I am currently working at a nodeJS robotics app and i am trying to use sockets.io in order to show some messages and data in browser.
I have the following nodeJS code:
app.get('/', function(req, res){
res.sendfile('index.html');
});
io.on('connection', function(socket){
console.log('A user connected');
socket.on('clientEvent', function(data){
function take_tool() {
while(!take_tool_flag) {
if(fs.existsSync('D:/flag.txt')) {
fs.writeFileSync('D:/input_robot.txt', '-1');
socket.emit('testerEvent', 'Robot is taking the writing tool!');
console.log('Robot is taking the writing tool!');
fs.unlinkSync('D:/flag.txt');
take_tool_flag = true;
}
}
}
function draw_table() {
while(!draw_table_flag && take_tool_flag) {
if(fs.existsSync('D:/flag.txt')) {
fs.writeFileSync('D:/input_robot.txt', '-3');
socket.emit('testerEvent', 'Robot is drawing the table game!');
console.log('Robot is drawing the table game!');
fs.unlinkSync('D:/flag.txt');
draw_table_flag = true;
}
}
}
function game() {
socket.emit('testerEvent', 'A new game has started!');
console.log("A new game has started!");
fs.writeFileSync('D:/input_robot.txt', '-99');
if(!take_tool_flag) { take_tool(); }
if(!draw_table_flag) { draw_table(); }
}
game();
});
socket.on('disconnect', function () {
console.log('A user disconnected');
});
});
http.listen(3000, function(){
console.log('listening on localhost:3000');
});
And then in HTML:
<!DOCTYPE html>
<html>
<head><title>Hello world</title></head>
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io();
socket.on('testerEvent', function(data){document.write(data)});
function start() {
socket.emit('clientEvent', 'Sent an event from the client!');
}
</script>
<body>Hello world
<button onclick="start()">Start</button>
</body>
</html>
When i press the start button from html the first 3 instructions from game(); function are executed:
socket.emit('testerEvent', 'A new game has started!');
console.log("A new game has started!");
fs.writeFileSync('D:/input_robot.txt', '-99');
and i get the message in browser from socket.emit;
Then it enters in take_tool(); function where it waits for 'D:/flag.txt' to be created. When i create this file the execution of take_tool(); continues but i don't get in browser the message from socket.emit. Same thing for draw_table(); function. I receive those messages instead at the end of game(); function execution. I need those messages to be shown in browser in real time not at the end of function execution. What seems to be the problem? Thank you!
