[Paraview] Using MobileSocketPlugin to get metadata

[Pat Marion]

Hi Travis,

I think you mean the MobileRemoteControl plugin, right?  Can you paste more
of your code?  From what you have shared, it's hard to know where things
are going wrong.  My guess is that you are forgetting to receive the
"ready" command: after connecting to the socket, you should first receive 4
bytes and convert them to an int.  The int should have the value 1.  That's
the "ready" command.  Next comes the code you showed in your email: send
the "send metadata command" which is an int with value 2 and should be 4
bytes.  In the code you pasted, you are using sizeof(command) but don't
show where you declare command, so that might also be a problem, if your
data type is not 4 bytes.

Here is a python example that connects to paraview and receives the
metadata:


import socket
from struct import pack
from struct import unpack


def connect(host, port):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((host, port))
    return s


def receiveReadyCommand(s):
    data = s.recv(4)
    assert unpack('i', data)[0] == 1


def sendCommand(s, command):
    data = pack('i', command)
    s.send(data)


def receiveMetaData(s):
    sendCommand(s, 2)
    data = s.recv(8)
    length = unpack('Q', data)[0]
    return s.recv(length)


def main():

    s = connect('localhost', 40000)
    receiveReadyCommand(s)

    print receiveMetaData(s)


if __name__ == '__main__':
    main()





On Sat, Apr 20, 2013 at 6:23 AM, Bueter, Travis J. (S&T-Student) <
tjbxv7 at mail.mst.edu> wrote:

>  Hi,****
>
> ** **
>
> I am trying to get the “metadata” from ParaView by connecting to the
> socket. I’m having an issue where I am correctly sending the command to
> send the data but I’m not receiving the length value or string correctly.
> Below is my method how I am currently trying to get the length value:****
>
> ** **
>
> // In the main program //****
>
>                 command = 2;****
>
>                 if(-1 == send(socket, &command, sizeof(command), 0))****
>
>                                 exit(1);****
>
> ** **
>
>                 int size;****
>
>                 unsigned long long length;****
>
>                 if((size = Receive(socket, &length, sizeof(unsigned long
> long)) <= 0)****
>
>                                 exit(1);****
>
>                 cout << size << endl;****
>
>                 cout << length << endl;****
>
> ** **
>
> // Receive function //****
>
> int Receive( cons int sk, void* data, int len)****
>
> {****
>
>                                 char* buffer =
> reinterpret_cast<char*>(data);****
>
>                                 int total = 0;****
>
>                                 do****
>
>                                 {****
>
>                                                 int nRecvd = recv(socket,
> buffered+total, len-total, 0);****
>
>                                                 if(nRecvd == 0)****
>
>                                                 {****
>
>                                                                 cout <<
> “No Data Received” << endl;****
>
>                                                                 exit(1);**
> **
>
>                                                 }****
>
>                                                 if(nRecvd == -1)****
>
>                                                 {****
>
>                                                                 cout <<
> “Error” << endl;****
>
>                                                                 exit(1);**
> **
>
>                                                 }****
>
>                                                 total += nRecvd;****
>
>                                 }while(total < len);****
>
>                                 return total;****
>
>                 }****
>
> ** **
>
> Now in the source code of the MobileSocketPlugin, I added a printf to show
> the value of “length” before it is sent over the socket.  When I run my
> code, it succeeds without an error but the value of my “length” is not
> equal.  For example, if I connect and run my code immediately after
> starting up ParaView, it always sends a value of “1733”  but I receive a
> value of “7443178323969” every time.  I’m really not sure what I need to
> change to get this correct.  If someone could point me in the right
> direction on what I need to be doing to receive the metadata through
> MobileSocketPlugin, I would greatly appreciate it! ****
>
> ** **
>
> Thanks,****
>
> ** **
>
> *Travis J. Bueter*
>
> ----------------------------------------------------------------------****
>
> *Missouri University of Science and Technology - Junior*
>
> B.S. Computer Engineering/Computer Science****
>
> tjbxv7 at mail.mst.edu****
>
> (573)-238-5843****
>
> ** **
>
> IT RSS****
>
> Treasurer – MS&T Robotics Competition Team****
>
> ----------------------------------------------------------------------****
>
> ** **
>
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