NominatimSearchProvider.ts

import { Feature, Point } from "geojson";
import { makeObservable, runInAction } from "mobx";
import CesiumMath from "terriajs-cesium/Source/Core/Math";
import Rectangle from "terriajs-cesium/Source/Core/Rectangle";
import Resource from "terriajs-cesium/Source/Core/Resource";
import {
  Category,
  SearchAction
} from "../../Core/AnalyticEvents/analyticEvents";
import loadJson from "../../Core/loadJson";
import LocationSearchProviderMixin from "../../ModelMixins/SearchProviders/LocationSearchProviderMixin";
import NominatimSearchProviderTraits from "../../Traits/SearchProviders/NominatimSearchProviderTraits";
import CreateModel from "../Definition/CreateModel";
import Terria from "../Terria";
import SearchProviderResult from "./SearchProviderResults";
import SearchResult from "./SearchResult";

export default class NominatimSearchProvider extends LocationSearchProviderMixin(
  CreateModel(NominatimSearchProviderTraits)
) {
  static readonly type = "nominatim-search-provider";

  get type() {
    return NominatimSearchProvider.type;
  }

  constructor(uniqueId: string | undefined, terria: Terria) {
    super(uniqueId, terria);

    console.warn(
      "%c" +
        "This map is using the Nominatim search provider. It is not recommended for production use, consider using a different search provider instead.",
      "color: white; font-size: 24px; font-weight: bold; font-family: Helvetica, sans-serif;"
    );

    makeObservable(this);
  }

  protected logEvent(searchText: string) {
    this.terria.analytics?.logEvent(
      Category.search,
      SearchAction.nominatim,
      searchText
    );
  }

  protected async doSearch(
    searchText: string,
    searchResults: SearchProviderResult
  ): Promise<void> {
    searchResults.results.length = 0;
    searchResults.message = undefined;

    const view = this.terria.currentViewer.getCurrentCameraView();
    const bboxStr =
      CesiumMath.toDegrees(view.rectangle.west) +
      ", " +
      CesiumMath.toDegrees(view.rectangle.north) +
      ", " +
      CesiumMath.toDegrees(view.rectangle.east) +
      ", " +
      CesiumMath.toDegrees(view.rectangle.south);

    const promise = loadJson(
      new Resource({
        url: this.url,
        queryParameters: {
          q: searchText,
          viewbox: bboxStr,
          bounded: 0,
          format: "geojson",
          countrycodes: this.countryCodes,
          limit: this.maxResults
        }
      })
    );
    return promise
      .then((result) => {
        if (searchResults.isCanceled) {
          // A new search has superseded this one, so ignore the result.
          return;
        }

        if (
          !result?.features ||
          !Array.isArray(result.features) ||
          result.features.length === 0
        ) {
          searchResults.message = {
            content: "translate#viewModels.searchNoLocations"
          };
          return;
        }

        const locations: SearchResult[] = (result.features as Feature<Point>[])
          .filter(
            (feat) =>
              feat.properties && feat.geometry && feat.properties.display_name
          )
          .sort((a, b) => b.properties!.importance - a.properties!.importance)
          .map((feat) => {
            return new SearchResult({
              name: feat.properties!.display_name,
              clickAction: createZoomToFunction(this, feat),
              location: {
                latitude: feat.geometry.coordinates[1],
                longitude: feat.geometry.coordinates[0]
              }
            });
          });

        runInAction(() => {
          searchResults.results.push(...locations);
        });

        if (searchResults.results.length === 0) {
          searchResults.message = {
            content: "translate#viewModels.searchNoLocations"
          };
        }
      })
      .catch(() => {
        if (searchResults.isCanceled) {
          // A new search has superseded this one, so ignore the result.
          return;
        }

        searchResults.message = {
          content: "translate#viewModels.searchErrorOccurred"
        };
      });
  }
}

function createZoomToFunction(
  model: NominatimSearchProvider,
  resource: Feature<Point>
) {
  const [west, south, east, north] = resource.bbox!;
  const rectangle = Rectangle.fromDegrees(west, south, east, north);

  return function () {
    const terria = model.terria;
    terria.currentViewer.zoomTo(rectangle, model.flightDurationSeconds);
  };
}