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Diffstat (limited to 'examples/node/dynamic_codegen/route_guide/route_guide_server.js')
-rw-r--r-- | examples/node/dynamic_codegen/route_guide/route_guide_server.js | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/examples/node/dynamic_codegen/route_guide/route_guide_server.js b/examples/node/dynamic_codegen/route_guide/route_guide_server.js new file mode 100644 index 0000000000..6d59348cc9 --- /dev/null +++ b/examples/node/dynamic_codegen/route_guide/route_guide_server.js @@ -0,0 +1,253 @@ +/* + * + * Copyright 2015, 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; |