Client server implementation

[Babloo]

Hi everyone,

i wanted to implement a client- server connection
and transfer a file over the network. i was able to implement a normal
set up where in i was able to send chat messages and small chunks of
data.
I want to implement the file transfer with out using the FTP library
available in python .

So can anyone suggest a piece of code by which i can
do that.

Thanks
Pruthvi

 

[Larry Bates]

Hi everyone,

i wanted to implement a client- server connection
and transfer a file over the network. i was able to implement a normal
set up where in i was able to send chat messages and small chunks of
data.
I want to implement the file transfer with out using the FTP library
available in python .

So can anyone suggest a piece of code by which i can
do that.

Thanks
Pruthvi

What Client OS? What Server OS? On LAN or Internet? You need to give is some
information to help you.

-Larry

 

[Benjamin]

Hi everyone,

                  i wanted to implement a client- server connection
and transfer a file over the network. i was able to implement a normal
set up where in i was able to send chat messages and small chunks of
data.
I want to implement the file transfer with out using the FTP library
available in python .

                  So can anyone suggest a piece of code by which i can
do that.

I don't know what you really want, but look at Twisted. http://twistedmatrix.com

 

[Babloo]

I don't know what you really want, but look at Twisted.http://twistedmatrix.com

I am beginner at using python language.
I mean i am implementing that in a windows based machine and wanted
to transfer files over the LAN. I have written down two files as
client.py and server.py . I ran these files at two different Computers
in the LAN and I was able to send small chunks of messages( like
chat).

I was successful in establishing connection and sending small
messages. But now i want to transfer a complete file with out using
the ftplib(FTP LIBRARY) in python.


The files look like this.i hope this would help.

______________________________________________
# Server program

from socket import *

# Set the socket parameters
host = "117.105.224.94"
port = 21567
buf = 1024
addr = (host,port)

# Create socket and bind to address
UDPSock = socket(AF_INET,SOCK_DGRAM)
UDPSock.bind(addr)

# Receive messages
while 1:
data,addr = UDPSock.recvfrom(buf)
if not data:
print "Client has exited!"
break
else:
print "\nReceived message '", data,"'"

# Close socket
UDPSock.close()
__________________________________________________

# Client program

from socket import *

# Set the socket parameters
host = "117.105.224.94"
port = 21567
buf = 1024
addr = (host,port)

# Create socket
UDPSock = socket(AF_INET,SOCK_DGRAM)

def_msg = "===Enter message to send to server===";
print "\n",def_msg

# Send messages
while (1):
data = raw_input('>> ')
if not data:
break
else:
if(UDPSock.sendto(data,addr)):
print "Sending message '",data,"'....."

# Close socket
UDPSock.close()

_____________________________________________________________

 

[r0g]

I am beginner at using python language.
I mean i am implementing that in a windows based machine and wanted
to transfer files over the LAN. I have written down two files as
client.py and server.py . I ran these files at two different Computers
in the LAN and I was able to send small chunks of messages( like
chat).

I was successful in establishing connection and sending small
messages. But now i want to transfer a complete file with out using
the ftplib(FTP LIBRARY) in python.


The files look like this.i hope this would help.

______________________________________________
# Server program

from socket import *

# Set the socket parameters
host = "117.105.224.94"
port = 21567
buf = 1024
addr = (host,port)

# Create socket and bind to address
UDPSock = socket(AF_INET,SOCK_DGRAM)
UDPSock.bind(addr)

# Receive messages
while 1:
data,addr = UDPSock.recvfrom(buf)
if not data:
print "Client has exited!"
break
else:
print "\nReceived message '", data,"'"

# Close socket
UDPSock.close()
__________________________________________________

# Client program

from socket import *

# Set the socket parameters
host = "117.105.224.94"
port = 21567
buf = 1024
addr = (host,port)

# Create socket
UDPSock = socket(AF_INET,SOCK_DGRAM)

def_msg = "===Enter message to send to server===";
print "\n",def_msg

# Send messages
while (1):
data = raw_input('>> ')
if not data:
break
else:
if(UDPSock.sendto(data,addr)):
print "Sending message '",data,"'....."

# Close socket
UDPSock.close()

_____________________________________________________________

You're really not far away then, you basically need to come up with a
simple protocol that can transmit

1) The file name
2) The file length
3) The file data itself

You could also transmit the files metadata: datestamps, permissions etc
if you wanted to make it better. Also, there might be security issues to
consider too if you're running this on anything other than your own home
network.

So anyway, for a simple solution howabout you send:

filename + "\n"
filesize + "\n" (make sure you use str() to send this as text)

Then loop through your filedata
send a chunk
wait for an OK back from the other side
loop

At the receiving end as the chunks arrive:

Get the filename
Open a file for writing
Get the filesize
Setup a loop to receive the file data
Send OK
Get chunk from socket
Write data to file
Break (stop) if filesize reached
Loop
Close file

This, of course has no error correction and will probably die if you
have any packet loss on your network, a more robust solution would be to
use TCP sockets rather than UDP sockets.

Hope this helps


Roger Heathcote

http://www.technicalbloke.com
http://movingtoubuntu.technicalbloke.co.uk