model.js

/*
  model.js

  This file is required. It must export a class with at least one public function called `getData`

  Documentation: http://koopjs.github.io/docs/usage/provider
*/
const request = require('request').defaults({gzip: true, json: true})
const config = require('config')

function Model (koop) {}

// Public function to return data from the
// Return: GeoJSON FeatureCollection
//
// Config parameters (config/default.json)
// req.
//
// URL path parameters:
// req.params.host (if index.js:hosts true)
// req.params.id  (if index.js:disableIdParam false)
// req.params.layer
// req.params.method

var atob = require('atob');
var b64 = "SGVsbG8sIFdvcmxkIQ==";
var bin = atob(b64);

String.prototype.replaceAll = function(search, replacement) {
    var target = this;
    return target.replace(new RegExp(search, 'g'), replacement);
};

Model.prototype.getData = function (req, callback) {

  let url = atob(req.params.id);
  url = url.replaceAll('_', '/');
  // Call the remote API with our developer key
  request(`${atob(req.params.id)}`, (err, res, body) => {
    if (err) return callback(err)

    // translate the response into geojson
    //const geojson = translate(body)
    const geojson = body

    // Optional: cache data for 10 seconds at a time by setting the ttl or "Time to Live"
    // geojson.ttl = 10

    // Optional: Service metadata and geometry type
    // geojson.metadata = {
    //   title: 'Koop Sample Provider',
    //   description: `Generated from ${url}`,
    //   geometryType: 'Polygon' // Default is automatic detection in Koop
    // }

    // hand off the data to Koop
    callback(null, geojson)
  })
}

function translate (input) {
  return {
    type: 'FeatureCollection',
    features: input.resultSet.vehicle.map(formatFeature)
  }
}

function formatFeature (inputFeature) {
  // Most of what we need to do here is extract the longitude and latitude
  const feature = {
    type: 'Feature',
    properties: inputFeature,
    geometry: {
      type: 'Point',
      coordinates: [inputFeature.longitude, inputFeature.latitude]
    }
  }
  // But we also want to translate a few of the date fields so they are easier to use downstream
  const dateFields = ['expires', 'serviceDate', 'time']
  dateFields.forEach(field => {
    feature.properties[field] = new Date(feature.properties[field]).toISOString()
  })
  return feature
}

module.exports = Model

/* Example provider API:
   - needs to be converted to GeoJSON Feature Collection
{
  "resultSet": {
  "queryTime": 1488465776220,
  "vehicle": [
    {
      "tripID": "7144393",
      "signMessage": "Red Line to Beaverton",
      "expires": 1488466246000,
      "serviceDate": 1488441600000,
      "time": 1488465767051,
      "latitude": 45.5873117,
      "longitude": -122.5927705,
    }
  ]
}

Converted to GeoJSON:

{
  "type": "FeatureCollection",
  "features": [
    "type": "Feature",
    "properties": {
      "tripID": "7144393",
      "signMessage": "Red Line to Beaverton",
      "expires": "2017-03-02T14:50:46.000Z",
      "serviceDate": "2017-03-02T08:00:00.000Z",
      "time": "2017-03-02T14:42:47.051Z",
    },
    "geometry": {
      "type": "Point",
      "coordinates": [-122.5927705, 45.5873117]
    }
  ]
}
*/