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'std::out_of_range' error in sending an image with sockets

I am using this code in Python to send an image with sockets (and OpenCV) to another computer:
#!/usr/bin/env python3
import socket
import cv2
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serversocket.bind(("XXX.XXX.X.XXX", 9999))
serversocket.listen(5)
print ('server started and listening')
while 1:
(clientsocket, address) = serversocket.accept()
print ("connection found!")
img = cv2.imread('testImage.jpeg')
if (img.any()):
clientsocket.sendall(img)
It works pretty well, but at some point it eventually shuts down, showing this error message:
terminate called after throwing an instance of 'std::out_of_range'
what(): basic_string::substr: __pos (which is 140) > this->size() (which is 0)
Aborted
I have searched in forums but I can't find an answer to my problem. Anyone can help me?
EDIT:
My socket client, that receives the image, is written in C#, and the code is the following:
private void connectSocket()
{
receiveSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint hostIpEndPoint = new IPEndPoint(IPAddress.Parse("XXX.XXX.X.XXX"), 9999);
receiveSocket.Connect(hostIpEndPoint);
}
private void btnImagem_Click(object sender, EventArgs e)
{
if (stream==0)
{
stream = 1;
}
else
{
stream = 0;
}
while (stream == 1)
{
connectSocket();
wait(300);
int dataSize;
int y, x, t = 0;
Bitmap bmp2 = new Bitmap(160, 120);
dataSize = 0;
byte[] b = new byte[receiveSocket.ReceiveBufferSize];
dataSize = receiveSocket.Receive(b);
if (dataSize > 0)
{
for (y = 0; y < 120; y++)
{
for (x = 0; x < 160; x++)
{
bmp2.SetPixel(x, y, Color.FromArgb(Convert.ToInt32(b[t + 2]), Convert.ToInt32(b[t + 1]), Convert.ToInt32(b[t])));
t = t + 3;
}
}
}
videoBox.Image = bmp2;
receiveSocket.Close();
wait(10);
}
videoBox.Image = null;
}
public void wait(int milliseconds)
{
System.Windows.Forms.Timer timer1 = new System.Windows.Forms.Timer();
if (milliseconds == 0 || milliseconds < 0) return;
timer1.Interval = milliseconds;
timer1.Enabled = true;
timer1.Start();
timer1.Tick += (s, e) =>
{
timer1.Enabled = false;
timer1.Stop();
};
while (timer1.Enabled)
{
Application.DoEvents();
}
}

why is C# getting a distorted image from a python server?

I'm trying to transfer camera stream from my raspberry pi to pc as fast as possible. Now I'm trying to transfer it using MJPEG method. So I have a python script on my raspberry as server:
import io
import socket
import struct
import time
import cv2
class SplitFrames(object):
def __init__(self, connection):
self.connection = connection
self.stream = io.BytesIO()
self.count = 0
def write(self, buf):
if buf.startswith(b'\xff\xd8'):
# Start of new frame; send the old one's length
# then the data
size = self.stream.tell()
if size > 0:
self.connection.write(struct.pack('<L', size))
self.connection.flush()
self.stream.seek(0)
self.connection.write(self.stream.read(size))
self.count += 1
self.stream.seek(0)
self.stream.write(buf)
server_socket = socket.socket()
server_socket.bind(('0.0.0.0', 8001))
server_socket.listen(0)
# Accept a single connection and make a file-like object out of it
connection = server_socket.accept()[0].makefile('wb')
try:
output = SplitFrames(connection)
time.sleep(2)
cap = cv2.VideoCapture(0)
while True:
ret, img = cap.read()
ret, jpg = cv2.imencode('.jpg', img)
output.write(jpg.tostring())
connection.write(struct.pack('<L', 0))
finally:
connection.close()
server_socket.close()
that works well. Also I have a python script on my pc as client, that also works well and I receive a good stream:
import io
import socket
import struct
from PIL import Image
import cv2
import numpy as np
# Start a socket listening for connections on 0.0.0.0:8000 (0.0.0.0 means
# all interfaces)
client_socket = socket.socket()
client_socket.connect(("10.12.34.2", 8001))
connection = client_socket.makefile('rb')
try:
while True:
# Read the length of the image as a 32-bit unsigned int. If the
# length is zero, quit the loop
a = connection.read(struct.calcsize('<L'))
image_len = struct.unpack('<L', a)[0]
if not image_len:
break
# Construct a stream to hold the image data and read the image
# data from the connection
image_stream = io.BytesIO()
image_stream.write(connection.read(image_len))
# Rewind the stream, open it as an image with PIL and do some
# processing on it
image_stream.seek(0)
image = Image.open(image_stream)
cv_image = np.array(image)
cv2.imshow('Stream',cv_image)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
finally:
connection.close()
client_socket.close()
But I needed to write client side on WPF, so I wrote it, but it doesn't work well. I receive distorted stream and after a few seconds WPF app breaks and gives me System.IO.FileFormatException. Here is the image from WPF:
What could be the reason of this? Thanks for any advice!
Here is the minimum reproducible code:
C#
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Windows;
using System.Windows.Media.Imaging;
namespace WPFTest
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private static bool connected = false;
private Socket sct;
private IPEndPoint ipPoint;
// TCP
private bool stopThread = false;
private Thread thread;
public MainWindow()
{
InitializeComponent();
}
private void ConnectButton_Click(object sender, RoutedEventArgs e)
{
if (!connected)
{
try
{
//this.ipPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), int.Parse("8001", CultureInfo.InvariantCulture));
this.ipPoint = new IPEndPoint(IPAddress.Parse("10.12.34.2"), int.Parse("8001", CultureInfo.InvariantCulture));
}
catch (Exception error)
{
return;
}
this.sct = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);
stopThread = false;
thread = new Thread(() => { Listening(); });
thread.IsBackground = false;
thread.Start();
connected = true;
}
}
private void DisconnectButton_Click(object sender, RoutedEventArgs e)
{
if (connected)
{
StopListening();
connected = false;
}
}
private void Listening()
{
try
{
sct.Connect(ipPoint);
}
catch (Exception e)
{
StopListening();
connected = false;
return;
}
Thread.Sleep(1000);
try
{
while (!this.stopThread)
{
byte[] data = GetInputBytes(sct);
Application.Current.Dispatcher.Invoke(() =>
{
SetImage(data);
});
}
sct.Shutdown(SocketShutdown.Both);
sct.Close();
}
catch (Exception e)
{
StopListening();
}
}
public void StopListening()
{
this.stopThread = true;
try
{
thread.Abort();
sct.Shutdown(SocketShutdown.Both);
sct.Close();
}
catch (Exception e)
{
//
}
}
private void SetImage(byte[] array)
{
var image = new BitmapImage();
using (var mem = new MemoryStream(array))
{
mem.Position = 0;
image.BeginInit();
image.CreateOptions = BitmapCreateOptions.PreservePixelFormat;
image.CacheOption = BitmapCacheOption.OnLoad;
image.UriSource = null;
image.StreamSource = mem;
image.EndInit();
}
image.Freeze();
ImageCamera.Source = image;
}
public static byte[] GetInputBytes(Socket clientSocket)
{
byte[] rcvLenBytes = new byte[4];
clientSocket.Receive(rcvLenBytes);
UInt32 rcvLen = BytesToInt(rcvLenBytes);
byte[] rcvBytes;
byte[] clientData;
List<byte> rcvBytesList = new List<byte>();
int totalBytes = 0;
while (totalBytes < rcvLen)
{
if (rcvLen - totalBytes < 262144)
{
clientData = new byte[rcvLen - totalBytes];
}
else
{
clientData = new byte[262144];
}
int bytesReceived = clientSocket.Receive(clientData);
rcvBytesList.AddRange(clientData);
totalBytes += bytesReceived;
}
rcvBytes = rcvBytesList.ToArray();
return rcvBytes;
}
public static UInt32 BytesToInt(byte[] arr)
{
UInt32 wd = ((UInt32)arr[3] << 24) | ((UInt32)arr[2] << 16) | ((UInt32)arr[1] << 8) | (UInt32)arr[0];
return wd;
}
}
}
XAML
<Window x:Class="WPFTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WPFTest"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="200px"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" ></ColumnDefinition>
<ColumnDefinition Width="220px" ></ColumnDefinition>
<ColumnDefinition Width="*" ></ColumnDefinition>
<ColumnDefinition Width="180px" ></ColumnDefinition>
</Grid.ColumnDefinitions>
<Button Grid.Column="2" Grid.Row="3" Height="60" Width="140" Content="Connect" x:Name="ConnectButton" FontSize="20" FontFamily="LilyUPC" FontWeight="Bold" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="20, 80, 20, 0" Click="ConnectButton_Click"/>
<Button Grid.Column="0" Grid.Row="3" Height="60" Width="140" Content="Disconnect" x:Name="DisconnectButton" FontSize="20" FontFamily="LilyUPC" FontWeight="Bold" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="20, 80, 20, 0" Click="DisconnectButton_Click"/>
<Image Grid.Column="0" Grid.Row="0" Grid.RowSpan="2" Grid.ColumnSpan="3" Margin="10" RenderOptions.BitmapScalingMode="NearestNeighbor" RenderOptions.EdgeMode="Aliased" x:Name="ImageCamera"></Image>
</Grid>
</Window>

Thanks to #ThomasWeller for their answer in comments! As they said:
AddRange adds the whole buffer. How should it know how many bytes were received?
So I rewrote my receive method like this:
public static byte[] GetInputBytes(Socket clientSocket)
{
byte[] rcvLenBytes = new byte[4];
clientSocket.Receive(rcvLenBytes);
UInt32 rcvLen = BytesToInt(rcvLenBytes);
byte[] rcvBytes;
byte[] clientData;
List<byte> rcvBytesList = new List<byte>();
int totalBytes = 0;
while (totalBytes < rcvLen)
{
if (rcvLen - totalBytes < 262144)
{
clientData = new byte[rcvLen - totalBytes];
}
else
{
clientData = new byte[262144];
}
int bytesReceived = clientSocket.Receive(clientData);
rcvBytesList.AddRange(clientData.Take(bytesReceived).ToArray());
totalBytes += bytesReceived;
}
rcvBytes = rcvBytesList.ToArray();
return rcvBytes;
}
Changed line is: rcvBytesList.AddRange(clientData.Take(bytesReceived).ToArray());
It works fine now.

Same BSD socket API program works in Python but not in C++ or Rust

I've been trying to listen to multicast UDP messages from my Yeelight smart bulb. At a regular interval, the bulb broadcasts its presence on IP 239.255.255.250 port 1982. Also, when sending a specific request (found on page 5 - section 3.1) on the same IP and port, the bulb will respond.
Using sockets, I am trying to establish the communication. On two machines (macOS and Linux), the Python program shown below run at the REPL works, but the Rust code and C++ code also shown below (essentially doing the same thing) doesn't. The Rust program seems to successfully receive 0 bytes twice and then hangs waiting. In the C++ program, the recv function just hangs right away, never returning.
What could be the problem? Why can only Python successfully communicate?
import socket as s
import struct
sock = s.socket(s.AF_INET, s.SOCK_DGRAM, s.IPPROTO_UDP)
sock.setsockopt(s.IPPROTO_IP, s.IP_ADD_MEMBERSHIP, struct.pack("4sL", s.inet_aton("239.255.255.250"), s.INADDR_ANY))
sock.sendto("M-SEARCH * HTTP/1.1\r\nHOST: 239.255.255.250:1982\r\nMAN: \"ssdp:discover\"\r\nST: wifi_bulb\r\n".encode('UTF-8'), ("239.255.255.250", 1982))
sock.recv(4096) # Message received successfully right away from first call
#[macro_use] extern crate log;
use socket2::{Socket, Domain, Type, Protocol, SockAddr};
use std::net::{SocketAddrV4, Ipv4Addr};
fn main() {
env_logger::init();
let yeelight_ip = Ipv4Addr::new(239, 255,255, 250);
let yeelight_port: u16 = 1982;
let socket = Socket::new(
Domain::ipv4(),
Type::dgram(),
Some(Protocol::udp())
).expect("Failed to create socket!");
socket.join_multicast_v4(
&yeelight_ip,
&Ipv4Addr::UNSPECIFIED
).expect("Unable to join multicast broadcast!");
let msg = "M-SEARCH * HTTP/1.1\r\nHOST: 239.255.255.250:1982\r\nMAN: \"ssdp:discover\"\r\nST: wifi_bulb\r\n";
match socket.send_to(
msg.as_bytes(),
&SockAddr::from(
SocketAddrV4::new(
yeelight_ip,
yeelight_port
)
)
) {
Ok(bytes_sent) => {
// Some lines of debug printing
},
Err(_) => eprintln!("Error broadcasting request for identification!")
loop {
let mut buffer = Vec::with_capacity(1024 * 1024);
let received_bytes = socket
.recv(&mut buffer)
.expect("Unable to receive message!");
debug!("Received {} bytes", received_bytes);
}
}
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <iostream>
#include <string>
#include <array>
const std::string msg = "M-SEARCH * HTTP/1.1\r\nHOST: 239.255.255.250:1982\r\nMAN: \"ssdp:discover\"\r\nST: wifi_bulb\r\n";
int main() {
auto yeelight_ip = in_addr();
inet_aton("239.255.255.250", &yeelight_ip);
unsigned int yeelight_port = 1982;
auto sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
std::cerr << "Created socket!" << std::endl;
auto mreq = ip_mreq();
mreq.imr_interface.s_addr = INADDR_ANY;
mreq.imr_multiaddr.s_addr = yeelight_ip.s_addr;
if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) != 0) {
std::cerr << "Error joining multicast!" << std::endl;
exit(errno);
}
else {
std::cerr << "Joined multicast!" << std::endl;
}
auto addr = sockaddr_in();
addr.sin_port = yeelight_port;
for (int i = 0; i < 8; i++) addr.sin_zero[i] = 0;
addr.sin_family = AF_INET;
addr.sin_addr = yeelight_ip;
if (sendto(sock, msg.c_str(), msg.length(), 0, (sockaddr*)(&addr), sizeof(addr)) == -1) {
std::cerr << "Error broadcasting request for identification!" << std::endl;
std::cerr << errno << std::endl;
}
else {
std::cerr << "Sent broadcast request for idetification!" << std::endl;
}
while (true) {
std::array<char, 1024 * 1024> buffer;
auto bytes_read = recv(sock, buffer.data(), buffer.size(), 0);
if (bytes_read == -1) {
std::cerr << "Unable to receive message!" << std::endl;
std::cerr << errno << std::endl;
}
else {
std::cerr << "Read " << bytes_read << " bytes..." << std::endl;
std::cout << std::string(buffer.begin(), buffer.begin() + bytes_read) << std::endl;
}
}
return 0;
}

The Python program works as expected due to Python nicely implementing conversions behind the scenes.
The C(++) program didn't work because the endianness of the port was wrong. I forgot that I have to use addr.sin_port = htons(yeelight_port);.
As for the Rust program, I forgot that with_capacity only allocated the internal buffer, but the Vec is still empty. The solution, described here, is to call buffer.resize(buffer.capacity(), 0);.

Flask C++ Socket Code 400, message Bad request syntax

I'm trying to connect a Flask server with C++ client through a socket connection:
Server:
from flask import Flask
from os.path import dirname, abspath
from queue import Queue
import base64
import cv2
import numpy as np
from PIL import Image
import io
from object_detection import detect_object
d = dirname(dirname(abspath(__file__)))
app = Flask(__name__)
app.queue = Queue()
#app.route("/")
def home():
return "Hello"
#app.route("/")
def test_live(message):
app.queue.put(message['data'])
img_bytes = base64.b64decode(app.queue.get())
img_np = np.array(Image.open(io.BytesIO(img_bytes)))
img_np = detect_object(img_np)
frame = cv2.imencode('.jpg', cv2.cvtColor(img_np, cv2.COLOR_BGR2RGB))[
1
].tobytes()
base64_bytes = base64.b64encode(frame)
base64_string = base64_bytes.decode('utf-8')
if __name__ == '__main__':
app.run(app, host = '127.0.0.1', port = 5000, debug = True)
C++ client
#include <iostream>
#include <string>
#include <WS2tcpip.h>
#include <iostream>
#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#pragma comment(lib, "ws2_32.lib")
using namespace std;
using namespace cv;
void main()
{
string ipAddress = "127.0.0.1"; // IP Address of the server
int port = 5000; // Listening port # on the server
// Initialize WinSock
WSAData data;
WORD ver = MAKEWORD(2, 2);
int wsResult = WSAStartup(ver, &data);
if (wsResult != 0)
{
cerr << "Can't start Winsock, Err #" << wsResult << endl;
return;
}
// Create socket
SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock == INVALID_SOCKET)
{
cerr << "Can't create socket, Err #" << WSAGetLastError() << endl;
WSACleanup();
return;
}
// Fill in a hint structure
sockaddr_in hint;
hint.sin_family = AF_INET;
hint.sin_port = htons(port);
inet_pton(AF_INET, ipAddress.c_str(), &hint.sin_addr);
// Connect to server
int connResult = connect(sock, (sockaddr*)&hint, sizeof(hint));
if (connResult == SOCKET_ERROR)
{
cerr << "Can't connect to server, Err #" << WSAGetLastError() << endl;
closesocket(sock);
WSACleanup();
return;
}
// Do-while loop to send and receive data
char buf[4096];
string userInput;
do
{
// Prompt the user for some text
cout << "> ";
getline(cin, userInput);
if (userInput.size() > 0) // Make sure the user has typed in something
{
// Send the text
Mat frame;
frame = imread(userInput.c_str(), IMREAD_COLOR);
int imgSize = frame.total() * frame.elemSize();
int sendResult = send(sock, (const char*) frame.data, imgSize, 0);
if (sendResult != SOCKET_ERROR)
{
// Wait for response
ZeroMemory(buf, 4096);
int bytesReceived = recv(sock, buf, 4096, 0);
if (bytesReceived > 0)
{
// Echo response to console
cout << "SERVER> " << string(buf, 0, bytesReceived) << endl;
}
}
}
} while (userInput.size() > 0);
// Gracefully close down everything
closesocket(sock);
WSACleanup();
}
I'm getting this error on the server when I try to send a image from the client:
Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
127.0.0.1 - - [10/Feb/2020 11:45:40] code 400, message Bad request syntax ('54043/0.--+*/--1//2-.2-./+**(\'#! \x19\x1c\x1a\x12\x19\x16\x0f\x1a\x17\x13 \x1e\x14%"\x16*+\x17,-\x180.\x1830\x1b63\x1c96\x1b:7\x1c;8\x1e?;\x1eA= C?\x1fGB#JH&QN*WT-\\Y2_\\5b_9ga<jd>jc>jc>jc>jc7e_6f`9ic:mf;oh:ng9pg;riCxn<qg;sh=uj:ti=wlB{sC|t?ytB|wE}xBzu#yq#yq?xo:vl7rj;wo;wo;wo;vn7rj5nf0f_+^Z\'VS\'TQ\'OM%LJ\x1eCA\x1c<;\x1654\x17//\x15--\x13--\x1400\x13++')
127.0.0.1 - - [10/Feb/2020 11:45:40] "54043/0.--+*/--1//2-.2-./+**('#! %"*+,-0.306396:7;8?;A= C?GB#JH&QN*WT-\Y2_\5b_9ga<jd>jc>jc>jc>jc7e_6f`9ic:mf;oh:ng9pg;riCxn<qg;sh=uj:ti=wlB{sC|t?ytB|wE}xBzu#yq#yq?xo:vl7rj;wo;wo;wo;vn7rj5nf0f_+^Z'VS'TQ'OM%LJCA<;54//----00++" HTTPStatus.BAD_REQUEST -
127.0.0.1 - - [10/Feb/2020 11:46:00] code 400, message Bad request syntax ('54043/0.--+*/--1//2-.2-./+**(\'#! \x19\x1c\x1a\x12\x19\x16\x0f\x1a\x17\x13 \x1e\x14%"\x16*+\x17,-\x180.\x1830\x1b63\x1c96\x1b:7\x1c;8\x1e?;\x1eA= C?\x1fGB#JH&QN*WT-\\Y2_\\5b_9ga<jd>jc>jc>jc>jc7e_6f`9ic:mf;oh:ng9pg;riCxn<qg;sh=uj:ti=wlB{sC|t?ytB|wE}xBzu#yq#yq?xo:vl7rj;wo;wo;wo;vn7rj5nf0f_+^Z\'VS\'TQ\'OM%LJ\x1eCA\x1c<;\x1654\x17//\x15--\x13--\x1400\x13++')
127.0.0.1 - - [10/Feb/2020 11:46:00] "54043/0.--+*/--1//2-.2-./+**('#! %"*+,-0.306396:7;8?;A= C?GB#JH&QN*WT-\Y2_\5b_9ga<jd>jc>jc>jc>jc7e_6f`9ic:mf;oh:ng9pg;riCxn<qg;sh=uj:ti=wlB{sC|t?ytB|wE}xBzu#yq#yq?xo:vl7rj;wo;wo;wo;vn7rj5nf0f_+^Z'VS'TQ'OM%LJCA<;54//----00++" HTTPStatus.BAD_REQUEST -
I have read that's because my client is trying to connect via HTTPS but I don't find how to change it.
Thanks for your help

C++ GUI freezes during communication over socket thread with Python

First of all I want to mention that I've gone through a lot of socket threading tutorials before attempting to integrate it into my own GUI, but I still consider myself fairly new to the subject.
I have a server written in python that opens a socket and starts a thread over localhost, and listens over the port for a client:
def StartThread():
tcpsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcpsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
tcpsock.bind((TCP_IP, TCP_PORT))
threads = []
tcpsock.listen(5)
print "Waiting for incoming connections from client..."
(conn, (ip,port)) = tcpsock.accept()
print 'Got connection from ', (ip,port)
newthread = ClientThread(ip,port,conn, 1)
newthread.start()
return newthread
Here is the ClientThread class:
class ClientThread(Thread):
def __init__(self,ip,port,sock, status):
Thread.__init__(self)
self.ip = ip
self.port = port
self.sock = sock
self.status = 1
print " New thread started for "+ip+":"+str(port)
After I run the server code, I click a button on my C++ GUI which runs the client code StartConnection() based off the Microsoft Winsock client template.
void CPSR_CRSDlg::OnBnClickedInit2()
{
if(!checkTimerStarted())
// Set mmtimer to aquire the data
{
m_ntimerID = timeSetEvent( TIMERINTRRVAL,
1,
timerHandler,
0,
TIME_PERIODIC);
SetTimer(1,TIMERINTRRVAL_2,NULL);
m_bTimer_started = true;
}
StartConnection();
}
The connection does start successfully and the python code prints the address of the connection and the thread, but then my GUI freezes, so that I can't click any of the other buttons to actually send data over the connection.
Why does my application freeze? Am I not instantiating the thread correctly?
The StartConnection() code is off the msdn website but here is my slightly modified version if needed:
void StartConnection(){
//printf("Connection Starting... \n");
WSADATA wsaData;
ConnectSocket = INVALID_SOCKET;
struct addrinfo *result = NULL,
*ptr = NULL,
hints;
int argc = 2;
// Validate the parameters
if (argc != 2) {
printf("usage: %s server-name\n", "client");
return;
}
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed with error: %d\n", iResult);
return;
}
ZeroMemory( &hints, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
// Resolve the server address and port
//iResult = getaddrinfo(argv[1], DEFAULT_PORT, &hints, &result);
iResult = getaddrinfo("localhost", DEFAULT_PORT, &hints, &result);
if ( iResult != 0 ) {
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return;
}
// Attempt to connect to an address until one succeeds
for(ptr=result; ptr != NULL ;ptr=ptr->ai_next) {
// Create a SOCKET for connecting to server
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
ptr->ai_protocol);
if (ConnectSocket == INVALID_SOCKET) {
printf("socket failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return;
}
// Connect to server.
iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;
continue;
}
break;
}
freeaddrinfo(result);
if (ConnectSocket == INVALID_SOCKET) {
printf("Unable to connect to server!\n");
WSACleanup();
return;
}
return;
}
void StopConnection(){
closesocket(ConnectSocket);
WSACleanup();
return;
}
void SendJointValues(double *joints){
iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
j = parseJSON(joints[0],joints[1],joints[2],joints[3], \
joints[4],joints[5]);
int x = send(ConnectSocket, j, strlen(j), 0);
//iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
}
Edit:
The GUI does respond again after I send data via the server, and the client then successfully sends back one iteration of data. But after this exchange the GUI freezes again until more data is sent.
Here is the send+receive portion of the server:
def receiveData(self):
while (self.status == 1):
joints = [0,0,0,0,0,0]
self.sock.sendall('send')
print "Data Sent!"
data = self.sock.recv(4096)
print "Data received: ", data
self.checkStatus(data)
print "Status is: ", self.status
if (self.status == 1):
data_loaded = json.loads(data)
joints = self.createJointArr(data_loaded['Joints'])
time.sleep(0.5)
print joints
return joints
And the SendJointValues() in the client is called in this Timer function:
void CPSR_CRSDlg::OnTimer(UINT_PTR nIDEvent)
{
CString str;
long Position;
double engPosition;
double dblPosition;
double dblSpeed;
bool ret;
// Arch
USB4_01.Controller_3.getEncoderPosition(Position);
countTodegree(Position,engPosition,ARCH);
str.Format(_T("%10.2f"),engPosition);
m_staPosArch.SetWindowText(str);
// Wrist Pitch
USB4_01.Controller_2.getEncoderPosition(Position);
countTodegree(Position,engPosition,TILT);
str.Format(_T("%10.2f"),engPosition);
m_staPosPitch.SetWindowText(str);
// Linear
USB4_02.Controller_1.getEncoderPosition(Position);
countTodegree(Position,engPosition,LINEAR);
str.Format(_T("%10.2f"),engPosition);
m_staPosLinear.SetWindowText(str);
// Turret
USB4_02.Controller_2.getEncoderPosition(Position);
countTodegree(Position,engPosition,TURRET);
str.Format(_T("%10.2f"),engPosition);
m_staPosTurret.SetWindowText(str);
// Roll
USB4_02.Controller_4.getEncoderPosition(Position);
countTodegree(Position,engPosition,ROLL);
str.Format(_T("%10.2f"),engPosition);
m_staPosRoll.SetWindowText(str);
// Drill/Tool
USB4_02.Controller_3.getEncoderPosition(Position);
countTodegree(-Position,engPosition,DRILL);
str.Format(_T("%10.2f"),engPosition);
m_staPosDrill.SetWindowText(str);
// For Penetrate joint
if(JntPenetration.isInitialized())
{
// Get Position feedback
ret = JntPenetration.getPosition(dblPosition);
if(ret) // get position feedback successfully
{
Position = (long) dblPosition;
countTodegree(Position,engPosition,PENETRATE);
str.Format(_T("%10.2f"),engPosition);
m_staPosPenetrate.SetWindowText(str);
m_dCurentPentrationPosition = engPosition;
}
// Get Speed feedback;
if(m_bDrilling_started)
{
// Penetration position close enough AND At least on cycle reached
if( (abs(engPosition - m_dDrilling_target_position) < 0.1) &&(m_Direction_Changed == true))
m_bPenetrationStopped = true;
else
m_bPenetrationStopped = false;
//JntPenetration.getSpeed(dblSpeed);
//if(dblSpeed < .05 )
// m_bPenetrationStopped = true;
//else
// m_bPenetrationStopped = false;
}
}
SendJointValues(JointArray);
// For drilling motion control
if(m_bDrilling_started)
drilingProcedure();
CDialog::OnTimer(nIDEvent);
}