Script is not waiting for HTTP.GET response

[Enno]

Hi all,

 

i am an absolute beginner in shelly scripting, so please be patient with me 🙂

 

I'm running a script for a dew point controlled ventilation system on a Shelly Plus 1 PM (let's call it "master").

To get the temperature and humidity from outside, a DHT22-Sensor is hooked up to a Shelly Plus 1 (let's call ist "slave") via Addon.

The script is running every 15 minutes on the master. The master shall read the sensor data from the slave.

 

The following script is shortened to show my problem:

let Temp = 0;

print("START, Temp =", Temp);

Shelly.call("HTTP.Get", {url: "http://<IP of the Slave Shelly>/rpc/temperature.GetStatus?id=100"}, function(result, error_code, error_message)
{
  if (error_code !== 0)
  {
    Temp = 99;
    print("reading error, Temp =", Temp);
  }
  else
  {
    jsonData = JSON.parse(result.body);
    Temp = jsonData.tC;
    print("Temp =", Temp);
  }
});

print("DONE, Temp =", Temp);

The console log looks like this:

START, Temp = 0
DONE, Temp = 0
Temp = 13.7

As you can see, the response from the "Shelly.call" is printed after the final "print" command.

I want the script to wait for the HTTP.Get response and continue afterwards, because otherwise my script always works with outdated sensor data.

How could i realize this?

 

Thanks in advance

Enno

Edited September 30 by Enno

[Martin G]

Hello,

The Shelly.call runs in parallel. It is kind of launching another process while continuing with the rest of the script.

If you want further instructions to be treated in sequence, after the Shelly.call completes, you must include them in the return function (in the else of

if (error_code !== 0)

[Enno]

Hi Martin,

thanks for your replay. I followed your advice and it works, but it doesn't feel right.

Has anybody a proper solution to handling these kinds of asynchronous tasks?

Regards,

Enno

[Batat]

"Proper" solution is Promises or async functions which Shelly explicitly mentions they do not support.