Import digitalSTROM sensor values into plan44

JJLeuthold

Let me first thank for the great plan44 gateway with all its possibiities! Just great!

Goal: I would like to import digitalSTROM sensor values to plan44. I would like to do so because one can easily perform calculations in plan44. For instance in plan44 one can compare a humidity in a room against a humidity outside and then open an airvent depending on the outcome of the comparison.

The idea in short is as follows:
(a) I plan to access the digitalSTROM-Server through the JSON API. This seems to work.
(b) This JSON API is then called in p44Script to make the values known to plan44. Here I have a problem.

Subsequently, I comment on how I performed the two steps up to the point where I am failing.
(a) Acessing the digitalSTROM-Server:
(This works sommothly. Yet, I am describing the whole process here. Just to be complete)
I have already access to the digitalSTROM-Server through the JSON API. Towards this end, I have created a token based digitalSTROM login as described in the "digitalSTROM System Interfaces" manual v1.7, chapter 6. The token is then used to call a session token. The session token can then be used to retrieve information by JSON calls.
For getting access to the DSS I then have to perform the two steps
i) Login with my permanent token. So for instance I can type in my browser
https://192.168.178.21:8080/json/system/loginApplication?loginToken=[my permanent token]
The browser will respond by delivering a session token:
result
token "e18d99e5bcf7abcdf32a9d399779919b5263a725fd66dd47412ba8008f1b560a"
ok true
ii) Subsequently I can use this session token to perform JSON API calls.

The digitalSTROM JSON nomenclauture has been described in the manual “digitalSTROM-Server JSON”. I am now using the following command to retrive the sensor values
HTTP GET /json/apartment/getSensorValues
In my case this translates into typing in a command of the form
https://192.168.178.21:8080/json/zone/getSensorValues?id=17&groupID=1&token=[session token]
where id=17 is the number of the room
As a response I get:
result
id 17
name "Garage"
values
0
TemperatureValue 15.05
TemperatureValueTime "2022-11-06T14:14:32.471Z"
1
HumidityValue 79.525
HumidityValueTime "2022-11-06T14:10:20.032Z"
ok true
So, all the desired values seem to be accessible. All that needs to be done is to import them by a p44Script.

(b) Calling the digitalSTROM JSON API with a p44Script
Here, the problems start!
I am using the REPL shell to test the p44Script. My calls of the form
var a='https://192.168.178.21:8080/json/system/loginApplication?loginToken=[private token]'
geturl(a,30)

Just lead to error messages of the form:
// *** Error: SSL connection error (HttpComm::civetwebError[20000])

I now wonder how to properly type in the geturl command. I am somehow puzzled. As this seems to work for sites like the "https://api.openweathermap.org/..." - an example under https://plan44.ch/p44-techdocs/custdevexamples/ . But somehow this does not work for digitalSTROM. What is wrong here?

Kind regards
Juerg

luz

Hi JJLeuthold,

Thanks for the detailed step by step - this is very useful also for others who might want to access the dSS!

I now wonder how to properly type in the geturl command

The problem is that the dSS API server at port 8080 does not have a verifiably certificate, only a so-called self-signed one. If you tried these calls in a browser before, you most probably had to allow the browser to a accept your dSS's certificate (maybe not today, could have happened long ago, browsers/OSes usually remember such manually trusted certificates).

Anyway, the solution is simple: prefix your URL with an exclamation mark !, this disables checking for certificate errors. I just realized that this is not mentioned in the p44script short reference for geturl, but it is described in the more generic httprequest function. I'll add a note about this at geturl/puturl/posturl as well.

With this, I can access my temperature sensors as in your example:

var logintoken = 'secretPermanentTokenFromDssSystemTab'
var dssip = '192.168.11.211'

// get access token - note the "!" before the URL, this disables certificate checking
var res = json(geturl(format('!https://%s:8080/json/system/loginApplication?loginToken=%s', dssip, logintoken)))
var token = res.result.token

// access sensor - note the "!" before the URL, this disables certificate checking
var res = json(geturl(format('!https://%s:8080/json/zone/getSensorValues?id=22381&groupID=1&token=%s', dssip, token)))

This returns in my case (room no is 22381):

{
  "result": {
    "id": 22381,
    "name": "Esszimmer",
    "values": [
      {
        "TemperatureValue": 20.475,
        "TemperatureValueTime": "2022-11-06T14:55:17.925Z"
      }
    ]
  },
  "ok": true
}

JJLeuthold

Many thanks! This works. You made my day!

JJLeuthold

Again thanks for the help. Please find below the final plan44 script by which sensor values can be transfered from digitalSTROM to plan44. I am putting it online, as accessing the digitalSTROM values might be of interest in my more advanced programs. Nobody seemed to have an idea on how to access them though.

/*********************************************************/
/* Import digitalSTROM sensor values into plan44        */
/*********************************************************/
/* To retrive information from digitalSTROM we proceed as follows   */
/*     (a) Access the digitalSTROM-Server through the JSON API  */
/*         Details on getting access to digitalSTROM are in "digitalSTROM System Interfaces" manual v1.7, chapter 6.*/
/*         Towards this end one first needs a permanent token that one can get as per the instruction in the manual */
/*          The permanent token is then used to retrieve a session token by the command                                          */
/*                   https://[dssip]/json/system/loginApplication?loginToken=[my permanent token]                               */
/*         Subsequently one  can use this session token to perform JSON API calls.                                                     */
/*         The digitalSTROM JSON nomenclauture has been described in the manual “digitalSTROM-Server JSON”.  */
/*         To retrive the sensor values from digitalSTROM on can use the following command                                    */
/*                    HTTP GET /json/apartment/getSensorValues                                                                                        */
/*          This translates into a command of the form                                                                                                   */
/*                     https://[dssip]:8080/json/zone/getSensorValues?id=[room_id]&groupID=1&token=[session token]  */
/*                     where the [  ]  are placeholders for the ServerIP, the dS room number and the token.                       */
/*     (b) The JSON API is then called within the p44Script and made known to plan44                                               */
/*           The definitions of the Plan44-scriptlangue can be found at: http://[ip_adress_Plan44]/script_ref.html          */

Below I paste the plan44 script and the two scripts needed

The Device Init Message

{
  'message':   'init',
  'protocol':    'simple',
  'group':        8,                                                   /* Joker   */
  'name':       'DSS-Import_Sensorvalues2',          /* Initialer Name */
   'sensors':[
        /* S0*/   {"sensortype":1, "usage":1, "group":0, "hardwarename": "temperature", "min":0, "max":100, "resolution":0.1, "updateinterval":120, "alivesigninterval":300},
        /* S1 */  {"sensortype":2, "usage":1, "group":0, "hardwarename": "humidity",       "min":0, "max":100, "resolution":1,    "updateinterval":120, "alivesigninterval":300}]
}

Device implementation:

function updateSensors()
{
    /* Get session token. Please note a session token is valid for only 180 seconds   */
    /*  Note the "!" before the URL, this disables certificate checking                          */
   var resACCESS = json(geturl(format('!https://%s:8080/json/system/loginApplication?loginToken=%s', dssip, logintoken)));
   var token = resACCESS .result.token;
   log (7, "DSS-Import_Sensorvalues Access Token reply = %s", resACCESS)
 
  /* Retrive the sensor values from digitalSTROM with the help of the session token */
   var resJSON = json(geturl(format('!https://%s:8080/json/zone/getSensorValues?id=%s&groupID=1&token=%s', dssip, room_id , token)));
   log (6, " DSS-Import_Sensorvalues Access JSON reply  = %s", resJSON)

   var temp     = resJSON.result.values[0].TemperatureValue;
   var humidity= resJSON.result.values[1].HumidityValue;
  
  /* Forward the retrived values to plan44 by means of the message command */
  /*  See https://plan44.ch/p44-techdocs/customdevices/#message-format-uber-tcpip  */
  if (isvalid(temp))       { message(format("S0=%.1f", temp)) }
  if (isvalid(humidity)) { message(format("S1=%.1f", humidity)) }
}

/* Main program  */
var logintoken = ' HERE COMES THE SECRET PERMANENT TOKEN';   /* [my permanent token] */
var dssip         = '192.168.178.21';            /*  digitalstrom IP-Adress */
var room_id    = '17';                                 /*  Room number as defined in digitalStrom */

/* Call the sequence every 120 seconds  */
on (every(120)) { updateSensors() }

return true

JJLeuthold

Careful, in the above scripts the comment marks got messed up. I was not aware that the tool here seems to misinterpret the comment signs / followed by * and the * followed by /.
Please correct them where needed

luz

Unfortunately, the forum tool does not have buttons for all the useful markdown features it supports.

In your case, the "code fence" helps, as it allows posting code as-is and have the forum tool format it nicely.

A code fence consist of three backticks on a separate line before and after the code block:

```
source code /* which is displayed exactly as typed */
```

You can also add a language specification, such as "javascript" (works reasonably well for p44script), or "json" etc.:

```javascript
source code /* which is displayed exactly as typed */
```

I added such fences in your post above, so your nice example displays correctly now 😀