Node-RED: Writing MQTT Messages to MySQL DB with UNIX timestamp

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Old 02-09-2020
Node-RED: Writing MQTT Messages to MySQL DB with UNIX timestamp

First, I want to thank Neo (LOL) for this post from 2018, Node.js and mysql - ER_ACCESS_DENIED_ERROR

I could not get the Node-RED mysql module to work and searched Google until all my links were purple! I kept getting ER_ACCESS_DENIED_ERROR with the right credentials. Nothing on the web was helpful.

Then, I got out of Node-RED and tested using node directly on the command line. Same error. No joy on the net. Google links all purple.

Finally, I found a post by Neo of (Thanks again Neo!! LOL) which solved this problem!


The problem with the Node-RED module for mysql is that it only accepts an int as a port number, but my Ubuntu Linux MySQL configuration requires a socket as the port (a string); for other wayward travelers working on Node-RED, here is a sure-fire way to get MySQL working.

Do not use the Node-RED mysql module (node) or the Node-RED moment module (nodes) in Node-RED directly (you can still install and use for other flows, fo course); but you need to install mysql and moment for node.js as a JS lib, like so:

ubuntu$ npm install mysql
ubuntu$ npm install moment

Then, edit your Node-RED settings.js file:

ubuntu$ cd ~/.node-red
vi settings.js

and add this code:

functionGlobalContext: {
        // whatever you might have had here before
       // add these two libs

Restart Node-RED.

Now, in Node-RED create a (JS) function like this one:

 *   Node-RED MYSQL INSERT using Node.js mysql and moment modules
 *   Neo: 9 Feb 2020
 *   Use as you like.  It's in the public domain! Hope it helps.
 * **************************************************************/

var mysql = global.get("mysql");
var moment = global.get("moment");
var connection = mysql.createConnection({
  host: "localhost",
  user: "YOUR_USER_NAME",
  // Check your Linux server for the exact location
  // of your mysql socket, this is KEY
  port: "/var/run/mysqld/mysqld.sock",

var thetopic;
var thepayload;

// EXTRA:  add a string for your clientid, or get it by adding a clientid to your MQTT topic (or payload)
// I just use "mqtt" for now.
var clientid = "mqtt";
var unixtime = moment().unix();

if(unixtime < 10000)
  unixtime = 99999;

if (msg.topic) {
// some basic topic filtering
  thetopic = msg.topic.replace(/[^a-zA-Z0-9\/ ]/g, "");
} else {
  thetopic = "no_topic";

// some basic string filtering
 thepayload = msg.payload.replace(/[^a-zA-Z0-9\/\. ]/g, "");
 thepayload = "no_payload";

 *  In the INSERT example, I use an IOT table I created as follows, FYI ONLY
 *  mysql> describe neo_iotonoff
 * +----------+------------------+------+-----+---------+----------------+
 * | Field    | Type             | Null | Key | Default | Extra          |
 * +----------+------------------+------+-----+---------+----------------+
 * | id       | int(20) unsigned | NO   | PRI | NULL    | auto_increment |
 * | topic    | varchar(64)      | NO   |     | NULL    |                |
 * | message  | varchar(64)      | NO   |     | NULL    |                |
 * | clientid | varchar(128)     | NO   |     | NULL    |                |
 * | dateline | int(20) unsigned | NO   |     | NULL    |                |
 * +----------+------------------+------+-----+---------+----------------+
 * 5 rows in set (0.00 sec)

// . you should trap all MySQL values inserted for NULL and errors first (as  you like to trap errors)
// and filter all mqtt input to insure DB integrity (no mysql injection)

  "INSERT INTO neo_iotonoff (topic, message,clientid,dateline) VALUES ('" +
    thetopic +
    "','" +
    thepayload +
    "','" +
    clientid +
    "'," +
    unixtime +

  function(err, results, fields) {
// maybe return any mysql error code or results boolean in msg in future
return msg;

In my case, I connected my Node-RED function to an MQTT node for an IOT app using some ESP devices, but of course you can the use return as your app requires:

Node-RED:  Writing MQTT Messages to MySQL DB with UNIX timestamp-screen-shot-2020-02-09-13928-pmjpg

Most interesting to me, I found it very cool that the only solution which worked (that I could find after hours of searching and turning all my links purple), across the net, was one posted on in 2018, two years ago, by that "jack-off-all-trades-master-of-none, systems engineer" Neo guy Smilie LOL


Node.js and mysql - ER_ACCESS_DENIED_ERROR

What does that mean when we search the entire Internet for hours for a solution to a tech problem, with no joy, and we finally find a solution which works, and it was something that we posted years ago?
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