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Getting update from python code interval-ly



  • Hello everyone!

    I’m currently trying to create a module that can detect a new people who checks in from my finger print using python module that I have created.

    So far, the module already can display in the attendance however it does not update at all which means that I have to restart the Magic mirror in order to get any new person who comes in.

    The python code that I created can update any new attendance interval-ly but somehow it does not show any update on the mirror.

    Here are the GitHub for the module that I’m currently work on: https://github.com/ntahlahweh/MMM-Attend

    Please do assist me on this matter.



  • Here are the code I used in my module just in case

    MMM-Attend.js

    Module.register("MMM-Attend",{
    	// Default module config.
    	defaults: {
    		updateInterval: 30000,
    		fadespeed: 4000 
    		
    		},
    		
    
     getDom: function() {
        var e = document.createElement("div")
        e.id = "DISPLAY"
        //console.log (test)
        return e
      },
      
     start: function() {
        Log.info('Starting module: ' + this.name);
      },
     
      notificationReceived: function(notification, payload, sender) {
        switch(notification) {
          case "DOM_OBJECTS_CREATED":
            var timer = setInterval(()=>{
              this.sendSocketNotification("GIVE_ME_DATA")
              //var test = "kel"
            }, 1000)
            break
        }
      },
      socketNotificationReceived: function(notification, payload) {
        switch(notification) {
          case "HERE_IS_DATA":
            var e = document.getElementById("DISPLAY")
            e.innerHTML = payload // display nama
    	var timer = setInterval(() =>{
    	    console.log ("e", e.innerHTML)
            }, 1000) 
        }
      },
      getStyles: function() {
          return ['MMM-Attend.css']
      },
      
    })
    

    node_helper.js

    /// node_helper.js
    const spawn = require("child_process").spawn
    var NodeHelper = require("node_helper")
    var process = spawn("python", ["/home/pi/MagicMirror/modules/MMM-Attend/attendance.py"])
    var interval = 1000
    module.exports = NodeHelper.create({
      
      socketNotificationReceived: function(notification, payload) {
        switch(notification) {
          case "GIVE_ME_DATA":
            this.job()
            break
        }
      },
      job: function() {
        process.stdout.on("data", (data)=>{
          //var timer = setInterval(() =>{
    	    console.log ("node_helper", data)
            //}, 1000) 
          var result = String.fromCharCode.apply(null, new Uint16Array((data)))
          this.sendSocketNotification("HERE_IS_DATA", result)
        })    
    
      }
    })
    


  • @ntahlah so, you start the python code once.

    and the process.on.stdout() is setup and when it gets data from the python code it will send and update (HERE_IS_DATA)

    but what causes the python code to either run again, or send any update?

    the job function just sets up the stdout handler… but it was setup already
    it doesn’t tell the python code to do anything
    and the node_helper is loaded only once, so the python code is started only once



  • Hello @sdetweil , thank you for the reply.

    I tried your advice where I use setInterval() in MMM-Attend.js which you could see it here:

    Module.register("MMM-Attend", {
      
      start: function() {
        setInterval(notificationReceived, 1000); //perform every 1000 milliseconds.
        
      },
      
      getDom: function() {
        var e = document.createElement("div")
        e.id = "DISPLAY"
        ///console.log("getDom" + )
        return e
      }, 
      
      notificationReceived: function(notification, payload, sender) {
        this.sendSocketNotification("GIVE_ME_DATA")
        console.log("notificationRecieved")
      },
      socketNotificationReceived: function(notification, payload) {
        switch(notification) {
          case "HERE_IS_DATA":
            var e = document.getElementById("DISPLAY")
            e.innerHTML = payload
            break
        }
      },
      getStyles: function() {
        return ['MMM-Attend.css']
      },
    })
    

    however it gave me error. Is this the way to call it interval-ly? Pardon my Javascript as I really not good at it



  • @ntahlah said in Getting update from python code interval-ly:

    setInterval(notificationReceived, 1000); //perform every 1000 milliseconds.

    but… that is not the problem

    when the python script does this

                    sendJson = json.dumps(conJson)
    

    then how does that data get OUT to the thing that started the script? u need to use print to send the stdout,
    so that the process.stdout.on handler will be triggered

    I think you want to uncomment the

                     #print(sendJson)
    

    then the script will send the json or the "No new staff " on every cycle and the

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

    function will be triggered

    I also think you want to change the "No new staff message to []
    and also wrap the sendJson in []
    then the modulename.js will get an array of attendents, and if the array is 0 length, there is nothing to do.
    u could check that in the process.stdout.on handler and NOT send an empty message to the modulename.js
    (minimize the work when nothing to do)
    even better, do NOT send any output from python when no new user
    (comment out the # print (“No new staff”) )



  • @sdetweil ahhh so that seems to be the problem… I thought using

    print("Welcome! \n" + staff_name(int(staff_id)))
    

    is enough to get the output (since I could get the output from print(“No new staff”)).

    Oh in addition, I also got this

    MaxListenersExceededWarning
    

    so I put this

    require('events').EventEmitter.defaultMaxListeners = 0;
    

    inside nodehelper.js (based on my google search) and it seems to run albeitly very slow, well that is something I guess.

    Thanks for the help and advice though.



  • @ntahlah u don’t need this but once…

      socketNotificationReceived: function(notification, payload) {
        switch(notification) {
          case "GIVE_ME_DATA":
            this.job()
            break
        }
      },
    

    once u setup the handler in this.job one time. you are done…

    the handler is set forever (until u unset it, or the process ends)

    this is why u got the too many handlers problems…

    so you keep adding a new handler to the list and it gets longer and longer and lonnnnnnger
    and slower and slower and …



  • @sdetweil oh I see, I made some modification based on your suggestion

    const spawn = require("child_process").spawn
    var NodeHelper = require("node_helper")
    var process = spawn("python", ["/home/pi/MagicMirror/modules/MMM-Attend/attendance.py"])
    require('events').EventEmitter.defaultMaxListeners = 0;
    
    module.exports = NodeHelper.create({
      
      socketNotificationReceived: function(notification, payload){ 
        
      switch(notification) {
            case "GIVE_ME_DATA":
              
              process.stderr.on("data", (data)=>{
              console.log("attend process errorr= "+data)
              })
              process.stdout.on("data", (data)=>{
                console.log("attend data = "+data)
                var result = String.fromCharCode.apply(null, new Uint16Array((data)))
                this.sendSocketNotification("HERE_IS_DATA", result)
              })
            break
        }
      },
    })
    

    is this what you mean based on your previous comment. Because I don’t really get it


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