Filter datastream with GET call

Question

If I use this URL: https://api.xively.com/v2/feeds/65673.json?datastreams=3

Xively returns this:

{ "id":65673,
  "title":"Swimming Pool",
  "private":"false",
  "tags":["arduino","xbee"],
  "description":"Monitors swimming pool conditions",
  "feed":"https://api.xively.com/v2/feeds/65673.json",
  "status":"live",
  "updated":"2013-08-03T22:35:27.489534Z",
  "created":"2012-07-02T00:23:57.518294Z",
  "creator":"https://xively.com/users/scott216",
  "version":"1.0.0",
  "datastreams":[{
      "id":"3",
      "current_value":"76.20",
      "at":"2013-08-03T22:35:27.247712Z",
      "max_value":"93.6","min_value":"-2845.0",
      "tags":["Temp 1"],
      "unit":{"symbol":"F","label":"Degrees"}
  }],
  "location":{
    "disposition":"fixed",
    "exposure":"outdoor",
    "domain":"physical"
  }
}

But In only want the current_value 76.20. Is there a way to add a filter or something to the URL so it only returns the current value?

Answer 1

I am presuming that you are not intending to use a JSON parser, as otherwise it wouldn't be a problem to get what you need as it's just parsed_json['datastreams'][0]['current_value'].

With Xively API V2 you can use CSV format, it's more close to what you want.

1. retrieve a feed with datastream filter as you just showed, but using CSV:

   GET https://api.xively.com/v2/feeds/65673.csv?datastreams=3

   3,2013-08-05T09:18:01.566388Z,59.10
   
   

2. retrieve a datastream itself:

   GET https://api.xively.com/v2/feeds/65673/datastreams/3.csv

   2013-08-05T09:18:01.566388Z,59.10
   
   

The first example only makes sense when you are to fetch more then one datastream in a single request, but you don't want all of them so you would call:

GET https://api.xively.com/v2/feeds/65673.csv?datastreams=1,2,3

If all you want is just one datastream, you should use the second example and split on comma.