featureserver/lib/query/render-features.js

*An open source implementation of the GeoServices specification*

const _ = require('lodash')
const {
  QueryFields
} = require('../helpers/fields')
const {
  getCollectionCrs,
  normalizeSpatialReference
} = require('../helpers')
const featureResponseTemplate = require('../../templates/features.json')

/**
 * Modifies a template features json file with metadata, capabilities, and data from the model
 * @param {object} data - data from provider model
 * @param {object} params
 * @return {object} formatted features data
 */
function renderFeaturesResponse (data = {}, params = {}) {
  const template = _.cloneDeep(featureResponseTemplate)

  const {
    uniqueIdField: uniqueIdFieldDefault,
    objectIdFieldName: objectIdFieldNameDefault
  } = template

  const {
    metadata: {
      limitExceeded,
      transform,
      idField
    } = {}
  } = data

  const computedProperties = {
    geometryType: params.geometryType,
    spatialReference: getOutputSpatialReference(data, params),
    fields: QueryFields.create({ ...data, ...params }),
    features: data.features || [],
    exceededTransferLimit: !!limitExceeded,
    objectIdFieldName: idField || objectIdFieldNameDefault,
    uniqueIdField: {
      ...uniqueIdFieldDefault,
      name: idField || uniqueIdFieldDefault.name
    }
  }

  if (transform) {
    computedProperties.transform = transform
  }

  return { ...template, ...computedProperties }
}

function getOutputSpatialReference (collection, {
  outSR,
  outputCrs,
  inputCrs,
  sourceSR
}) {
  const spatialReference = outputCrs || outSR || inputCrs || sourceSR || getCollectionCrs(collection) || 4326

  const { wkid, wkt, latestWkid } = normalizeSpatialReference(spatialReference)

  if (wkid && latestWkid) {
    return { wkid, latestWkid }
  }

  if (wkid) {
    return { wkid }
  }

  if (latestWkid) {
    return { latestWkid }
  }

  return { wkt }
}

module.exports = { renderFeaturesResponse }