Kagane Downloader Extension

A powerful, developer-friendly Chrome extension designed to download manga chapters directly from kagane.to with support for multiple high-quality output formats including raw Images, CBZ (Comic Book ZIP), and PDF.

Tip

Looking for a CLI or GUI application? Check out Kagane Downloader – the Python-based alternative with both command-line and graphical interfaces for batch chapter downloads.

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Preview

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Features

• Multi-Format Export: Convert and export downloaded chapters to:
  • Images: Raw images (.jpg/.png) in structured directories.
  • CBZ: Comic Book ZIP archives, ready for your favorite reader.
  • PDF: Single, high-quality document per chapter.
• Smart Metadata Loading: Paste any kagane.to series URL, reader URL, or Series ID to load chapter lists instantly.
• Background Downloader: Built on Chrome Extension Manifest V3 (MV3). Downloads run asynchronously in a Service Worker, preventing loss of progress even when closing the popup.
• Secure Bypass & DNR Routing: Utilizes declarativeNetRequest (DNR) rules to handle request headers (Referer and Origin), bypassing hotlinking protections on CDN hosts (e.g., kstatic.to, yuzuki.kagane.to, akari.kagane.to).
• Concurrent Processing & Queue: Configure chapter and page concurrency to balance speed and rate-limiting safety.
• Dynamic Progress Tracking: Live-updated progress bars, statuses, and history logs inside the extension popup.

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Installation

Method 1: Prebuilt Release (Recommended)

1. Navigate to the Releases page of the repository.
2. Download the latest kagane-extension.zip.
3. Extract the downloaded ZIP file to a preferred directory on your local machine.
4. Open Google Chrome and navigate to chrome://extensions/.
5. Enable Developer mode using the toggle switch in the top-right corner.
6. Click the Load unpacked button in the top-left corner.
7. Select the folder where you extracted the ZIP archive.

Method 2: Build from Source

Prerequisites

• Node.js (v18 or higher recommended)
• npm

Steps

1. Clone the repository:

   git clone https://github.com/Yui007/kagane-extension.git
   cd kagane-extension

2. Install the project dependencies:

   npm install

3. Compile TypeScript and bundle the assets:

   # For production build
   npm run build
   
   # For development build (with file watch)
   npm run dev

4. Load the extension in Chrome:
   • Open chrome://extensions/ and enable Developer mode.
   • Click Load unpacked and select the built dist directory.

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Architecture & Codebase Overview

kagane-extension/
├── public/
│   ├── manifest.json      # Extension configuration and permission rules
│   ├── icons/             # Custom extension icons (16x16, 48x48, 128x128)
│   └── content-reader.js  # Script injected into reader tabs to query DRM assets
├── src/
│   ├── api/
│   │   ├── client.ts      # Fetch-based API client with auto-retries and backoff
│   │   └── types.ts       # Types and normalization logic for Kagane responses
│   ├── background/
│   │   ├── download-queue.ts  # Class managing parallel chapter job queues
│   │   ├── image-downloader.ts# Downloads images, converts to blobs/data URLs
│   │   └── settings.ts    # Manages user-defined concurrency & format settings
│   └── background.ts      # Main MV3 service worker router and tab manager
├── popup/
│   ├── popup.html         # Main user interface markup
│   ├── popup.css          # Styling for popup tabs, lists, and forms
│   └── popup.ts           # Controls UI actions, updates progress, saves settings
├── offscreen/             # Offscreen document for heavy processing operations
└── vite.config.ts         # Vite bundler configuration

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Configuration Settings

Accessible via the Settings tab in the extension popup:

• Download Format: Select between raw Images, CBZ, and PDF formats.
• Max Concurrent Chapters: Controls how many chapters are processed in parallel (1-5, default: 3).
• Max Concurrent Images: Controls how many image pages are fetched in parallel per chapter (1-10, default: 5).

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Development & Tech Stack

• Core: HTML5, Vanilla CSS, TypeScript.
• Bundler: Vite with Rollup.
• Libraries:
  • JSZip (for packaging CBZ files).
  • jsPDF (for generating PDF files).
• Linter & Type Checker: TypeScript compiler (tsc --noEmit).

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License

This project is licensed under the MIT License. See the LICENSE file for more details.