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node-red-nodes/hardware/PiSrf/pisrf.js

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module.exports = function(RED) {
"use strict";
var util = require("util");
var spawn = require('child_process').spawn;
var fs = require('fs');
var gpioCommand = __dirname + '/nrsrf.py';
if (!fs.existsSync("/dev/ttyAMA0")) { // unlikely if not on a Pi
//util.log("Info : Ignoring Raspberry Pi specific node.");
throw "Info : Ignoring Raspberry Pi specific node.";
}
if (!fs.existsSync("/usr/share/doc/python-rpi.gpio")) {
util.log("[rpi-srf] Info : Can't find Pi RPi.GPIO python library.");
throw "Warning : Can't find Pi RPi.GPIO python library.";
}
if (!(1 & parseInt ((fs.statSync(gpioCommand).mode & parseInt ("777", 8)).toString (8)[0]))) {
util.log("[rpi-srf] Error : " + gpioCommand + " needs to be executable.");
throw "Error : " + gpioCommand + " must to be executable.";
}
function PiSrfNode(n) {
RED.nodes.createNode(this, n);
this.pins = n.pins;
var node = this;
if (node.pins !== undefined) {
node.child = spawn(gpioCommand, [node.pins]);
node.running = true;
if (RED.settings.verbose) { node.log("pin: " + node.pins + " :"); }
node.child.stdout.on('data', function(data) {
if (RED.settings.verbose) { node.log("out: " + data + " :"); }
data = data.toString().trim();
if (data.length > 0) {
node.send({topic:"SRF",payload:data});
}
});
node.child.stderr.on('data', function(data) {
if (RED.settings.verbose) { node.log("err: " + data + " :"); }
});
node.child.on('close', function(code) {
if (RED.settings.verbose) { node.log("ret: " + code + " :"); }
node.child = null;
node.running = false;
});
node.child.on('error', function(err) {
if (err.errno === "ENOENT") { node.warn('Command not found'); }
else if (err.errno === "EACCES") { node.warn('Command not executable'); }
else { node.log('error: ' + err); }
});
}
else {
node.error("Invalid GPIO pins: " + node.pin);
}
var wfi = function(done) {
if (!node.running) {
if (RED.settings.verbose) { node.log("end"); }
done();
return;
}
setTimeout(function() { wfi(done); }, 333);
}
node.on("close", function(done) {
if (node.child != null) {
node.child.kill('SIGKILL');
}
wfi(done);
});
}
RED.nodes.registerType("rpi-srf", PiSrfNode);
}