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Diffstat (limited to 'examples/csharp/route_guide/RouteGuideServer/RouteGuideImpl.cs')
| -rw-r--r-- | examples/csharp/route_guide/RouteGuideServer/RouteGuideImpl.cs | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/examples/csharp/route_guide/RouteGuideServer/RouteGuideImpl.cs b/examples/csharp/route_guide/RouteGuideServer/RouteGuideImpl.cs new file mode 100644 index 0000000000..0bdf386fc3 --- /dev/null +++ b/examples/csharp/route_guide/RouteGuideServer/RouteGuideImpl.cs @@ -0,0 +1,184 @@ +using System; +using System.Collections.Concurrent; +using System.Collections.Generic; +using System.Diagnostics; +using System.Linq; +using System.Text; +using System.Threading.Tasks; + +namespace examples +{ + /// <summary> + /// Example implementation of RouteGuide server. + /// </summary> + public class RouteGuideImpl : RouteGuide.IRouteGuide + { + readonly List<Feature> features; + private readonly ConcurrentDictionary<Point, List<RouteNote>> routeNotes = + new ConcurrentDictionary<Point, List<RouteNote>>(); + + public RouteGuideImpl(List<Feature> features) + { + this.features = features; + } + + /// <summary> + /// Gets the feature at the requested point. If no feature at that location + /// exists, an unnammed feature is returned at the provided location. + /// </summary> + public Task<Feature> GetFeature(Grpc.Core.ServerCallContext context, Point request) + { + return Task.FromResult(CheckFeature(request)); + } + + /// <summary> + /// Gets all features contained within the given bounding rectangle. + /// </summary> + public async Task ListFeatures(Grpc.Core.ServerCallContext context, Rectangle request, Grpc.Core.IServerStreamWriter<Feature> responseStream) + { + int left = Math.Min(request.Lo.Longitude, request.Hi.Longitude); + int right = Math.Max(request.Lo.Longitude, request.Hi.Longitude); + int top = Math.Max(request.Lo.Latitude, request.Hi.Latitude); + int bottom = Math.Min(request.Lo.Latitude, request.Hi.Latitude); + + foreach (var feature in features) + { + if (!RouteGuideUtil.Exists(feature)) + { + continue; + } + + int lat = feature.Location.Latitude; + int lon = feature.Location.Longitude; + if (lon >= left && lon <= right && lat >= bottom && lat <= top) + { + await responseStream.WriteAsync(feature); + } + } + } + + /// <summary> + /// 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. + /// </summary> + public async Task<RouteSummary> RecordRoute(Grpc.Core.ServerCallContext context, Grpc.Core.IAsyncStreamReader<Point> requestStream) + { + int pointCount = 0; + int featureCount = 0; + int distance = 0; + Point previous = null; + var stopwatch = new Stopwatch(); + stopwatch.Start(); + + while (await requestStream.MoveNext()) + { + var point = requestStream.Current; + pointCount++; + if (RouteGuideUtil.Exists(CheckFeature(point))) + { + featureCount++; + } + if (previous != null) + { + distance += (int) CalcDistance(previous, point); + } + previous = point; + } + + stopwatch.Stop(); + return RouteSummary.CreateBuilder().SetPointCount(pointCount) + .SetFeatureCount(featureCount).SetDistance(distance) + .SetElapsedTime((int) (stopwatch.ElapsedMilliseconds / 1000)).Build(); + } + + /// <summary> + /// Receives a stream of message/location pairs, and responds with a stream of all previous + /// messages at each of those locations. + /// </summary> + public async Task RouteChat(Grpc.Core.ServerCallContext context, Grpc.Core.IAsyncStreamReader<RouteNote> requestStream, Grpc.Core.IServerStreamWriter<RouteNote> responseStream) + { + while (await requestStream.MoveNext()) + { + var note = requestStream.Current; + List<RouteNote> notes = GetOrCreateNotes(note.Location); + + List<RouteNote> prevNotes; + lock (notes) + { + prevNotes = new List<RouteNote>(notes); + } + + foreach (var prevNote in prevNotes) + { + await responseStream.WriteAsync(prevNote); + } + + lock (notes) + { + notes.Add(note); + } + } + } + + + /// <summary> + /// Get the notes list for the given location. If missing, create it. + /// </summary> + private List<RouteNote> GetOrCreateNotes(Point location) + { + List<RouteNote> notes = new List<RouteNote>(); + routeNotes.TryAdd(location, notes); + return routeNotes[location]; + } + + /// <summary> + /// Gets the feature at the given point. + /// </summary> + /// <param name="location">the location to check</param> + /// <returns>The feature object at the point Note that an empty name indicates no feature.</returns> + private Feature CheckFeature(Point location) + { + foreach (var feature in features) + { + if (feature.Location.Latitude == location.Latitude + && feature.Location.Longitude == location.Longitude) + { + return feature; + } + } + + // No feature was found, return an unnamed feature. + return Feature.CreateBuilder().SetName("").SetLocation(location).Build(); + } + + /// <summary> + /// Calculate the distance between two points using the "haversine" formula. + /// This code was taken from http://www.movable-type.co.uk/scripts/latlong.html. + /// </summary> + /// <param name="start">the starting point</param> + /// <param name="end">the end point</param> + /// <returns>the distance between the points in meters</returns> + private static double CalcDistance(Point start, Point end) + { + double lat1 = RouteGuideUtil.GetLatitude(start); + double lat2 = RouteGuideUtil.GetLatitude(end); + double lon1 = RouteGuideUtil.GetLongitude(start); + double lon2 = RouteGuideUtil.GetLongitude(end); + int r = 6371000; // metres + double φ1 = ToRadians(lat1); + double φ2 = ToRadians(lat2); + double Δφ = ToRadians(lat2 - lat1); + double Δλ = ToRadians(lon2 - lon1); + + double a = Math.Sin(Δφ / 2) * Math.Sin(Δφ / 2) + Math.Cos(φ1) * Math.Cos(φ2) * Math.Sin(Δλ / 2) * Math.Sin(Δλ / 2); + double c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a)); + + return r * c; + } + + private static double ToRadians(double val) + { + return (Math.PI / 180) * val; + } + } +} |