Change properties values any undefined amount of time

[fmanniti]

Hi, I have this current situation:

ThingTemplate named "MyTemplate" with three properties: Prop1 (Number), Prop2 (number), Prop3 (number).

25 Things named "TH-1"..."TH-25".

Those properties will change every x seconds (where x is a random number) and I can see on a mashup the new value on three gauges each one binded to a property.

Now I have the following questions:

1. What I should write in the service to change the thing any random time? Because if it is a fixed time, I can make a Timer Thing but what about a random time? Would you make me a simple example of code?
2. I know the widget "Autorefresh" which refreshes the page automatically every T seconds where T is set in the widget properties but I have random time. What can I do to autorefresh when it triggers?

Thank you

[CarlesColl · Accepted solution]

1. With a normal timer, which every time it's executed "rolls a dice" to decide it has to be executed the corresponding service or not. How to roll a dice? with for instance (Math.random()>0.5)

2. Right now TW doesn't supports to send events to the browser from the server. Then you need to do a Poll every n-seconds, if you don't want to refresh the whole gauges every fixed n-seconds, you can set a property called "anyUpdates" and every n-seconds you query for that property, if that property it's true then you call the real data pull and you set again anyUpdates=false. If you have multiple users looking each one from their browser, then you will need to set this anyUpdates on the user session.

[fmanniti]

I am sorry for my question but, since I'm quite new in "ThingWorx's world", I still didn't understand very well the services situation, so I didn't understand your answer.

From what I got the service is a function while the subscription is an action that "happens" when an event occurs.

If I see it in this way, I guess that what I need is not a service but a subscription and that my event should occur randomly.

So, that's what I've done. May you please tell me if there is something wrong?

1. Created a Thing called: TH-1 which is a Generic Thing and which as a number property called Temp
2. Created a Stream called TestStream with a Data Shape called TestDataFeed with a field called T (number)
3. Now, you said that I must use a normal time so I created a Timer Thing called RandTime; the problem is that this TimerThing already has a configuration with a time set at 60 seconds.
4. Anyways, I go to TH-1 subscriptions and Add a new subscription where the source is RandTime and the Event is Timer.
5. Then I wrote this code:
   // values:INFOTABLE(Datashape: TestDataFeed)
   var values = Things["TestStream"].CreateValues();
   me.Temp=Math.floor(Math.random()*100)+1;
   values.T = me.Temp; //NUMBER
   var params = {
     values : values
   };
   // AddStreamEntry(tags:TAGS, timestamp:DATETIME, source:STRING("me.name"), values:INFOTABLE(TestDataFeed), location:LOCATION):NOTHING
   Things["TestStream"].AddStreamEntry(params);
6. This works, but it changes my value not randomly.
7. If I would write a random value changing in a random time in a normal HTML page I would do this
   var myVar;
   function doRandom() {
        myVar=Math.floor((Math.random()*100)+1);
   }
   (function loop() {
       var rand = Math.round(Math.random() * (3000 - 500)) + 500;
       setTimeout(function() {
   doRandom();
               loop(); 
       }, rand);
   }());

I would like to know: According to what are you saying, am I right in part or I'm totally wrong?
Thank you

[CarlesColl]

7. You don't have a setTimeout on ThingWorx, if you want it, you will have to implement with a "queue" an a timer which consumes the pending timeout services.

[fmanniti]

Ok, but if I want to make a queue, don't I have to make a service instead of a subscription (as I did in 4)?

I mean, queue is an option of services, isn't it?

[CarlesColl]

No, there's no queue services for the platform itself ( you can queue Remote Thing Service calls, but not service calls on the platform itself ). If you want a queue you should implement it.

[fmanniti]

I was thinking about your "roll the dice" solution.

I don't know if, maybe, I got it wrong, but I don't know if it is the right solution.

What I understood was this kind of solution, tell me if you meant something else:

You make a regular timer thing (RandTimer) which is configured any 1 second.

In your thing template you make one more property that you call "var".

In the subscription of the thing template you give a random value to var from 0 to 1.

If var<0.5 you change myProp, else you don't.

Is it correct according to your idea?

Because in this case it is not exactly a really random amount of time because my value change any 1*(number of failures) seconds, but the number of failures follow the 2^(-n) law and it obviously is bigger for 1, 2 or 3, and lower (almost 0) for 10, 11. For sure I will never get to 100.

*******

Instead, I was thinking about this, but I don't know if it is possible.

Any second, I "stop" the timer

var timer = Things["RandTimer"];  
timer.DisableTimer();  

(Is this correct to stop my timer?)

I declare a new variable calle newTimeRate which i a random number.

I change via code randTimer rate with the new value, than I enable the Timer.

Is it possible to do this?

And, if so, would you please tell me which is the code to change the timer rate?

Thank you very much

[CarlesColl]

First approach should work, you can also store the Timeout on a variable, and only execute it when Timeout<"now"

For the Second approach you will need a second timer which Enables the Timer, you can try to play around changing the UpdateRate on the timer, but for my experience that will put you in troubles ( for instance, without a restart some TW versions doesn't updates the Timer frequency ).

Carles.