app.js

const app = require('express')();
const _ = require('lodash');
const Router = require('express').Router;
const adminLookup = require('pelias-wof-admin-lookup');
const fs = require('fs');
const path = require('path');

const morgan = require( 'morgan' );
const logger = require('pelias-logger').get('pip');
const through = require( 'through2' );

function isFiniteNumber(value) {
  return !_.isEmpty(_.trim(value)) && _.isFinite(_.toNumber(value));
}

const validate = (req, res, next) => {
  if (_.at(req.params, ['lat', 'lon']).every(isFiniteNumber)) {
    // both lat and lon are non-blank finite numbers, so validation step passes
    req.query.centroid = {
      lat: _.toNumber(req.params.lat),
      lon: _.toNumber(req.params.lon)
    };
    next();

  } else {
    res.status(400).send('Cannot parse input');
    next('route'); // skip lookup middleware and output, still logs

  }


};

// middleware that cleans up layers parameters, eg:
// 'layers=layer1,layer2' => ['layer1', 'layer2']
// 'layers= layer1 ,  , layer2 ' => ['layer1', 'layer2']
// 'layers= , , ' => undefined
// 'layers=' => undefined
// no layers parameter => undefined
const parseLayers = (req, res, next) => {
  const layers = _.split(req.query.layers, ',').reduce((layers, layer) => {
    // only add to the valid layers list if it's not reduceable to an empty string
    if (!_.isEmpty(_.trim(layer))) {
      layers.push(_.trim(layer));
    }
    return layers;
  }, []);

  // if there are no layers, remove the parameter
  if (_.isEmpty(layers)) {
    delete req.query.layers;
  } else {
    req.query.layers = layers;
  }

  next();

};

function lookup(pointInPoly) {
  return (req, res, next) => {
    pointInPoly.lookup(req.query.centroid, req.query.layers, (err, result) => {
      req.query.resolved = result;
      next();
    });
  };
}

const output = (req, res, next) => {
  res.status(200).send(req.query.resolved);
  next();
};

function log() {
  morgan.token('url', (req, res) => {
    // if there's a DNT header, just return '/' as the URL
    if (['DNT', 'dnt', 'do_not_track'].some((header) => {
      return req.headers.hasOwnProperty(header);
    })) {
      return '/[removed]/[removed]';
    } else {
      return req.originalUrl;
    }
  });

  return morgan('combined', {
    stream: through( function write( ln, _, next ){
      logger.info( ln.toString().trim() );
      next();
    })
  });
}

module.exports = () => {
  const pointInPoly = adminLookup.localResolver();

  const router = new Router();
  router.get('/:lon/:lat', validate, parseLayers, lookup(pointInPoly), output);

  app.use(log(), router);
  return app;

};