1) basic code for the websocket server.
A) The place for your normal code.
2) replacement for the "repeat for ever" Blockly. This because of the asyncio endless loop.
3) the additional imports.
Used technogies: Python, JSON, HTML5 (XML-technology), sockets.
This examples shows how the communication works only. It is up to you to add the right JSON definitions and the communication with the sensors and actuators.
Have fun and happy new year
- websocketserver01.JPG (106.29 KiB) 2004 mal betrachtet
Program code 1
Code: Alles auswählen
#(c) 2022 C. van Leeuwen
# Code may be used in whole or in part with this copyright notice.
# Only for non-commercial applications.
# [2022-01-02]
print('start')
async def server(websocket, path):
# Get received data from websocket
print("wait for recv")
try:
data = await websocket.recv()
# Send response back to client to acknowledge receiving message
print('server: recv raw=' + data)
except exceptions.ConnectionClosed as e:
print("exception 01 "+str(e.code)+" ",str(e.reason))
else:
try:
respondsData=""
mesg1=json.loads(data) #From JSON to Python format
#mesg=json.dumps(data)
#mesg=json.dumps(data, indent=4)
#respondsData=mesg
#From JSON to Python dictionary format
dictP=eval(data)
print(" ="+ str(dictP))
t=dictP['actuators']
print(" ="+ str(dictP['actuators']))
tt=dictP['actuators']
print(" ="+str(tt[0]))
print(" ="+str(tt[1]))
#print(" ="+str(tt[1]['M']['p'][2]))
print(" ="+str(tt[1]['S'][2]))
print(" ="+str(tt[2]))
respondsData=json.dumps(mesg1)
except JSONDecodeError as e:
respondsData="no JSON format "+e.msg+ " pos="+str(e.pos)+" doc="+e.doc
try:
#await websocket.send("msg Thanks for your message: " +respondsData)
await websocket.send( respondsData)
print("server: send data="+respondsData)
except exceptions.ConnectionClosed:
print("exception 02")
try:
await server( websocket, path)
# print("try empty")
except exceptions.ConnectionClosed:
print("exception 03")
print('test1')
# Create websocket server 0.0.0.0 open for external acces, localhost only local
start_server = serve(server, "0.0.0.0", 8085, ssl=None)
print('test2')
# Start and run websocket server forever
loop=asyncio.get_event_loop()
loop.run_until_complete(start_server)
print('test3A')
Code: Alles auswählen
#(c) 2022 C. van Leeuwen
# Code may be used in whole or in part with this copyright notice.
# Only for non-commercial applications.
# [2022-01-02]
print('test3B')
# this repplace the normal repeat endless loop from the Blockly,
# which is not asyncio
loop.run_forever()
print('test4')
Program code 3
Code: Alles auswählen
import asyncio
import time
import subprocess
from json import JSONDecodeError
import json
#from lib.controller import *
from websockets import serve, exceptions
Don't forget to replace the IP-address 192.168.20.175 with the actual IP-address of your TXT4.0!!
[2022-01-02 22:45, updated]
Code: Alles auswählen
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<!--(c) 2022 C. van Leeuwen Enschede -->
<head>
<title>Test</title>
<script type='text/javascript' language="javascript">
<!--
var connection;
var keepAlive = false;
var printError = function(error, explicit) {
console.log(`[${explicit ? 'EXPLICIT' : 'INEXPLICIT'}] ${error.name}: ${error.message}`);
}
const jj= '{"actuators":[{"M":{"i":1,"p":[0,0,214,214]}},{"M":{"i":2,"p":[0,0,214,214]}},{"M":{"i":3,"p":[0,0,214,214]}}]}';
const j={"actuators":[{"M":{"i":1,"p":[0,0,214,214]}},{"S":[0, 6,512]},{"firstName":"Peter","lastName":"Jones"}]};
//const j= {"actuators":[{"M":{"i":1,"p":[0,0,214,214]}},{"M":{"i":2,"p":[0,0,214,214]}},{"M":{"i":3,"p":[0,0,214,214]}}]};
function sendButton1(par1,par2){
//parameters not is use for the moment
myJSON=JSON.stringify(j);// to a JSON object
document.getElementById('msg').innerHTML="Not yet send";
console.log('sendButton1: ' + myJSON );
if (typeof connection === 'undefined'){
console.log('Server: connection is undefined');
}else {
if (connection.readyState === WebSocket.OPEN){
connection.send(myJSON);
} else {
console.log('Server: connection closed, state='+connection.readyState);
}
} }
function sendButton2(par1,par2){
//parameters not is use for the moment
myJSON=JSON.stringify(j);// to a JSON object
document.getElementById('msg').innerHTML="Not yet send";
console.log('sendButton2: ' + myJSON );
if (typeof connection === 'undefined'){
console.log('Server: connection is undefined');
}else {
if (connection.readyState === WebSocket.OPEN){
connection.send(myJSON);
} else {
console.log('Server: connection closed, state='+connection.readyState);
}
}
}
function sendButton3(par1,par2){
//parameters not is use for the moment
myJSON=JSON.stringify(j);// to a JSON object
document.getElementById('msg').innerHTML="Not yet send";
console.log('sendButton3: ' + myJSON );
if (typeof connection === 'undefined'){
console.log('Server: connection is undefined');
}else {
if (connection.readyState === WebSocket.OPEN){
connection.send(myJSON);
} else {
console.log('Server: connection closed, state='+connection.readyState);
}
} }
function load() {
connection = new WebSocket("ws://192.168.20.175:8085/");
connection.onopen = function () {
//var send = "init " + Math.round(Math.random()*4294967294+1);
console.log('Client: connection with server has been created' );
document.getElementById('msg').innerHTML="Client: connection with server has been created";
};
connection.onclose = () => {
console.log('WebSocket connectionhas been closed');
document.getElementById('msg').innerHTML="WebSocket connectionhas been closed";
};
connection.onerror = function (error) {
keepAlive = false;
connection.close();
console.log('WebSocket error: ' + error);
alert("WebSocket error: "+ error);
};
connection.onmessage = function (e) {
console.log('Message: ' + e.data);
var msgStr = document.getElementById('msg');
try{
var objJ=JSON.parse(e.data);
var tt=objJ.actuators[1].S;//tt=objJ.actuators[1].S[1];
msgStr.innerHTML ="<strong>Data received: </strong><br/>"+ e.data+" <br/><br/><b>JSON object:</b><br> "+JSON.stringify(objJ) +" <br><br><b>JSON object selection:</b><br>"+JSON.stringify(tt);
}catch(ex){
if (ex instanceof SyntaxError) {
printError(ex, true);
msgStr.innerHTML = "Exception: Parse syntax error, data received=<br/>"+ e.data;
} else {
printError(ex, false);
msgStr.innerHTML = "Exception: No parse error, data received=<br/>"+ e.data;
}
}
};
}
//-->
</script>
</head>
/<!-- <body onload="load()"> -->
<body>
<input type="button" onclick="load();" value="Open websocket server"></button>
<input type="button" onclick="connection.close();" value="Close websocket server"></button>
<input type="button" onclick="sendButton1('msg A','10');" value="msg 1"></button>
<input type="button" onclick="sendButton2('msg B','10');" value="msg 2"></button>
<input type="button" onclick="sendButton3('msg C','10');" value="msg 3"></button>
<input type="button" onclick="connection.send('msg D');" value="msg 4"></button>
<br/>
<p id="msg"></p>
</body>
</html>
