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1# Copyright 2016 gRPC authors.
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14"""A gRPC server servicing both Greeter and RouteGuide RPCs."""
15
16from concurrent import futures
17import time
18import math
19
20import grpc
21
22import helloworld_pb2
23import helloworld_pb2_grpc
24import route_guide_pb2
25import route_guide_pb2_grpc
26import route_guide_resources
27
28_ONE_DAY_IN_SECONDS = 60 * 60 * 24
29
30
31def _get_feature(feature_db, point):
32    """Returns Feature at given location or None."""
33    for feature in feature_db:
34        if feature.location == point:
35            return feature
36    return None
37
38
39def _get_distance(start, end):
40    """Distance between two points."""
41    coord_factor = 10000000.0
42    lat_1 = start.latitude / coord_factor
43    lat_2 = end.latitude / coord_factor
44    lon_1 = start.longitude / coord_factor
45    lon_2 = end.longitude / coord_factor
46    lat_rad_1 = math.radians(lat_1)
47    lat_rad_2 = math.radians(lat_2)
48    delta_lat_rad = math.radians(lat_2 - lat_1)
49    delta_lon_rad = math.radians(lon_2 - lon_1)
50
51    a = (pow(math.sin(delta_lat_rad / 2), 2) +
52         (math.cos(lat_rad_1) * math.cos(lat_rad_2) * pow(
53             math.sin(delta_lon_rad / 2), 2)))
54    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
55    R = 6371000
56    # metres
57    return R * c
58
59
60class _GreeterServicer(helloworld_pb2_grpc.GreeterServicer):
61
62    def SayHello(self, request, context):
63        return helloworld_pb2.HelloReply(
64            message='Hello, {}!'.format(request.name))
65
66
67class _RouteGuideServicer(route_guide_pb2_grpc.RouteGuideServicer):
68    """Provides methods that implement functionality of route guide server."""
69
70    def __init__(self):
71        self.db = route_guide_resources.read_route_guide_database()
72
73    def GetFeature(self, request, context):
74        feature = _get_feature(self.db, request)
75        if feature is None:
76            return route_guide_pb2.Feature(name="", location=request)
77        else:
78            return feature
79
80    def ListFeatures(self, request, context):
81        left = min(request.lo.longitude, request.hi.longitude)
82        right = max(request.lo.longitude, request.hi.longitude)
83        top = max(request.lo.latitude, request.hi.latitude)
84        bottom = min(request.lo.latitude, request.hi.latitude)
85        for feature in self.db:
86            if (feature.location.longitude >= left and
87                    feature.location.longitude <= right and
88                    feature.location.latitude >= bottom and
89                    feature.location.latitude <= top):
90                yield feature
91
92    def RecordRoute(self, request_iterator, context):
93        point_count = 0
94        feature_count = 0
95        distance = 0.0
96        prev_point = None
97
98        start_time = time.time()
99        for point in request_iterator:
100            point_count += 1
101            if _get_feature(self.db, point):
102                feature_count += 1
103            if prev_point:
104                distance += _get_distance(prev_point, point)
105            prev_point = point
106
107        elapsed_time = time.time() - start_time
108        return route_guide_pb2.RouteSummary(
109            point_count=point_count,
110            feature_count=feature_count,
111            distance=int(distance),
112            elapsed_time=int(elapsed_time))
113
114    def RouteChat(self, request_iterator, context):
115        prev_notes = []
116        for new_note in request_iterator:
117            for prev_note in prev_notes:
118                if prev_note.location == new_note.location:
119                    yield prev_note
120            prev_notes.append(new_note)
121
122
123def serve():
124    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
125    helloworld_pb2_grpc.add_GreeterServicer_to_server(_GreeterServicer(),
126                                                      server)
127    route_guide_pb2_grpc.add_RouteGuideServicer_to_server(
128        _RouteGuideServicer(), server)
129    server.add_insecure_port('[::]:50051')
130    server.start()
131    try:
132        while True:
133            time.sleep(_ONE_DAY_IN_SECONDS)
134    except KeyboardInterrupt:
135        server.stop(0)
136
137
138if __name__ == '__main__':
139    serve()
140