Overview
This document provides a technical overview of kotatsu-dl, a cross-platform manga downloader command-line application that supports a wide range of manga sources. It explains the system's core architecture, components, and general workflow.
For detailed installation instructions, see Installation & Setup. For usage examples and command line options, see Usage Guide.
What is kotatsu-dl?
kotatsu-dl is a command-line tool written in Kotlin that allows users to download manga from various online sources into local archives (CBZ, ZIP) or directory structures. It provides a simple interface for specifying manga URLs, selecting chapters to download, and configuring output formats.
Key features include:
- Support for numerous manga sources (websites)
- Multiple output formats (CBZ, ZIP, directory)
- Parallel downloading capabilities
- Throttling to avoid IP blocking
- Interactive chapter selection
System Architecture
kotatsu-dl follows a modular architecture with clear separation of concerns. The system consists of these main components:
- Command Line Interface: Handles user input and provides feedback
- Link Resolver: Analyzes and validates manga URLs
- Manga Downloader: Orchestrates the download process
- Output Manager: Handles saving content in different formats
Workflow
The typical workflow of kotatsu-dl follows these steps:
- User provides a manga URL and optional parameters via command line
- The system resolves the source and validates the URL
- Manga metadata and chapter information are fetched
- User selects which chapters to download (interactively or via parameters)
- The system downloads chapter content in parallel (with optional throttling)
- Content is processed and saved in the specified output format
Integration with kotatsu-parsers
kotatsu-dl leverages the kotatsu-parsers library to support a wide range of manga sources. This integration allows the application to:
- Interpret URLs from various manga websites
- Extract metadata consistently across sources
- Navigate chapter structures regardless of source format
- Handle website-specific quirks through specialized parsers
The MangaLoaderContextImpl class initializes the parsing system and provides access to the appropriate parser for each supported source.
Output Formats
kotatsu-dl supports multiple output formats to accommodate different user preferences:
| Format | Description | Best Use Case |
|---|---|---|
| CBZ | Comic Book ZIP - standard comic reader format | Reading in comic/manga reader apps |
| ZIP | Standard ZIP archive | General storage and distribution |
| DIR | Plain directory structure | Editing or manual organization |
Technologies and Dependencies
kotatsu-dl is built with Kotlin and relies on several key dependencies:
| Dependency | Purpose |
|---|---|
| Kotlin Coroutines | Asynchronous programming and parallel downloads |
| Clikt | Command-line interface framework |
| kotatsu-parsers | Manga source parsing capabilities |
| OkHttp | HTTP client for network requests |
| Shadow | JAR packaging for distribution |
Build and Distribution
kotatsu-dl is packaged using the Shadow plugin to create a self-contained executable JAR file. This approach ensures that all dependencies are included in a single file, making distribution and execution straightforward across platforms.