145 lines
3.5 KiB
JavaScript
145 lines
3.5 KiB
JavaScript
import fs from 'node:fs';
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import PMTiles from 'pmtiles';
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import { isValidHttpUrl } from './utils.js';
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const PMTilesFileSource = class {
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constructor(fd) {
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this.fd = fd;
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}
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getKey() {
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return this.fd;
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}
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async getBytes(offset, length) {
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const buffer = Buffer.alloc(length);
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await ReadFileBytes(this.fd, buffer, offset);
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return { data: BufferToArrayBuffer(buffer) };
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}
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};
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const ReadFileBytes = async (fd, buffer, offset) => {
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return new Promise((resolve, reject) => {
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fs.read(fd, buffer, 0, buffer.length, offset, (err) => {
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if (err) {
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return reject(err);
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}
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resolve();
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});
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});
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};
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export const PMtilesOpen = (FilePath) => {
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let pmtiles = undefined;
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let fd = undefined;
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if (isValidHttpUrl(FilePath)) {
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const source = new PMTiles.FetchSource(FilePath);
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pmtiles = new PMTiles.PMTiles(source);
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} else {
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fd = fs.openSync(FilePath, 'r');
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const source = new PMTilesFileSource(fd);
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pmtiles = new PMTiles.PMTiles(source);
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}
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return { pmtiles: pmtiles, fd: fd };
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};
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export const PMtilesClose = (fd) => {
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fs.closeSync(fd);
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};
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export const GetPMtilesInfo = async (pmtiles) => {
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const header = await pmtiles.getHeader();
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const metadata = await pmtiles.getMetadata();
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//Add missing metadata from header
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metadata['format'] = GetPmtilesTileType(header.tileType).type;
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metadata['minzoom'] = header.minZoom;
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metadata['maxzoom'] = header.maxZoom;
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if (header.minLon && header.minLat && header.maxLon && header.maxLat) {
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metadata['bounds'] = [
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header.minLon,
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header.minLat,
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header.maxLon,
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header.maxLat,
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];
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} else {
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metadata['bounds'] = [-180, -85.05112877980659, 180, 85.0511287798066];
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}
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if (header.centerZoom) {
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metadata['center'] = [
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header.centerLon,
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header.centerLat,
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header.centerZoom,
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];
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} else {
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metadata['center'] = [
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header.centerLon,
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header.centerLat,
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parseInt(metadata['maxzoom']) / 2,
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];
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}
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return metadata;
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};
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export const GetPMtilesTile = async (pmtiles, z, x, y) => {
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const header = await pmtiles.getHeader();
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const TileType = GetPmtilesTileType(header.tileType);
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let zxyTile = await pmtiles.getZxy(z, x, y);
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if (zxyTile && zxyTile.data) {
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zxyTile = ArrayBufferToBuffer(zxyTile.data);
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} else {
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zxyTile = undefined;
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}
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return { data: zxyTile, header: TileType.header };
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};
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const GetPmtilesTileType = (typenum) => {
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let head = {};
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let tileType;
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switch (typenum) {
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case 0:
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tileType = 'Unknown';
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break;
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case 1:
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tileType = 'pbf';
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head['Content-Type'] = 'application/x-protobuf';
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break;
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case 2:
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tileType = 'png';
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head['Content-Type'] = 'image/png';
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break;
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case 3:
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tileType = 'jpeg';
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head['Content-Type'] = 'image/jpeg';
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break;
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case 4:
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tileType = 'webp';
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head['Content-Type'] = 'image/webp';
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break;
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case 5:
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tileType = 'avif';
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head['Content-Type'] = 'image/avif';
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break;
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}
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return { type: tileType, header: head };
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};
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const BufferToArrayBuffer = (buffer) => {
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const arrayBuffer = new ArrayBuffer(buffer.length);
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const view = new Uint8Array(arrayBuffer);
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for (let i = 0; i < buffer.length; ++i) {
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view[i] = buffer[i];
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}
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return arrayBuffer;
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};
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const ArrayBufferToBuffer = (array_buffer) => {
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var buffer = Buffer.alloc(array_buffer.byteLength);
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var view = new Uint8Array(array_buffer);
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for (var i = 0; i < buffer.length; ++i) {
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buffer[i] = view[i];
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}
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return buffer;
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};
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