Adds a limit for number of results returned in Nearest service, resolves #2872

src/engine/engine.cpp

@@ -146,7 +146,7 @@ Engine::Engine(EngineConfig &config)
 
     route_plugin = create<ViaRoutePlugin>(*query_data_facade, config.max_locations_viaroute);
     table_plugin = create<TablePlugin>(*query_data_facade, config.max_locations_distance_table);
-    nearest_plugin = create<NearestPlugin>(*query_data_facade);
+    nearest_plugin = create<NearestPlugin>(*query_data_facade, config.max_results_nearest);
     trip_plugin = create<TripPlugin>(*query_data_facade, config.max_locations_trip);
     match_plugin = create<MatchPlugin>(*query_data_facade, config.max_locations_map_matching);
     tile_plugin = create<TilePlugin>(*query_data_facade);

src/engine/engine_config.cpp

@@ -15,11 +15,15 @@ bool EngineConfig::IsValid() const
         storage_config.datasource_names_path.empty() &&
         storage_config.datasource_indexes_path.empty() && storage_config.names_data_path.empty();
 
-    const bool limits_valid =
-        (max_locations_distance_table == -1 || max_locations_distance_table > 2) &&
-        (max_locations_map_matching == -1 || max_locations_map_matching > 2) &&
-        (max_locations_trip == -1 || max_locations_trip > 2) &&
-        (max_locations_viaroute == -1 || max_locations_viaroute > 2);
+    const auto unlimited_or_more_than = [](const int v, const int limit) {
+        return v == -1 || v > limit;
+    };
+
+    const bool limits_valid = unlimited_or_more_than(max_locations_distance_table, 2) &&
+                              unlimited_or_more_than(max_locations_map_matching, 2) &&
+                              unlimited_or_more_than(max_locations_trip, 2) &&
+                              unlimited_or_more_than(max_locations_viaroute, 2) &&
+                              unlimited_or_more_than(max_results_nearest, 0);
 
     return ((use_shared_memory && all_path_are_empty) || storage_config.IsValid()) && limits_valid;
 }

src/engine/plugins/nearest.cpp

@@ -16,13 +16,24 @@ namespace engine
 namespace plugins
 {
 
-NearestPlugin::NearestPlugin(datafacade::BaseDataFacade &facade) : BasePlugin{facade} {}
+NearestPlugin::NearestPlugin(datafacade::BaseDataFacade &facade, const int max_results_)
+    : BasePlugin{facade}, max_results{max_results_}
+{
+}
 
 Status NearestPlugin::HandleRequest(const api::NearestParameters &params,
                                     util::json::Object &json_result)
 {
     BOOST_ASSERT(params.IsValid());
 
+    if (params.number_of_results > max_results)
+    {
+        return Error("TooBig",
+                     "Number of results " + std::to_string(params.number_of_results) +
+                         " is higher than current maximum (" + std::to_string(max_results) + ")",
+                     json_result);
+    }
+
     if (!CheckAllCoordinates(params.coordinates))
         return Error("InvalidOptions", "Coordinates are invalid", json_result);