Develop Reference

Python how to use string in multiple scripts

I'm running a python script on a raspberry pi that reads keyboard input to a string and will be sending that string through TCP. I've made two script one that reads the input and one that can send the string if needed. How can i use one string and use it in both scripts for readings and writings?
I've used an text document. Only becaue of the sd card i wanne achieve an connecting between the two scripts
Reading part:
#loops for Barcode_Data
def Create_File():
file = open("Barcode_data.txt", "w")
file.write(" // ")
file.close()
empty = ''
def Barcode_Read():
Barcode_Data= input("Input: ",)
print(Barcode_Data)
file = open("Barcode_data.txt", "a")
file.write(Barcode_Data)
file.write(" // ")
file.close()
#Loop that will only run once
Create_File()
#Loop that will run continuesly
while True:
Barcode_Read()
TCP Server:
#TCP server
def TCP_Connect(socket):
socket.listen()
conn, addr = socket.accept()
with conn:
data = conn.recv(1024)
if data == b'Barcode_Data':
tcp_file = open("Barcode_data.txt", "r")
Barcode_Data = tcp_file.read()
tcp_file.close()
conn.sendall(Barcode_Data.encode('utf-8'))
elif data == b'Clear Barcode_Data':
tcp_file = open("Barcode_data.txt", "w")
tcp_file.write(" // ")
tcp_file.close()
#TCP Socket setup
HOST = '' # Standard loopback interface address (localhost)
PORT = 1025 # Port to listen on (non-privileged ports are > 1023)
import socket
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
#Loop that wil run continuesly
while True:
TCP_Connect(s)

You can use the code from this question as is: Interprocess communication in Python
Server process:
from multiprocessing.connection import Listener
address = ('localhost', 6000) # family is deduced to be 'AF_INET'
listener = Listener(address, authkey='secret password')
conn = listener.accept()
print 'connection accepted from', listener.last_accepted
while True:
msg = conn.recv()
# do something with msg
if msg == 'close':
conn.close()
break
listener.close()
Client process:
from multiprocessing.connection import Client
address = ('localhost', 6000)
conn = Client(address, authkey='secret password')
conn.send('close')
# can also send arbitrary objects:
# conn.send(['a', 2.5, None, int, sum])
conn.close()
Documentation is available here: https://docs.python.org/3.7/library/multiprocessing.html#multiprocessing-listeners-clients

how can we use both tcpSerSock.listen(0) and tcpSerSock.send(str.encode(message)) at the same time

my raspberry pi is the server and Im trying to send continuous message from rpi to android while recieving a command from client (android app),i really dont know if this is possible and how to do it is out of my reach and it is not a feedback message here is my code hope you will help me thank you.
import apptopi
from socket import *
from time import ctime
from nanpy import (ArduinoApi, SerialManager)
apptopi.setup()
connection = SerialManager()
a = ArduinoApi(connection = connection)
ctrCmd = ['Up','Down','Left','Right','Stop','Connect']
add = 0
add += 1
a = str(add) //**this is a sample that i want to send continously
HOST = ''
PORT = 21567
BUFSIZE = 1024
ADDR = (HOST,PORT)
tcpSerSock = socket(AF_INET, SOCK_STREAM)
tcpSerSock.bind(ADDR)
tcpSerSock.listen(0)
tcpSerSock.send(str.encode(a)) <== i really don't know how to send
continuously
while True:
print 'Waiting for connection'
tcpCliSock,addr = tcpSerSock.accept()
print '...connected from :', addr
try:
while True:
data = ''
data = tcpCliSock.recv(BUFSIZE)
if not data:
break
if data == ctrCmd[0]:
apptopi.forw()
print 'forward'
if data == ctrCmd[1]:
apptopi.back()
print 'backward'
if data == ctrCmd[2]:
apptopi.left()
print 'leftturn'
if data == ctrCmd[3]:
apptopi.right()
print 'rightturn'
if data == ctrCmd[4]:
apptopi.stp()
print 'stop'
except KeyboardInterrupt:
apptopi.close()
GPIO.cleanup()
tcpSerSock.close();

OK one approach is to use the select() function for this. There is information in the documentation about its operation.
As an example I've made a modified version of your program (see below). I don't have a raspberry pi, so that part of the code is commented out, but you can replace it as needed.
The example uses the timeout feature of select() to send "continuous" messages to clients whilst also monitoring them for incoming messages. You can adjust the message contents and timeout to whatever works for you. NB you may also need to respond to client messages, as this code only sends data to clients after a timeout. Make whatever changes you need.
import sys
import socket
import select
ctrCmd = ['Up','Down','Left','Right','Stop','Connect']
HOST = ''
PORT = 21567
BUFSIZE = 1024
ADDR = (HOST,PORT)
tcpSerSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpSerSock.bind(ADDR)
tcpSerSock.listen(1)
print 'Waiting for connection'
sendInterval = 1.0 # interval(sec) for sending messages to connected clients
rxset = [tcpSerSock]
txset = []
while 1:
rxfds, txfds, exfds = select.select(rxset, txset, rxset, sendInterval)
if rxfds:
for sock in rxfds:
if sock is tcpSerSock:
# a client is connecting
tcpCliSock, addr = tcpSerSock.accept()
tcpCliSock.setblocking(0)
rxset.append(tcpCliSock)
print '...connected from :', addr
else:
# a client socket has data or has closed the connection
try:
data = sock.recv(BUFSIZE)
if not data:
print "...connection closed by remote end"
rxset.remove(sock)
sock.close()
else:
if data == ctrCmd[0]:
#apptopi.forw()
print 'forward'
if data == ctrCmd[1]:
#apptopi.back()
print 'backward'
if data == ctrCmd[2]:
#apptopi.left()
print 'leftturn'
if data == ctrCmd[3]:
#apptopi.right()
print 'rightturn'
if data == ctrCmd[4]:
#apptopi.stp()
print 'stop'
except:
print "...connection closed by remote end"
rxset.remove(sock)
sock.close()
else:
# timeout - send data to any active client
for sock in rxset:
if sock is not tcpSerSock:
sock.send("Hello!\n")
The simple client program I used to test this is here:
import sys
import socket
import time
ctrCmd = ['Up','Down','Left','Right','Stop','Connect']
HOST = '127.0.0.1'
PORT = 21567
BUFSIZE = 1024
ADDR = (HOST,PORT)
tcpCliSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpCliSock.connect(ADDR)
time.sleep(1)
for i in range(len(ctrCmd)):
tcpCliSock.send(ctrCmd[i])
time.sleep(1)
data = tcpCliSock.recv(BUFSIZE)
print data
tcpCliSock.close()
Hope this helps, best of luck.

python 3.4.3 file is not writing completly

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

Socket Programming; File corrupts when transferring over multiple devices

The problem I'm having is to get a file from the server to client across devices. Everything works fine on localhost.
Lets say I want to "get ./testing.pdf" which sends the pdf from the server to the client. It sends but it is always missing bytes. Is there any problems with how I am sending the data. If so how can I fix it? I left out the code for my other functionalities since they are not used for this function.
sending a txt file with "hello" in it works perfectly
server.py
import socket, os, subprocess # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
#host = ''
port = 5000 # Reserve a port for your service.
bufsize = 4096
s.bind((host, port)) # Bind to the port
s.listen(5) # Now wait for client connection.
while True:
c, addr = s.accept() # Establish connection with client.
print 'Got connection from', addr
while True:
userInput = c.recv(1024)
.... CODE ABOUT OTHER FUNCTIONALITY
elif userInput.split(" ")[0] == "get":
print "inputed get"
somefile = userInput.split(" ")[1]
size = os.stat(somefile).st_size
print size
c.send(str(size))
bytes = open(somefile).read()
c.send(bytes)
print c.recv(1024)
c.close()
client.py
import socket, os # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
#host = '192.168.0.18'
port = 5000 # Reserve a port for your service.
bufsize = 1
s.connect((host, port))
print s.recv(1024)
print "Welcome to the server :)"
while 1 < 2:
userInput = raw_input()
.... CODE ABOUT OTHER FUNCTIONALITY
elif userInput.split(" ")[0] == "get":
print "inputed get"
s.send(userInput)
fName = os.path.basename(userInput.split(" ")[1])
myfile = open(fName, 'w')
size = s.recv(1024)
size = int(size)
data = ""
while True:
data += s.recv(bufsize)
size -= bufsize
if size < 0: break
print 'writing file .... %d' % size
myfile = open('Testing.pdf', 'w')
myfile.write(data)
myfile.close()
s.send('success')
s.close

I can see two problems right away. I don't know if these are the problems you are having, but they are problems. Both of them relate to the fact that TCP is a byte stream, not a packet stream. That is, recv calls do not necessarily match one-for-one with the send calls.
size = s.recv(1024) It is possible that this recv could return only some of the size digits. It is also possible that this recv could return all of the size digits plus some of the data. I'll leave it for you to fix this case.
data += s.recv(bufsize) / size -= bufsize There is no guarantee that that the recv call returns bufsize bytes. It may return a buffer much smaller than bufsize. The fix for this case is simple: datum = s.recv(bufsize) / size -= len(datum) / data += datum.

Python socket server receive image

I am trying to receive an image from Android to PC using socket in Python. My server code is as follows:
import socket
address = ("10.0.0.12", 5000)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(address)
s.listen(1000)
client, addr = s.accept()
print 'got connected from', addr
filename = open('tst.jpg', 'wb')
while True:
strng = client.recv(1024)
if not strng:
break
filename.write(strng)
filename.close()
print 'received, yay!'
client.close()
And it returns me a tst.jpg which is the same size of that on my Android. But I cannot open the pic.
Here is my Android code:
Socket photoSocket = new Socket(ipString, port);
DataOutputStream dos = new DataOutputStream(photoSocket.getOutputStream());
FileInputStream fis = new FileInputStream(PhotoActivity.filePath);
int size = fis.available();
byte[] data = new byte[size];
fis.read(data);
dos.writeInt(size);
dos.write(data);
dos.flush();
dos.close();
fis.close();
photoSocket.close();

so the android code is sending the size as int in front of the data, but the python code doesn't read it.
import socket
import struct
address = ("10.0.0.12", 5000)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(address)
s.listen(1000)
client, addr = s.accept()
print 'got connected from', addr
buf = ''
while len(buf)<4:
buf += client.recv(4-len(buf))
size = struct.unpack('!i', buf)
print "receiving %s bytes" % size
with open('tst.jpg', 'wb') as img:
while True:
data = client.recv(1024)
if not data:
break
img.write(data)
print 'received, yay!'
client.close()