From 3abef6ea75891ae572af8d776695a069e181b0fa Mon Sep 17 00:00:00 2001
From: Huang Xin <chrox.huang@gmail.com>
Date: Tue, 23 Dec 2025 15:53:50 +0800
Subject: [PATCH] fix(opds): correctly parse file extension for CBZ files from
 OPDS servers, closes #2765 (#2771)

---
 apps/readest-app/src/app/opds/page.tsx           | 13 ++++++++++---
 apps/readest-app/src/app/opds/utils/opdsUtils.ts | 11 +++++++++++
 apps/readest-app/src/libs/document.ts            |  6 ++++--
 3 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/apps/readest-app/src/app/opds/page.tsx b/apps/readest-app/src/app/opds/page.tsx
index 5ed53836..80a62fac 100644
--- a/apps/readest-app/src/app/opds/page.tsx
+++ b/apps/readest-app/src/app/opds/page.tsx
@@ -19,7 +19,13 @@ import { useLibrary } from '@/hooks/useLibrary';
 import { eventDispatcher } from '@/utils/event';
 import { getFileExtFromMimeType } from '@/libs/document';
 import { OPDSFeed, OPDSPublication, OPDSSearch } from '@/types/opds';
-import { isSearchLink, MIME, parseMediaType, resolveURL } from './utils/opdsUtils';
+import {
+  getFileExtFromPath,
+  isSearchLink,
+  MIME,
+  parseMediaType,
+  resolveURL,
+} from './utils/opdsUtils';
 import { getProxiedURL, fetchWithAuth, probeAuth, needsProxy } from './utils/opdsReq';
 import { READEST_OPDS_USER_AGENT } from '@/services/constants';
 import { FeedView } from './components/FeedView';
@@ -403,8 +409,9 @@ export default function BrowserPage() {
           }
           return;
         } else {
-          const ext = parsed?.mediaType ? getFileExtFromMimeType(parsed.mediaType) : '';
-          const basename = new URL(url).pathname.replaceAll('/', '_');
+          const pathname = new URL(url).pathname;
+          const ext = getFileExtFromMimeType(parsed?.mediaType) || getFileExtFromPath(pathname);
+          const basename = pathname.replaceAll('/', '_');
           const filename = ext ? `${basename}.${ext}` : basename;
           const dstFilePath = await appService?.resolveFilePath(filename, 'Cache');
           if (dstFilePath) {
diff --git a/apps/readest-app/src/app/opds/utils/opdsUtils.ts b/apps/readest-app/src/app/opds/utils/opdsUtils.ts
index 17a828fa..9508de4a 100644
--- a/apps/readest-app/src/app/opds/utils/opdsUtils.ts
+++ b/apps/readest-app/src/app/opds/utils/opdsUtils.ts
@@ -1,5 +1,6 @@
 import { isOPDSCatalog } from 'foliate-js/opds.js';
 import { OPDSLink } from '@/types/opds';
+import { EXTS } from '@/libs/document';
 import { fetchWithAuth } from './opdsReq';
 
 export const groupByArray = <T, K>(arr: T[] | undefined, f: (el: T) => K | K[]): Map<K, T[]> => {
@@ -215,3 +216,13 @@ export const validateOPDSURL = async (
     };
   }
 };
+
+export const getFileExtFromPath = (pathname: string, delimiter = '/'): string => {
+  const parts = pathname.split(delimiter);
+  for (const ext of Object.values(EXTS)) {
+    if (parts.includes(ext)) {
+      return ext;
+    }
+  }
+  return '';
+};
diff --git a/apps/readest-app/src/libs/document.ts b/apps/readest-app/src/libs/document.ts
index 10c7a9b8..4fc06776 100644
--- a/apps/readest-app/src/libs/document.ts
+++ b/apps/readest-app/src/libs/document.ts
@@ -87,7 +87,7 @@ export const MIMETYPES: Record<BookFormat, string[]> = {
   MOBI: ['application/x-mobipocket-ebook'],
   AZW: ['application/vnd.amazon.ebook'],
   AZW3: ['application/vnd.amazon.mobi8-ebook', 'application/x-mobi8-ebook'],
-  CBZ: ['application/vnd.comicbook+zip', 'application/zip'],
+  CBZ: ['application/vnd.comicbook+zip', 'application/zip', 'application/x-cbz'],
   FB2: ['application/x-fictionbook+xml', 'text/xml', 'application/xml'],
   FBZ: ['application/x-zip-compressed-fb2', 'application/zip'],
 };
@@ -243,7 +243,9 @@ export const getDirection = (doc: Document) => {
   return { vertical, rtl };
 };
 
-export const getFileExtFromMimeType = (mimeType: string): string => {
+export const getFileExtFromMimeType = (mimeType?: string): string => {
+  if (!mimeType) return '';
+
   for (const format in MIMETYPES) {
     const list = MIMETYPES[format as BookFormat];
     if (list.includes(mimeType)) {