PMTiles/js/adapters.ts

declare const L: any;
declare const window: any;
declare const document: any;

import { PMTiles, Source, TileType } from "./index";

export const leafletRasterLayer = (source: PMTiles, options: any) => {
  const cls = L.GridLayer.extend({
    createTile: function (coord: any, done: any) {
      const el: any = document.createElement("img");
      const controller = new AbortController();
      const signal = controller.signal;
      el.cancel = () => {
        controller.abort();
      };
      source
        .getZxy(coord.z, coord.x, coord.y, signal)
        .then((arr) => {
          if (arr) {
            const blob = new Blob([arr.data]);
            const imageUrl = window.URL.createObjectURL(blob);
            el.src = imageUrl;
            el.cancel = null;
            done(null, el);
          }
        })
        .catch((e) => {
          if (e.name !== "AbortError") {
            throw e;
          }
        });
      return el;
    },

    _removeTile: function (key: string) {
      const tile = this._tiles[key];
      if (!tile) {
        return;
      }

      if (tile.el.cancel) tile.el.cancel();

      tile.el.width = 0;
      tile.el.height = 0;
      tile.el.deleted = true;
      L.DomUtil.remove(tile.el);
      delete this._tiles[key];
      this.fire("tileunload", {
        tile: tile.el,
        coords: this._keyToTileCoords(key),
      });
    },
  });
  return new cls(options);
};

// copied from MapLibre /util/ajax.ts
type RequestParameters = {
  url: string;
  headers?: any;
  method?: "GET" | "POST" | "PUT";
  body?: string;
  type?: "string" | "json" | "arrayBuffer";
  credentials?: "same-origin" | "include";
  collectResourceTiming?: boolean;
};

type ResponseCallback = (
  error?: Error | null,
  data?: any | null,
  cacheControl?: string | null,
  expires?: string | null
) => void;

type Cancelable = {
  cancel: () => void;
};

export class Protocol {
  tiles: Map<string, PMTiles>;

  constructor() {
    this.tiles = new Map<string, PMTiles>();
  }

  add(p: PMTiles) {
    this.tiles.set(p.source.getKey(), p);
  }

  get(url: string) {
    return this.tiles.get(url);
  }

  tile = (
    params: RequestParameters,
    callback: ResponseCallback
  ): Cancelable => {
    if (params.type == "json") {
      const pmtiles_url = params.url.substr(10);
      let instance = this.tiles.get(pmtiles_url);
      if (!instance) {
        instance = new PMTiles(pmtiles_url);
        this.tiles.set(pmtiles_url, instance);
      }

      // TODO: create vector_layers if present to return valid TileJSON

      instance.getHeader().then((h) => {
        const tilejson = {
          tiles: [params.url + "/{z}/{x}/{y}"],
          minzoom: h.minZoom,
          maxzoom: h.maxZoom,
        };
        callback(null, tilejson, null, null);
      });
      return {
        cancel: () => {},
      };
    } else {
      const re = new RegExp(/pmtiles:\/\/(.+)\/(\d+)\/(\d+)\/(\d+)/);
      const result = params.url.match(re);
      if (!result) {
        throw new Error("Invalid PMTiles protocol URL");
        return {
          cancel: () => {},
        };
      }
      const pmtiles_url = result[1];

      let instance = this.tiles.get(pmtiles_url);
      if (!instance) {
        instance = new PMTiles(pmtiles_url);
        this.tiles.set(pmtiles_url, instance);
      }
      const z = result[2];
      const x = result[3];
      const y = result[4];

      const controller = new AbortController();
      const signal = controller.signal;
      let cancel = () => {
        controller.abort();
      };

      instance.getHeader().then((header) => {
        instance!
          .getZxy(+z, +x, +y, signal)
          .then((resp) => {
            if (resp) {
              callback(
                null,
                new Uint8Array(resp.data),
                resp.cacheControl,
                resp.expires
              );
            } else {
              if (header.tileType == TileType.Mvt) {
                callback(null, new Uint8Array(), null, null);
              } else {
                callback(null, null, null, null);
              }
            }
          })
          .catch((e) => {
            if ((e as Error).name !== "AbortError") {
              throw e;
            }
          });
      });
      return {
        cancel: cancel,
      };
    }
  };
}