aboutsummaryrefslogtreecommitdiffhomepage
path: root/examples/node/dynamic_codegen/route_guide/route_guide_server.js
blob: 6d59348cc925659e4d0d9e7664b72d7289fe19ab (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
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;