Hi,
A few weeks ago I started looking into getting notifications onto the mirror from python. Whilst it was relatively straight forward to run python within a shell from the node-helper, I ran into various problems with user privileges and environments.
To get around this I had a play with rabbitmq. Using amqp for the node end and pika for the python. This opens up a whole world of possibilities for my mirror without having to learn javascript (above the basics & plagiarising code snippets from the built in modules) .
node-helper end looks like. Sorry it’s a bit messy & I went overboard on the error capture.
var amqp = require("amqplib/callback_api");
PStart: function starter() {
const self = this;
amqp.connect("amqp://localhost", function(err, conn) {
if (err) {
console.error("[AMQP]", err.message);
return setTimeout(starter, 1000);
}
conn.on("error", function(err) {
if (err.message !== "Connection closing") {
console.error("[AMQP] conn error", err.message);
}
});
conn.on("close", function() {
console.error("[AMQP] reconnecting");
return setTimeout(starter, 1000);
});
console.log("[AMQP] connected");
amqpConn = conn;
amqpConn.createChannel(function(err, ch) {
if (closeOnErr(err)) return;
ch.on("error", function(err) {
console.error("[AMQP] channel error", err.message);
});
ch.on("close", function() {
console.log("[AMQP] channel closed");
});
ch.prefetch(10);
ch.assertQueue("message", { durable: false }, function(err, _ok) {
if (closeOnErr(err)) return;
ch.consume("message", function(msg) {
try {
var fp = JSON.parse(msg.content.toString());
ch.ack(msg);
} catch (e) {
closeOnErr(e);
}
if (fp[0].data == "data"){
self.sendData({"PlrStat": fp[0].PlrStat, "TrkNxt":fp[0].TrkNext, "Station": fp[0].Station, "Said": fp[0].Said);
} else if (fp[0] == "status") {
console.log("[MMM-Radio]" + fp[0].status);
} else {
console.log("Got something");
console.log(msg);
console.log(fp[0].data);}
})}, { noAck: false });
console.log("Worked");
});
});
} });
function closeOnErr(err) {
if (!err) return false;
console.error("[AMQP] error", err);
amqpConn.close();
this.Pstart();
return true;
}
Python end:
import pika
def to_node(message):
try:
channel.basic_publish(exchange='',
routing_key='message',
body=json.dumps(message))
except Exception:
connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channel = connection.channel()
channel.queue_declare(queue='message')
channel.basic_publish(exchange='',
routing_key='message',
body=json.dumps(message))
The bit in the exception is the initial setup for the connection, it does occasionally time out so re-establish if the publishing doesn’t work.
Some useful tutorials on rabbitmq can be found here
Hope this is a help to some of you who know very little about js & do all the complicated stuff with other languages.
, I’ll ask on the snowboy forum why that might be), but everything else worked.