Use Zip.js to support ZIP files that do not contain compressed size i…

…nfo (#47)
FacilMap · Jul 18, 2024 · 181d1c7 · 181d1c7
1 parent 285bbd2
commit 181d1c7
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Showing 3 changed files with 18 additions and 30 deletions.
diff --git a/frontend/package.json b/frontend/package.json
@@ -42,6 +42,7 @@
     "@ckpack/vue-color": "^1.5.0",
     "@tmcw/togeojson": "^5.8.1",
     "@vitejs/plugin-vue": "^5.0.4",
+    "@zip.js/zip.js": "^2.7.47",
     "blob": "^0.1.0",
     "bootstrap": "^5.3.3",
     "copy-to-clipboard": "^3.3.3",

diff --git a/frontend/src/lib/utils/files.ts b/frontend/src/lib/utils/files.ts
@@ -24,36 +24,15 @@ export interface FileResultObject {
 }
 
 async function extractKmz(zip: Uint8Array): Promise<Uint8Array | undefined> {
-	const dataView = new DataView(zip.buffer);
-	let index = 0;
-	while (true) { // eslint-disable-line no-constant-condition
-		const signature = dataView.getUint32(index, true);
-		if (signature === 0x04034b50) { // local file
-			const fileNameLength = dataView.getUint16(index + 26, true);
-			const fileName = [...zip.slice(index + 30, index + 30 + fileNameLength)].map((b) => String.fromCharCode(b)).join("");
-			const startsAt = index + 30 + fileNameLength + dataView.getUint16(index + 28, true);
-			const compressedSize = dataView.getUint32(index + 18, true);
-			// According to https://developers.google.com/kml/documentation/kmzarchives#recommended-directory-structure, the first .kml
-			// file on the root level is used.
-			if (!fileName.includes("/") && fileName.toLowerCase().endsWith(".kml")) {
-				const compressionMethod = dataView.getUint16(index + 8, true);
-				const buffer = zip.slice(startsAt, startsAt + compressedSize);
-				if (compressionMethod === 0x00){
-					return buffer;
-				} else if (compressionMethod === 0x08) {
-					return new Uint8Array(await new Response(new Blob([buffer]).stream().pipeThrough(new DecompressionStream("deflate-raw"))).arrayBuffer());
-				} else {
-					throw new Error(`Unknown compression method 0x${compressionMethod.toString(16)}`);
-				}
-			} else {
-				index = startsAt + compressedSize;
-			}
-		} else if (signature === 0x02014b50) { // central directory
-			index += 46 + dataView.getUint16(index + 28, true) + dataView.getUint16(index + 30, true) + dataView.getUint16(index + 32, true);
-		} else if (signature === 0x06054b50) { // end of central directory
-			break;
-		} else {
-			throw new Error(`Unrecognized signature 0x${signature.toString(16)}`);
+	const { ZipReader, Uint8ArrayReader, Uint8ArrayWriter } = await import("@zip.js/zip.js");
+
+	const entries = await new ZipReader(new Uint8ArrayReader(zip)).getEntries();
+
+	for (const entry of entries) {
+		// According to https://developers.google.com/kml/documentation/kmzarchives#recommended-directory-structure, the first .kml
+		// file on the root level is used.
+		if (entry.filename.toLowerCase().endsWith(".kml") && !entry.filename.includes("/") && entry.getData) {
+			return await entry.getData(new Uint8ArrayWriter());
 		}
 	}
 }

diff --git a/yarn.lock b/yarn.lock
@@ -1862,6 +1862,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@zip.js/zip.js@npm:^2.7.47":
+  version: 2.7.47
+  resolution: "@zip.js/zip.js@npm:2.7.47"
+  checksum: 027c72f20babd58feb672a0a4edde9bd8630fd5350805d95afe4ad6f6470897da918ff4fd06e4c41398f391162796aac53564f80baa36acb8e07a22244ff9224
+  languageName: node
+  linkType: hard
+
 "JSONStream@npm:0.8.0":
   version: 0.8.0
   resolution: "JSONStream@npm:0.8.0"
@@ -3978,6 +3985,7 @@ __metadata:
     "@types/lodash-es": ^4.17.12
     "@types/pluralize": ^0.0.33
     "@vitejs/plugin-vue": ^5.0.4
+    "@zip.js/zip.js": ^2.7.47
     blob: ^0.1.0
     bootstrap: ^5.3.3
     copy-to-clipboard: ^3.3.3