e.g. length field OK
valid_protocol, cmd = protocol.get_msg(client_socket)
print(f"got message {valid_protocol}")
if valid_protocol:
# Check if params are good, e.g. correct number of params, file name exists
valid_cmd, command, params = check_client_request(cmd)
print(f"check_client_request {valid_cmd}")
if valid_cmd:
# (6)
if command == 'EXIT':
break
if command == 'SEND_PHOTO':
data = handle_client_request(command, params)
client_socket.sendall(data.encode())
continue
# prepare a response using "handle_client_request"
data = handle_client_request(command,params)
# add length field using "create_msg"
is_vaild_response , response = protocol.create_msg(data)
print(f"creat_msg {is_vaild_response}")
# send to client
if is_vaild_response:
client_socket.sendall(response.encode())
else:
# prepare proper error to client
resp = 'Bad command or parameters'
is_vaild_response , response = protocol.create_msg(resp)
# send to client
client_socket.sendall(response.encode())
else:
# prepare proper error to client
resp = 'Packet not according to protocol'
is_vaild_response, response = protocol.create_msg(resp)
#send to client
client_socket.sendall(response.encode())
# Attempt to clean garbage from socket
client_socket.recv(1024)
# close sockets
resp = "Closing connection"
print(resp)
is_vaild_response, response = protocol.create_msg(resp)
client_socket.sendall(response.encode())
client_socket.close()
server_socket.close()
if __name__ == '__main__':
main()
and the client:
import socket
import base64
import protocol
IP = "127.0.0.1"
SAVED_PHOTO_LOCATION = r'C:\Users\Innon\Pictures\Saved Pictures\screenShot.jpg' # The path + filename where the copy of the screenshot at the client should be saved
def handle_server_response(my_socket, cmd):
"""
Receive the response from the server and handle it, according to the request
For example, DIR should result in printing the contents to the screen,
Note- special attention should be given to SEND_PHOTO as it requires and extra receive
"""
# (8) treat all responses except SEND_PHOTO
if "SEND_PHOTO" not in cmd:
vaild_data, data = protocol.get_msg(my_socket)
if vaild_data:
return data
# (10) treat SEND_PHOTO
else:
pic_data = ""
vaild_pick_len, pic_len = protocol.get_msg(my_socket)
if pic_len.isdigit() == False:
print(f"picture length is not valid. got massage: {pic_len}")
return
with open(SAVED_PHOTO_LOCATION, "wb") as file:
while len(pic_data) < int(pic_len):
vaild_data, data = protocol.get_msg(my_socket)
if not vaild_data:
return f"img data isnt valid. {data}"
pic_data += data
print(pic_data)
file.write(base64.b64decode(pic_data.encode()))
return "img was recived succesfully "
def main():
# open socket with the server
my_socket = socket.socket()
my_socket.connect((IP,8820))
# (2)
# print instructions
print('Welcome to remote computer application. Available commands are:\n')
print('TAKE_SCREENSHOT\nSEND_PHOTO\nDIR\nDELETE\nCOPY\nEXECUTE\nEXIT')
# loop until user requested to exit
while True:
cmd = input("Please enter command:\n")
if protocol.check_cmd(cmd):
valid_pack , packet = protocol.create_msg(cmd)
if valid_pack:
my_socket.sendall(packet.encode())
print(handle_server_response(my_socket, cmd))
if cmd == 'EXIT':
break
else:
print("Not a valid command, or missing parameters\n")
my_socket.close()
if __name__ == '__main__':
main()
here is how the problem looks like:thi is how it looks
here is how to needs look like: the right way
thank you.
