I wrote a basic socket program where the client sends an image to a server.
client.py
import socket
from PIL import ImageFile
import struct
ImageFile.LOAD_TRUNCATED_IMAGES = True
HOST = "127.0.0.1" # The server's hostname or IP address
PORT = 65432 # The port used by the server
img_byte = None
with open('test-images/hummingbird-1.jpeg', 'rb') as fp:
img_byte = fp.read()
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
length = len(img_byte)
s.sendall(struct.pack('!I', length))
s.sendall(img_byte)
, and server.py
import socket
import struct
HOST = "127.0.0.1" # Standard loopback interface address (localhost)
PORT = 65432 # Port to listen on (non-privileged ports are > 1023)
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print(f"Connected by {addr}")
while True:
buf = conn.recv(4)
(length, ) = struct.unpack('!I', buf)
data = b''
while len(data) < length:
to_read = length - len(data)
data += conn.recv(4096 if to_read > 4096 else to_read)
if not data:
break
On ther server side, I'm getting this error:
(length, ) = struct.unpack('!I', buf)
struct.error: unpack requires a buffer of 4 bytes
I think I'm missing something decisive, but I can't figure it out.
Based on the suggestion by #Mark Tolonen, I was able to modify and run server.py as follows:
import socket
import struct
HOST = "127.0.0.1" # Standard loopback interface address (localhost)
PORT = 65432 # Port to listen on (non-privileged ports are > 1023)
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print(f"Connected by {addr}")
data = b''
buf = b''
payload_size = struct.calcsize("!I")
print("payload_size: {}".format(payload_size))
while True:
while len(buf) < payload_size:
buf += conn.recv(4096)
length = struct.unpack('!I', buf[:payload_size])[0]
data = buf[payload_size:]
while len(data) < length:
to_read = length - len(data)
data += conn.recv(4096 if to_read > 4096 else to_read)
if not data:
break
file = open('rec-images/image.jpeg', 'wb')
file.write(data)
file.close()
Related
So here is the code hangs on the while loop.
client.py:
import socket
ip = "127.0.0.7"
port = 65000
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((ip, port))
while True:
file = input("Filename:")
s.sendall(file.encode())
b = b""
while True:
data = s.recv(4096)
if not data:
break
b+=data
with open(file, "wb") as f:
f.write(donne)
break
server.py:
import socket
import os
ip = "127.0.0.7"
port = 65000
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((ip, port))
s.listen(5)
conn, addr = s.accept()
while True:
receive = conn.recv(1024).decode()
if os.path.exists(receive):
with open(receive, "rb") as f:
data = f.read()
conn.sendall(data)
break
else:
print("File not found")
The problem is with the client code.
I would like to receive all the data and write them to a file but the loop in client.py does not stop.
Below are my three scripts. I need to send the message from sricpt 1(Sensor.py) to script 2.(Client.py). And then the script 2 should send the message to script 3(Server.py).
It works fine till script 2 but the message isn't being received at the script 3 and the recvfrom() keeps waiting. There is no error but the script 3 doesn't show the message. Im using UDP. Please help.
SCRIPT 1(Sensor.py)
from socket import *
from time import ctime
CLIENT_IP = '192.168.1.109'
PORT = 23567
BUFSIZE = 1024
ADDR = (CLIENT_IP, PORT)
udpCliSock = socket(AF_INET, SOCK_DGRAM)
while True:
sendData = input("> ")
if sendData is None:
break
udpCliSock.sendto(sendData.encode(), ADDR)
udpCliSock.close()
SCRIPT 2(Client.py)
from socket import *
from time import ctime
HOST = '192.168.1.103'
CLIENT_IP='192.168.1.109'
PORT = 5005
SENSOR_PORT_NO=23567
BUFSIZE = 1024
ADDR = (HOST, PORT)
CLIENT_ADDR=(CLIENT_IP,SENSOR_PORT_NO)
udpCliSock = socket(AF_INET, SOCK_DGRAM)
client = socket(AF_INET, SOCK_DGRAM)
client.bind(CLIENT_ADDR)
while True:
print("...waiting for response...")
#recv_data, ADDR = udpCliSock.recvfrom(BUFSIZE)
recv_data, ADDR = client.recvfrom(1024)
if recv_data is not None:
recv_data = recv_data.decode()
print("[%s]: receiving data from server %s:%s :%s" % (ctime(),ADDR[0], ADDR[1], recv_data))
sendData = recv_data
udpCliSock.sendto(sendData.encode(), ADDR)
udpCliSock.close()
SCRIPT 3(Server.py)
from socket import *
from time import ctime
HOST = '192.168.1.103'
PORT = 5005
BUFSIZE = 1024
ADDR = (HOST, PORT)
udpSerSock = socket(AF_INET, SOCK_DGRAM)
udpSerSock.bind(ADDR)
while True:
print("...waiting for message...")
data, ADDR = udpSerSock.recvfrom(BUFSIZE)
print(data.decode)
if data is None:
break
print("[%s]: From Address %s:%s receive data: %s" % (ctime(),ADDR[0],ADDR[1], data.decode()))
udpSerSock.close()
The problem is that, in the Client.py, you are overwriting the address of the server when you receive the datagram from the sensor. Here:
recv_data, ADDR = client.recvfrom(1024)
ADDR starts out with the server's socket address, but this function overwrites that variable with the sensor's socket address. So when you try to send, you're sending it back to the sensor (who of course isn't ever receiving it).
A better method is to connect that socket to the server at the beginning. Then you can just use send instead of sendto since the address won't be changing. Should work after that:
...
udpCliSock = socket(AF_INET, SOCK_DGRAM)
udpCliSock.connect(ADDR) # <<<<<<===============
client = socket(AF_INET, SOCK_DGRAM)
client.bind(CLIENT_ADDR)
while True:
print("...waiting for response...")
recv_data, addr = client.recvfrom(1024)
if recv_data is not None:
recv_data = recv_data.decode()
print("[%s]: receiving data from server %s:%s :%s" % (ctime(),addr[0], addr[1], recv_data))
sendData = recv_data
udpCliSock.send(sendData.encode()) # <<<<<<===============
udpCliSock.close()
I can send my data through CSV file. First, write my random numbers into CSV file then send it, but is it possible to send it directly?
my socket code:
import socket
host = 'localhost'
port = 8080
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((host, port))
s.listen(1)
while True:
print('\nListening for a client at',host , port)
conn, addr = s.accept()
print('\nConnected by', addr)
try:
print('\nReading file...\n')
while 1:
out = "test01"
print('Sending line', line)
conn.send(out)
except socket.error:
print ('Error Occured.\n\nClient disconnected.\n')
conn.close()
spark streaming code:
from pyspark import SparkContext
from pyspark.streaming import StreamingContext
sc = SparkContext("local[2]","deneme")
ssc = StreamingContext(sc, 10)
socket_stream = ssc.socketTextStream("localhost",8080)
random_integers = socket_stream.window( 30 )
digits = random_integers.flatMap(lambda line: line.split(" ")).map(lambda digit: (digit, 1))
digit_count = digits.reduceByKey(lambda x,y:x+y)
digit_count.pprint()
ssc.start()
This is because socket blocks sending the data and never moves on. The most basic solution is to send some amount of data and close the connection:
import socket
import time
host = 'localhost'
port = 50007
i = 0
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((host, port))
s.listen(1)
try:
while True:
conn, addr = s.accept()
try:
for j in range(10):
conn.send(bytes("{}\n".format(i), "utf-8"))
i += 1
time.sleep(1)
conn.close()
except socket.error: pass
finally:
s.close()
To get something more interesting check non-blocking mode with timeouts.
The following is complete client , server and sendproc codes:
Client.py
from socket import *
import pickle
import sendproc
import struct
s = socket(AF_INET, SOCK_STREAM) # Create a socket object
host = "192.168.1.4" # Get local machine name
port = 1094 # Reserve a port for your service.
s.connect((host, port))
with open("file.txt",'rb') as f:
print ('file opened')
print('Sending file...')
for data in f:
print(data)
print("MSG sent")
sendproc.send_msg(s, data)
Server.py
from socket import *
import pickle
import sendproc
port = 1094 # Reserve port for service.
s = socket(AF_INET,SOCK_STREAM) # Create a socket object
host = "192.168.1.4" # Get local machine name
s.bind((host, port)) # Bind to the port
s.listen(5)
print('server is listening')
conn,addr = s.accept()
with open("file1.txt",'w') as fb:
print("File downloading\n",fb)
while True:
print("hi")
data = sendproc.recv_msg(conn)
print(data)
if not data:
print("No data")
break
fb.write(data)
fb.flush()
print("Download complete\n")
SendRecieveProcedure.py
import struct
def send_msg(s, msg):
msg2 = struct.pack('>I', len(msg)) + msg
s.send(msg2)
def recv_msg(s):
# Read message length and unpack it into an integer
raw_msglen = s.recv(4)
print(raw_msglen)
if not raw_msglen:
return None
n = struct.unpack('>I',raw_msglen)[0]
# Read the message data
data = ' '
while len(data) < n:
packet = s.recv(n - len(data)).decode("cp437")
if not packet:
return None
data += packet
#print("hwllo",data )
return data
output prints correctly to the console, but if I go open up the file it's only writing starting lines.so what is the problem in code
I am trying to make a timestamp server and client. The client code is:
from socket import *
HOST = '127.0.0.1' # or 'localhost'
PORT = 21567
BUFSIZ = 1024
ADDR = (HOST, PORT)
tcpCliSock = socket(AF_INET, SOCK_STREAM)
tcpCliSock.connect(ADDR)
while True:
data = input('> ')
if not data:
break
tcpCliSock.send(data)
data = tcpCliSock.recv(BUFSIZ)
if not data:
break
print(data.decode('utf-8'))
tcpCliSock.close()
and the server code is:
from socket import *
from time import ctime
HOST = ''
PORT = 21567
BUFSIZ = 1024
ADDR = (HOST, PORT)
tcpSerSock = socket(AF_INET, SOCK_STREAM)
tcpSerSock.bind(ADDR)
tcpSerSock.listen(5)
while True:
print('waiting for connection...')
tcpCliSock, addr = tcpSerSock.accept()
print('connected from: ', addr)
while True:
data = tcpCliSock.recv(BUFSIZ)
if not data:
break
tcpCliSock.send('[%s] %s' % (bytes(ctime(), 'utf-8'), data))
tcpCliSock.close()
tcpSerSock.close()
The server is working fine but when I send any data to the server from the client I get the following error:
File "tsTclnt.py", line 20, in <module>
tcpCliSock.send(data)
TypeError: 'str' does not support the buffer interface
You need to encode the string in data to a buffer using the appropriate codepage. For example:
data = input('> ')
if not data:
break
tcpCliSock.send(data.encode('utf-8'))
The server code needs to change too:
response = '[%s] %s' % (ctime(), data.decode('utf-8'))
tcpCliSock.send(response.encode('utf-8'))
See more at:
How do I convert a string to a buffer in Python 3.1?