Send a file through sockets in Python
Question:
I’m trying to make a program in python that implements sockets. Each client sends a PDF file and the server receives it and the title is changed to "file_(number).pdf" (e.g.: file_1.pdf). The problem presented is that only a client can send a file successfully. When a second client tries to send the file, the program crashes. What am I doing wrong and how can I solve my code to allow N clients (with N < 20) to connect to the server and transfer files?
Here’s the server code:
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10) # Accepts up to 10 incoming connections..
sc, address = s.accept()
print address
i=1
f = open('file_'+ str(i)+".pdf",'wb') # Open in binary
i=i+1
while (True):
# We receive and write to the file.
l = sc.recv(1024)
while (l):
f.write(l)
l = sc.recv(1024)
f.close()
sc.close()
s.close()
Here’s the client code:
import socket
import sys
s = socket.socket()
s.connect(("localhost",9999))
f = open ("libroR.pdf", "rb")
l = f.read(1024)
while (l):
s.send(l)
l = f.read(1024)
s.close()
To simplify my code, I always use a book with file name "libroR.pdf", but in the full code it is chosen by a GUI.
Answers:
You are closing the server socket (s
in your code) after handling the first client connection. Thus only one client is ever handled by your server. Make a loop around accept
and reading from the sc
.
You must put all the code from sc, address = s.accept()
upto sc.close()
into another loop or the server simply terminates after receiving the first file. It doesn’t crash, the script is just finished.
[EDIT] Here is the revised code:
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10) # Accepts up to 10 connections.
while True:
sc, address = s.accept()
print address
i=1
f = open('file_'+ str(i)+".pdf",'wb') #open in binary
i=i+1
while (True):
# receive data and write it to file
l = sc.recv(1024)
while (l):
f.write(l)
l = sc.recv(1024)
f.close()
sc.close()
s.close()
Note that s.listen(10)
means “set maximum accept rate to 10 connections“, not “stop after 10 connections”.
Your code is getting stuck in the second while loop.
See:
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10)
i=1
while True:
sc, address = s.accept()
print address
f = open('file_'+str(i)+".pdf",'wb') #open in binary
i=i+1
print(i)
l = 1
while(l):
l = sc.recv(1024)
while (l):
f.write(l)
l = sc.recv(1024)
f.close()
sc.close()
s.close()
Using this code you can send files multiple time using the same client.py
Server.py
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10) # Acepta hasta 10 conexiones entrantes.
i = 1
while True:
sc, address = s.accept()
print address
f = open('file_'+ str(i)+".wav",'wb') #open in binary
i=i+1
while (True):
# recibimos y escribimos en el fichero
l = sc.recv(1024)
f.write(l)
if not l:
break
f.close()
sc.close()
print('copied the file.')
s.close()
Server:
import socket
from threading import Thread
TCP_IP = 'localhost'
TCP_PORT = 9001
BUFFER_SIZE = 1024
class ClientThread(Thread):
def __init__(self, ip, port, sock):
Thread.__init__(self)
self.ip = ip
self.port = port
self.sock = sock
print(" New thread started for "+ip+":"+str(port))
def run(self):
filename = 'anon234.jpeg'
f = open(filename, 'rb')
while True:
l = f.read(BUFFER_SIZE)
while (l):
self.sock.send(l)
#print('Sent ',repr(l))
l = f.read(BUFFER_SIZE)
if not l:
f.close()
self.sock.close()
break
tcpsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
tcpsock.bind((TCP_IP, TCP_PORT))
threads = []
while True:
tcpsock.listen(5)
print("Waiting for incoming connections...")
(conn, (ip, port)) = tcpsock.accept()
print('Got connection from ', (ip, port))
newthread = ClientThread(ip, port, conn)
newthread.start()
threads.append(newthread)
for t in threads:
t.join()
Client:
import socket
import time
TCP_IP = 'localhost'
TCP_PORT = 9001
BUFFER_SIZE = 1024
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, TCP_PORT))
recived_f = 'imgt_thread'+str(time.time()).split('.')[0]+'.jpeg'
with open(recived_f, 'wb') as f:
print('file opened')
while True:
#print('receiving data...')
data = s.recv(BUFFER_SIZE)
print('data=%s', (data))
if not data:
f.close()
print('file close()')
break
# write data to a file
f.write(data)
print('Successfully get the file')
s.close()
print('connection closed')
I’m trying to make a program in python that implements sockets. Each client sends a PDF file and the server receives it and the title is changed to "file_(number).pdf" (e.g.: file_1.pdf). The problem presented is that only a client can send a file successfully. When a second client tries to send the file, the program crashes. What am I doing wrong and how can I solve my code to allow N clients (with N < 20) to connect to the server and transfer files?
Here’s the server code:
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10) # Accepts up to 10 incoming connections..
sc, address = s.accept()
print address
i=1
f = open('file_'+ str(i)+".pdf",'wb') # Open in binary
i=i+1
while (True):
# We receive and write to the file.
l = sc.recv(1024)
while (l):
f.write(l)
l = sc.recv(1024)
f.close()
sc.close()
s.close()
Here’s the client code:
import socket
import sys
s = socket.socket()
s.connect(("localhost",9999))
f = open ("libroR.pdf", "rb")
l = f.read(1024)
while (l):
s.send(l)
l = f.read(1024)
s.close()
To simplify my code, I always use a book with file name "libroR.pdf", but in the full code it is chosen by a GUI.
You are closing the server socket (s
in your code) after handling the first client connection. Thus only one client is ever handled by your server. Make a loop around accept
and reading from the sc
.
You must put all the code from sc, address = s.accept()
upto sc.close()
into another loop or the server simply terminates after receiving the first file. It doesn’t crash, the script is just finished.
[EDIT] Here is the revised code:
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10) # Accepts up to 10 connections.
while True:
sc, address = s.accept()
print address
i=1
f = open('file_'+ str(i)+".pdf",'wb') #open in binary
i=i+1
while (True):
# receive data and write it to file
l = sc.recv(1024)
while (l):
f.write(l)
l = sc.recv(1024)
f.close()
sc.close()
s.close()
Note that s.listen(10)
means “set maximum accept rate to 10 connections“, not “stop after 10 connections”.
Your code is getting stuck in the second while loop.
See:
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10)
i=1
while True:
sc, address = s.accept()
print address
f = open('file_'+str(i)+".pdf",'wb') #open in binary
i=i+1
print(i)
l = 1
while(l):
l = sc.recv(1024)
while (l):
f.write(l)
l = sc.recv(1024)
f.close()
sc.close()
s.close()
Using this code you can send files multiple time using the same client.py
Server.py
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10) # Acepta hasta 10 conexiones entrantes.
i = 1
while True:
sc, address = s.accept()
print address
f = open('file_'+ str(i)+".wav",'wb') #open in binary
i=i+1
while (True):
# recibimos y escribimos en el fichero
l = sc.recv(1024)
f.write(l)
if not l:
break
f.close()
sc.close()
print('copied the file.')
s.close()
Server:
import socket
from threading import Thread
TCP_IP = 'localhost'
TCP_PORT = 9001
BUFFER_SIZE = 1024
class ClientThread(Thread):
def __init__(self, ip, port, sock):
Thread.__init__(self)
self.ip = ip
self.port = port
self.sock = sock
print(" New thread started for "+ip+":"+str(port))
def run(self):
filename = 'anon234.jpeg'
f = open(filename, 'rb')
while True:
l = f.read(BUFFER_SIZE)
while (l):
self.sock.send(l)
#print('Sent ',repr(l))
l = f.read(BUFFER_SIZE)
if not l:
f.close()
self.sock.close()
break
tcpsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
tcpsock.bind((TCP_IP, TCP_PORT))
threads = []
while True:
tcpsock.listen(5)
print("Waiting for incoming connections...")
(conn, (ip, port)) = tcpsock.accept()
print('Got connection from ', (ip, port))
newthread = ClientThread(ip, port, conn)
newthread.start()
threads.append(newthread)
for t in threads:
t.join()
Client:
import socket
import time
TCP_IP = 'localhost'
TCP_PORT = 9001
BUFFER_SIZE = 1024
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, TCP_PORT))
recived_f = 'imgt_thread'+str(time.time()).split('.')[0]+'.jpeg'
with open(recived_f, 'wb') as f:
print('file opened')
while True:
#print('receiving data...')
data = s.recv(BUFFER_SIZE)
print('data=%s', (data))
if not data:
f.close()
print('file close()')
break
# write data to a file
f.write(data)
print('Successfully get the file')
s.close()
print('connection closed')