I've made this sending / receiving scripts but i corrupted file !
i have no idea why I'm getting this issue !
sender.py
#!/usr/bin/env python
from socket import *
import sys
s = socket(AF_INET,SOCK_DGRAM)
host =sys.argv[1]
port = 9999
buf =1024
addr = (host,port)
file_name=sys.argv[2]
f=open(file_name,"rb")
data = f.read(buf)
s.sendto(file_name,addr)
s.sendto(data,addr)
while (data):
if(s.sendto(data,addr)):
print "sending ..."
data = f.read(buf)
s.close()
f.close()
receiver.py
#!/usr/bin/env python
from socket import *
import sys
import select
host="0.0.0.0"
port = 9999
s = socket(AF_INET,SOCK_DGRAM)
s.bind((host,port))
addr = (host,port)
buf=1024
data,addr = s.recvfrom(buf)
print "Received File:",data.strip()
f = open(data.strip(),'wb')
data,addr = s.recvfrom(buf)
try:
while(data):
f.write(data)
s.settimeout(2)
data,addr = s.recvfrom(buf)
except timeout:
f.close()
s.close()
print "File Downloaded"
and this the original receiver that I've modify it (works fine 100%)
#!/usr/bin/env python
from socket import *
import sys
import select
host="0.0.0.0"
port = 9999
s = socket(AF_INET,SOCK_DGRAM)
s.bind((host,port))
addr = (host,port)
buf=1024
f = open("file.pdf",'wb')
data,addr = s.recvfrom(buf)
try:
while(data):
f.write(data)
s.settimeout(2)
data,addr = s.recvfrom(buf)
except timeout:
f.close()
s.close()
print "File Donwloaded"
as you notice it's making file at the beginning.
exacted:
client => send file (name.ext) => server:save it (name.ext)
my output :
corrupted file for pdf and empty for txt
The problem with your code:
When data is send through sockets, normally the lower layers will merge the data from multiple sendTo calls and send them together to reduce network load.
You are sending the first 1024 bytes of the file twice.
What you should do:
Use some kind of a delimiter string having couple of characters (like "**_$$") so that it won't exist in the actual file binary representation. Then append this delimiter to the end of the filename.
Read from file again before starting the while loop.
At receiver end, receive everything into a single stream and then split using the delimiter. You will have the filename and the file data.
Update:
Working Code (Ubuntu / Windows XP)
# ----- sender.py ------
#!/usr/bin/env python
from socket import *
import sys
s = socket(AF_INET,SOCK_DGRAM)
host =sys.argv[1]
port = 9999
buf =1024
addr = (host,port)
file_name=sys.argv[2]
s.sendto(file_name,addr)
f=open(file_name,"rb")
data = f.read(buf)
while (data):
if(s.sendto(data,addr)):
print "sending ..."
data = f.read(buf)
s.close()
f.close()
# ----- receiver.py -----
#!/usr/bin/env python
from socket import *
import sys
import select
host="0.0.0.0"
port = 9999
s = socket(AF_INET,SOCK_DGRAM)
s.bind((host,port))
addr = (host,port)
buf=1024
data,addr = s.recvfrom(buf)
print "Received File:",data.strip()
f = open(data.strip(),'wb')
data,addr = s.recvfrom(buf)
try:
while(data):
f.write(data)
s.settimeout(2)
data,addr = s.recvfrom(buf)
except timeout:
f.close()
s.close()
print "File Downloaded"
Usage
>> python recevier.py
>> python sender.py localhost filename.txt
There are two problems here:
Syntax errors:
You're using a from socket import *. It's not an error on its own, but it becomes one when you do except socket.timeout.
Using UDP:
Using UDP, corruption shouldn't be a surprise. You probably don't want to be using UDP here, you should switch to TCP.
Here's why UDP is not appropriate here:
Packets may be lost but others could still reach their destination.
Packets may be duplicated
Packets may arrive in the wrong order
Note that switching to TCP will involve some refactoring of your code (it's a bit more complicated that just replacing SOCK_DGRAM with SOCK_STREAM), but in your case, you have to do it.
I'm not saying UDP is bad, but it's not appropriate in your case.
Related
I want to send i file over TCP but when i try to run this the connection fails, the server receives the file but it gives this error: ERROR: Client timed out before sending a file
import selectors
import sys
from socket import *
import sock
sel1 = selectors.DefaultSelector()
print(len(sys.argv), sys.argv[1], sys.argv[2], sys.argv[3])
host = sys.argv[1]
port = int(sys.argv[2])
file = sys.argv[3]
try:
# Instaniating socket object
s = socket(AF_INET, SOCK_STREAM)
# Getting ip_address through host name
host_address = gethostbyname(host)
# Connecting through host's ip address and port number using socket object
s.connect((host_address, port))
sel1.register(
sock,
selectors.EVENT_READ, data = None)
fileToSend = open("file.txt", "rb")
data = fileToSend.read(1024)
while data:
print("Sending...")
fileToSend.close()
s.send(b"Done")
print("Done Sending")
print(s.recv(1024))
s.shutdown(2)
s.close()
except:
# Returning False in case of an exception
sys.stderr.write("Connection Failed")
Do the writing in a loop. There's no particular reason to chop it into 1024-byte pieces; the network stack will handle that for you.
By the way, your "Done" signal is not a good idea, especially since you're writing a binary file that might very well contain the word "Done". Remember that TCP is a streaming protocol. The other end does not see the exact packets you're sending. That is, just because you send 1024 bytes and 4 bytes, the other end might see it as reads of 256 and 772 bytes.
# Instaniating socket object
s = socket(AF_INET, SOCK_STREAM)
# Getting ip_address through host name
host_address = gethostbyname(host)
# Connecting through host's ip address and port number using socket object
s.connect((host_address, port))
fileToSend = open("file.txt", "rb")
print("Sending...")
while True:
data = fileToSend.read(1024)
if not data:
break
s.send( data )
fileToSend.close()
s.send(b"Done")
print("Done Sending")
print(s.recv(1024))
s.close()
I'm trying to send data over UDP point to point (looping back to a second NIC) but am losing data. Here is the code (from: sending/receiving file UDP in python):
----- sender.py ------
#!/usr/bin/env python
from socket import *
import sys
s = socket(AF_INET,SOCK_DGRAM)
host =sys.argv[1]
port = 9999
buf =1024
addr = (host,port)
file_name=sys.argv[2]
s.sendto(file_name,addr)
f=open(file_name,"rb")
data = f.read(buf)
while (data):
if(s.sendto(data,addr)):
#print "sending ..."
data = f.read(buf)
s.close()
f.close()
----- receiver.py -----
#!/usr/bin/env python
from socket import *
import sys
import select
host="192.0.0.2" #second nic
port = 9999
s = socket(AF_INET,SOCK_DGRAM)
s.bind((host,port))
addr = (host,port)
buf=1024
data,addr = s.recvfrom(buf)
print "Received File:",data.strip()
f = open(data.strip(),'wb')
data,addr = s.recvfrom(buf)
try:
while(data):
f.write(data)
s.settimeout(2)
data,addr = s.recvfrom(buf)
except timeout:
f.close()
s.close()
print "File Downloaded"
I create my file with dd:
dd if=/dev/urandom of=test_file bs=1024 count=100
I found that when count is over approx 100 it starts to fail. I tried different bs all the way down to 32 and it still fails. When I change bs I change buf in the code to match. I repeat creating a new file and running the command in a loop. With different combinations, sometimes it fails every transfer, sometimes it fails in a pattern (ie every 5)
I found that if I add a delay in the while loop in sender to delay by 0.0005 seconds, then it works fine and I can send any amount of data. If I bring the delay down to 0.0001, then it fails again. I'm getting approx 1.5MB/sec
I'd appreciate any recommendations to improve my performance. I am thinking that perhaps there is a receive buffer that is overflowing and I'm just not reading it fast enough.
I am currently working on my assignment and I am using python socket to connect through terminal. However, I encountered a problem where after I send my message to the server and try to receive its reply, it kind of hangs. My codes are as follows:
import socket
import sys
import md5
import re
hostname = "cs2107.spro.ink"
ip = socket.gethostbyname(hostname)
port = 9000
server_address = (ip, port)
bufferSize = 1024
# Socket connection
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print >>sys.stderr, 'connecting to %s port %s' % server_address
s.connect((ip, port))
try:
while True:
data = s.recv(bufferSize)
if not data:
break
print data
regex = re.compile(r'\n([0-9a-fA-F]+)(?:\n)', re.I | re.S | re.M)
checkHex = re.findall(regex, data)
if len(checkHex) != 0:
receiveHex = str(checkHex).strip("['']")
decode = receiveHex.decode()
m = md5.new()
m.update(decode)
hexReply = m.hexdigest()
s.sendall(hexReply.encode())
print hexReply
finally:
print >>sys.stderr, 'closing socket.....'
s.close()
The output is shown in the link: output. After I kill it, it says the most recent call is `data = s.recv(bufferSize) link: after killing the terminal. Anyone have any idea how to solve this? Appreciate your help!
The line s.recv(bufferSize) is still waiting for some incoming data from the server. However the server sends nothing more than what you see. Try to reply to the server with your hexReply variable and see what happens. Just insert s.send(hexReply + "\r\n") after the print statement.
I am working on a Networks course project, in which I have to create a video streaming server. I found this link for a simple python client/server socket binary stream that seems quite useful. I am able to send video files as packets over the network, but the receiving side is saving the incoming packets as a file. I would like to display the incoming packets as a video stream (preferably on a web browser using HTML), instead of writing to a file. Please suggest some possible method of doing this. Thanks.
As I am doing a project, I would like to create a streaming server from scratch rather than use existing implementations like Flumotion.
Here's the code for the sending and receiving sides:
Sending side:
import socket
HOST = 'localhost'
PORT = 9876
ADDR = (HOST,PORT)
BUFSIZE = 4096
videofile = "./test2.mp4"
bytes = open(videofile).read()
print len(bytes)
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(ADDR)
client.send(bytes)
client.close()
Receiving side:
import socket
HOST = ''
PORT = 9876
ADDR = (HOST,PORT)
BUFSIZE = 4096
serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serv.bind(ADDR)
serv.listen(5)
print 'listening ...'
while True:
conn, addr = serv.accept()
print 'client connected ... ', addr
myfile = open('testfile.mov', 'w')
while True:
data = conn.recv(BUFSIZE)
if not data: break
myfile.write(data)
print 'writing file ....'
myfile.close()
print 'finished writing file'
conn.close()
print 'client disconnected'
I've successfully been able to copy the file contents (image) to a new file. However when I try the same thing over TCP sockets I'm facing issues. The server loop is not exiting. The client loop exits when it reaches the EOF, however the server is unable to recognize EOF.
Here's the code:
Server
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12345 # Reserve a port for your service.
s.bind((host, port)) # Bind to the port
f = open('torecv.png','wb')
s.listen(5) # Now wait for client connection.
while True:
c, addr = s.accept() # Establish connection with client.
print 'Got connection from', addr
print "Receiving..."
l = c.recv(1024)
while (l):
print "Receiving..."
f.write(l)
l = c.recv(1024)
f.close()
print "Done Receiving"
c.send('Thank you for connecting')
c.close() # Close the connection
Client
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12345 # Reserve a port for your service.
s.connect((host, port))
s.send("Hello server!")
f = open('tosend.png','rb')
print 'Sending...'
l = f.read(1024)
while (l):
print 'Sending...'
s.send(l)
l = f.read(1024)
f.close()
print "Done Sending"
print s.recv(1024)
s.close # Close the socket when done
Here's the screenshot:
Server
Client
Edit 1: Extra data copied over. Making the file "not complete."
The first column shows the image that has been received. It seems to be larger than the one sent. Because of this, I'm not able to open the image. It seems like a corrupted file.
Edit 2: This is how I do it in the console. The file sizes are the same here.
Client need to notify that it finished sending, using socket.shutdown (not socket.close which close both reading/writing part of the socket):
...
print "Done Sending"
s.shutdown(socket.SHUT_WR)
print s.recv(1024)
s.close()
UPDATE
Client sends Hello server! to the server; which is written to the file in the server side.
s.send("Hello server!")
Remove above line to avoid it.
Remove below code
s.send("Hello server!")
because your sending s.send("Hello server!") to server, so your output file is somewhat more in size.
You can send some flag to stop while loop in server
for example
Server side:
import socket
s = socket.socket()
s.bind(("localhost", 5000))
s.listen(1)
c,a = s.accept()
filetodown = open("img.png", "wb")
while True:
print("Receiving....")
data = c.recv(1024)
if data == b"DONE":
print("Done Receiving.")
break
filetodown.write(data)
filetodown.close()
c.send("Thank you for connecting.")
c.shutdown(2)
c.close()
s.close()
#Done :)
Client side:
import socket
s = socket.socket()
s.connect(("localhost", 5000))
filetosend = open("img.png", "rb")
data = filetosend.read(1024)
while data:
print("Sending...")
s.send(data)
data = filetosend.read(1024)
filetosend.close()
s.send(b"DONE")
print("Done Sending.")
print(s.recv(1024))
s.shutdown(2)
s.close()
#Done :)
The problem is extra 13 byte which server.py receives at the start. To resolve that write "l = c.recv(1024)" twice before the while loop as below.
print "Receiving..."
l = c.recv(1024) #this receives 13 bytes which is corrupting the data
l = c.recv(1024) # Now actual data starts receiving
while (l):
This resolves the issue, tried with different format and sizes of files. If anyone knows what this starting 13 bytes refers to, please reply.
Put file inside while True like so
while True:
f = open('torecv.png','wb')
c, addr = s.accept() # Establish connection with client.
print 'Got connection from', addr
print "Receiving..."
l = c.recv(1024)
while (l):
print "Receiving..."
f.write(l)
l = c.recv(1024)
f.close()
print "Done Receiving"
c.send('Thank you for connecting')
c.close()
you may change your loop condition according to following code, when length of l is smaller than buffer size it means that it reached end of file
while (True):
print "Receiving..."
l = c.recv(1024)
f.write(l)
if len(l) < 1024:
break