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How do I send information from a MQTT node into a MYSQL database?

I'm trying to recieve data from a MQTT node which I then want to proceed with putting into a MYSQL database. From what I've understood I need to use Javascript to do this, I however can't find any examples of this which will work. Is there anyone who have done this before who could help out? This specifically is about how to make a script in Javascript to send the information from the MQTT broker to a MYSQL database in node red. The question that was suggested as an answer is not specifically for Node Red nor does it offer any answers to my question about using Javascript as a way to achieve what I'm trying to do. The answer to that question was to use Node red but it was to no help with how you should use it.

yeah, you can use any language for sending payload from MQTT to MYSQL.
basically what you can do is set a small node which will subscribe to all the incoming payload and dump it in your MYSQL Db
here is the JS script:-
var mqtt = require('mqtt'); //https://www.npmjs.com/package/mqtt
var Topic = '#'; //subscribe to all topics
var Broker_URL = 'mqtt://MQTT_BROKER_URL';
var Database_URL = 'Database_URL';
var options = {
clientId: 'MyMQTT',
port: 1883,
keepalive : 60
};
var client = mqtt.connect(Broker_URL, options);
client.on('connect', mqtt_connect);
client.on('reconnect', mqtt_reconnect);
client.on('message', mqtt_messsageReceived);
client.on('close', mqtt_close);
function mqtt_connect() {
console.log("Connecting MQTT");
client.subscribe(Topic, mqtt_subscribe);
};
function mqtt_subscribe(err, granted) {
console.log("Subscribed to " + Topic);
if (err) {console.log(err);}
};
function mqtt_reconnect(err) {
console.log("Reconnect MQTT");
if (err) {console.log(err);}
client = mqtt.connect(Broker_URL, options);
};
function after_publish() {
//do nothing
};
//receive a message from MQTT broker
function mqtt_messsageReceived(topic, message, packet) {
var message_str = message.toString(); //convert byte array to string
console.log("message to string", message_str);
message_str = message_str.replace(/\n$/, ''); //remove new line
//message_str = message_str.toString().split("|");
console.log("message to params array",message_str);
//payload syntax: clientID,topic,message
if (message_str.length == 0) {
console.log("Invalid payload");
} else {
insert_message(topic, message_str, packet);
//console.log(message_arr);
}
};
function mqtt_close() {
//console.log("Close MQTT");
};
////////////////////////////////////////////////////
///////////////////// MYSQL ////////////////////////
////////////////////////////////////////////////////
var mysql = require('mysql'); //https://www.npmjs.com/package/mysql
//Create Connection
var connection = mysql.createConnection({
host: Database_URL,
user: "newuser", //DB Username
password: "mypassword", //DB Password
database: "mydb" //DB Name
});
connection.connect(function(err) {
if (err) throw err;
//console.log("Database Connected!");
});
//insert a row into the tbl_messages table
function insert_message(topic, message_str, packet) {
var message_arr = extract_string(message_str); //split a string into an array
var clientID= message_arr[0];
var message = message_arr[1];
var date= new Date();
var sql = "INSERT INTO ?? (??,??,??,??) VALUES (?,?,?,?)";
var params = ['tbl_messages', 'clientID', 'topic', 'message','date', clientID, topic, message, date];
sql = mysql.format(sql, params);
connection.query(sql, function (error, results) {
if (error) throw error;
console.log("Message added: " + message_str);
});
};
//split a string into an array of substrings
function extract_string(message_str) {
var message_arr = message_str.split(","); //convert to array
return message_arr;
};
//count number of delimiters in a string
var delimiter = ",";
function countInstances(message_str) {
var substrings = message_str.split(delimiter);
return substrings.length - 1;
};
Reference:-
https://github.com/karan6190/MQTT-DB-plugin/blob/master/mqttTOmysql.js

You can use any language to send messages from MQTT to MySQL database(or any other).
For example, you can create a separate python service which uses Paho MQTT client and subscribes to all the topics and adds that data to a database when the message is received.
Here is how the code will look like in Python:
def on_message(client, userdata, msg):
topic = msg.topic
payload = msg.payload
# run mysql query using library like MySQLdb
# https://www.tutorialspoint.com/python/python_database_access.htm
topic = '#" #subscribe to all topics
client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.subscribe(topic)
client.connect(mqttserver)
client.loop_forever()

React Native Websocket outside access

Im trying to send an answer to my websocket-server from a component which does not contain the websocket. My Websocket server looks like this:
componentDidMount() {
var ws = new WebSocket('ws:// URL');
ws.onmessage = this.handleMessage.bind(this);
...
}
How can I pass the "var ws" to another class or component. Or is it possible to make the websocket globally accessable?
Thank you very much for any help!

I found a solution with help from this question in stackoverflow:
visit:
React native: Always running component
I created a new class WebsocketController like this:
let instance = null;
class WebsocketController{
constructor() {
if(!instance){
instance = this;
}
this.ws = new WebSocket('ws://URL');
return instance;
}
}
export default WebsocketController
And then in my other class where I need my websocket I just called it like this:
let controller = new WebsocketController();
var ws = controller.ws;
 

websocket connection
keep this code in some file, name it with .js extenstion. ex: websocket.js
var WebSocketServer = require("ws").Server;
var wss = new WebSocketServer({port:8100});
wss.broadcast = function broadcast(msg) {
console.log(msg);
wss.clients.forEach(function each(client) {
client.send(msg);
});
};
wss.on('connection', function connection(ws) {
// Store the remote systems IP address as "remoteIp".
var remoteIp = ws.upgradeReq.connection.remoteAddress;
// Print a log with the IP of the client that connected.
console.log('Connection received: ', remoteIp);
ws.send('You successfully connected to the websocket.');
ws.on('message',wss.broadcast);
});
In your app/website side. create .js file. Ex: client.js
var SERVER_URL = 'ws://127.0.0.1:8100';
var ws;
function connect() {
//alert('connect');
ws = new WebSocket(SERVER_URL, []);
// Set the function to be called when a message is received.
ws.onmessage = handleMessageReceived;
// Set the function to be called when we have connected to the server.
ws.onopen = handleConnected;
// Set the function to be called when an error occurs.
ws.onerror = handleError;
}
function handleMessageReceived(data) {
// Simply call logMessage(), passing the received data.
logMessage(data.data);
}
function handleConnected(data) {
// Create a log message which explains what has happened and includes
// the url we have connected too.
var logMsg = 'Connected to server: ' + data.target.url;
// Add the message to the log.
logMessage(logMsg)
ws.send("hi am raj");
}
function handleError(err) {
// Print the error to the console so we can debug it.
console.log("Error: ", err);
}
function logMessage(msg) {
// $apply() ensures that the elements on the page are updated
// with the new message.
$scope.$apply(function() {
//Append out new message to our message log. The \n means new line.
$scope.messageLog = $scope.messageLog + msg + "\n";
});
}
Please let me know if you face any issue with this code

node.js eventListener not listen

i'm a noob of node.js and i'm following the examples on "Node.js in action".
I've a question about one example :
The following code implements a simple chat server via telnet. When i write a message, the script should send message to all connected client.
var events = require('events');
var net = require('net');
var channel = new events.EventEmitter();
channel.clients = {};
channel.subscriptions = {};
channel.on('join',function(id,client){
this.clients[id] = client;
this.subscriptions[id] = function(senderId,message){
if(id != senderId){
this.clients[id].write(message);
}
};
this.on('broadcast',this.subscriptions);
});
var server = net.createServer(function(client){
var id = client.remoteAddress+':'+client.remotePort;
client.on('connect',function(){
channel.emit('join',id,client);
});
client.on('data',function(data){
data = data.toString();
channel.emit('broadcast',id,data);
});
});
server.listen(8888);
But when i try to connect via telnet and send a message it doesn't work.
Thanks

A couple issues I noticed. See the comments in the code.
var events = require('events');
var net = require('net');
var channel = new events.EventEmitter();
channel.clients = {};
channel.subscriptions = {};
channel.on('join',function(id, client) {
this.clients[id] = client;
this.subscriptions[id] = function(senderId,message) {
if(id != senderId)
this.clients[id].write(message);
};
//added [id] to "this.subscriptions"
//Before you were passing in the object this.subscriptions
//which is not a function. So that would have actually thrown an exception.
this.on('broadcast',this.subscriptions[id]);
});
var server = net.createServer(function(client) {
//This function is called whenever a client connects.
//So there is no "connect" event on the client object.
var id = client.remoteAddress+':'+client.remotePort;
channel.emit('join', id, client);
client.on('data',function(data) {
data = data.toString();
channel.emit('broadcast',id,data);
});
});
server.listen(8888);
Also note: If a client disconnects and another client sends a message then this.clients[id].write(message); will throw an exception. This is because, as of now, you're not listening for the disconnect event and removing clients which are no longer connected. So you'll attempt to write to a client which is no longer connected which will throw an exception. I assume you just haven't gotten there yet, but I wanted to mention it.

calling a socket inside another socket using node.js and socket.io

I am a trying to use socket.io and node.js like this :
The browser sends an event to socket.io, in the data event I call another server to get some data, and I would like to send back a message to the browser using a socket.emit.
This looks like that :
socket.on('ask:refresh', function (socket) {
const net = require("net");
var response = new net.Socket();
response.setTimeout(1000);
response.get_response = function (command, port, host) {
this.connect(port, host, function () {
console.log("Client: Connected to server");
});
this.write(JSON.stringify({ "command": command }))
console.log("Data to server: %s", command);
};
response.on("data", function (data) {
var ret = data.toString();
var tmp_data = JSON.parse(ret.substring(0, ret.length - 1).toString());
var data = new Object();
var date = new Date(tmp_data.STATUS[0].When * 1000 );
data.date = date.toString();
socket.emit('send:refresh', JSON.stringify(data) );
});
response.get_response("version", port, host);
});
};
The thing is that I cannot access "socket.emit" inside response.on.
Could you please explain me how I can put a hand on this ?
Thanks a lot

You appear to be overwriting the actual socket with the one of the callback parameters:
socket.on('ask:refresh', function(socket) {
// socket is different
});
Change the name of your callback variable, and you won't have this problem.

Node.js client and server game using Telnet

I'm trying to create a basic game (only text) using Node.js, and it's 'net' library.
I'm hitting a bit of a wall. I can't seem to figure out how to prompt the user to enter some information, and wait for the user to enter said information.
Here's the code I have so far. It's fairly basic, and will print out 2 lines for you when you run the client, and then hang. It's at that point I want the user to be able to enter information. I'm unsure of a few things here:
1. How do I enable the user to type? (more specifically, is it client or server side)
2. How do I send that data to the server when enter is pressed?
I have read up on some documentation as far as Telnet goes, and it leads me to my last question: is the Telnet module in Node really the right one for this, or is there a better alternative for client/server creation and communication?
Client Code:
var connect = require('net');
var client = connect.connect('80', 'localhost');
console.log('Connection Success!\n\n');
client.on('data', function(data) {
// Log the response from the HTTP server.
console.log('' + data);
}).on('connect', function() {
// Manually write an HTTP request.
//I'm assuming I could send data at this point here, on connect?
}).on('end', function() {
console.log('Disconnected');
});
Server Code:
var net = require('net');
var sockets = [];
function cleanInput(data) {
return data.toString().replace(/(\r\n|\n|\r)/gm,"");
}
function receiveData(socket, data) {
var cleanData = cleanInput(data);
if(cleanData === "quit") {
socket.end('Goodbye!\n');
}
else {
for(var i = 0; i<sockets.length; i++) {
if (sockets[i] !== socket) {
sockets[i].write(data);
}
}
}
}
function closeSocket(socket) {
var i = sockets.indexOf(socket);
if (i != -1) {
sockets.splice(i, 1);
}
}
function newSocket(socket) {
sockets.push(socket);
socket.write('Welcome to the Battleship Server!\n\n');
socket.write('Please enter a username: ');
socket.on('data', function(data) {
receiveData(socket, data);
})
socket.on('end', function() {
closeSocket(socket);
})
}
var server = net.createServer(newSocket);
server.listen(80);
Thanks in advance!

you want to use process.stdin and process.stdout to interact with input/output from/to the terminal. Have a look here.
You can send data to the server when enter is pressed with process.stdin.once('data', function(data){ /* ... */ }). The .once method ensures that the callback is called just once when the user hits enter.
The client code should look like:
var connect = require('net');
var client = connect.connect('80', 'localhost');
client.on('data', function(data) {
console.log('' + data);
process.stdin.once('data', function (chunk) {
client.write(chunk.toString());
});
}).on('connect', function() {
client.write('Hello');
}).on('end', function() {
console.log('Disconnected');
});