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Python Socket file transfer without closing sockets [duplicate]

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sending multiple files in python
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Sending multiple files through a TCP socket
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I've been trying to transfer large files through python sockets, I can do it but it only works well if I close the connection, I want to keep the connection open and keep transfering files after that
Server:
import socket
import sys
from tqdm import tqdm
IP =
PORT =
ADDR = (IP, PORT)
SIZE = 4096
FORMAT = "utf-8"
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind(ADDR)
server.listen()
print("[+] Listening...")
conn, addr = server.accept()
print(f"[+] Client connected from {addr[0]}:{addr[1]}")
#last try:
def receiver():
file_name = conn.recv(1024).decode()
file_size = conn.recv(1024).decode()
with open(file_name, "wb") as file:
c = 0
while c <= int(file_size):
data = conn.recv(1024)
if not (data):
break
file.write(data)
c += len(data)
def execute_rem(command):
conn.send(command.encode(FORMAT))
if command[0] == "exit":
conn.close()
server.close()
exit()
def run():
while True:
command = input(">> ")
if len(command) != 0:
conn.send(command.encode(FORMAT))
command = command.split(" ")
if command[0] == "download" and len(command) == 2:
receiver()
else:
result = conn.recv(SIZE)
if result == "1":
continue
else:
print(str(result, FORMAT))
run()
client:
import os
import sys
import socket
import time
import subprocess
from tqdm import tqdm
IP =
PORT =
ADDR = (IP, PORT)
SIZE = 4096
FORMAT = "utf-8"
WAITTIME = 10
client = 0
while True:
try:
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(ADDR)
break
except socket.error:
time.sleep(WAITTIME)
def exec_comnd(command):
cmd = subprocess.Popen(command,shell = True, stderr = subprocess.PIPE, stdout = subprocess.PIPE, stdin = subprocess.PIPE)
byte = cmd.stdout.read()+cmd.stderr.read()
if len(byte) == 0:
byte = "1"
return byte
def f_send(file_name):
file_size = os.path.getsize(file_name)
client.send(file_name.encode())
client.send(str(file_size).encode())
with open(file_name, "rb") as file:
c = 0
while c <= file_size:
data = file.read(1024)
if not (data):
break
client.sendall(data)
c += len(data)
def run():
while True:
command = client.recv(SIZE).decode(FORMAT)
command = command.split(" ")
if command[0] == "exit":
client.close()
exit()
elif command[0] == "cd" and len(command) == 2:
path = command[1]
os.chdir(path)
client.send(("Cambio a directorio " + path).encode(FORMAT))
elif command[0] == "download" and len(command) == 2:
f_send(command[1])
else:
res_comnd = exec_comnd(command)
client.send(res_comnd)
run()
This is my last attempt but I have tried different ways. The file gets sent but the server gets stuck until I ctl+c, after that, based on the output, server gets stuck on "data = conn.recv(1024))" (terminal output stops at "download test.jpg") and client gets stuck on "client.send(res_comnd)". I don't see why, is the only way closing the socket after the file transfer?
server output:
[+] Listening... [+] Client connected from
IP:PORT
>> download test.jpg
^CTraceback (most recent call last): File "/home/xxxx/project/nuev/server.py", line 94, in <module>
run() File "/home/xxxx/project/nuev/server.py", line 84, in run
receiver() File "/home/xxxx/project/nuev/server.py", line 36, in receiver
data = conn.recv(1024) KeyboardInterrupt
client output:
Traceback (most recent call last): File "C:\Users\xxxx\Desktop\client.py", line 108, in <module>
run() File "C:\Users\xxxx\Desktop\client.py", line 105, in run
client.send(res_comnd) ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine

Python Sockets multiple file transfers

So I have a python program that basically let's the client connect to the server and send it an excel file which is used as an input for an optimization problem. I then want the server to send the output of this optimization (also an excel file) back to the client. The model itself takes about a minute to solve, and I think this is causing some issues with the client trying to receive the output 'too early'.
The client code:
SEPARATOR = "<SEPARATOR>"
BUFFER_SIZE = 4096
HEADER = 64
HEADERSIZE = 10
port = 1234
FORMAT = 'utf-8'
DISCONNECT_MESSAGE = "!DISCONNECT"
host = "123.45.678.910"
s = socket.socket()
s.connect((host, port))
filename = "input/Model_Input.xlsx"
filesize = os.path.getsize(filename)
s.send(f"{filename}{SEPARATOR}{filesize}".encode())
with open(filename, "rb") as f:
while True:
bytes_read = f.read(BUFFER_SIZE)
if not bytes_read:
break
s.sendall(bytes_read)
out_received = s.recv(BUFFER_SIZE).decode()
out_filename, out_filesize = out_received.split(SEPARATOR)
out_filename = os.path.basename(out_filename)
out_filesize = int(out_filesize)
with open(out_filename, "wb") as h:
while True:
out_bytes_read = s.recv(BUFFER_SIZE)
if not out_bytes_read:
break
h.write(out_bytes_read)
And the server code:
SERVER_PORT = 1234
SERVER_HOST = socket.gethostbyname(socket.gethostname())
BUFFER_SIZE = 4096
SEPARATOR = "<SEPARATOR>"
s = socket.socket()
s.bind((SERVER_HOST, SERVER_PORT))
s.listen(5)
client_socket, address = s.accept()
received = client_socket.recv(BUFFER_SIZE).decode()
filename, filesize = received.split(SEPARATOR)
filename = os.path.basename(filename)
filesize = int(filesize)
with open(filename, "wb") as f:
while True:
bytes_read = client_socket.recv(BUFFER_SIZE)
if not bytes_read:
break
f.write(bytes_read)
##################
## MODEL CODE ##
##################
outfilename = 'Model_Output.xlsx'
outfilesize = os.path.getsize(filename)
client_socket.send(f"{outfilename}{SEPARATOR}{outfilesize}".encode())
with open(outfilename, "rb") as h:
while True:
# read the bytes from the file
bytes_readed = h.read(BUFFER_SIZE)
if not bytes_readed:
break
client_socket.sendall(bytes_readed)
I am able to send the input file to the server and get the model to run, and save the output to storage. However, as soon as I add in the part to try send it back to the client, it gets stuck. It still sends and receives the input file successfully, but then the model never runs. Neither the client nor the server disconnect, they both just seem to be stuck.
Thank you

I can be very difficult for someone (i.e. me) to remotely debug this type of code, so I can't really point to a particular line of code that is necessarily the problem. If, however, your client and server are running on the same machine, then there is a potential problem in the client code that begins:
with open(out_filename, "wb") as h:
while True:
out_bytes_read = s.recv(BUFFER_SIZE)
if not out_bytes_read:
break
h.write(out_bytes_read)
When the open is executed, this sets the file size to 0. The server, meanwhile is reading this file to transmit it to the file and can possibly find that there are now only 0 bytes. But it has already sent a "header" saying that there are N bytes where N is non-zero. But that is a different problem than the one you describe. But it could be happening in the other direction, also. That is, when the client is sending the file and the server is opening the file for output, it is now zeroing out the file that the client is still reading. The code below solves that problem in both directions. Of course, if your client and server are on different computers not accessing the same files concurrently, then what I have described is not an issue. Not yet, anyway.
I can, however, offer a slightly different approach, which does seem to work:
See the Using a Socket section from the Socket Programming HOWTO article in the Python 3 Manual. I have adopted the suggestion to use fixed length messages. It's a little more laborious, perhaps, but also a bit more fullproof. That means that if you want to transmit the filename, you have to first transmit the length of the encoded filename as fixed length length message (3 bytes can handle encoded filenames up to 999 bytes in length) and then you can transmit the encode filename. Similarly, we transmit the length of a file as a 9 byte length (left-padded with zeroes), which can handle file sizes up to 999,999,999 bytes (I set the width of 9 arbitrarily). I have two functions, receive_msg and send_msg that will robustly send and receive complete byte messages and can be used by both the client and server. These are modeled on the MySocket.mysend and MySocket.myreceive methods from the article.
I assumed that the server should be able to handle more than one request before terminating. In fact, it should be able to handle requests concurrently. To that end the server passes a request to a thread pool worker function, process_request, for processing. It wasn't clear what the nature of the so-called "Model Code" was. Assuming the function that performs this computation, process_model, is CPU-intensive, process_requestis passed a multiprocessing pool instance that can be used to perform the process_model processing so that the CPU-intensive portion of processing will not be limited by the Global Interpreter Lock. If there is no real CPU-intensive processing involved, then remove the code that created the multiprocessing pool and then call process_model as a regular function.
Server Code
import socket
from multiprocessing.pool import Pool, ThreadPool
import os.path
BUFFER_SIZE = 4096
SERVER_PORT = 1234
SERVER_HOST = socket.gethostbyname(socket.gethostname())
def receive_msg(sock, msg_length):
chunks = []
bytes_recd = 0
while bytes_recd < msg_length:
chunk = sock.recv(min(msg_length - bytes_recd, BUFFER_SIZE))
if chunk == b'':
raise RuntimeError("socket connection broken")
chunks.append(chunk)
bytes_recd = bytes_recd + len(chunk)
return b''.join(chunks)
def send_msg(sock, msg):
msg_length = len(msg)
totalsent = 0
while totalsent < msg_length:
sent = sock.send(msg[totalsent:])
if sent == 0:
raise RuntimeError("socket connection broken")
totalsent = totalsent + sent
def server():
s = socket.socket()
s.bind((SERVER_HOST, SERVER_PORT))
s.listen(5)
process_pool = Pool(5)
thread_pool = ThreadPool(5)
while True:
client_socket, address = s.accept()
thread_pool.apply_async(process_request, args=(process_pool, client_socket))
def process_request(process_pool, s):
# Fixed length fields:
# width 3 for filename length, followed by filename, width 9 for filesize
filename_size = int(receive_msg(s, 3).decode())
filename = receive_msg(s, filename_size).decode()
filename = os.path.basename(filename)
filesize = int(receive_msg(s, 9).decode())
msg = receive_msg(s, filesize)
with open(filename, "wb") as f:
f.write(msg)
# Assuming processing the model is CPU-intensive,
# we use a process pool for doing that:
out_filename = process_pool.apply(process_model, args=(filename,))
out_filesize = os.path.getsize(out_filename)
encoded_filename = out_filename.encode()
msg1 = b"%03d%s%09dfilesize" % (len(encoded_filename), encoded_filename, out_filesize)
with open(out_filename, "rb") as h:
msg2 = h.read()
send_msg(s, msg1)
send_msg(s, msg2)
def process_model(filename):
...
# Returned filename should probably be a function of the passed filename
return 'Model_Output.xlsx' # name of the output file
if __name__ == '__main__':
server()
Client Code
import socket
import os.path
BUFFER_SIZE = 4096
port = 1234
host = "123.45.678.910"
def receive_msg(sock, msg_length):
chunks = []
bytes_recd = 0
while bytes_recd < msg_length:
chunk = sock.recv(min(msg_length - bytes_recd, BUFFER_SIZE))
if chunk == b'':
raise RuntimeError("socket connection broken")
chunks.append(chunk)
bytes_recd = bytes_recd + len(chunk)
return b''.join(chunks)
def send_msg(sock, msg):
msg_length = len(msg)
totalsent = 0
while totalsent < msg_length:
sent = sock.send(msg[totalsent:])
if sent == 0:
raise RuntimeError("socket connection broken")
totalsent = totalsent + sent
def client():
s = socket.socket()
s.connect((host, port))
filename = "input/Model_Input.xlsx"
filesize = os.path.getsize(filename)
# Fixed length fields:
# width 3 for filename length, followed by filename, width 9 for filesize
encoded_filename = filename.encode()
msg1 = b"%03d%s%09dfilesize" % (len(encoded_filename), encoded_filename, filesize)
with open(filename, "rb") as f:
msg2 = f.read()
send_msg(s, msg1)
send_msg(s, msg2)
out_filename_size = int(receive_msg(s, 3).decode())
out_filename = receive_msg(s, out_filename_size).decode()
out_filename = os.path.basename(out_filename)
out_filesize = int(receive_msg(s, 9).decode())
msg = receive_msg(s, out_filesize)
with open(out_filename, "wb") as h:
h.write(msg)
if __name__ == '__main__':
client()
Update
The entire programming can greatly be simplified by implementing the service as a Remote Procedure Call. The code is based on Python Cookbook, 3rd Edition:
Server
import socket
import pickle
from multiprocessing.connection import Listener
from threading import Thread
from multiprocessing.pool import Pool
import os.path
SERVER_PORT = 1234
SERVER_HOST = socket.gethostbyname(socket.gethostname())
class RPCHandler:
def __init__(self):
self._functions = { }
def register_function(self, func):
self._functions[func.__name__] = func
def handle_connection(self, connection):
try:
while True:
# Receive a message
func_name, args, kwargs = pickle.loads(connection.recv())
# Run the RPC and send a response
try:
r = self._functions[func_name](*args,**kwargs)
connection.send(pickle.dumps(r))
except Exception as e:
connection.send(pickle.dumps(e))
except EOFError:
pass
def server():
global process_pool
handler = RPCHandler()
handler.register_function(process_request)
sock = Listener((SERVER_HOST, SERVER_PORT))
process_pool = Pool(5)
while True:
client = sock.accept()
t = Thread(target=handler.handle_connection, args=(client,))
t.daemon = True
t.start()
def process_request(filename, contents):
filename = os.path.basename(filename)
with open(filename, "wb") as f:
f.write(contents)
# Assuming processing the model is CPU-intensive,
# we use a process pool for doing that:
out_filename = process_pool.apply(process_model, args=(filename,))
with open(out_filename, "rb") as h:
out_contents = h.read()
return (out_filename, out_contents)
def process_model(filename):
...
# Returned filename should probably be a function of the passed filename
return 'Model_Output.xlsx' # name of the output file
if __name__ == '__main__':
server()
Client
import pickle
import socket
import os.path
from multiprocessing.connection import Client
port = 1234
host = "123.45.678.910"
class RPCProxy:
def __init__(self, connection):
self._connection = connection
def __getattr__(self, name):
def do_rpc(*args, **kwargs):
self._connection.send(pickle.dumps((name, args, kwargs)))
result = pickle.loads(self._connection.recv())
if isinstance(result, Exception):
raise result
return result
return do_rpc
def client():
c = Client((host, port))
proxy = RPCProxy(c)
filename = "input/Model_Input.xlsx"
with open(filename, "rb") as f:
contents = f.read()
(out_filename, out_contents) = proxy.process_request(filename, contents)
out_filename = os.path.basename(out_filename)
with open(out_filename, "wb") as h:
h.write(out_contents)
if __name__ == '__main__':
client()

OSError: [Errno 9] Bad file descriptor

I initially tried using python to run but there were different errors so I tried using python3 and received the error in the title. I am trying to connect to server and download a file that has tls implemented.
import socket, ssl, pprint
import os, time
import threading
def main():
s2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
ssl_sock = ssl.wrap_socket(s2,
server_side = False,
ca_certs="CA.crt",
cert_reqs=ssl.CERT_REQUIRED)
s2.connect(('localhost',10024))
filename = raw_input("What file do you wish to download? -> ")
if filename != 'q':
s2.send(filename)
data = s2.recv(1024)
if data [:7] == 'fEXISTS':
fSize = long(data[7:])
message = raw_input("The file you wish to download is " +str(fSize)+\
"bytes, would you like to proceed? (y/n): ")
if message == 'y':
s2.send ('OK')
f = open('new_'+filename, 'wb')
data = s2.recv(2000000)
totalRecv = len(data)
f.write(data)
while totalRecv < fSize:
data = s2.recv(2000000)
totalRecv += len(data)
f.write(data)
progress = ((totalRecv/float(fSize))*100)
print ("{0: .2F}".format(progress)+\
"% Completed")
else:
print ("ERROR: File does not exist!")
s2.close()
if __name__ == '__main__':
main()

After wrapping the socket in an SSL context (with ssl.wrap_socket), you should not be using the original socket anymore.
You should be calling connect, send, recv, etc. on ssl_sock, not on s2.
(Specifically, when you call ssl.wrap_socket, the .detach method is called on the original socket which removes the file descriptor from it. The file descriptor is transferred to the SSL socket instance. The only thing you can do with the original then is close/destroy it.)

Sending Multiple Files Python Using Socket

I currently am trying to create a client-server application in which the client can send multiple files to the server using TCP protocol. The server will eventually create a hash-algorithm and send it back to the client but I am running into issues sending multiple files from the client to the server. In it's current form, the first file sends correctly but the files after encounter an error where the information is merged together. IE the file size is listed as the second file's name. I am a javascript dude and very new to python so an explanation to how I can make this happen would be much appreciated. I believe threading is the answer but with my limited understanding of python, I do not know how to make this work. Currently I can send one file at a time and the server stays open. However, I would like to enter several file names from my current directory and have them processed. I eventually will convert the entire client side into C but I am struggling to get the server to work correctly in python. Any advice would be much appreciated!
Server.py
import socket
import hashlib
import threading
import struct
HOST = '127.0.0.1'
PORT = 2345
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(10)
print("Waiting for a connection.....")
conn, addr = s.accept()
print("Got a connection from ", addr)
while True:
hash_type = conn.recv(1024)
print('hash type: ', hash_type)
if not hash_type:
break
file_name = conn.recv(1024)
print('file name: ', file_name)
file_size = conn.recv(1024)
file_size = int(file_size, 2)
print('file size: ', file_size )
f = open(file_name, 'wb')
chunk_size = 4096
while file_size > 0:
if file_size < chunk_size:
chuk_size = file_size
data = conn.recv(chunk_size)
f.write(data)
file_size -= len(data)
f.close()
print('File received successfully')
s.close()
Client.py
import socket
import threading
import os
HOST = '127.0.0.1'
PORT = 2345
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
hash_type = input('Enter hash type: ')
files = input('Enter file(s) to send: ')
files_to_send = files.split()
for file_name in files_to_send:
s.send(hash_type.encode())
print(file_name)
s.send(file_name.encode())
file_size = os.path.getsize(file_name)
file_size = bin(file_size)
print(file_size)
s.send(file_size.encode())
f = open(file_name, 'rb')
l = f.read()
while(l):
s.send(l)
l = f.read()
f.close()
print('File Sent')
s.close()

One way to handle what you're doing is to buffer your socket data. Below is a class that buffers data and knows how to send and receive null-terminated, UTF-8-encoded strings, and raw chunks of bytes:
buffer.py:
class Buffer:
def __init__(self,s):
'''Buffer a pre-created socket.
'''
self.sock = s
self.buffer = b''
def get_bytes(self,n):
'''Read exactly n bytes from the buffered socket.
Return remaining buffer if <n bytes remain and socket closes.
'''
while len(self.buffer) < n:
data = self.sock.recv(1024)
if not data:
data = self.buffer
self.buffer = b''
return data
self.buffer += data
# split off the message bytes from the buffer.
data,self.buffer = self.buffer[:n],self.buffer[n:]
return data
def put_bytes(self,data):
self.sock.sendall(data)
def get_utf8(self):
'''Read a null-terminated UTF8 data string and decode it.
Return an empty string if the socket closes before receiving a null.
'''
while b'\x00' not in self.buffer:
data = self.sock.recv(1024)
if not data:
return ''
self.buffer += data
# split off the string from the buffer.
data,_,self.buffer = self.buffer.partition(b'\x00')
return data.decode()
def put_utf8(self,s):
if '\x00' in s:
raise ValueError('string contains delimiter(null)')
self.sock.sendall(s.encode() + b'\x00')
With this class, your client and server become:
client.py:
import socket
import threading
import os
import buffer
HOST = '127.0.0.1'
PORT = 2345
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
with s:
sbuf = buffer.Buffer(s)
hash_type = input('Enter hash type: ')
files = input('Enter file(s) to send: ')
files_to_send = files.split()
for file_name in files_to_send:
print(file_name)
sbuf.put_utf8(hash_type)
sbuf.put_utf8(file_name)
file_size = os.path.getsize(file_name)
sbuf.put_utf8(str(file_size))
with open(file_name, 'rb') as f:
sbuf.put_bytes(f.read())
print('File Sent')
server.py:
import socket
import os
import buffer
HOST = ''
PORT = 2345
# If server and client run in same local directory,
# need a separate place to store the uploads.
try:
os.mkdir('uploads')
except FileExistsError:
pass
s = socket.socket()
s.bind((HOST, PORT))
s.listen(10)
print("Waiting for a connection.....")
while True:
conn, addr = s.accept()
print("Got a connection from ", addr)
connbuf = buffer.Buffer(conn)
while True:
hash_type = connbuf.get_utf8()
if not hash_type:
break
print('hash type: ', hash_type)
file_name = connbuf.get_utf8()
if not file_name:
break
file_name = os.path.join('uploads',file_name)
print('file name: ', file_name)
file_size = int(connbuf.get_utf8())
print('file size: ', file_size )
with open(file_name, 'wb') as f:
remaining = file_size
while remaining:
chunk_size = 4096 if remaining >= 4096 else remaining
chunk = connbuf.get_bytes(chunk_size)
if not chunk: break
f.write(chunk)
remaining -= len(chunk)
if remaining:
print('File incomplete. Missing',remaining,'bytes.')
else:
print('File received successfully.')
print('Connection closed.')
conn.close()
Demo
client:
Enter hash type: abc
Enter file(s) to send: demo1.dat demo2.dat
demo1.dat
File Sent
demo2.dat
File Sent
server:
Waiting for a connection.....
Got a connection from ('127.0.0.1', 22126)
hash type: abc
file name: uploads\demo1.dat
file size: 488892
File received successfully.
hash type: abc
file name: uploads\demo2.dat
file size: 212992
File received successfully.
Connection closed.

1.
file_size = conn.recv(1024)
In your server code you read 1024 bytes as your file_size, file_size is only 4 or 8 bytes long
2.
file_name = conn.recv(1024) Your server don't know how long the filename/hashtype is.
-> Use a long for both sizes and read only sizeof(long) bytes from the stream.
You can use https://docs.python.org/2/library/struct.html for packing/encoding of these numbers
-> Or just go the easy way and use https://docs.python.org/3/library/pickle.html for serialization

TypeError in socket, when pickle

I'm trying to write a client-server program where server receives the requests for a database records, or files, and sends it back. Everything was working just fine until I used the pickle function to send data from client to server,
Exception in thread Thread-1:
Traceback (most recent call last):
File "/usr/lib/python2.7/threading.py", line 551, in __bootstrap_inner
self.run()
File "server.py", line 71, in run
data = pickle.loads(data)
File "/usr/lib/python2.7/pickle.py", line 1381, in loads
file = StringIO(str)
TypeError: expected read buffer, NoneType found
When I send data from server to client, there is no problem. I worked like this for a few weeks but when there is about 50 exceptions, the server program closes.
client.py file:
import socket
import sys
import time
import pickle
import struct
def recvall(sock, n):
# Helper function to recv n bytes or return None if EOF is hit
data = ''
while len(data) < n:
packet = sock.recv(n - len(data))
if not packet:
return None
data += packet
return data
def recv_msg(sock):
# Read message length and unpack it into an integer
raw_msglen = recvall(sock, 4)
if not raw_msglen:
return None
msglen = struct.unpack('>I', raw_msglen)[0]
# Read the message data
return recvall(sock, msglen)
def sending(msg):
host = 'localhost'
port = 50000
size = 1024
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host,port))
lenght = len(msg)
if lenght>0:
msg = pickle.dumps(msg)
msg = struct.pack('>I', len(msg)) + msg
s.sendall(msg)
print 'sended string lenght: '+str(lenght)
else:
s.send('nothing sended')
data = recv_msg(s)
lenght2 = len(data)
print data
print 'received string lenght: '+str(lenght2)
#sys.stdout.write(data)
s.close()
while 1:
msg = raw_input('Input:')
sending(msg)
server.py:
class Client(threading.Thread):
def __init__(self,(client,address)):
threading.Thread.__init__(self)
self.client = client
self.address = address
self.size = 1024
def run(self):
running = 1
while running:
sock = self.client
data = self.recv_msg(sock)
data = pickle.loads(data)
if data:
msg = struct.pack('>I', len(data)) + data
self.client.sendall(msg)
else:
self.client.close()
running = 0
def recv_msg(self, sock):
# Read message length and unpack it into an integer
raw_msglen = self.recvall(sock, 4)
if not raw_msglen:
return None
msglen = struct.unpack('>I', raw_msglen)[0]
# Read the message data
return self.recvall(sock, msglen)
def recvall(self, sock, n):
# Helper function to recv n bytes or return None if EOF is hit
data = ''
while len(data) < n:
packet = sock.recv(n - len(data))
if not packet:
return None
data += packet
return data
In previous version I puted the pickle function from server to client, and it worked fine, no problems, but now I started to write it from the beginning to find the problem, but I didn't.
The recv_msg method was found here:
Python Socket Receive Large Amount of Data

The recv_msg method returns None when EOF is reached, and you pass that None to pickle.loads, which is an error.
To fix the problem, place the call to pickle.loads() after the EOF-check:
data = self.recv_msg(sock)
if data is not None:
data = pickle.loads(data)
msg = struct.pack('>I', len(data)) + data
self.client.sendall(msg)
else:
self.client.close()
running = 0