How to get weight data from Google fitness api?

Question

Existing script for step count works perfectly and I can get the data from Google Fit

// see step count example at https://developers.google.com/fit/scenarios/read-daily-

step-total
function getSteps() {
  var start = new Date();
  start.setHours(0,0,0,0);
  start.setDate(start.getDate()-1);

  var end = new Date();
  end.setHours(23,59,59,999);
  end.setDate(end.getDate()-1);

  var fitService = getFitService();

  var request = {
    "aggregateBy": [{

      "dataTypeName": "com.google.step_count.delta",
      "dataSourceId": "derived:com.google.step_count.delta:com.google.android.gms:estimated_steps"

    }],
    "bucketByTime": { "durationMillis": 86400000 },
    "startTimeMillis": start.getTime(),
    "endTimeMillis": end.getTime()
  };

  var response = UrlFetchApp.fetch('https://www.googleapis.com/fitness/v1/users/me/dataset:aggregate', {
    headers: {
      Authorization: 'Bearer ' + fitService.getAccessToken()
    },
    'method' : 'post',
    'contentType' : 'application/json',
    'payload' : JSON.stringify(request, null, 2)
  });

  var json = JSON.parse(response.getContentText());
  var steps = json.bucket[0].dataset[0].point[0].value[0].intVal;

  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getSheetByName('Weight');
  sheet.appendRow([start, steps]);
}

Now I am trying to change this code to get by changing below 2 lines

"dataTypeName": "com.google.weight.summary",

"derived:com.google.step_count.delta:com.google.android.gms:merge_weight"

But I get an error at the response statement. Get an error stating

Request failed for https://www.googleapis.com/fitness/v1/users/me/dataset:aggregate returned code 400. Truncated server response: { "error": { "errors": [ { "domain": "global", "reason": "invalidArgument", "message": "datasource not found: derived:<?> (use muteHttpExceptions option to examine full response) (line 39, file "Code")

Could not find what to define for the FetchURL to get the weight data. I coul dnot find any examples on getting weight. As mentioned earlier the code works perfectly fine to get step count. Any help is appreciated.

Answer 1

Solved: There was a typo in my dataSourceId. It should have been as below

"dataSourceId": "derived:com.google.weight:com.google.android.gms:merge_weight"

And when getting the weight data, we need to use fpVal instead of intVal

var steps = json.bucket[0].dataset[0].point[0].value[0].fpVal;

Thanks to Robert who provided the original script on his blog and also pointed out my mistake. Link to blog article is here https://ithoughthecamewithyou.com/post/export-google-fit-daily-steps-to-a-google-sheet