Send a multidimensional numpy array over a socket

Question

Good day,

I've searched for this but haven't come up with any responses. I wish to send a multi dimensional numpy array over a socket. Hence, I decided to convert it to a string:

However, it destroys the representation of the array:

>>> import numpy as np
>>> x = np.array([[0, 1], [2, 3]])
>>> xstring = x.tostring()
>>> print xstring

>>> print x
[[0 1]
 [2 3]]
>>> print xstring

>>> nparr = np.fromstring(xstring, dtype=np.uint8)
>>> print nparr
[0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0]

Is there anyway I can get the conversion to string to somehow, save the dimension of it?

Answer 1

Try this example:-

import socket
import numpy as np
from cStringIO import StringIO

class numpysocket():
    def __init__(self):
        pass

    @staticmethod
    def startServer():
        port=7555
        server_socket=socket.socket() 
        server_socket.bind(('',port))
        server_socket.listen(1)
        print 'waiting for a connection...'
        client_connection,client_address=server_socket.accept()
        print 'connected to ',client_address[0]
        ultimate_buffer=''
        while True:
            receiving_buffer = client_connection.recv(1024)
            if not receiving_buffer: break
            ultimate_buffer+= receiving_buffer
            print '-',
        final_image=np.load(StringIO(ultimate_buffer))['frame']
        client_connection.close()
        server_socket.close()
        print '\nframe received'
        return final_image

    @staticmethod
    def startClient(server_address,image):
        if not isinstance(image,np.ndarray):
            print 'not a valid numpy image'
            return
        client_socket=socket.socket()
        port=7555
        try:
            client_socket.connect((server_address, port))
            print 'Connected to %s on port %s' % (server_address, port)
        except socket.error,e:
            print 'Connection to %s on port %s failed: %s' % (server_address, port, e)
            return
        f = StringIO()
        np.savez_compressed(f,frame=image)
        f.seek(0)
        out = f.read()
        client_socket.sendall(out)
        client_socket.shutdown(1)
        client_socket.close()
        print 'image sent'
        pass

In this model client sends multidimensional ndarray to server. There are two functions startServer() and startClient(). startServer takes no arguments but startClient needs server address as well as the ndarray as arguments. First start Server and then start client. Server starts reading from buffer only after receiving the shutdown message from client.