refactor: add promisified wrapper for MBTiles

Signed-off-by: Aarni Koskela <akx@iki.fi>

src/main.js

@@ -8,9 +8,11 @@ import path from 'path';
 import { fileURLToPath } from 'url';
 import axios from 'axios';
 import { server } from './server.js';
-import MBTiles from '@mapbox/mbtiles';
 import { isValidHttpUrl } from './utils.js';
 import { openPMtiles, getPMtilesInfo } from './pmtiles_adapter.js';
+import { program } from 'commander';
+import { existsP } from './promises.js';
+import { openMbTilesWrapper } from './mbtiles_wrapper.js';
 
 const __filename = fileURLToPath(import.meta.url);
 const __dirname = path.dirname(__filename);
@@ -23,8 +25,6 @@ if (args.length >= 3 && args[2][0] !== '-') {
   args.splice(2, 0, '--mbtiles');
 }
 
-import { program } from 'commander';
-import { existsP } from './promises.js';
 program
   .description('tileserver-gl startup options')
   .usage('tileserver-gl [mbtiles] [options]')
@@ -184,21 +184,16 @@ const startWithInputFile = async (inputFile) => {
       );
       process.exit(1);
     }
-    const instance = new MBTiles(inputFile + '?mode=ro', (err) => {
-      if (err) {
-        console.log('ERROR: Unable to open MBTiles.');
+    let info;
+    try {
+      const mbw = await openMbTilesWrapper(inputFile);
+      info = await mbw.getInfo();
+      if (!info) throw new Error('Metadata missing in the MBTiles.');
+    } catch (err) {
+      console.log('ERROR: Unable to open MBTiles or read metadata:', err);
       console.log(`Make sure ${path.basename(inputFile)} is valid MBTiles.`);
       process.exit(1);
     }
-
-      instance.getInfo(async (err, info) => {
-        if (err || !info) {
-          console.log('ERROR: Metadata missing in the MBTiles.');
-          console.log(
-            `Make sure ${path.basename(inputFile)} is valid MBTiles.`,
-          );
-          process.exit(1);
-        }
     const bounds = info.bounds;
 
     if (
@@ -238,8 +233,6 @@ const startWithInputFile = async (inputFile) => {
     }
 
     return startServer(null, config);
-      });
-    });
   }
 };
 

src/mbtiles_wrapper.js

@@ -0,0 +1,46 @@
+import MBTiles from '@mapbox/mbtiles';
+import util from 'node:util';
+
+/**
+ * Promise-ful wrapper around the MBTiles class.
+ */
+class MBTilesWrapper {
+  constructor(mbtiles) {
+    this._mbtiles = mbtiles;
+    this._getInfoP = util.promisify(mbtiles.getInfo.bind(mbtiles));
+  }
+
+  /**
+   * Get the underlying MBTiles object.
+   * @returns {MBTiles}
+   */
+  getMbTiles() {
+    return this._mbtiles;
+  }
+
+  /**
+   * Get the MBTiles metadata object.
+   * @returns {Promise<object>}
+   */
+  getInfo() {
+    return this._getInfoP();
+  }
+}
+
+/**
+ * Open the given MBTiles file and return a promise that resolves with a
+ * MBTilesWrapper instance.
+ * @param inputFile Input file
+ * @returns {Promise<MBTilesWrapper>}
+ */
+export function openMbTilesWrapper(inputFile) {
+  return new Promise((resolve, reject) => {
+    const mbtiles = new MBTiles(inputFile + '?mode=ro', (err) => {
+      if (err) {
+        reject(err);
+        return;
+      }
+      resolve(new MBTilesWrapper(mbtiles));
+    });
+  });
+}

src/serve_data.js

@@ -5,7 +5,6 @@ import path from 'path';
 
 import clone from 'clone';
 import express from 'express';
-import MBTiles from '@mapbox/mbtiles';
 import Pbf from 'pbf';
 import { VectorTile } from '@mapbox/vector-tile';
 
@@ -16,6 +15,7 @@ import {
   openPMtiles,
 } from './pmtiles_adapter.js';
 import { gunzipP, gzipP } from './promises.js';
+import { openMbTilesWrapper } from './mbtiles_wrapper.js';
 
 export const serve_data = {
   init: (options, repo) => {
@@ -242,17 +242,9 @@ export const serve_data = {
       }
     } else if (inputType === 'mbtiles') {
       sourceType = 'mbtiles';
-      const sourceInfoPromise = new Promise((resolve, reject) => {
-        source = new MBTiles(inputFile + '?mode=ro', (err) => {
-          if (err) {
-            reject(err);
-            return;
-          }
-          source.getInfo((err, info) => {
-            if (err) {
-              reject(err);
-              return;
-            }
+      const mbw = await openMbTilesWrapper(inputFile);
+      const info = await mbw.getInfo();
+      source = mbw.getMbTiles();
       tileJSON['name'] = id;
       tileJSON['format'] = 'pbf';
 
@@ -269,12 +261,6 @@ export const serve_data = {
       if (options.dataDecoratorFunc) {
         tileJSON = options.dataDecoratorFunc(id, 'tilejson', tileJSON);
       }
-            resolve();
-          });
-        });
-      });
-
-      await sourceInfoPromise;
     }
 
     repo[id] = {

src/serve_rendered.js

@@ -24,7 +24,6 @@ import express from 'express';
 import sanitize from 'sanitize-filename';
 import SphericalMercator from '@mapbox/sphericalmercator';
 import mlgl from '@maplibre/maplibre-gl-native';
-import MBTiles from '@mapbox/mbtiles';
 import polyline from '@mapbox/polyline';
 import proj4 from 'proj4';
 import axios from 'axios';
@@ -43,6 +42,7 @@ import {
 import { renderOverlay, renderWatermark, renderAttribution } from './render.js';
 import fsp from 'node:fs/promises';
 import { gunzipP } from './promises.js';
+import { openMbTilesWrapper } from './mbtiles_wrapper.js';
 
 const FLOAT_PATTERN = '[+-]?(?:\\d+|\\d+.?\\d+)';
 const PATH_PATTERN =
@@ -1131,7 +1131,6 @@ export const serve_rendered = {
     };
     repo[id] = repoobj;
 
-    const queue = [];
     for (const name of Object.keys(styleJSON.sources)) {
       let sourceType;
       let source = styleJSON.sources[name];
@@ -1205,19 +1204,13 @@ export const serve_rendered = {
             }
           }
         } else {
-          queue.push(
-            new Promise(async (resolve, reject) => {
-              inputFile = path.resolve(options.paths.mbtiles, inputFile);
           const inputFileStats = await fsp.stat(inputFile);
           if (!inputFileStats.isFile() || inputFileStats.size === 0) {
             throw Error(`Not valid MBTiles file: "${inputFile}"`);
           }
-              map.sources[name] = new MBTiles(inputFile + '?mode=ro', (err) => {
-                map.sources[name].getInfo((err, info) => {
-                  if (err) {
-                    console.error(err);
-                    return;
-                  }
+          const mbw = await openMbTilesWrapper(inputFile);
+          const info = await mbw.getInfo();
+          map.sources[name] = mbw.getMbTiles();
           map.sourceTypes[name] = 'mbtiles';
 
           if (!repoobj.dataProjWGStoInternalWGS && info.proj4) {
@@ -1238,11 +1231,7 @@ export const serve_rendered = {
           delete source.scheme;
 
           if (options.dataDecoratorFunc) {
-                    source = options.dataDecoratorFunc(
-                      name,
-                      'tilejson',
-                      source,
-                    );
+            source = options.dataDecoratorFunc(name, 'tilejson', source);
           }
 
           if (
@@ -1257,17 +1246,10 @@ export const serve_rendered = {
               tileJSON.attribution += source.attribution;
             }
           }
-                  resolve();
-                });
-              });
-            }),
-          );
         }
       }
     }
 
-    await Promise.all(queue);
-
     // standard and @2x tiles are much more usual -> default to larger pools
     const minPoolSizes = options.minRendererPoolSizes || [8, 4, 2];
     const maxPoolSizes = options.maxRendererPoolSizes || [16, 8, 4];