From 6fd3f8f3e2e3335dda582c202549e4ef389146f3 Mon Sep 17 00:00:00 2001
From: Ib Green <ib@foursquare.com>
Date: Mon, 2 Oct 2023 00:00:57 +0200
Subject: [PATCH] feat(pmtiles): Create PMTileSource from Blob (#2668)

---
 modules/loader-utils/src/loader-types.ts    |  1 +
 modules/pmtiles/src/pmtiles-source.ts       | 38 ++++++++++++++++++---
 modules/pmtiles/test/pmtiles-source.spec.ts | 26 +++++++++++---
 3 files changed, 55 insertions(+), 10 deletions(-)

diff --git a/modules/loader-utils/src/loader-types.ts b/modules/loader-utils/src/loader-types.ts
index 33eb973195..719e53f9dd 100644
--- a/modules/loader-utils/src/loader-types.ts
+++ b/modules/loader-utils/src/loader-types.ts
@@ -166,6 +166,7 @@ export type LoaderWithParser<DataT = any, BatchT = any, LoaderOptionsT = LoaderO
     options?: LoaderOptionsT,
     context?: LoaderContext
   ) => Promise<DataT>;
+  parseFile?: (file: Blob, options?: LoaderOptionsT, context?: LoaderContext) => Promise<DataT>;
   /** Parse atomically from an arraybuffer synchronously */
   parseSync?: (
     arrayBuffer: ArrayBuffer,
diff --git a/modules/pmtiles/src/pmtiles-source.ts b/modules/pmtiles/src/pmtiles-source.ts
index 38b1828574..3d1b5326b3 100644
--- a/modules/pmtiles/src/pmtiles-source.ts
+++ b/modules/pmtiles/src/pmtiles-source.ts
@@ -4,16 +4,43 @@ import {DataSource, resolvePath} from '@loaders.gl/loader-utils';
 import {ImageLoader} from '@loaders.gl/images';
 import {MVTLoader, MVTLoaderOptions} from '@loaders.gl/mvt';
 
-import {PMTiles} from 'pmtiles';
-// import type {pPMTilesMetadata} from './lib/parse-pmtiles';
-import {PMTilesMetadata, parsePMTilesHeader} from './lib/parse-pmtiles';
+import {PMTiles, Source, RangeResponse} from 'pmtiles';
+
+import type {PMTilesMetadata} from './lib/parse-pmtiles';
+import {parsePMTilesHeader} from './lib/parse-pmtiles';
 import {TileLoadParameters} from 'modules/loader-utils/src/lib/sources/tile-source';
 
 export type PMTilesSourceProps = DataSourceProps & {
-  url: string;
+  url: string | Blob;
   attributions?: string[];
 };
 
+export class BlobSource implements Source {
+  blob: Blob;
+  key: string;
+
+  constructor(blob: Blob, key: string) {
+    this.blob = blob;
+    this.key = key;
+  }
+
+  // TODO - how is this used?
+  getKey() {
+    // @ts-expect-error url is only defined on File subclass
+    return this.blob.url || '';
+  }
+
+  async getBytes(offset: number, length: number, signal?: AbortSignal): Promise<RangeResponse> {
+    const slice = this.blob.slice(offset, offset + length);
+    const data = await slice.arrayBuffer();
+    return {
+      data
+      // etag: response.headers.get('ETag') || undefined,
+      // cacheControl: response.headers.get('Cache-Control') || undefined,
+      // expires: response.headers.get('Expires') || undefined
+    };
+  }
+}
 /**
  * A PMTiles data source
  * @note Can be either a raster or vector tile source depending on the contents of the PMTiles file.
@@ -26,7 +53,8 @@ export class PMTilesSource extends DataSource implements ImageTileSource, Vector
   constructor(props: PMTilesSourceProps) {
     super(props);
     this.props = props;
-    const url = resolvePath(props.url);
+    const url =
+      typeof props.url === 'string' ? resolvePath(props.url) : new BlobSource(props.url, 'pmtiles');
     this.pmtiles = new PMTiles(url);
     this.getTileData = this.getTileData.bind(this);
     this.metadata = this.getMetadata();
diff --git a/modules/pmtiles/test/pmtiles-source.spec.ts b/modules/pmtiles/test/pmtiles-source.spec.ts
index 8f15083b35..ac452bd91a 100644
--- a/modules/pmtiles/test/pmtiles-source.spec.ts
+++ b/modules/pmtiles/test/pmtiles-source.spec.ts
@@ -1,21 +1,37 @@
 // loaders.gl, MIT license
 
 import test from 'tape-promise/tape';
-import {isBrowser} from '@loaders.gl/loader-utils';
+import {isBrowser, fetchFile} from '@loaders.gl/core';
 
 import {PMTILESETS} from './data/tilesets';
 import {PMTilesSource} from '@loaders.gl/pmtiles';
 
-test('PMTilesSource', async (t) => {
+test('PMTilesSource#urls', async (t) => {
   if (!isBrowser) {
     t.comment('PMTilesSource currently only supported in browser');
     t.end();
     return;
   }
   for (const tilesetUrl of PMTILESETS) {
-    const source = new PMTilesSource({
-      url: tilesetUrl
-    });
+    const source = new PMTilesSource({url: tilesetUrl});
+    t.ok(source);
+    const metadata = await source.getMetadata();
+    t.ok(metadata);
+    // console.error(JSON.stringify(metadata.tileJSON, null, 2));
+  }
+  t.end();
+});
+
+test('PMTilesSource#Blobs', async (t) => {
+  if (!isBrowser) {
+    t.comment('PMTilesSource currently only supported in browser');
+    t.end();
+    return;
+  }
+  for (const tilesetUrl of PMTILESETS) {
+    const response = await fetchFile(tilesetUrl);
+    const blob = await response.blob();
+    const source = new PMTilesSource({url: blob});
     t.ok(source);
     const metadata = await source.getMetadata();
     t.ok(metadata);