Custom node require failure

Developing Nodes
1

Hi,

I'm writing a custom node for Node-red (see versions below) but i require other modules/scripts in it.
When i add the require line (see my code) it failes to show up in the node-red brwoser interface. when i comment out the require lines i can see my node.
Ofcorse my node doesn't work as it requires the GPIO package...

What am i doing wrong?

the 'error' code:
26 Jan 12:40:30 - [info] Waiting for missing types to be registered:
26 Jan 12:40:30 - [info] - input-test

My code (JS)

module.exports = function(RED) {

    const CAN = require('mcpreadwrite');
    const SPI = require('spi-device');
	const gpiop = require('rpi-gpio').promise;
	//const gpiop = require('rpi-gpio').promise;


   function INPUTTEST(config) {
        RED.nodes.createNode(this,config);
		//this.on('input', function(msg) {
		//	
		//	this.send(msg);
		//});
		
		gpiop.setup(config.pin, gpiop.DIR_IN, gpiop.EDGE_BOTH);
		gpiop.on('change', function(channel, value) {
			msg.payload = value;			
			this.send(msg);
		});
    }
    RED.nodes.registerType("input-test", INPUTTEST);
}

HTML:

<script type="text/javascript">
    RED.nodes.registerType('input-test',{
        category: 'US_Input',
        color: '#38F6F6',
        defaults: {
			pin: {value:0}
        },        
        outputs:1,
        icon: "serial.png",
        label: "input-test"
    });
</script>

<script type="text/x-red" data-template-name="input-test">
    <div class="form-row">
		<label for="node-input-pin"><i class="icon-tag"></i>Pin</label>
		<input id="node-input-pin">
    </div>
</script>

<script type="text/x-red" data-help-name="input-test">
    <p>Unwritten</p>
</script>

JSON:

{
  "name": "input",
  "version": "1.0.0",
  "description": "Controll the US-Input cart",
  "main": "input.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "mcpreadwrite": "file:../MCP2515-ReadWrite",
    "rpi-gpio": "^2.1.7",
    "spi-device": "^3.1.0"
  },
  "node-red": {
    "nodes": {
      "main": "input.js"
    }
  }
}

NPM version: 6.14.10
Node.jS version: v12.20.1
Node-Red version: v1.2.6
Running on a RPi 3B+: Linux version 5.4.79-v7+ (dom@buildbot) (gcc version 8.4.0 (Ubuntu/Linaro 8.4.0-3ubuntu1))

Edit reason: added OS

2

Are the required modules installed?

If you are able to step debug (e.g. in VScode) the put the keyword debugger before the require.

This might help...

3

Hi steve,

Thanks for your reply.
to the first question: Yes required nodes are installed in the correct place.
I'll have to take a look in the debugger but don't know how it works . (lets find out :slight_smile: )

5

A more immediate step forward would be to wrap your require() statements in a try/catch block to see what error is actually being reported:

try {
   const CAN = require('mcpreadwrite');
   const SPI = require('spi-device');
   const gpiop = require('rpi-gpio').promise;
} catch(err) {
   console.log(err);
   throw err;
}
1 Like