/* * * Copyright 2015-2016, Google Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ var PROTO_PATH = __dirname + '/../../protos/route_guide.proto'; var fs = require('fs'); var parseArgs = require('minimist'); var path = require('path'); var _ = require('lodash'); var grpc = require('grpc'); var routeguide = grpc.load(PROTO_PATH).routeguide; var COORD_FACTOR = 1e7; /** * For simplicity, a point is a record type that looks like * {latitude: number, longitude: number}, and a feature is a record type that * looks like {name: string, location: point}. feature objects with name==='' * are points with no feature. */ /** * List of feature objects at points that have been requested so far. */ var feature_list = []; /** * Get a feature object at the given point, or creates one if it does not exist. * @param {point} point The point to check * @return {feature} The feature object at the point. Note that an empty name * indicates no feature */ function checkFeature(point) { var feature; // Check if there is already a feature object for the given point for (var i = 0; i < feature_list.length; i++) { feature = feature_list[i]; if (feature.location.latitude === point.latitude && feature.location.longitude === point.longitude) { return feature; } } var name = ''; feature = { name: name, location: point }; return feature; } /** * getFeature request handler. Gets a request with a point, and responds with a * feature object indicating whether there is a feature at that point. * @param {EventEmitter} call Call object for the handler to process * @param {function(Error, feature)} callback Response callback */ function getFeature(call, callback) { callback(null, checkFeature(call.request)); } /** * listFeatures request handler. Gets a request with two points, and responds * with a stream of all features in the bounding box defined by those points. * @param {Writable} call Writable stream for responses with an additional * request property for the request value. */ function listFeatures(call) { var lo = call.request.lo; var hi = call.request.hi; var left = _.min([lo.longitude, hi.longitude]); var right = _.max([lo.longitude, hi.longitude]); var top = _.max([lo.latitude, hi.latitude]); var bottom = _.min([lo.latitude, hi.latitude]); // For each feature, check if it is in the given bounding box _.each(feature_list, function(feature) { if (feature.name === '') { return; } if (feature.location.longitude >= left && feature.location.longitude <= right && feature.location.latitude >= bottom && feature.location.latitude <= top) { call.write(feature); } }); call.end(); } /** * Calculate the distance between two points using the "haversine" formula. * This code was taken from http://www.movable-type.co.uk/scripts/latlong.html. * @param start The starting point * @param end The end point * @return The distance between the points in meters */ function getDistance(start, end) { function toRadians(num) { return num * Math.PI / 180; } var lat1 = start.latitude / COORD_FACTOR; var lat2 = end.latitude / COORD_FACTOR; var lon1 = start.longitude / COORD_FACTOR; var lon2 = end.longitude / COORD_FACTOR; var R = 6371000; // metres var φ1 = toRadians(lat1); var φ2 = toRadians(lat2); var Δφ = toRadians(lat2-lat1); var Δλ = toRadians(lon2-lon1); var a = Math.sin(Δφ/2) * Math.sin(Δφ/2) + Math.cos(φ1) * Math.cos(φ2) * Math.sin(Δλ/2) * Math.sin(Δλ/2); var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); return R * c; } /** * recordRoute handler. Gets a stream of points, and responds with statistics * about the "trip": number of points, number of known features visited, total * distance traveled, and total time spent. * @param {Readable} call The request point stream. * @param {function(Error, routeSummary)} callback The callback to pass the * response to */ function recordRoute(call, callback) { var point_count = 0; var feature_count = 0; var distance = 0; var previous = null; // Start a timer var start_time = process.hrtime(); call.on('data', function(point) { point_count += 1; if (checkFeature(point).name !== '') { feature_count += 1; } /* For each point after the first, add the incremental distance from the * previous point to the total distance value */ if (previous != null) { distance += getDistance(previous, point); } previous = point; }); call.on('end', function() { callback(null, { point_count: point_count, feature_count: feature_count, // Cast the distance to an integer distance: distance|0, // End the timer elapsed_time: process.hrtime(start_time)[0] }); }); } var route_notes = {}; /** * Turn the point into a dictionary key. * @param {point} point The point to use * @return {string} The key for an object */ function pointKey(point) { return point.latitude + ' ' + point.longitude; } /** * routeChat handler. Receives a stream of message/location pairs, and responds * with a stream of all previous messages at each of those locations. * @param {Duplex} call The stream for incoming and outgoing messages */ function routeChat(call) { call.on('data', function(note) { var key = pointKey(note.location); /* For each note sent, respond with all previous notes that correspond to * the same point */ if (route_notes.hasOwnProperty(key)) { _.each(route_notes[key], function(note) { call.write(note); }); } else { route_notes[key] = []; } // Then add the new note to the list route_notes[key].push(JSON.parse(JSON.stringify(note))); }); call.on('end', function() { call.end(); }); } /** * Get a new server with the handler functions in this file bound to the methods * it serves. * @return {Server} The new server object */ function getServer() { var server = new grpc.Server(); server.addProtoService(routeguide.RouteGuide.service, { getFeature: getFeature, listFeatures: listFeatures, recordRoute: recordRoute, routeChat: routeChat }); return server; } if (require.main === module) { // If this is run as a script, start a server on an unused port var routeServer = getServer(); routeServer.bind('0.0.0.0:50051', grpc.ServerCredentials.createInsecure()); var argv = parseArgs(process.argv, { string: 'db_path' }); fs.readFile(path.resolve(argv.db_path), function(err, data) { if (err) throw err; feature_list = JSON.parse(data); routeServer.start(); }); } exports.getServer = getServer;