I am developing a temperature monitoring application in a hen house with a web interface. I use two arduinos and a Raspberry.
Arduino 1: I connected a temperature / humidity sensor and an RF433Mhz transmitter.
Arduino 2: An RF433Mhz receiver is connected to it. It receives data from Arduino 1.
Raspberry: Arduino 2 is connected to my raspberry which reads the data received in the serial monitor and send them to the web page via the websockets (package ws of nodejs).
At first I wanted to read this data directly with Nodejs, but I had some problems with the installation of the serial port package.
So I changed my approach: I read the data in the serial monitor with python, write it in files, and Nodejs reads these files and sends the data to the web page.
here are the two codes I use:
Phyton script
import serial
import time
ser = serial.Serial('/dev/ttyACM0', 9600)
while True:
data = ser.readline()
if data:
t = data[0:2]
h = data[6:8]
#decode utf-8
tc = t.decode("utf-8")
hc = h.decode("utf-8")
#write the temperature in the temp file
fileTc=open('temp', 'w')
fileTc.write(str(tc))
fileTc.close
#write the humidity in the hum file
fileHc=open('hum', 'w')
fileHc.write(str(hc))
fileHc.close
#sleep
time.sleep(.1)
Nodejs Script
var express = require("express");
const WebSocket = require('ws');
const wss = new WebSocket.Server({port: 4400});
var path = require("path");
var fs = require("fs");
var sys = require("util");
var exec = require("child_process").exec;
var tempcpu = 0;
var temp = 0;
var hum = 0;
var app = express();
app.set("port", process.env.PORT || 5500);
app.set("views", path.join(__dirname, "views"));
app.set("view engine", "ejs");
app.use('/', express.static('public'));
wss.on('connection', function connection(ws) {
ws.on('message', function incoming(message) {
console.log('received: %s', message);
});
setInterval(function(){
child1 = exec("cat /sys/class/thermal/thermal_zone0/temp",
function(error, stdout,stderr){
if (error !== null){
console.log('exec error: ' +error);
} else{
tempcpu = parseFloat(stdout)/1000;
}
});
child2 = exec("cat temp", function(error, stdout,stderr){
if (error !== null){
console.log('exec error: ' +error);
} else{
temp = parseFloat(stdout);
}
});
child3 = exec("cat hum", function(error, stdout,stderr){
if (error !== null){
console.log('exec error: ' +error);
} else{
hum = parseFloat(stdout);
}
});
var tempCPU = JSON.stringify(["cpu",tempcpu]);
var temperature = JSON.stringify(["temp",temp]);
var humidity = JSON.stringify(["hum",hum]);
ws.send(tempCPU);
ws.send(temperature);
ws.send(humidity);
}, 5000);
});
app.get("/", function(request, response) {
response.render("dashboard");
});
app.listen(app.get("port"), function() {
console.log("Server started at port " + app.get("port"));
});
for now I have to launch both scripts separately. I would like to run my python script directly from nodejs when I start the node server, and stop it when I stop my nodejs code (CTRL + C).
Do you have an idea of how to do it?
What you want to achieve is spawn a new process in which you execute something from either a Node app or a Python app:
NodeJS approach: Child process
const { spawn } = require('child_process');
const pythonApp = spawn('python', ['my_python_app.py']);
Python approach: Subprocess
import subprocess
node_app = subprocess.Popen(["node","my_node_app.js"], stdin=subprocess.PIPE, stderr=subprocess.PIPE, stdout=subprocess.PIPE)
EDIT
Regarding catching the INTERRUPT (CTRL+C) signal, this can also be done in both languages; and leveraged to kill the process you spawned:
With NodeJS:
process.on('SIGINT', () => {
console.log("Caught interrupt signal");
if(pythonApp) pythonApp.exit();
});
With Python:
import sys
try:
# Your app here...
except KeyboardInterrupt:
print("Caught interrupt signal")
if node_app: node_app.kill()
sys.exit()
Related
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()
}
}
I want to run .py file from my C# project, and get the result. The python script is making an API request, and returns an auth_key token, which I want to use in my C# code. The only problem is that, for some reason the C# code doesn't wait for the process to finish, and thus that not every account has auth_key. Here is my C# code.
private static void GenerateTokens()
{
var url = ConfigurationManager.AppSetting[GeSettingsNode() + ":ip"];
for (int i = 0; i < accounts.Count; i++)
{
ProcessStartInfo start = new ProcessStartInfo();
start.FileName = ConfigurationManager.AppSetting["PythonPath"];
start.Arguments = string.Format($"python_operation_processor.py {accounts[i].client_key_id} {accounts[i].key_sercret_part} {url}");
start.UseShellExecute = false;
start.RedirectStandardOutput = true;
Process process = Process.Start(start);
using (StreamReader reader = process.StandardOutput)
{
accounts[i].auth_key = reader.ReadToEnd().Trim();
}
}
}
And here is my Python script ( python_operation_processor.py )that's making the API requests.
if __name__ == '__main__':
client_key_id = sys.argv[1]
client_secret = sys.argv[2]
API_URL = sys.argv[3]
nonce = str(uuid.uuid4())
d = datetime.datetime.now() - datetime.timedelta(hours=3)
timestamp = d.strftime('%Y-%m-%dT%H:%M:%S.%f')[:-3] + 'Z'
signature = b64encode(hmac.new(b64decode(client_secret), msg=bytes(client_key_id + nonce + timestamp, 'utf-8'),
digestmod=hashlib.sha256).digest()).decode('utf-8')
r = requests.post(API_URL + '/v1/authenticate',
json={'client_key_id': client_key_id, 'timestamp': timestamp, 'nonce': nonce,
'signature': signature})
if r.status_code != 200:
raise Exception('Failed to authenticate: ' + r.text)
auth_token = r.json()['token']
print(auth_token)
Do you have any idea, how I can wait for the execution of every process, and get the token for every account ?
I recently created something similar and ended up with this because, whilst waiting for the process is easy, it is tricky to get the output stream filled correctly.
The method presented also allow you to display the output into a textblock or similar in your application.
If you use it like this, the token will be written to the StringBuilder, and used as return value.
private async Task<string> RunCommand(string fileName, string args)
{
var timeoutSignal = new CancellationTokenSource(TimeSpan.FromMinutes(3));
ProcessStartInfo start = new ProcessStartInfo();
start.FileName = fileName;
start.Arguments = string.Format("{0}", args);
start.RedirectStandardOutput = true;
start.RedirectStandardError = true;
start.UseShellExecute = false;
start.CreateNoWindow = true;
var sb = new StringBuilder();
using (Process process = new Process())
{
process.StartInfo = start;
process.OutputDataReceived += (sender, eventArgs) =>
{
sb.AppendLine(eventArgs.Data); //allow other stuff as well
};
process.ErrorDataReceived += (sender, eventArgs) => {};
if (process.Start())
{
process.EnableRaisingEvents = true;
process.BeginOutputReadLine();
process.BeginErrorReadLine();
await process.WaitForExitAsync(timeoutSignal.Token);
//allow std out to be flushed
await Task.Delay(100);
}
}
return sb.ToString();
}
To render this to a textblock in a UI application, you'll need to:
implement an event which signals a new line has been read, which means forwarding the process.OutputDataReceived event.
if your thinking about a live feed, make sure you flush the stdio buffer in python setting flush to true: print(""hello world"", flush=True)
If you're using an older .net version; you can implement the WaitForExitAsync as described here: https://stackoverflow.com/a/17936541/2416958 as an extention method:
public static class ProcessHelpers
{
public static Task<bool> WaitForExitAsync(this Process process, TimeSpan timeout)
{
ManualResetEvent processWaitObject = new ManualResetEvent(false);
processWaitObject.SafeWaitHandle = new SafeWaitHandle(process.Handle, false);
TaskCompletionSource<bool> tcs = new TaskCompletionSource<bool>();
RegisteredWaitHandle registeredProcessWaitHandle = null;
registeredProcessWaitHandle = ThreadPool.RegisterWaitForSingleObject(
processWaitObject,
delegate(object state, bool timedOut)
{
if (!timedOut)
{
registeredProcessWaitHandle.Unregister(null);
}
processWaitObject.Dispose();
tcs.SetResult(!timedOut);
},
null /* state */,
timeout,
true /* executeOnlyOnce */);
return tcs.Task;
}
}
I try to send data from a simple python programm to a node server. But no success. That's why I ask some help.
My simple python :
import requests
SIGNUP_URL = 'http://localhost:8000/timer'
def submit_form():
obj = {name:'whateever'}
resp = requests.post(SIGNUP_URL, data = obj)
if __name__ == '__main__':
submit_form()
my nodejs (light, I remove not concern lines) :
var http = require('http');
var express = require('express');
var app = express();
app.get('/', function (request, response) {
response.sendFile(__dirname + '/public/index.html');
});
var server = http.createServer(app);
var io = require('socket.io')(server);
const bodyParser = require('body-parser');
const path = require('path');
const {execFile, exec, spawn} = require ('child_process');
app.use(express.static('public'));
app.use(bodyParser.urlencoded({ extended: true }));
app.post('/timer', function(req, res){
res.sendFile(__dirname + '/public/status.html');
var test = "test";
var data = req.body;
var info = data.name;
io.emit('messageFromServer', { info });
console.log('info')
});
server.listen(8000, console.log("listening to port 8000"));
So, when I execute my python I want transfering to the server the data "name : whatever", then I want the server write the data into the console (to be sure the data is well sent), and I all is ok, I want to emit this data to my html page...
Thanks for helping me.
The answer :
python code :
import requests
SIGNUP_URL = 'http://localhost:8000/timer'
def submit_form():
obj = {'name':'whateever'}
resp = requests.post(SIGNUP_URL, data = obj)
if __name__ == '__main__':
submit_form()
nodejs code :
app.post('/timer', function(req, res){
res.sendFile(__dirname + '/public/status.html');
var info= req.body;
io.emit('messageFromServer', info);
console.log(info)
});
It works.
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);
}
I am trying to communicate between a node.js application and python using socket.io with the socketIO-client 0.5.1 library on the python side. Below are the two code chunks:
var http = require('http').createServer();
http.listen(6000);
var io = require('socket.io').listen(http, { log: false });
var events = require('events');
var eventEmitter = new events.EventEmitter();
var counter = 0;
io.sockets.on('connection', function (socket) {
eventEmitter.on('observe', function(message){
socket.emit('sendVoltage', {});
});
socket.on('voltage', function (data) {
console.log(counter + " - " + data.voltage);
if (counter++ < 500) {
eventEmitter.emit('observe', '');
}
});
eventEmitter.emit('observe', '');
});
#!/usr/bin/python
import time, signal, sys
from Adafruit_ADS1x15 import ADS1x15
from socketIO_client import SocketIO
ADS1115 = 0x01 # 16-bit ADC
adc = ADS1x15(ic=ADS1115)
socketIO = SocketIO('chair01', 6000)
def on_voltage_response(*args):
print 'on_voltage_response', args
def on_sendVoltage(*args):
voltage = adc.readADCSingleEnded(0, 4096, 250) / 1000
print "Emitting voltage"
socketIO.emit('voltage', {'voltage': voltage}, on_voltage_response)
socketIO.wait_for_callbacks(seconds=1)
print "Voltage emitted"
socketIO.on('sendVoltage', on_sendVoltage)
socketIO.wait(seconds=1)
When the sendVoltage message is detected the on_sendVoltage function is executed, the voltage message is emitted, but control is never returned from the emit. The next message comes in, and the next etc.with never a return. At some point, it dies with too many recursive calls.
What am I doing wrong ?
You're calling socketIO.wait_for_callbacks() in the on_sendVoltage function. Your main should instead be something like this:
state = 'waiting'
while state == 'waiting':
self.socket.wait(seconds=1)
That will keep Python running waiting forever but your callbacks will still run. You can change the state in your callbacks if you want to do something else.