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ESP32: How to send a jpg out of SPIFFS via WiFiClient to a python server socket?

I want that my ESP32 takes a picture, stores it in the SPIFFS and then send it via a WiFiClient from WiFi.h. The reciever is a python server socket. The server should store it as a jpg in the local windows filesystem.
So far i can connect the esp to the wifi, take a picture and store it in the SPIFFS. In another project i already send char from the WiFiClientto the python server without any problem. But if i want to send the picture a bytes with WiFiClient.print() it only sends two bytes and that cannot be correct i think.
What i need is help for sending the bytes of the jpg from the esp and decode the recieved bytes from the python socket server and store the bytes as a jpg. If there is a better way then using a the esp32 WiFiClient-class or python socket, feel free to say it.
Here is my ESP code (yes i know. The structure is not the best. Its only an example for me):
#include <WiFi.h>
const char* ssid = "xxx";
const char* password = "xxx";
const uint16_t port = xxx;
const char * host = "xxx";
/*********
Rui Santos
Complete instructions at https://RandomNerdTutorials.com/esp32-cam-projects-ebook/
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files.
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*********/
#include "esp_camera.h"
//#include "SPI.h"
//#include "driver/rtc_io.h"
#include <FS.h>
#include <SPIFFS.h>
#define CAMERA_MODEL_WROVER_KIT
#if defined(CAMERA_MODEL_WROVER_KIT)
#define PWDN_GPIO_NUM -1
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM 21
#define SIOD_GPIO_NUM 26
#define SIOC_GPIO_NUM 27
#define Y9_GPIO_NUM 35
#define Y8_GPIO_NUM 34
#define Y7_GPIO_NUM 39
#define Y6_GPIO_NUM 36
#define Y5_GPIO_NUM 19
#define Y4_GPIO_NUM 18
#define Y3_GPIO_NUM 5
#define Y2_GPIO_NUM 4
#define VSYNC_GPIO_NUM 25
#define HREF_GPIO_NUM 23
#define PCLK_GPIO_NUM 22
#else
#error "Camera model not selected"
#endif
// Photo File Name to save in SPIFFS
#define FILE_PHOTO "/photo.jpg"
File file;
camera_fb_t * fb;
WiFiClient client;
void setup() {
//WRITE_PERI_REG(RTC_CNTL_BROWN_OUT_REG, 0); //disable brownout detector
Serial.begin(115200);
Serial.println();
// Connect to Wi-Fi
WiFi.begin(ssid, password);
Serial.print("Connecting to WiFi...");
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println();
if (!SPIFFS.begin(true)) {
Serial.println("An Error has occurred while mounting SPIFFS");
ESP.restart();
}
else {
delay(500);
Serial.println("SPIFFS mounted successfully");
}
// Print ESP32 Local IP Address
Serial.print("IP Address: http://");
Serial.println(WiFi.localIP());
camera_config_t config;
config.ledc_channel = LEDC_CHANNEL_0;
config.ledc_timer = LEDC_TIMER_0;
config.pin_d0 = Y2_GPIO_NUM;
config.pin_d1 = Y3_GPIO_NUM;
config.pin_d2 = Y4_GPIO_NUM;
config.pin_d3 = Y5_GPIO_NUM;
config.pin_d4 = Y6_GPIO_NUM;
config.pin_d5 = Y7_GPIO_NUM;
config.pin_d6 = Y8_GPIO_NUM;
config.pin_d7 = Y9_GPIO_NUM;
config.pin_xclk = XCLK_GPIO_NUM;
config.pin_pclk = PCLK_GPIO_NUM;
config.pin_vsync = VSYNC_GPIO_NUM;
config.pin_href = HREF_GPIO_NUM;
config.pin_sscb_sda = SIOD_GPIO_NUM;
config.pin_sscb_scl = SIOC_GPIO_NUM;
config.pin_pwdn = PWDN_GPIO_NUM;
config.pin_reset = RESET_GPIO_NUM;
config.xclk_freq_hz = 20000000;
config.pixel_format = PIXFORMAT_JPEG;
if(psramFound()){
config.frame_size = FRAMESIZE_UXGA;
config.jpeg_quality = 10;
config.fb_count = 2;
} else {
config.frame_size = FRAMESIZE_SVGA;
config.jpeg_quality = 12;
config.fb_count = 1;
}
// Initialize camera
esp_err_t err = esp_camera_init(&config);
if (err != ESP_OK) {
Serial.printf("Camera init failed with error 0x%x", err);
return;
}
}
void loop()
{
if (!client.connect(host, port)) {
Serial.println("Connection to host failed");
delay(1000);
return;
}
Serial.println("Connected to server successful!");
fb = NULL; // pointer
bool ok = 0; // Boolean indicating if the picture has been taken correctly
do {
// Take a photo with the camera
Serial.println("Taking a photo...");
fb = esp_camera_fb_get();
if (!fb) {
Serial.println("Camera capture failed");
return;
}
// Photo file name
Serial.printf("Picture file name: %s\n", FILE_PHOTO);
file = SPIFFS.open(FILE_PHOTO, FILE_WRITE);
// Insert the data in the photo file
if (!file) {
Serial.println("Failed to open file in writing mode");
}
else {
file.write(fb->buf, fb->len); // payload (image), payload length
Serial.print("The picture has been saved in ");
Serial.print(FILE_PHOTO);
Serial.print(" - Size: ");
Serial.print(file.size());
Serial.println(" bytes");
}
// check if file has been correctly saved in SPIFFS
ok = checkPhoto(SPIFFS);
} while ( !ok );
while(file.available()){
Serial.println(client.print(file.read()));
}
// Close the file
file.close();
esp_camera_fb_return(fb);
delay(1000);
}
// Check if photo capture was successful
bool checkPhoto( fs::FS &fs ) {
File f_pic = fs.open( FILE_PHOTO );
unsigned int pic_sz = f_pic.size();
return ( pic_sz > 100 );
}
and this is my python code:
import socket
s = socket.socket()
s.bind(('yyy', yyy ))
s.listen(0)
while True:
try:
print("-------------------------------------------------------------------")
client, addr = s.accept()
print("Accepted a connection request from %s:%s"%(addr[0], addr[1]));
while True:
content = client.recv(131072)
if len(content) ==0:
break
else:
msg_recieved = content
msg_recieved_decode = content.decode()
print(msg_recieved)
print("Message decoded recieved: " + msg_recieved_decode)
f = open("demofile.jpg", "wb")
f.write(msg_recieved)
f.close()
print("Client closed")
client.close()
except Exception as e:
print("===================================================================")
print("Something went wrong")
print(e)
print("===================================================================")

Apple Watch stops transmitting gyroscope/accelometer data after a few minutes for unknown reason

I have created a watchOS app that fetches data from the accelerometer and gyroscope and sends it to a socket server. The server just prints the data on the console. The socket server is made in python. My app works fine for a few minutes but then stops working.
I tested by creating an iPhone app and it's working fine. The problem is with the apple watch app.
Can someone help me with this? I don't understand what's going on.
server.py
import socket
localIP = ""
localPort = 20001
bufferSize = 10240
msgFromServer = "Hello UDP Client"
bytesToSend = str.encode(msgFromServer)
# Create a datagram socket
UDPServerSocket = socket.socket(family=socket.AF_INET, type=socket.SOCK_DGRAM)
# Bind to address and ip
UDPServerSocket.bind((localIP, localPort))
print("UDP server up and listening")
# Listen for incoming datagrams
while(True):
bytesAddressPair = UDPServerSocket.recvfrom(bufferSize)
message = bytesAddressPair[0]
address = bytesAddressPair[1]
clientMsg = "Message from Client:{}".format(message)
clientIP = "Client IP Address:{}".format(address)
print(clientMsg)
print(clientIP)
# Sending a reply to client
UDPServerSocket.sendto(bytesToSend, address)
InterfaceController.swift
#IBOutlet weak var stopButton: WKInterfaceButton!
#IBOutlet weak var startButton: WKInterfaceButton!
var session = WKExtendedRuntimeSession()
private var host: NWEndpoint.Host = "172.16.105.162"
private var port: NWEndpoint.Port = 20001
private var updateTimeInterval: Double = 1/60
override func awake(withContext context: Any?) {
// Configure interface objects here.
// startButton.setHidden(false)
startButton.setEnabled(true) // // stopButton.setHidden(true)
stopButton.setEnabled(false)
setUPSession()
}
override func willActivate() {
// This method is called when watch view controller is about to be visible to user
print("ACTIVATE")
}
override func didDeactivate() {
// This method is called when watch view controller is no longer visible
print("DEACTIVATE")
}
#IBAction func actionStop() { // startButton.setHidden(false)
startButton.setEnabled(true) // // stopButton.setHidden(true)
stopButton.setEnabled(false)
self.stopSession()
// MotionDatafetcher.shared.startSession() //stopWorkoutSEssion() //stopFetch()
}
#IBAction func actionStart() { // startButton.setHidden(true)
startButton.setEnabled(false) // // stopButton.setHidden(false)
stopButton.setEnabled(true)
self.startSession()
// MotionDatafetcher.shared.startFetch()
//MotionDatafetcher.shared.stopSession() //startWorkoutSession() //startDeviceMotionFetch()
}
}
extension InterfaceController : WKExtendedRuntimeSessionDelegate{
func setUPSession() {
// Create the session object.
session = WKExtendedRuntimeSession()
// Assign the delegate.
session.delegate = self
MySocketManager.shared.setUpConn()
}
func startSession() {
session.start()
MySocketManager.shared.connectToUDP(host, port)
MotionDatafetcher.shared.startDeviceMotionFetch(updateTimeInterval)
}
func stopSession() {
session.invalidate()
MotionDatafetcher.shared.stopFetch()
MySocketManager.shared.cancelConnToUDP()
}
func extendedRuntimeSession(_ extendedRuntimeSession: WKExtendedRuntimeSession, didInvalidateWith reason: WKExtendedRuntimeSessionInvalidationReason, error: Error?) {
}
func extendedRuntimeSessionDidStart(_ extendedRuntimeSession: WKExtendedRuntimeSession) {
}
func extendedRuntimeSessionWillExpire(_ extendedRuntimeSession: WKExtendedRuntimeSession) {
self.stopSession()
}
}

Error while reading image received from socket

I have an android app that sends an image from gallery to a Python server via sockets using DataOutputStream to write to the socket in the client app. The image is loaded from external storage directory and buffered before being sent. The image is received by the server and written to disk memory. When I try to open the image it gives me: "Fatal Error reading the image file. Not a PNG". However the image occupies an actual image size of 430 KiB. When I print the data being received it gives me something that looks like a raw image:
b'\x97\xa7p\xc0\x04\xfbv\xf6\\\xed\x8a\xe9^\xbf\xa4p9\xae\x8eu:N\xb5\x8e\xcc\x06\xa6\xf1\tyL\xf3.^W\xb5RR\xd3)\x7fS\xf3\x8f\x1b\xc6\xf8\xa7\x9b\xf5\xb8\xc3f\xa9\xdf\xa1\xbd\xaa\xbeS\xbc\x84zt\xedT\xbfn|I\xfb\x0e\xfb\xae6\x18sS\x9b\x9e\xd8\xff\xc4>\xaf\xeb\xba\xbe>{\xe2\x87~\xe8\x87~\xe8\x87~\xe8\x87~\xe8\x87~\xe8\x87~\xe8\x87~\xe8\x87~\xe8\x87~\xe8\x87~\xe8\x87\xfe\xbf\xa4\xff\x07\xe5\x9f\xdc\xd5\xe2d\xc5\xcb\x00\x00\x00\x00IEND\xaeB`\x82'
b''
The text is longer but I cut it down..
The client code that loads the image from directory and writes to socket:
class send extends AsyncTask<Void, Void, Void> {
Socket s; //Socket Variable
#Override
protected Void doInBackground(Void... params) {
try {
s = new Socket("192.168.0.14", 9999);
String image = getLatestFilefromDir("/storage/emulated/0/DCIM");
File file = new File(image);
try (InputStream is = new BufferedInputStream(new FileInputStream(file));
DataOutputStream dos = new DataOutputStream(s.getOutputStream())) {
dos.writeLong(file.length());
int val;
while ((val = is.read()) != -1) {
dos.write(val);
}
dos.flush();
} catch (IOException e) {
e.printStackTrace();
}
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
private String getLatestFilefromDir(String dirPath){
File dir = new File(dirPath);
File[] files = dir.listFiles();
if (files == null || files.length == 0) {
return null;
}
File lastModifiedFile = files[0];
for (int i = 1; i < files.length; i++) {
if (lastModifiedFile.lastModified() < files[i].lastModified()) {
lastModifiedFile = files[i];
}
}
return lastModifiedFile.toString();
}
Python server:
#Imports modules
import socket
import datetime
date_string = datetime.datetime.now().strftime("%Y-%m-%d-%H:%M")
listensocket = socket.socket()
listenPort = 9999
numberOfConnections=1
thisIp = socket.gethostname()
listensocket.bind(('', listenPort))
listensocket.listen(numberOfConnections)
print("Started Listening")
(clientsocket, address) = listensocket.accept()
print("Connected")
fname = "/home/pi/Desktop/Images/"+date_string+".PNG"
f = open(fname, 'wb')
datain = 1
while datain:
datain = clientsocket.recv(100000000)
print(datain)
bytearray(f.write(datain))
f.close()
listensocket.close()

This answer may not be robust but does demonstrate a mechanism for efficiently transferring files from a Java application to a Python server. Certain paths are hard-coded for demonstration purposes. Also note that this may not be appropriate if the file being transferred is very large due to the fact that the entire file contents will be held in memory on the server side before writing to the target file. Obviously that can be accounted for with more elaborate code.
Here's the Java client:
package com.aprk;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.Socket;
import java.util.logging.Level;
import java.util.logging.Logger;
public class GetImage {
public static void main(String[] args) {
try {
Socket s = new Socket("localhost", 7070);
File image = new File("/Volumes/G-DRIVE Thunderbolt 3/Pictures/rgb_colour_wheel.png");
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(image));
BufferedOutputStream bos = new BufferedOutputStream(s.getOutputStream());
bos.write(nio(image.length()));
byte[] buff = new byte[4096];
int n;
while ((n = bis.read(buff, 0, buff.length)) > 0) {
bos.write(buff, 0, n);
}
bos.flush();
} catch (IOException ex) {
Logger.getLogger(GetImage.class.getName()).log(Level.SEVERE, null, ex);
}
}
private static byte[] nio(long n) {
byte[] v = new byte[8];
int shift = 56;
for (int i = 0; i < 8; i++) {
v[i] = (byte)(n>>shift);
shift -= 8;
}
return v;
}
}
Here's the Python server:
import socket
from struct import unpack
HOST = '0.0.0.0'
PORT = 7070
def main():
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, _ = s.accept()
with conn:
p = conn.recv(8, socket.MSG_WAITALL)
n = unpack('!Q', p)[0]
with open('/tmp/image.png', 'wb') as image:
while n > 0:
data = conn.recv(n)
image.write(data)
n -= len(data)
if __name__ == '__main__':
main()

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.

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);
}