Initial checkin of gRPC to third_party/

third_party/grpc/examples/node/route_guide/route_guide_server.js

+/*
+ *
+ * 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;