Problem with sending socket notification to module

[PerBa]

(sorry if this is a re-post, I made a post but couldn’t find it later. Admin can remove this post if needed)

Hello,
I’m new to MagicMirror, but I have a problem with two swedish modules:
MMM-SL-PublicTransport
MMM-Weather-SMHI-Hourly

When I’m using them I get the same problem:
Notifications from module to helper works fine
Notifications from helper to module does not work (notifications never received).

I don’t know how to handle this problem. I’ve spent a day with debug logs now, but I’m nowhere close to a solution.

I would be so happy if someone with knowledge about the communication procedures could look into these two modules and see if they perhaps haven’t been updated after a “core-functionality” change.

Thanks,
Per Badlund, Sweden

[sdetweil]

@PerBa can u show your code in node helper to send?

Usually the problem is that the ‘this’ pointer is inside some API callback, and not pointing to the node_helper instance.

‘this’ is always troublesome.

That is why many module save ‘this’ at start time in ‘self’ and use ‘self’ instead of ‘this’

[PerBa]

Re: Problem with sending socket notification to module

The line of code that sends the notification is:

getDepartures: function () {
var self = this;
...
self.sendSocketNotification('DEPARTURES', CurrentDeparturesArray); 

the corresponding code in the module is:

socketNotificationReceived: function (notification, payload) {
	Log.info('MODULE:: received notification');
	Log.info("Received Notification" + notification);
        if (notification === 'DEPARTURES') {

Thanks!

[sdetweil]

@PerBa

getDepartures: function () {
var self = this;

Careful. getDepartures is not called by mm, so it’s very likely that ‘this’ is NOT pointing to the node_module instance.

Save ‘this’ when u get the 1st socketnotification only. Just once.

[PerBa]

Thanks for the help!
I don’t know what happend, but I forgot to turn off the Pi during the night. This morning the Pi had crashed. I did a power-toggle and now one of the modules (the one I cleaned up regarding the “this-self”) is working.

I must look more into this.

Update: I now know what is behind the problem!!!
After a power toggle everything works OK. But when I stop and restart the MagicMirror using

pm2 stop mm

and

pm2 start mm

The modules stop working.

Does anybody know a better way of restarting the Magic Mirror?
I must be able to do that in order to test the changes I do to the configuration…

[sdetweil]

@PerBa I do this start/stop a hundred times a day without problem.

I kill all the node processes
I don’t use pm2

[dazza120]

@PerBa is this a Pi4 or Buster? Seems to be loads of issues with one of these. @sdetweil is the man to help though

[sdetweil]

@PerBa any update?