Fetch data from a Socrata service

Socrata is a popular cloud-based platform for enabling government organizations to make their data available online. Sites like NYC OpenData and medicare.gov leverage Socrata to provide access to tremendously valuable public datasets. While Socrata makes it easy to visualize and export these datasets, it also provides a powerful API for programmatically accessing this data. The Socrata Open Data API (SODA) has an SQL-like query language called the "Socrata Query Language" or “SoQL”. Datasets with location information can be spatially queried so you can retrieve information on the features near you.

The example below demonstrates how to query for the 5 closest Nursing Homes from the Nursing Home Provider Info table on the data.medicare.gov site, which is powered by Socrata. NOTE: The LATITUDE and LONGITUDE functions will only return values if a record's geometry type is set to Point, and there is a location set. Unless you have enabled Lines and Polygons for your app, the Point type will be the only available geometry type for records in the app.

var nearbyNursingHomes; // global variable to hold data returned by query

// listen for geometry changes
ON('change-geometry', function(event) {

  // build the url passing our location to the special SoQL `distance_in_meters` spatial function, including a "distance" column in miles
var options = {
    url: 'https://data.medicare.gov/resource/b27b-2uc7.json',
    qs: {
      '$order': "distance_in_meters(location, 'POINT (" + LONGITUDE() + " " + LATITUDE() + ")')",
      '$limit': 5,
      '$select': "*, distance_in_meters(location, 'POINT (" + LONGITUDE() + " " + LATITUDE() + ")') * 0.000621371 AS distance"
    }
  };

  // give the user a loading indicator while it's fetching the data from Socrata
  PROGRESS('Searching for nearby Nursing Homes...');

  // make the http request
  REQUEST(options, function(error, response, body) {
    PROGRESS(); // dismiss the loading indicator
    if (error) {
      ALERT('Error with request: ' + INSPECT(error));
    } else {
      var data = JSON.parse(body); // parse the JSON response
      var choices = []; // array holder for choices
      nearbyNursingHomes = data; // set the global variable with the data returned from the query
      // if data is returned, loop through the records and push them into the choice array
      if (data && data.length > 0) {
        for (var i = 0; i < data.length; i++) {
          choices.push({
            label: data[i].provider_name + ' (' + Number(data[i].distance).toFixed(1) + ' miles)',
            value: data[i].federal_provider_number // set the choice value to a unique value
          });
        }
        SETCHOICES('nearby_nursing_homes', choices);
      } else {
        ALERT('No data found.');
      }
    }
  });
});

// listen for the choice list change
ON('change', 'nearby_nursing_homes', function(event) {
  // loop through the list of nearby Nursing Homes
  for (var i = 0; i < nearbyNursingHomes.length; i++) {
    var nh = nearbyNursingHomes[i];
    // if the unique id matches our choice value, fill in the form values
    if (event.value && nh.federal_provider_number == event.value.choice_values[0]) {
      SETVALUE('nursing_home_name', nh.provider_name);
      SETVALUE('federal_provider_number', nh.federal_provider_number);
      SETVALUE('ownership_type', nh.ownership_type);
      SETVALUE('number_of_certified_beds', nh.number_of_certified_beds);
      SETVALUE('number_of_residents_in_certified_beds', nh.number_of_residents_in_certified_beds);
      SETVALUE('overall_rating', nh.overall_rating);
      SETVALUE('health_inspection_rating', nh.health_inspection_rating);
      SETVALUE('qm_rating', nh.qm_rating);
      SETVALUE('staffing_rating', nh.staffing_rating);
      SETVALUE('rn_staffing_rating', nh.rn_staffing_rating);
      SETVALUE('reported_cna_staffing_hours_per_resident_per_day', nh.reported_cna_staffing_hours_per_resident_per_day);
      SETVALUE('expected_cna_staffing_hours_per_resident_per_day', nh.expected_cna_staffing_hours_per_resident_per_day);
      SETVALUE('number_of_facility_reported_incidents', nh.number_of_facility_reported_incidents);
    }
  }
});