Executing python in js - troublshooting/development

beejay22

Hi. I’m very new to coding and I have a pyscript that simply prints out the latest titles from a website using BeautifulSoup. However, when I launch magic mirror it’s just a black screen. I deleted all other modules besides my own in the config file so that it’s just my module that runs. I’ve done ample research and can’t seem to figure out what’s going on (updated mm software, reinstalled dependencies in the css directory just in case it wasn’t installed correctly, checked to see node was up to date - v10.21.0, etc.). I’m starting to think it may be my pyscript but it runs correctly in the console (I can attach my pyscript if needed). I’m not sure what the problem is so I appreciate any and all help!

Core module: MMM-Whitehouse

Module.register("MMM-Whitehouse", {
  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

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/Desktop/realTester.py"])
    process.stdout.on("data", (data)=>{
      console.log(data)
      var result = String.fromCharCode.apply(null, new Uint16Array((data)))
      this.sendSocketNotification("HERE_IS_DATA", data)
    })
  }
})

config.js

var config = {
	address: "localhost", // Address to listen on, can be:
	                      // - "localhost", "127.0.0.1", "::1" to listen on loopback interface
	                      // - another specific IPv4/6 to listen on a specific interface
	                      // - "0.0.0.0", "::" to listen on any interface
	                      // Default, when address config is left out or empty, is "localhost"
	port: 8080,
	ipWhitelist: ["127.0.0.1", "::ffff:127.0.0.1", "::1"], // Set [] to allow all IP addresses
	                                                       // or add a specific IPv4 of 192.168.1.5 :
	                                                       // ["127.0.0.1", "::ffff:127.0.0.1", "::1", "::ffff:192.168.1.5"],
	                                                       // or IPv4 range of 192.168.3.0 --> 192.168.3.15 use CIDR format :
	                                                       // ["127.0.0.1", "::ffff:127.0.0.1", "::1", "::ffff:192.168.3.0/28"],

	useHttps: false, 		// Support HTTPS or not, default "false" will use HTTP
	httpsPrivateKey: "", 	// HTTPS private key path, only require when useHttps is true
	httpsCertificate: "", 	// HTTPS Certificate path, only require when useHttps is true

	language: "en",
	timeFormat: 24,
	units: "metric",
	// serverOnly:  true/false/"local" ,
			     // local for armv6l processors, default
			     //   starts serveronly and then starts chrome browser
			     // false, default for all  NON-armv6l devices
			     // true, force serveronly mode, because you want to.. no UI on this device

	modules: [
		{
 			module: "MMM-Whitehouse",
 			position: "top_left",
  			config: {}
		},
	]

};

/*************** DO NOT EDIT THE LINE BELOW ***************/
if (typeof module !== "undefined") {module.exports = config;}

Error message (from dev mode):

Initializing MagicMirror.
translator.js:202 Loading core translation file: translations/en.json
translator.js:225 Loading core translation fallback file: translations/en.json
loader.js:179 Load script: modules/MMM-Whitehouse//MMM-Whitehouse.js
module.js:479 Module registered: MMM-Whitehouse
loader.js:150 Bootstrapping module: MMM-Whitehouse
loader.js:155 Scripts loaded for: MMM-Whitehouse
loader.js:157 Styles loaded for: MMM-Whitehouse
loader.js:159 Translations loaded for: MMM-Whitehouse
loader.js:194 Load stylesheet: css/custom.css
(index):1 Refused to apply style from 'http://localhost:8080/css/custom.css' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.
loader.js:203 Error on loading stylesheet: css/custom.css
module.js:46 Starting module: MMM-Whitehouse
main.js:474 All modules started!
/home/pi/MagicMirror…rity-warnings.js:95 Electron Security Warning (Insecure Resources) This renderer process loads resources using insecure
  protocols.This exposes users of this app to unnecessary security risks.
  Consider loading the following resources over HTTPS or FTPS. 
 - http://localhost:8080/css/main.css
- http://localhost:8080/fonts/roboto.css
- http://localhost:8080/socket.io/socket.io.js
- http://localhost:8080/vendor/node_modules/nunjucks/browser/nunjucks.min.js
- http://localhost:8080/js/defaults.js
- http://localhost:8080/config/config.js
- http://localhost:8080/vendor/vendor.js
- http://localhost:8080/modules/default/defaultmodules.js
- http://localhost:8080/js/logger.js
- http://localhost:8080/translations/translations.js
- http://localhost:8080/js/translator.js
- http://localhost:8080/js/class.js
- http://localhost:8080/js/module.js
- http://localhost:8080/js/loader.js
- http://localhost:8080/js/socketclient.js
- http://localhost:8080/js/main.js
- http://localhost:8080/fonts/node_modules/roboto-fontface/fonts/roboto-condensed/Roboto-Condensed-Regular.woff2
- http://localhost:8080/translations/en.json
- http://localhost:8080/translations/en.json
- http://localhost:8080/modules/MMM-Whitehouse//MMM-Whitehouse.js
  
 
For more information and help, consult
https://electronjs.org/docs/tutorial/security.
 This warning will not show up
once the app is packaged.
/home/pi/MagicMirror…ity-warnings.js:145 Electron Security Warning (Insecure Content-Security-Policy) This renderer process has either no Content Security
    Policy set or a policy with "unsafe-eval" enabled. This exposes users of
    this app to unnecessary security risks.
 
For more information and help, consult
https://electronjs.org/docs/tutorial/security.
 This warning will not show up
once the app is packaged.
(index):1 Refused to apply style from 'http://localhost:8080/css/custom.css' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

sdetweil

@beejay22 I copy/pasted your code, and only see a black screen cause there is nothing to display…

there is a bug in the node_helper

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":
        console.log("received notification")
        this.job()
        break
    }
  },
  job: function() {

    // type A, you specify the pgm to execute your script HERE
    var process = spawn("python",["/home/sam/Desktop/realTester.py"])

    // type B, you specify the pgm to execute your script IN the script.
    var process = spawn("/home/sam/Desktop/realTester.py")

    process.stdout.on("data", (data)=>{
      console.log(data)
      var result = String.fromCharCode.apply(null, new Uint16Array((data)))   // < --- you processed data to result
      this.sendSocketNotification("HERE_IS_DATA", data)    // < ---- then sent data, which is still a 'buffer'
    })
  }
})

i fixed to this

onst spawn = require("child_process").spawn
var NodeHelper = require("node_helper")

module.exports = NodeHelper.create({
  socketNotificationReceived: function(notification, payload) {
    switch(notification) {
      case "GIVE_ME_DATA":
        console.log("received notification")
        this.job()
        break
    }
  },
  job: function() {

    // type A, you specify the pgm to execute your script HERE
    var process = spawn("python",["/home/sam/Desktop/realTester.py"])

    // type B, you specify the pgm to execute your script IN the script.
   //  I prefer this , before u needed two things, python and the script..
   // but if u changed the script to bash, or java, or whatever, then the app would break..
    var process = spawn("/home/sam/Desktop/realTester.py")

    process.stdout.on("data", (data)=>{
      console.log(data.toString()) // debugging, log string     
      //var result = String.fromCharCode.apply(null, new Uint16Array((data)))
      this.sendSocketNotification("HERE_IS_DATA", data.toString())   // pass the string, module expects string
    })
  }
})

the script for example is

#!/usr/bin/python3 

print("hello");

beejay22

Thanks for the insightful reply! I changed my node_helper to what you posted:

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":
        console.log("received notification")
        this.job()
        break
    }
  },
  job: function(){
    var process = spawn("/home/pi/Desktop/realTester.py")
    process.stdout.on("data", (data)=>{
      console.log(data.toString())    
      this.sendSocketNotification("HERE_IS_DATA", data.toString())
    })
  }
})

However, when I changed it I got an error message in the terminal which hasn’t happened before. Error message in terminal:

[2020-08-23 22:36:26.161] [ERROR]  Error: spawn /home/pi/Desktop/testing.py EACCES
    at Process.ChildProcess._handle.onexit (internal/child_process.js:264:19)
    at onErrorNT (internal/child_process.js:456:16)
    at processTicksAndRejections (internal/process/task_queues.js:84:9) {
  errno: 'EACCES',
  code: 'EACCES',
  syscall: 'spawn /home/pi/Desktop/realTester.py',
  path: '/home/pi/Desktop/realTester.py',
  spawnargs: []
}
[2020-08-23 22:36:26.171] [LOG]    MagicMirror will not quit, but it might be a good idea to check why this happened. Maybe no internet connection?
[2020-08-23 22:36:26.172] [LOG]    If you think this really is an issue, please open an issue on GitHub: https://github.com/MichMich/MagicMirror/issues
[2020-08-23 22:36:27.069] [LOG]    received notification
[2020-08-23 22:36:27.094] [LOG]    Whoops! There was an uncaught exception...

Still getting the same error log in the magic mirror using dev mode though… lastly this is my pyscript, realTester.py:

from bs4 import BeautifulSoup                                             
import requests                                                           

url=requests.get("https://www.whitehouse.gov/presidential-actions/")      
src=url.content                                                           
soup = BeautifulSoup(src, 'lxml')
for h2_tag in soup.findAll('h2'):
    a_tag = h2_tag.find('a')
    print(a_tag.string)

sdetweil

@beejay22 sorry

2more things.

u need to add the 1st line to the script to tell the system what processor to use

#!/usr/bin/python

u need to make the script executable

chmod +x /home/pi/Desktop/realTester.py

beejay22

Okay so now my pycript looks like this:

#!/usr/bin/python
from bs4 import BeautifulSoup                                             
import requests                                                           

url=requests.get("https://www.whitehouse.gov/presidential-actions/")      
src=url.content                                                           
soup = BeautifulSoup(src, 'lxml')
for h2_tag in soup.findAll('h2'):
    a_tag = h2_tag.find('a')
    print(a_tag.string)

If I’m my understanding correctly, adding this shebang line lets shell know that my src code is a script, the type of interpreter we want to use and the path of said interpreter…

Also am I suppose to execute chmod +x /home/pi/Desktop/realTester.py in shell? If so how and when… sorry I’m still trying to understand how exactly to do all of this

sdetweil

@beejay22 yes, you need to execute the chmod command once, to mark the python script as executable. do this on a terminal window, or ssh session window

ANY file in Linux can be executable.

if you try to spawn/exec a file which does not have the execute permission set, u get the access error. it is not even opened.

once the bit is set, then it is searched for the shebang, if present the identified file is exec’d and the rest of the parms are passed on.

beejay22

Hmmm I did this in the terminal:
$ chmod +x /home/pi/Desktop/realTester.py

Nothing changed… still the same error log message… I think there’s something wrong with my custom’s css file since it says it’s not loading… in my css folder there’s only a main.css file there

sdetweil

@beejay22 so, can u run the script from the terminal like before

python /home/pi/Desktop/realTester.py
and then /home/pi/Desktop/realTester.py

both should work, produce the same results
that $ wasn’t part of the chmod

beejay22

I didn’t add the $ to the command, I just said that in my post for clarity lol. I typed just this in the command line:
chmod +x /home/pi/Desktop/realTester.py

And yes I can run my script in the terminal with “python3 /home/pi/Desktop/realTester.py” but not with “/home/pi/Desktop/realTester.py” because the module I’m using in my script includes bs4 which is available with python3 I believe so I have to say python3

I also tried ‘touch ~/MagicMirror/css/custom.css’, still showing same error log

sdetweil

@beejay22 u can run python3 as the shebang. I was just giving example

your node_helper code was spawning python, not python3. I just copied what u did. u can put python3 in the spawn as well

custom.css, doesn’t matter, it’s empty so no harm

beejay22

Tried this (all I changed was “python” to “python3”):

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("python3", ["/home/pi/Desktop/realTester.py"])
    process.stdout.on("data", (data)=>{
      console.log(data)
      var result = String.fromCharCode.apply(null, new Uint16Array((data)))
      this.sendSocketNotification("HERE_IS_DATA", data)
    })
  }
})

And also changed pyscript to this (just added python3 to the shebang):

#!/usr/bin/python3
from bs4 import BeautifulSoup                                             
import requests                                                           

url=requests.get("https://www.whitehouse.gov/presidential-actions/")      
src=url.content                                                           
soup = BeautifulSoup(src, 'lxml')
for h2_tag in soup.findAll('h2'):
    a_tag = h2_tag.find('a')
    print(a_tag.string)

Also tested “python” again (not python3) in my node_helper along with the updated shebang as shown above

If custom.css file doesn’t matter I wonder why it’s giving this error… Have no clue what’s going on now lol

sdetweil

@beejay22 u need the fix for the data conversion… as well…

custom.css cause its a file t=hat MM force loads, and while the browser is unhappy (thus the error), the MM runtime doesn’t care WHY there was no data, missing file, empty file, don’t care there were no css updates…

i don’t do python so I can’t help much…

but you gotta put in the fixes I gave you for data…

  process.stdout.on("data", (data)=>{
      console.log(data.toString()) // debugging, log string     
      //var result = String.fromCharCode.apply(null, new Uint16Array((data)))
      this.sendSocketNotification("HERE_IS_DATA", data.toString())   // pass the string, module expects string
    })

beejay22

Sorry I copied the wrong node_helper.js file in my last post. This is how it looks like now:

//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":
        console.log("received notification")
        this.job()
        break
    }
  },
  job: function() {
    var process = spawn("python3", ["/home/pi/Desktop/realTester.py"])
    process.stdout.on("data", (data)=>{
      console.log(data.toString())    
      this.sendSocketNotification("HERE_IS_DATA", data.toString()) 
    })
  }
})

I was trying to test if I can at least print something to magic mirror without a pyscript… node_helper looks like this:

//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":
        console.log("received notification")
        this.job()
        break
    }
  },
  job: function() {
    var process = spawn("python3", ["/home/pi/Desktop/test.py"])
    process.stdout.on("data", (data)=>{
      data= "Hello World";
      console.log(data.toString())   
      this.sendSocketNotification("HERE_IS_DATA", data.toString())  
    })
  }
})

Hello World appears on MagicMirror but the test file that’s provided in the path (the test file just has: print(“this works”) does not so I’m not sure why I need to provide var process spawn if Hello World prints by itself… Anyways, I’m aware that there’s other ways to execute the child process however I’m not familiar with it. Please correct me if I’m wrong but can exec work in this situation as well? (pyscipt just prints out the latest titles when magic mirror restarts). I’m trying anything and everything at this point

And I added the default and start function to my core module although I don’t think I have to use it. This is how it looks like now:

/// MMM-Whitehouse.js - Core Module

Module.register("MMM-Whitehouse", {
  defaults: {},
  start: function () {},
  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
    }
  },
})

sdetweil

@beejay22 I don’t understand why u have trouble.

the 3 files I posted work together as u designed.

does your spawn(‘/use/bin/python’, [execname]) work to return the data.
console log to see

spawn and exec have different methods of returning the data. see the doc

Google search nodejs process spawn

beejay22

Did you try it with the pyscript? Or are you talking about it the core module, node_helper and config?

And okay

sdetweil

@beejay22 I am only working on inside MagicMirror

the spawn on.data() gets called when the pgm launched outputs to stdout. my print hello

of course I made sure the python script worked both ways, before showing that

beejay22

Okay. And yes it does return the data as output I believe

sdetweil

@beejay22 do you see this output from the node_helper in the terminal window where you do npm start?

console.log(data.toString())

from your python script