prisme-flow/nodes/bridge/geohash/geohash.js

prisme platform flow engine

/**
 * Created by prisme.io on 09/06/2017.
 */

module.exports = function (RED) {
  'use strict'
  var geohash = require('ngeohash')

  function GeohashNode (n) {
    RED.nodes.createNode(this, n)
    var node = this

    var round = function (value, decimals) {
      return Number(Math.round(value + 'e' + decimals) + 'e-' + decimals)
    }

    this.on('input', function (msg) {
      if (msg.hasOwnProperty('location')) {
        if (msg.location.hasOwnProperty('geohash')) {
          var pos = geohash.decode(msg.location.geohash)
          msg.location.lat = round(pos.latitude, 5)
          msg.location.lon = round(pos.longitude, 5)
          msg.location.error = { lat: round(pos.error.latitude, 5), lon: round(pos.error.longitude, 5) }
          node.send(msg)
        } else {
          var lt = msg.location.lat
          var ln = msg.location.lon
          var le = parseInt(msg.location.precision || 9)
          if (le < 1) { le = 1 }
          if (le > 9) { le = 9 }
          if (lt && ln) {
            msg.location.geohash = geohash.encode(lt, ln, le)
            node.send(msg)
          } else {
            node.warn('lat or lon missing from msg.location')
          }
        }
      } else if (typeof msg.payload === 'string') {
                // try to decode it...
        var regexp = new RegExp('^[a-z0-9]{1,9}$') // can only contain a-z or 0-9 and length 1-9
        if (regexp.test(msg.payload)) {
          var po = geohash.decode(msg.payload)
          msg.payload = { lat: round(po.latitude, 5), lon: round(po.longitude, 5) }
          msg.payload.error = { lat: round(po.error.latitude, 5), lon: round(po.error.longitude, 5) }
          node.send(msg)
        } else if (msg.payload.indexOf(',') !== -1) {
                    // has a comma so assume it's lat,lon(,precision)
          var bits = msg.payload.split(',')
          if ((bits.length === 2) || (bits.length === 3)) {
            var li = 9
            if (bits.length === 3) {
              li = parseInt(bits[2])
              if (li < 1) { li = 1 }
              if (li > 9) { li = 9 }
            }
            var la = Number(bits[0])
            if (la < -90) { la = -90 }
            if (la > 90) { la = 90 }
            var lo = Number(bits[1])
            if (lo < -180) { lo = ((lo - 180) % 360) + 180 }
            if (lo > 180) { lo = ((lo + 180) % 360) - 180 }
            if (!isNaN(la) && !isNaN(lo)) {
              msg.payload = geohash.encode(la, lo, li)
              node.send(msg)
            } else {
              node.warn('Incorrect string format - should be lat,lon')
            }
          } else { node.warn('Unexpected string format - should be lat,lon') }
        } else { node.warn('Unexpected string format - should either be lat,lon or geohash') }
      } else if (typeof msg.payload === 'object') {
        var lat = msg.payload.lat || msg.payload.latitude
        var lon = msg.payload.lon || msg.payload.longitude
        var len = parseInt(msg.payload.precision || 9)
        if (len < 1) { len = 1 }
        if (len > 9) { len = 9 }
        if (lat && lon) {
          msg.payload.geohash = geohash.encode(lat, lon, len)
          node.send(msg)
        } else {
          node.warn('lat or lon missing from msg.payload')
        }
      } else {
        node.warn('This node only expects strings or objects.')
      }
    })
  }
  RED.nodes.registerType('geohash', GeohashNode)
}