DS18B20 PHP w1-gpio

<?php

$address = isset($_GET['address'])?$_GET['address']:null;

header("Access-Control-Allow-Origin: *");
header("Content-type: application/json");

function get_w1_address($address)
{
	$bus_addr = substr($address,0,2).'-';
	for ($i = -4; $i >= -14; $i += -2)
	{
		$bus_addr .= substr($address,$i,2);
	}
	return $bus_addr;
}

function get_w1_temp($address)
{
	$temp_array = array();
	$temp = 9999;

	$sys_sensor_output = file("/sys/bus/w1/devices/$address/w1_slave");
	preg_match('/^.*\s+crc=\S\S\s+(\w+)$/', $sys_sensor_output[0], $temp_array);
	if ($temp_array[1] == 'YES')
	{
		preg_match('/^.*\s+t=(-?\d+)$/', $sys_sensor_output[1], $temp_array);
		$temp = $temp_array[1] / 1000;
	}

	return $temp;
//	return 9999;
}

if ($address)
{
	$bus_addr = get_w1_address($address);
	$count = 0;

	do {
		$temp = get_w1_temp($bus_addr);
		$count++;
	} while ($temp == 9999 && !($count <= 3));

	if ($temp == 9999)
	{
		print "{\"status\":\"fail\", \"payload\":{\"message\":\"failed to read sensor $address - tried 3 times!\"}}";
	} else
	{
		print "{\"status\":\"ok\", \"payload\":{\"tempC\":\"$temp\"}}";
	}
} else
{
	print "{\"status\":\"fail\", \"payload\":{\"message\":\"no address provided\"}}";
}

?>