Python in to the magic mirror.

A Former User · Jan 23, 2019, 3:27 PM

@paulvanderheijden90
Your question contains two independent issues.

First you have to make your own module to display SOMETHING. That is not so difficult if you have some basic knowledge of Javascript, but not so simple to describe all of module development here. You can learn how to develop your module with these docs;

in node_helper.js of your custom module; you can do that like this;

var spawn = require("child_process").spawn;
var process = spawn('python',["YOUR_APPLICATION.py"]);

process.stdout.on('data', function(stdOutput_from_py){
    console.log(stdOutput_from_py);
  // do your job with stdOutput from your python program.
  // Usually, you will send this value to module with `.sendSocektNotification()`
});

You can catch the value with .socketNotificationReceived() in your module.

paulvanderheijden90 · Jan 23, 2019, 3:09 PM

@sean
Again Thank you very much for this information. Im getting there with the code and learning bij Trail and Error ;)
I have made my own working module but still had some Questions.

The .py project is in the map src/ How do I fill in that it is there? Ore is this enough ?
var process = spawn(‘python’,[“P2000Raw.py”]);
Do I need to run the Python project aswell ? or is then node_helper.js running it ?
I made this in the module but is looks like it is not working… :(
I add this to my code to test. it is seems to work. Can you please check if this stdout is ok?

A Former User · Jan 23, 2019, 3:29 PM

@paulvanderheijden90

Try absolute path of your target py script.
When your child_process.spawn is called, python script will be executed.
Well, node_helper.js is also needed.
3-1. Add your module into your config.js either.
When your python script is executed on the shell, normal stdout will be printed out on the shell.

paulvanderheijden90 · Jan 23, 2019, 3:47 PM

@sean
1.Try absolute path of your target py script.
( Oke I add the Path )

2.When your child_process.spawn is called, python script will be executed.
( oke that’s Clear.)

3 Well, node_helper.js is also needed. (* the codeYou send me I add in the node_helper.js.
3-1. Add your module into your config.js either. ( Yes I did. The example you send me was working. )
I can print something on the magic mirror on my own build Module.

4 When your python script is executed on the shell, normal stdout will be printed out on the shell.
( Yes this is working wenn I executed on the shell it will print what I give in so that site wil look fine.

So thank you for the answers. Im almost sure the Python project is oke. because it wil “print” thrue the sys.stdout.write function.
This is the Node_helper.js . I think this is fine aswell.

This is the MMM_. Module. im not sure I did this one oke.

And ofcourse I add the config. file.

Can you Please have a look what is going wrong because my magic mirror is now black and I can only restart bij ctrl alt del. so please help.

A Former User · Jan 23, 2019, 4:31 PM

@paulvanderheijden90
Your node_helper.js is not correct.

See other’s module as reference.

Or you can get a hint of executing python script in node_helper.js
https://github.com/eouia/MMM-GroveGestures/blob/master/node_helper.js
(I’m using PythonShell instead child_process in that module.)

sdetweil · Jan 23, 2019, 5:36 PM

@paulvanderheijden90 start the mirror in developer mode

npm start dev

and look at the console tab for errors (red text)

now in your node_helper spawn data.on() routine, you need to add a sendSocketNotification(:I_DID", some_data) to get the info to the Module.js socketNotificationReceived() method so you can do something to display it (call updateDom(), which will schedule a call to getDom()

paulvanderheijden90 · Jan 24, 2019, 11:25 AM

@sean said in Python in to the magic mirror.:

@paulvanderheijden90
Your node_helper.js is not correct.

Hello Sean,
Why is it wrong? I copy it from your post earlier.
I started in Dev mode. I noticed that wenn I add the Node_helper.js module in the MMM-P2000 map the Magic mirror crashes and give only black screen.
I studyed the Node_helper file. I see in the first line you define the function and in the second line you define the settings for that function. So that’s clear to me. In the next lines you define the stdout of the process and copy it in de Console Log. so that’s also clear for me. So I down’t know why is it not working and crashes.

I made in the same map ( home/pi/src/ ) a file called test.py Here I defined a string and I write the string to the stdout so as you say before the python project don’t need a separate call. So that should work as well.

Node_helper.js:

Python project:

I also getting in to the module setup so I changed the MMM-P2000.js and I think it is oke like this.
First the start function restart every 1000mS the dom function.
then the getdom Function is now showing the test “Hello World” in the module
so that should be oke aswell. I

How do I need to link the socked notification message to the Module string?

sdetweil · Jan 24, 2019, 11:46 AM

@paulvanderheijden90 node helper needs to look like this
see the doc here https://github.com/MichMich/MagicMirror/tree/master/modules#the-node-helper-node_helperjs

const NodeHelper = require('node_helper');

// any other imports (javascript require)

module.exports = NodeHelper.create({
   // local variables 
    self: 0,
		pins_loaded:[],
		pin_index:0,
		results:{},
		using_chartjs: true,
		suspended: false,
		timer:null,

    start: function() {
        console.log("Starting module: " + this.name);
        self = this;
    },
 socketNotificationReceived: function(notification, payload) {
        // usually the module send the config data down to the node_helper
        if (notification === 'CONFIG') {
            this.config = payload;
        }

// any other functions, u need, note, after each function is a ',' (comma)
}
});

A Former User · Jan 24, 2019, 12:22 PM

node_helper.js is helper script of your module to use various features of NodeJS. your main module script(MMM-P2000.js) is just front-end javascript on Browser(Electron/Chromium). So when you need more features which are not supported on browser level, use node_helper.js

MMM-P2000.js and node_helper.js can communicate with each other by socketNotification.

you need to make proper node_helper.js which could be used in MM framework.

Usual format is

var NodeHelper = require("node_helper")

module.exports = NodeHelper.create({
  start: function() {
    // ...
  },
  socketNotificationReceived: function(notification, payload) {
    // ...
  },
})

There are two entry points in node_helper.js from your main module .

start will be called when MM is executed and your module is loaded. Usually you can prepare things here.

socektNotificationReceived will be called when your main module send socketNotification with sendSocketNotification.

With this, you can transfer config values, specific datas or order to do something.

Your current MMM-P2000.js is not so good to use. I recommend you continue to read my https://forum.magicmirror.builders/topic/8534/head-first-developing-mm-module-for-extreme-beginners more.

paulvanderheijden90 · Jan 24, 2019, 1:07 PM

I changed the Node_helper.js:

But the minute I run the Start dev I get white screens. so im not able to debug anything.
Can I get a hand ?