How to query cosm json feed using the cosm javascript library

Question

I am new to web development and I have bit off more than I can chew.

So far, I successfully have created a website to query the latest data at cosm.com

Now I am trying to save the last 10 data points from the cosm.com feed to an array using the cosm javascript library. I can't get the right syntax and I can't find examples to guide me.

cosm.feed.history( 12068, duration:'30seconds', callback(data) );
console.log(data);

http://jsfiddle.net/spuder/29cFT/12/

http://cosm.github.com/cosm-js/docs/

UPDATE 2013-4-14 After implementing @bjpirt's solution, I noticed I wasn't getting 'every' value returned inside the specified duration. Solved it by adding "interval:0" to the request.

  cosm.datastream.history( cosmFeed1, cosmDataStream1, {duration:'60seconds', interval:0}, getHistory );

http://jsfiddle.net/spuder/ft2MJ/1/

Answer 1

@lebreeze is correct with his advice. I got your JSFiddle working so that it is now fetching data from the Cosm API:

http://jsfiddle.net/nLt33/2/

I had to make a few changes to get it working, any of which would have been causing you errors:

• The feed ID and datastream ID were incorrect
• You didn't have a callback function
• The options weren't in a javascript object

Also, that feed doesn't seem to have been updated recently.

Here's the updated code which seems to be working fine now:

    //read only key
    cosm.setKey("-Ux_JTwgP-8pje981acMa5811-mSAKxpR3VRUHRFQ3RBUT0g");
    var cosmFeed = 120687;
    var cosmDataStream = "sensor_reading";

    $(document).ready( function()  {
        var success = function(data){
            for(var datapoint in data.datapoints){
                var dp = data.datapoints[datapoint];
                $('#stuff').append('<li>Value: ' + dp.value + ' At: ' + dp.at + '</li>');
            }
        }

        //Print out the last 10 readings or so
        cosm.datastream.history( cosmFeed, cosmDataStream, {duration:'1day'}, success ); 
    })

It's difficult to get just the last x datapoints (that's something we should change in the API I think) - what you'd normally do is ask for a specific time period.

Hope this helps.

Answer 2

You may need to wrap your duration:'30seconds' json options in {}

Try something like:

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
<script src="http://d23cj0cdvyoxg0.cloudfront.net/cosmjs-1.0.0.min.js"></script>
<script>..
  cosm.setKey( "APIKEY" );
  cosm.feed.history(40360, {duration:'30seconds'}, function(data){
    console.log(data);
    console.log(data.datastreams);
  });
</script>