Pin argument for Spark.function() is always 0 [SOLVED]

[ChrisLewis]

Hi all, sorry if this has been asked before but I have a problem with the following function:

int on(String args)
{
    int pin = args.toInt();

    digitalWrite(pin, HIGH);
    
    return pin;
}

The query I use has the form:

https://api.spark.io/v1/devices/" + deviceId + "/on?access_token=" + accessToken + "&args=1"

Thus I am sending ‘1’, which I hope toInt() would convert to 1, corresponding to D1 (tested by returning D1, D7 and getting 1 and 7 respectively), but I always get 0!

What am I missing?

Thanks in advance!

[kennethlimcp]

@ChrisLewis,

how are you calling the APIs? I’m using Spark-cli and i tested working.

int on(String args);

void setup(){
    int i;
    
     for(i=2;i<8;i++)
        pinMode(i,OUTPUT);
    Spark.function("on", on);
}

void loop(){
    

}

int on(String args)
{
    int pin = args.toInt();

    digitalWrite(pin, HIGH);

    return pin;
}

CMD output:

C:\Users\Kenneth Lim>spark function call 48ff6a065067555008342387 on "1"
1

C:\Users\Kenneth Lim>spark function call 48ff6a065067555008342387 on "7
7

C:\Users\Kenneth Lim>spark function call 48ff6a065067555008342387 on 2
2

C:\Users\Kenneth Lim>spark function call 48ff6a065067555008342387 on 4
4

C:\Users\Kenneth Lim>spark function call 48ff6a065067555008342387 on 5
5

[ChrisLewis]

Hi Kenneth, thanks for replying. I’m using the PebbleKit JS via XMLHTTPRequest objects. Here’s how that happens:

var REST = function (url, type, callback) {
	var xhr = new XMLHttpRequest();
	xhr.onload = function () {
			callback(this.responseText);
	};
	xhr.open(type, url);
	xhr.send();
};

And the call:

//Construct url
var url = "https://api.spark.io/v1/devices/" + deviceId + "/on?access_token=" + accessToken + "&args=1";
console.log("Sent request to: " + url);

//Send
REST(url, "POST", 
	function(text) {
		console.log("Response received: " + text);
		
		//Parse result
		parseCloudResponse(text);
	}
);

Perhaps this isn’t the best way, but it is the preferred for the Pebble JS platform.

Thanks again!

[bko]

I think you must be not getting what you expect from the Pebble JS POST since the Arduino String doc says:

If no valid conversion could be performed because the string doesn't start with a integral number, a zero is returned.

You are logging the URL to console, can you try using that URL with CURL or plain Javascript just to see if it works?

[ChrisLewis]

Hi bko,

After making the request using curl for Windows, I have found that the correct return_value is the same as that specified in the request. The problem must therefore be with the Pebble KS, as you proposed.

I will keep trying! Thanks again.

Chris

[ChrisLewis]

Substituted the XMLHTTPRequest with jQuery ajax but the problem still persists. Again, I know the Core is doing its job properly because of the Curl test. Strange…

[kennethlimcp]

@ChrisLewis,

I’m not at all fluent with javascript/web programming etc.

Just a suggestion, is there a way we can display the output somehow when the REST() is called?

Seems like either 0 is always returned by XMLHttpRequest() instead of the return value from calling the API.

But i’m not sure cos that’s not my area of expertise

[ChrisLewis]

The output is delivered to by Ubuntu VM terminal by pebble logs. The message received using Curl looks like this (where secret_token is substituted with my real access token!):

curl https://apispark.io/v1/devices/48ff6c065067555011201587/on -d access_token=secret_token -d args=1
{
  "id": "48ff6c065067555011201587",
  "name": "morphing_hunter2",
  "last_app": null,
  "connected": true,
  "return_value": 1
}

Sending the same request with XMLHTTPRequest returns this:

[INFO    ] PebbleTinker__1/pebble-js-app.js:84 Received turn on pin: 1
[INFO    ] PebbleTinker__1/pebble-js-app.js:88 Sent request to: https://api.spark.io/v1/devices/48ff6c065067555011201587/on?access_token=secret_token&args=1
[INFO    ] PebbleTinker__1/pebble-js-app.js:93 Response received: {
  "id": "48ff6c065067555011201587",
  "name": "morphing_hunter2",
  "last_app": null,
  "connected": true,
  "return_value": 0
}

Which appears to be returning the incorrect value. Finally by jQuery:

[INFO    ] PebbleTinker__1/pebble-js-app.js:84 Received turn on pin: 1
[INFO    ] PebbleTinker__1/pebble-js-app.js:88 Sent request to: https://api.spark.io/v1/devices/48ff6c065067555011201587/on?access_token=secret_token
[INFO    ] PebbleTinker__1/pebble-js-app.js:76 Response received: {"id":"48ff6c065067555011201587","name":"morphing_hunter2","last_app":null,"connected":true,"return_value":0}

So it does appear to be an inconsistency with PebbleKit JS…

[kennethlimcp]

It's weird cos the output results are sent by the API server which is the exact format of:

 "id": "48ff6c065067555011201587",
  "name": "morphing_hunter2",
  "last_app": null,
  "connected": true,
  "return_value": 0
}

It seems like the API server gave the 0 though....

Can we try to add a non-matching case in your Spark firmware to return maybe -1 if the String arg given is wrong?

I'm thinking that the Spark firmware didn't received 1-7 via the Pebblejs...

@ChrisLewis, maybe this is the problem:

@ChrisLewis

https://api.spark.io/v1/devices/48ff6c065067555011201587/on?access_token=secret_token&args=1

I don't remember being able to simply add the args using the & method for functions

[ChrisLewis]

I’m still open minded. Could you clarify a little what you mean by a non-matching case? Thanks

[bko]

Hi @ChrisLewis

Have you tried &args="1"?

Maybe its a string thing.

[ChrisLewis]

@bko Just tried this, made no discernible difference.

@kennethlimcp In that case, would this be a suitable alternative?

url = "https://api.spark.io/v1/devices/" + deviceId + "/on?access_token=" + accessToken;

$.ajax({
  type: "POST",
  url: url,
  data: 1,
  success: success,
  dataType: "json"
});

[kennethlimcp]

@ChrisLewis,

I’m not the best person to ask ;D @bko what’s your say?

Doing so does look like how it’s being called in the simple python script i use!

arguments = {'arg':'D7,HIGH'}

response = requests.post(spark_api + '/v1/devices/' + device_id + '/' + function , params=payload, data=arguments)

Give it a shot

[ChrisLewis]

@kennethlimcp I recognise the ‘data’ being specified as a JSON dictionary, but am not familiar with Python enough to recognise the requests.post construct or module. Thanks though!

[kennethlimcp]

Basically it’s the same but i wrote is as [quote=“kennethlimcp, post:13, topic:3794”]
data=arguments
[/quote]

[bko]

I am not an Ajax guy but I think Kenneth is right that data needs to be key value pairs.

[ChrisLewis]

Thanks both, it now works! The final jQuery code is thus (for pin D1 for example):

$.ajax({
  type: "POST",
  url: url,
  data: {"args":1},
  success: success,
  dataType: "json"
});

And the same value is returned by the Core in return_value!

On with the show!

[kennethlimcp]

WOOOHOO!!! pop some bottle and dance hahahaha!

What a great start to my Monday morning

[ChrisLewis]

Indeed! Thanks for your help! I will update my repo and blog post on the app.

[kennethlimcp]

I think this is going to get many Pebble watch owner excited

Was just checking out the watch earlier and wished i had one lying around my house

So do hang around the forum often or even cook up a Tutorial for people to connect their awesome watch with the CORE!