✨ Check zip format

package.json

@@ -9,7 +9,8 @@
 		"check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
 		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",
 		"format": "prettier --write .",
-		"lint": "prettier --check . && eslint ."
+		"lint": "prettier --check . && eslint .",
+		"gen": "cd dduf-content && zip -r -0 ../file.dduf . && zip -r -0 -fz ../file-64.dduf ."
 	},
 	"devDependencies": {
 		"@eslint/compat": "^1.2.3",

src/lib/check-dduf.ts

@@ -1,3 +1,4 @@
+import { checkFilename } from './check-filename';
 import { WebBlob } from './WebBlob';
 
 export async function* checkDduf(url: string): AsyncGenerator<string> {
@@ -7,9 +8,105 @@ export async function* checkDduf(url: string): AsyncGenerator<string> {
 
 	// DDUF is a zip file, uncompressed.
 
-	const last100kb = await blob.slice(blob.size - 100000, blob.size).arrayBuffer();
+	const last100kB = await blob.slice(blob.size - 100000, blob.size).arrayBuffer();
 
-	const view = new DataView(last100kb);
+	const view = new DataView(last100kB);
 
 	let index = view.byteLength - 22;
+	let found = false;
+
+	while (index >= 0) {
+		if (view.getUint32(index, true) === 0x06054b50) {
+			found = true;
+			break;
+		}
+
+		index--;
+	}
+
+	if (!found) {
+		throw new Error('DDUF footer not found in last 100kB of file');
+	}
+
+	yield 'DDUF footer found at offset ' + (blob.size - last100kB.byteLength + index);
+
+	const diskNumber = view.getUint16(index + 4, true);
+
+	if (diskNumber === 0xffff) {
+		throw new Error('Spanned archives (ZIP64) not yet supported');
+	}
+
+	if (diskNumber !== 0) {
+		throw new Error('Multi-disk archives not supported');
+	}
+
+	const fileCount = view.getUint16(index + 10, true);
+	const centralDirSize = view.getUint32(index + 12, true);
+	const centralDirOffset = view.getUint32(index + 16, true);
+
+	yield 'File count: ' + fileCount;
+	yield 'Central directory size: ' + centralDirSize;
+	yield 'Central directory offset: ' + centralDirOffset;
+
+	const centralDir =
+		centralDirOffset > blob.size - last100kB.byteLength
+			? last100kB.slice(
+					centralDirOffset - (blob.size - last100kB.byteLength),
+					centralDirOffset - (blob.size - last100kB.byteLength) + centralDirSize
+				)
+			: await blob.slice(centralDirOffset, centralDirOffset + centralDirSize).arrayBuffer();
+
+	const centralDirView = new DataView(centralDir);
+	let offset = 0;
+
+	for (let i = 0; i < fileCount; i++) {
+		if (centralDirView.getUint32(offset + 0, true) !== 0x02014b50) {
+			throw new Error('Invalid central directory file header');
+		}
+
+		if (offset + 46 > centralDir.byteLength) {
+			throw new Error('Unexpected end of central directory');
+		}
+
+		const compressionMethod = centralDirView.getUint16(offset + 10, true);
+
+		if (compressionMethod !== 0) {
+			throw new Error('Unsupported compression method: ' + compressionMethod);
+		}
+
+		const size = centralDirView.getUint32(offset + 24, true);
+		const compressedSize = centralDirView.getUint32(offset + 20, true);
+
+		if (size !== compressedSize) {
+			throw new Error('Compressed size and size differ');
+		}
+
+		const filenameLength = centralDirView.getUint16(offset + 28, true);
+		const fileName = new TextDecoder().decode(
+			new Uint8Array(centralDir, offset + 46, filenameLength)
+		);
+
+		yield 'File ' + i;
+		yield 'File name: ' + fileName;
+		yield 'File size: ' + size;
+
+		checkFilename(fileName);
+
+		const fileDiskNumber = centralDirView.getUint16(34, true);
+
+		if (fileDiskNumber !== 0) {
+			throw new Error('Multi-disk archives not supported');
+		}
+
+		const extraFieldLength = centralDirView.getUint16(offset + 30, true);
+		const commentLength = centralDirView.getUint16(offset + 32, true);
+
+		const filePosition = centralDirView.getUint32(offset + 42, true);
+
+		yield 'File position in archive: ' + filePosition;
+
+		offset += 46 + filenameLength + extraFieldLength + commentLength;
+	}
+
+	yield 'All files checked';
 }

src/lib/check-filename.ts

@@ -0,0 +1,16 @@
+export function checkFilename(filename: string) {
+	if (
+		!filename.endsWith('.safetensors') &&
+		!filename.endsWith('.json') &&
+		!filename.endsWith('.gguf') &&
+		!filename.endsWith('/')
+	) {
+		throw new Error('Files must have a .safetensors, .gguf or .json extension');
+	}
+
+	const split = filename.split('/');
+
+	if (split.length > 2) {
+		throw new Error('Files must be only one level deep, not more');
+	}
+}

src/routes/+page.svelte

@@ -1,16 +1,22 @@
 <script lang="ts">
-	import { goto } from '$app/navigation';
 	import { checkDduf } from '$lib/check-dduf';
 
 	let url = 'https://huggingface.co/spaces/coyotte508/dduf-check/resolve/main/file.dduf';
 	let output = '';
+	let error = '';
 
 	async function handleSubmit(event: Event) {
 		event.preventDefault();
 		output = 'Checking...';
+		error = '';
 
-		for await (const str of checkDduf(url)) {
-			output += '\n' + str;
+		try {
+			for await (const str of checkDduf(url)) {
+				output += '\n' + str;
+			}
+		} catch (e) {
+			console.error(e);
+			error = (e as Error).message;
 		}
 	}
 </script>
@@ -35,5 +41,9 @@
 		<textarea class="w-full rounded-md border border-gray-300 p-2" rows="10" readonly
 			>{output}</textarea
 		>
+
+		{#if error}
+			<p class="text-red-500">{error}</p>
+		{/if}
 	</form>
 </div>