Python in to the magic mirror.

[paulvanderheijden90]

Hello,
I heave a raspberry running with python and a magic mirror modules.
In the python project I heave a string variable that I want to display in a line of the mirror.
I m a little bit of noob with all this and im learning bit by bit.

Can anyone tell me how to do this. what I need to program in the python code and what I need to use for module.

Please let me know.

[A Former User]

@paulvanderheijden90
If possible, Instead image, post code itself.
Anyway, You’d better to read docs more carefully.

MMM-P2000.js

/// MMM-P2000.js

Module.register("MMM-P2000", {
  getDom: function() {
    var e = document.createElement("div")
    e.id = "DISPLAY"
    return e
  },
  notificationReceived: function(notification, payload, sender) {
    switch(notification) {
      case "DOM_OBJECTS_CREATED":
        var timer = setInterval(()=>{
          this.sendSocketNotification("GIVE_ME_DATA")
        }, 1000)
        break
    }
  },
  socketNotificationReceived: function(notification, payload) {
    switch(notification) {
      case "HERE_IS_DATA":
        var e = document.getElementById("DISPLAY")
        e.innerHTML = payload
        break
    }
  },
})

node_helper.js

/// node_helper.js
const spawn = require("child_process").spawn
var NodeHelper = require("node_helper")

module.exports = NodeHelper.create({
  socketNotificationReceived: function(notification, payload) {
    switch(notification) {
      case "GIVE_ME_DATA":
        this.job()
        break
    }
  },
  job: function() {
    var process = spawn("python", ["/home/pi/src/test.py"])
    process.stdout.on("data", (data)=>{
      console.log(data)
      this.sendSocketNotification("HERE_IS_DATA", data)
    })
  }
})

I didn’t test. I wrote this code with only my brain. so there could be errors, but you can catch the concept.

[A Former User]

@paulvanderheijden90
https://nodejs.org/api/child_process.html
https://medium.freecodecamp.org/node-js-child-processes-everything-you-need-to-know-e69498fe970a

You can get standard output(and standard error) from your python script by spawn of nodeJS.

[paulvanderheijden90]

@Sean
Hello Sean,
Thank you very much for your replay. But can you be more specific over the module I need to use?
And how to fit in the variable in the magic mirror Module

[A Former User]

@paulvanderheijden90
Your question contains two independent issues.

1. 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;

• https://github.com/MichMich/MagicMirror/blob/master/modules/README.md
• https://forum.magicmirror.builders/topic/8534/head-first-developing-mm-module-for-extreme-beginners

2. 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]

@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.

1. 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”]);

2. Do I need to run the Python project aswell ? or is then node_helper.js running it ?

3. I made this in the module but is looks like it is not working… :(
   

4. 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]

@paulvanderheijden90

1. Try absolute path of your target py script.

2. When your child_process.spawn is called, python script will be executed.

3. Well, node_helper.js is also needed.
   3-1. Add your module into your config.js either.

4. When your python script is executed on the shell, normal stdout will be printed out on the shell.

[paulvanderheijden90]

@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]

@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]

@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]

@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]

@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]

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]

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 ?

[sdetweil]

the spawn stuff needs to be INSIDE the node helper…

probably called in Start or in the socketNotificationReceived, when the config is sent down from the module…

[paulvanderheijden90]

@sdetweil Thank you for you’re information.
I changed it like you said but unfortunly still get the With screens.

[A Former User]

@paulvanderheijden90
If possible, Instead image, post code itself.
Anyway, You’d better to read docs more carefully.

MMM-P2000.js

/// MMM-P2000.js

Module.register("MMM-P2000", {
  getDom: function() {
    var e = document.createElement("div")
    e.id = "DISPLAY"
    return e
  },
  notificationReceived: function(notification, payload, sender) {
    switch(notification) {
      case "DOM_OBJECTS_CREATED":
        var timer = setInterval(()=>{
          this.sendSocketNotification("GIVE_ME_DATA")
        }, 1000)
        break
    }
  },
  socketNotificationReceived: function(notification, payload) {
    switch(notification) {
      case "HERE_IS_DATA":
        var e = document.getElementById("DISPLAY")
        e.innerHTML = payload
        break
    }
  },
})

node_helper.js

/// node_helper.js
const spawn = require("child_process").spawn
var NodeHelper = require("node_helper")

module.exports = NodeHelper.create({
  socketNotificationReceived: function(notification, payload) {
    switch(notification) {
      case "GIVE_ME_DATA":
        this.job()
        break
    }
  },
  job: function() {
    var process = spawn("python", ["/home/pi/src/test.py"])
    process.stdout.on("data", (data)=>{
      console.log(data)
      this.sendSocketNotification("HERE_IS_DATA", data)
    })
  }
})

I didn’t test. I wrote this code with only my brain. so there could be errors, but you can catch the concept.

[paulvanderheijden90]

@Sean Thank you very much im going to check the code and see if I can implement it in the magic mirror.
Thank you I will let you know

[paulvanderheijden90]

@sean
Hello Sean, Again thank you very much for you’re valued help!.

I spend yesterday after midday and evening with a friend figure out how you’re code is working. and we did some tests to send also somthing back to the Node helper and alote came clear by you’re example.
So realy thank u very much.

To day I spend my morning figure out one last problem the text on the screen is [ Object ArrayBuffer] and not the string I put true the stdout.write.
The text that is displayed on the screen is :

I did some debugging of my own. and wenn I override the data in the node helper just after it come from the spawn function this is displayed on the mirror. so the code is working until the spawn function.

/// node_helper.js

const spawn = require("child_process").spawn

var NodeHelper = require("node_helper")



module.exports = NodeHelper.create({

  socketNotificationReceived: function(notification, payload) {

    switch(notification) {

      case "GIVE_ME_DATA":

        this.job()

        break

    }

  },

  job: function() {

    var process = spawn("python", ["/home/pi/src/test.py"])

    process.stdout.on("data", (data)=>{
	data= "test hello World"
      console.log(data)

      this.sendSocketNotification("HERE_IS_DATA", data)

    })

  }

})

So i tested also the python test project. and wenn I run it in the terminal it give no error. so the python project is fine aswell I think.

import sys


sys.stdout.write("Hallo Ik ben Paul")

So I think the spawn function is not correct at this time?
Can you help me out one more time please?

[A Former User]

@paulvanderheijden90 said in Python in to the magic mirror.:

Object ArrayBuffer

is one of javascript Object type. not text itself. (Sorry for my prior example. it needs to be converted from Object to HTMLText.)

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer

process.stdout.on("data", (data)=>{
  console.log(data) 
  // You can see the structure of this `data` object(ArrayBuffer) on the shell terminal.

  var result = String.fromCharCode.apply(null, new Uint16Array((data))
  // You need to convert or filter or manipulate `data` object whatever for your real usage.

  this.sendSocketNotification("HERE_IS_DATA", result)
 })

[paulvanderheijden90]

@Sean Hello Sean,
I was thinking somting was wrong because I see the buffer printing in the terminal showing:

Buffer 48 61 6c 6c 6f 20 49 6b 20 62 65 6e 20 50 61 75 6c>

i was trying to figure out the text line that it was representing but it was not showing something.

So im happy you came up with the solution for the buffer.

Unfortunly wenn at the var result code the magic mirror is crashing again and im not able to debug.
Can you please heave a look at it

/// node_helper.js

const spawn = require("child_process").spawn

var NodeHelper = require("node_helper")



module.exports = NodeHelper.create({

  socketNotificationReceived: function(notification, payload) {

    switch(notification) {

      case "GIVE_ME_DATA":

        this.job()

        break

    }

  },

  job: function() {

    var process = spawn("python", ["/home/pi/src/test.py"])

    process.stdout.on("data", (data)=>{
	
      console.log(data)

      var result = String.fromCharCode.apply(null, new Uint16Array((data))

      this.sendSocketNotification("HERE_IS_DATA", result)

    })

  }