feat: allow user to config Gemma 4 E4B and MDX-NET model download URL

src/util/localLLMConfig.ts

@@ -1,7 +1,8 @@
 export const LOCAL_LLM_PROVIDER_KEY = 'local_browser';
-export const LOCAL_LLM_MODEL_URL =
+export const LOCAL_LLM_DEFAULT_MODEL_URL =
   'https://huggingface.co/notabilia/gemma-4-E4B-it-litert-lm/resolve/main/gemma-4-E4B-it-web.task';
 export const LOCAL_LLM_MODEL_FILENAME = 'gemma-4-E4B-it-web.task';
+export const LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES = 2964324352;
 export const LOCAL_LLM_DISPLAY_NAME = 'Gemma 4 E4B';
 export const LOCAL_LLM_LEGACY_FILENAMES = [
   'gemma-3n-E4B-it-int4-Web.litertlm',

src/util/localLLMModelCache.ts

@@ -1,5 +1,5 @@
 import { OpfsModelCache, type ModelDownloadProgress } from './opfsModelCache';
-import { LOCAL_LLM_MODEL_FILENAME } from './localLLMConfig';
+import { LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES, LOCAL_LLM_MODEL_FILENAME } from './localLLMConfig';
 
 const cache = new OpfsModelCache({ directoryName: 'models' });
 let writingToCachePromise: Promise<void> | null = null;
@@ -51,7 +51,9 @@ const createProgressReader = (
 
 export class LocalLLMModelCache {
   public static async exists(filename: string = LOCAL_LLM_MODEL_FILENAME): Promise<boolean> {
-    return cache.exists(filename);
+    return cache.exists(filename, {
+      expectedSizeBytes: LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES,
+    });
   }
 
   public static async getFile(filename: string = LOCAL_LLM_MODEL_FILENAME): Promise<File> {
@@ -98,6 +100,9 @@ export class LocalLLMModelCache {
       streamForCache,
       filename,
       totalBytes > 0 ? totalBytes : null,
+      {
+        expectedSizeBytes: LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES,
+      },
       progress => onProgress?.({ ...progress, fromCache: false }),
     );
     writingToCachePromise = writingToCachePromise.finally(() => {
@@ -117,6 +122,13 @@ export class LocalLLMModelCache {
     filename: string = LOCAL_LLM_MODEL_FILENAME,
     onProgress?: (progress: ModelDownloadProgress) => void,
   ): Promise<void> {
-    await cache.download(sourceUrl, filename, onProgress);
+    await cache.download(
+      sourceUrl,
+      filename,
+      {
+        expectedSizeBytes: LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES,
+      },
+      onProgress,
+    );
   }
 }

src/util/localLLMModelManager.ts

@@ -2,7 +2,6 @@ import {
   detectLocalLLMRuntimeSupport,
   LOCAL_LLM_LEGACY_FILENAMES,
   LOCAL_LLM_MODEL_FILENAME,
-  LOCAL_LLM_MODEL_URL,
   type LocalLLMRuntimeSupport,
 } from './localLLMConfig';
 import { LocalLLMModelCache } from './localLLMModelCache';

src/util/localSeparatorConfig.ts

@@ -1,9 +1,10 @@
 import type { LocalSeparatorModelConfig } from './localSeparatorTypes';
 
-export const LOCAL_SEPARATOR_MODEL_URL =
+export const LOCAL_SEPARATOR_DEFAULT_MODEL_URL =
   'https://huggingface.co/notabilia/uvr5-models/resolve/main/UVR-MDX-NET-Inst_HQ_3.onnx';
 
 export const LOCAL_SEPARATOR_MODEL_FILENAME = 'UVR-MDX-NET-Inst_HQ_3.onnx';
+export const LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES = 66759214;
 
 export const LOCAL_SEPARATOR_MODEL_CONFIG: LocalSeparatorModelConfig = {
   filename: LOCAL_SEPARATOR_MODEL_FILENAME,

src/util/localSeparatorModelCache.ts

@@ -1,4 +1,7 @@
-import { LOCAL_SEPARATOR_MODEL_FILENAME } from './localSeparatorConfig';
+import {
+  LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES,
+  LOCAL_SEPARATOR_MODEL_FILENAME,
+} from './localSeparatorConfig';
 import { OpfsModelCache, type ModelDownloadProgress } from './opfsModelCache';
 
 const cache = new OpfsModelCache({ directoryName: 'models' });
@@ -7,7 +10,9 @@ export { type ModelDownloadProgress };
 
 export class LocalSeparatorModelCache {
   public static async exists(filename: string = LOCAL_SEPARATOR_MODEL_FILENAME): Promise<boolean> {
-    return cache.exists(filename);
+    return cache.exists(filename, {
+      expectedSizeBytes: LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES,
+    });
   }
 
   public static async getFile(filename: string = LOCAL_SEPARATOR_MODEL_FILENAME): Promise<File> {
@@ -27,6 +32,13 @@ export class LocalSeparatorModelCache {
     filename: string = LOCAL_SEPARATOR_MODEL_FILENAME,
     onProgress?: (progress: ModelDownloadProgress) => void,
   ): Promise<void> {
-    await cache.download(sourceUrl, filename, onProgress);
+    await cache.download(
+      sourceUrl,
+      filename,
+      {
+        expectedSizeBytes: LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES,
+      },
+      onProgress,
+    );
   }
 }

src/util/opfsModelCache.ts

@@ -9,6 +9,10 @@ interface OpfsModelCacheOptions {
   sizeSuffix?: string;
 }
 
+interface ModelCacheValidationOptions {
+  expectedSizeBytes?: number | null;
+}
+
 export class OpfsModelCache {
   private readonly directoryName: string;
   private readonly sizeSuffix: string;
@@ -18,7 +22,7 @@ export class OpfsModelCache {
     this.sizeSuffix = options.sizeSuffix ?? '.size';
   }
 
-  public async exists(filename: string): Promise<boolean> {
+  public async exists(filename: string, options: ModelCacheValidationOptions = {}): Promise<boolean> {
     try {
       const dir = await this.getDir();
       const fileHandle = await dir.getFileHandle(filename);
@@ -29,6 +33,10 @@ export class OpfsModelCache {
         await this.delete(filename);
         return false;
       }
+      if (options.expectedSizeBytes != null && expectedSize !== options.expectedSizeBytes) {
+        await this.delete(filename);
+        return false;
+      }
       if (file.size !== expectedSize) {
         await this.delete(filename);
         return false;
@@ -64,6 +72,7 @@ export class OpfsModelCache {
   public async download(
     sourceUrl: string,
     filename: string,
+    options: ModelCacheValidationOptions = {},
     onProgress?: (progress: ModelDownloadProgress) => void,
   ): Promise<void> {
     const response = await fetch(sourceUrl);
@@ -75,13 +84,14 @@ export class OpfsModelCache {
     if (!response.body) {
       throw new Error('Model download response did not include a readable body.');
     }
-    await this.downloadStream(response.body, filename, totalBytes, onProgress);
+    await this.downloadStream(response.body, filename, totalBytes, options, onProgress);
   }
 
   public async downloadStream(
     stream: ReadableStream<Uint8Array>,
     filename: string,
     totalBytes: number | null,
+    options: ModelCacheValidationOptions = {},
     onProgress?: (progress: ModelDownloadProgress) => void,
   ): Promise<void> {
     const dir = await this.getDir();
@@ -111,6 +121,9 @@ export class OpfsModelCache {
       if (!Number.isFinite(sizeValue) || sizeValue <= 0) {
         throw new Error('Model download did not provide a valid size.');
       }
+      if (options.expectedSizeBytes != null && receivedBytes !== options.expectedSizeBytes) {
+        throw new Error(`Model download size mismatch for ${filename}: expected ${options.expectedSizeBytes} bytes, got ${receivedBytes}.`);
+      }
 
       const sizeHandle = await dir.getFileHandle(this.getSizeFilename(filename), { create: true });
       const sizeWritable = await sizeHandle.createWritable();