hurricanepkt/index.html

## index.html
<!DOCTYPE html>
<html>
<head>
	<style>
		label {
			display: inline-block; width: 100px; height: 20px; float: left; text-align: left;
		}
		input {
			display: inline-block; width: 25%; height: 20px;
		}
		input.value {
			width: 60px;
		}
		input.checkbox {
			width: 20px;
		}
		strong {
			margin-left: 10px;
			height: 20px;
		}
	</style>
</head>
<body>
<h1> Marks Servo</h1>
<label for="servo">Servo</label><input id="servo" type="range" min="0" max="348" value="180"><input id="servo_value" class="value" type="number" min="0" max="348" value="180">
<br />
<span>Real frequency<strong id="real_frequency">0</strong></span>

<script>

	var servo = document.getElementById('servo');
	var servoValue = document.getElementById('servo_value');
	var allFields = [ servo];

	bindRangeChange(servo, servoValue);

	function bindRangeChange(rangeField, numericField) {
		rangeField.addEventListener('change', onRangeChange.bind(rangeField, numericField), false);
		numericField.addEventListener('change', onRangeChange.bind(numericField, rangeField), false);
	}
	function onRangeChange(valueEl) {
		valueEl.value = this.value;
	}


	bindChange(servoValue);

	function bindChange(field) {
		field.addEventListener('change', onChange.bind(field), false);
	}

	function onChange() {
		var id = this.id.replace(/_value$/, '');
		var value = this.value;
		sender(id, value);
	}
	function sender(str, val) {
		var xhr = new XMLHttpRequest();
		xhr.open('GET', ['/set?', str, '=', val].join(''), true);
		xhr.addEventListener('readystatechange', function() {
			if (xhr.readyState === 4) {
				console.log('set:', str, '=', value, '->', 'result:', xhr.responseText);
			}
		}, false);
		xhr.send();
	}

	function initialSettings() {
		sender('active',1);
		sender('delayed',0);
		sender('mode', 'pwm');
		sender('servo_max',360);
		sender('servo',180);
		sender('duty',50);
		sender('frequency',100);
		sender('mcf',16000);
		allFields.forEach(function (field) {
			onChange.call(field);
			bindChange(field);
		});
	}
	initialSettings();
</script>

<script>
	var realFrequency = document.getElementById('real_frequency');

	function connect() {
		var source = new EventSource('/listen');
		var eventName = 'real_frequency';

		source.addEventListener(eventName, function(event) {
			realFrequency.textContent = JSON.parse(event.data)[eventName];
		}, false);

		source.addEventListener('open', function(event) {
			console.log('SSE connection opened');
		}, false);
	}
	connect();
</script>

</body>
</html>

## rpiPwm.js
var fs = require('fs');
var path = require('path');
var basePath = '/sys/class/rpi-pwm/pwm0/';
//var basePath = path.join(__dirname, 'test-pwm0');

function set(object, callback) {
	// code is written only for one key in object!!!
	Object.keys(object).forEach(function(name) {
		var value = object[name] + '';
		fs.writeFile(path.join(basePath, name), value, { encoding: 'ascii' }, function(error) {
			if (error) return console.error(error);
			get(name, callback);
		});
	});
}

function get(name, callback) {
	fs.readFile(path.join(basePath, name), { encoding: 'ascii' }, function(error, data) {
		if (error) return console.error(error);
		var result = {};
		result[name] = data.trim();
		callback(result);
	});
}

module.exports = {
	set: set,
	get: get
};

## server.js
#!/usr/bin/env node
var http = require('http');
var fs = require('fs');
var path = require('path');
var url = require('url');
var query = require('querystring');
var sse = require('./sse');
var rpiPwm = require('./rpiPwm');

var app = http.createServer(function(request, response) {
	var parsedUrl = url.parse(request.url);
	var parsedQuery;
	var listenEvent = 'real_frequency';

	if (parsedUrl.pathname === '/') {
		response.writeHead(200);
		fs.readFile(path.join(__dirname, 'index.html'), function(error, buffer) {
			response.write(buffer);
			response.end();
		});
	}
	else if (parsedUrl.pathname === '/set' && parsedUrl.query) {
		parsedQuery = query.parse(parsedUrl.query);
		console.log('set', parsedQuery);
		rpiPwm.set(parsedQuery, function(result) {
			response.writeHead(200, { 'Content-Type': 'text/json' });
			response.end(JSON.stringify(result));
		});
	}
	else if (parsedUrl.pathname === '/listen') {
		response.connection.setTimeout(1000 * 60 * 20); // max idle 20 min.
		sse.writeHead(request, response, function(request, response) {
			sse.writeDataContinuosly(request, response, listenEvent, rpiPwm.get, 500);
		});
	}
	else if (parsedUrl.pathname === '/end') {
		response.writeHead(200);
		response.end();
		process.nextTick(function() {
			process.exit();
		});
	}
	else {
		response.writeHead(404);
		response.end();
	}
});

app.listen(8080);

## sse.js
function writeHead(request, response, callback) {
	response.writeHead(200, {
		'Content-Type': 'text/event-stream',
		'Cache-Control': 'no-cache',
		'Connection': 'keep-alive'
	});
	response.write('retry: 500\n');
	return callback(request, response);
}

function writeData(request, response, event, data, callback) {
	var id = (new Date().getTime());

	response.write('id: ' + id + '\n');
	response.write('event: ' + event + '\n');
	response.write('data: ' + JSON.stringify(data) + '\n\n');
	if (callback) {
		return callback(request, response);
	}
}

function writeDataContinuosly(request, response, event, fn, interval) {
	var timeoutId;
	var isClosed = false;

	fn(event, function writeResult(result) {
		if (isClosed) return;
		writeData(request, response, event, result, function(request, response) {
			if (isClosed) return;
			timeoutId = setTimeout(fn.bind(null, event, writeResult), interval);
		});
	});

	request.connection.addListener('close', function() {
		isClosed = true;
		if (timeoutId !== undefined) {
			clearInterval(timeoutId);
		}
	});
}

module.exports = {
	writeHead: writeHead,
	writeData: writeData,
	writeDataContinuosly: writeDataContinuosly
};
	<!DOCTYPE html>
	<html>
	<head>
	<style>
	label {
	display: inline-block; width: 100px; height: 20px; float: left; text-align: left;
	}
	input {
	display: inline-block; width: 25%; height: 20px;
	}
	input.value {
	width: 60px;
	}
	input.checkbox {
	width: 20px;
	}
	strong {
	margin-left: 10px;
	height: 20px;
	}
	</style>
	</head>
	<body>
	<h1> Marks Servo</h1>
	<label for="servo">Servo</label><input id="servo" type="range" min="0" max="348" value="180"><input id="servo_value" class="value" type="number" min="0" max="348" value="180">
	<br />
	<span>Real frequency<strong id="real_frequency">0</strong></span>

	<script>

	var servo = document.getElementById('servo');
	var servoValue = document.getElementById('servo_value');
	var allFields = [ servo];

	bindRangeChange(servo, servoValue);

	function bindRangeChange(rangeField, numericField) {
	rangeField.addEventListener('change', onRangeChange.bind(rangeField, numericField), false);
	numericField.addEventListener('change', onRangeChange.bind(numericField, rangeField), false);
	}
	function onRangeChange(valueEl) {
	valueEl.value = this.value;
	}


	bindChange(servoValue);

	function bindChange(field) {
	field.addEventListener('change', onChange.bind(field), false);
	}

	function onChange() {
	var id = this.id.replace(/_value$/, '');
	var value = this.value;
	sender(id, value);
	}
	function sender(str, val) {
	var xhr = new XMLHttpRequest();
	xhr.open('GET', ['/set?', str, '=', val].join(''), true);
	xhr.addEventListener('readystatechange', function() {
	if (xhr.readyState === 4) {
	console.log('set:', str, '=', value, '->', 'result:', xhr.responseText);
	}
	}, false);
	xhr.send();
	}

	function initialSettings() {
	sender('active',1);
	sender('delayed',0);
	sender('mode', 'pwm');
	sender('servo_max',360);
	sender('servo',180);
	sender('duty',50);
	sender('frequency',100);
	sender('mcf',16000);
	allFields.forEach(function (field) {
	onChange.call(field);
	bindChange(field);
	});
	}
	initialSettings();
	</script>

	<script>
	var realFrequency = document.getElementById('real_frequency');

	function connect() {
	var source = new EventSource('/listen');
	var eventName = 'real_frequency';

	source.addEventListener(eventName, function(event) {
	realFrequency.textContent = JSON.parse(event.data)[eventName];
	}, false);

	source.addEventListener('open', function(event) {
	console.log('SSE connection opened');
	}, false);
	}
	connect();
	</script>

	</body>
	</html>
	var fs = require('fs');
	var path = require('path');
	var basePath = '/sys/class/rpi-pwm/pwm0/';
	//var basePath = path.join(__dirname, 'test-pwm0');

	function set(object, callback) {
	// code is written only for one key in object!!!
	Object.keys(object).forEach(function(name) {
	var value = object[name] + '';
	fs.writeFile(path.join(basePath, name), value, { encoding: 'ascii' }, function(error) {
	if (error) return console.error(error);
	get(name, callback);
	});
	});
	}

	function get(name, callback) {
	fs.readFile(path.join(basePath, name), { encoding: 'ascii' }, function(error, data) {
	if (error) return console.error(error);
	var result = {};
	result[name] = data.trim();
	callback(result);
	});
	}

	module.exports = {
	set: set,
	get: get
	};
	#!/usr/bin/env node
	var http = require('http');
	var fs = require('fs');
	var path = require('path');
	var url = require('url');
	var query = require('querystring');
	var sse = require('./sse');
	var rpiPwm = require('./rpiPwm');

	var app = http.createServer(function(request, response) {
	var parsedUrl = url.parse(request.url);
	var parsedQuery;
	var listenEvent = 'real_frequency';

	if (parsedUrl.pathname === '/') {
	response.writeHead(200);
	fs.readFile(path.join(__dirname, 'index.html'), function(error, buffer) {
	response.write(buffer);
	response.end();
	});
	}
	else if (parsedUrl.pathname === '/set' && parsedUrl.query) {
	parsedQuery = query.parse(parsedUrl.query);
	console.log('set', parsedQuery);
	rpiPwm.set(parsedQuery, function(result) {
	response.writeHead(200, { 'Content-Type': 'text/json' });
	response.end(JSON.stringify(result));
	});
	}
	else if (parsedUrl.pathname === '/listen') {
	response.connection.setTimeout(1000 * 60 * 20); // max idle 20 min.
	sse.writeHead(request, response, function(request, response) {
	sse.writeDataContinuosly(request, response, listenEvent, rpiPwm.get, 500);
	});
	}
	else if (parsedUrl.pathname === '/end') {
	response.writeHead(200);
	response.end();
	process.nextTick(function() {
	process.exit();
	});
	}
	else {
	response.writeHead(404);
	response.end();
	}
	});

	app.listen(8080);
	function writeHead(request, response, callback) {
	response.writeHead(200, {
	'Content-Type': 'text/event-stream',
	'Cache-Control': 'no-cache',
	'Connection': 'keep-alive'
	});
	response.write('retry: 500\n');
	return callback(request, response);
	}

	function writeData(request, response, event, data, callback) {
	var id = (new Date().getTime());

	response.write('id: ' + id + '\n');
	response.write('event: ' + event + '\n');
	response.write('data: ' + JSON.stringify(data) + '\n\n');
	if (callback) {
	return callback(request, response);
	}
	}

	function writeDataContinuosly(request, response, event, fn, interval) {
	var timeoutId;
	var isClosed = false;

	fn(event, function writeResult(result) {
	if (isClosed) return;
	writeData(request, response, event, result, function(request, response) {
	if (isClosed) return;
	timeoutId = setTimeout(fn.bind(null, event, writeResult), interval);
	});
	});

	request.connection.addListener('close', function() {
	isClosed = true;
	if (timeoutId !== undefined) {
	clearInterval(timeoutId);
	}
	});
	}

	module.exports = {
	writeHead: writeHead,
	writeData: writeData,
	writeDataContinuosly: writeDataContinuosly
	};