Send image using socket programming Python

Question

I am trying to send an image file using socket programming in python. I am able to send a text file. But I have been trying to send an image file, by opening it and reading the contents of the image file in a string and then sending the string and receiving it on the client side and then writing it to a file with the same name in a different directory, but I am unable to open the file. Also I am posting my code below, the commented parts are an indication that I have already tried it. Also I am having problems sending the integer size but I am receiving some random string on the other side.

This is the Server script

import socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind(("", 5000))
server_socket.listen(5)
import os


client_socket, address = server_socket.accept()
print "Conencted to - ",address,"\n"
while (1):
    choice = client_socket.recv(1024)
    choice = int(choice)
    if(choice == 1):
        data = client_socket.recv(1024)
        print "The following data was received - ",data
        print "Opening file - ",data
        fp = open(data,'r')
        strng = fp.read()
        size = os.path.getsize(data)
        size = str(size)
        client_socket.send(size)
        client_socket.send (strng)
        #client_socket.close()

    if (choice == 2):
        data = client_socket.recv(1024)
        print "The following data was received - ",data
        print "Opening file - ",data
        fp = open(data,'r')
        strng = fp.read()
        #strng = str(fp)
        size = os.path.getsize(data)
        print size
        size = str(size)
        print size
        client_socket.send(size)
        client_socket.send (strng)
        #client_socket.close()

And this is the client side script -

#!/usr/bin/python
# TCP client example
import socket,os
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect(("", 5000))
k = ' '
size = 1024

while(1):
    print "Do you want to transfer a \n1.Text File\n2.Image\n3.Video\n"
    k = raw_input()
    client_socket.send(k)
    k = int (k)
    if(k == 1):
        print "Enter file name\n"
        strng = raw_input()
        client_socket.send(strng)
        size = client_socket.recv(1024)
        size = int(size)
        print "The file size is - ",size," bytes"
        size = size*2
        strng = client_socket.recv(size)
        print "\nThe contents of that file - "
        print strng

    if (k==2):
        print "Enter file name of the image with extentsion (example: filename.jpg,filename.png) - "
        fname = raw_input()
        client_socket.send(fname)
        size = client_socket.recv(1)
        print size
        #size = int(size)
        print "The file size is - ",size
        size = size*2
        strng = client_socket.recv(256456)
        print "\nThe file will be saved and opened- "
        fname = 'downloads/'+fname
        nf = open(fname,'w')
        nf.write(strng)
        nf.close()
        fname = 'viewnior '+ fname
        print fname
        os.system(fname)

I am programming on Crunchbang Linux - Unofficial Debian based Distro viewnior is the image viewer.

Answer 1

Thank you Sanket. :D I had a problem sending data in huge chunks so I split it into 512 bytes and now it works perfectly even for videos. :D Just need to add the pygtk interface for confirmation for receiving files and sending them :D

#!/usr/bin/python
# TCP client example
import socket,os
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect(("", 5005))
k = ' '
size = 1024

while(1):
    print "Do you want to transfer a \n1.Text File\n2.Image\n3.Video\n"
    k = raw_input()
    client_socket.send(k)
    k = int (k)
    if(k == 1):
        print "Enter file name\n"
        strng = raw_input()
        client_socket.send(strng)
        size = client_socket.recv(1024)
        size = int(size)
        print "The file size is - ",size," bytes"
        size = size*2
        strng = client_socket.recv(size)
        print "\nThe contents of that file - "
        print strng

    if (k==2 or k==3):
        print "Enter file name of the image with extentsion (example: filename.jpg,filename.png or if a video file then filename.mpg etc) - "
        fname = raw_input()
        client_socket.send(fname)
        fname = 'documents/'+fname
        fp = open(fname,'w')
        while True:
            strng = client_socket.recv(512)
            if not strng:
                break
            fp.write(strng)
        fp.close()
        print "Data Received successfully"
        exit()
        #data = 'viewnior '+fname
        #os.system(data)

And here is the server code

import socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind(("", 5005))
server_socket.listen(5)
import os


client_socket, address = server_socket.accept()
print "Conencted to - ",address,"\n"
while (1):
    choice = client_socket.recv(1024)
    choice = int(choice)
    if(choice == 1):
        data = client_socket.recv(1024)
        print "The following data was received - ",data
        print "Opening file - ",data
        fp = open(data,'r')
        strng = fp.read()
        size = os.path.getsize(data)
        size = str(size)
        client_socket.send(size)
        client_socket.send (strng)
        #client_socket.close()

    if (choice == 2 or choice == 3):
        data = client_socket.recv(1024)
        print "The following data was received - ",data
        print "Opening file - ",data
        img = open(data,'r')
        while True:
            strng = img.readline(512)
            if not strng:
                break
            client_socket.send(strng)
        img.close()
        print "Data sent successfully"
        exit()
        #data = 'viewnior '+data
        #os.system(data)

Answer 2

I ran the same code on my system (Ubuntu 11.10) and I found that, there is a problem with sending size as a string. When I inserted logic to handle that part, it ran smoothly. I could open the file also. This is how I could solve your problem : 1st change in client code(client.py) is while accepting size and sending acknowledgement about it :-

size = ' '
while(1):
   tmpsize = client_socket.recv(1)
   if tmpsize.isdigit() == True:
      print "Here : ",tmpsize
      size += tmpsize
   else:
      break

client_socket.send("received")

2nd change is in server side(server.py) code, to accept acknowledgement :-

client_socket.send(size)
ack = client_socket.recv(1024)
if ack == "received":
   client_socket.send (strng)

I hope this will help you to solve your problem.