EMHenTai

A lightweight, pure-Swift E-Hentai client for iOS.

English | 中文

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What is EMHenTai?

EMHenTai is a third-party iOS client for E-Hentai, one of the largest online gallery communities. Built entirely in Swift with zero Objective-C code, it provides a native mobile experience for browsing, searching, and downloading galleries on iPhone and iPad.

The app requires no backend server — it communicates directly with E-Hentai's web API, parsing HTML and JSON responses to deliver a fast, offline-capable reading experience.

Features

• E-Hentai & ExHentai — Switch between sources seamlessly; ExHentai unlocks after login
• Advanced Search — Filter by keyword, language, rating, and 10 content categories
• Gallery Viewer — Horizontal page-by-page reader with page jump and reading progress memory
• Download Manager — Background downloading with pause, resume, and delete support
• Browsing History — Automatic history tracking with bulk clear
• Tag Search — Browse and search by related tags from any gallery
• Tag Translation — Bilingual tag display (English + Chinese) powered by EhTagTranslation
• Content Filtering — Toggle filters for AI-generated and gore content
• Dual Login — Sign in via account/password (WebKit) or direct cookie injection
• Storage Management — View disk usage by category and clear cached data
• Universal — iPhone & iPad, portrait & landscape, dark mode, Chinese & English

Screenshots

Install

No pre-built IPA is provided due to legal considerations around E-Hentai content. You must build from source using Xcode.

iOS (17.0+, arm64)

Prerequisites

• A Mac with Xcode installed (free from the Mac App Store)
• An Apple ID (free; needed for code signing)
• An iPhone or iPad running iOS 17.0 or later

Steps

1. Clone the repository and open the project:

   git clone https://github.com/yuman07/EMHentai.git
   cd EMHentai
   open EMHenTai.xcodeproj

2. In Xcode, select the EMHenTai target, go to Signing & Capabilities, and choose your Apple ID team.
3. Connect your device via USB (or Wi-Fi) and select it as the run destination.
4. Press Cmd+R to build and install. No paid developer account is needed.

Trust the Developer Certificate

Since the app is sideloaded rather than installed from the App Store, you must trust the developer certificate on your device before the first launch:

1. On your device, open Settings > General > VPN & Device Management.
2. Tap your developer account under "Developer App".
3. Tap Trust and confirm.

Note: Free Apple ID provisioning profiles expire after 7 days, requiring you to reconnect and rebuild. A paid Apple Developer account ($99/year) extends this to one year.

Usage

• ExHentai access — ExHentai requires login. Go to the Settings tab, tap the login status row, and sign in via account/password or cookie.
• Long press a gallery — Opens a context menu with options to download, open the original webpage, or search related tags.
• Page jump — In the gallery viewer, tap the jump icon in the top-right corner to go to a specific page number.
• Select/deselect all categories — On the search screen, double-tap the Category section header to toggle all categories at once.
• Content filters — The Settings tab provides toggles to hide AI-generated and gore content from search results.

Development

Development is only supported on macOS.

Prerequisites

• macOS 26.2+ (Tahoe)
• Xcode 26.4+ (free from the Mac App Store)

Build

# Clone the repository
git clone https://github.com/yuman07/EMHentai.git

# Navigate to the project directory
cd EMHentai

# Open the Xcode project
# SPM dependencies (Alamofire, Kingfisher) resolve automatically on first open
open EMHenTai.xcodeproj

# Build and run on a simulator via Xcode (Cmd+R), or from the command line:
xcodebuild -project EMHenTai.xcodeproj -scheme EMHenTai \
  -destination 'platform=iOS Simulator,name=iPhone 16' build

Technical Overview

EMHenTai follows an MVVM architecture with a layer of singleton managers handling core business logic. The UI is built entirely in programmatic UIKit — no storyboards or XIBs — using UITableViewDiffableDataSource for smooth, animated list updates.

Concurrency relies on Swift's actor model. Both SearchManager and DownloadManager are declared as actor, providing compile-time data race safety without manual locking. A custom @globalActor isolates search state. Image downloads run in parallel via TaskGroup, with each gallery split into groups of 40 images for efficient batch fetching.

Reactive data flow is powered by Combine. Managers expose PassthroughSubject and CurrentValueSubject publishers; ViewModels subscribe via sink and drive UI through @Published properties. This creates a unidirectional cycle: user action → manager operation → Combine event → ViewModel state change → UI update.

Networking uses Alamofire with automatic retry policies. Gallery metadata comes from E-Hentai's gdata JSON endpoint, while page-level image URLs are extracted by lightweight HTML string parsing. Kingfisher manages image caching with cookie-aware sessions for seamless ExHentai support.

Persistence uses CoreData with two entities (HistoryBook, DownloadBook) sharing identical schemas. DBManager wraps a concurrent DispatchQueue with barrier flags — reads run concurrently, writes are serialized — ensuring thread safety outside of the actor system.

Authentication stores E-Hentai session cookies in HTTPCookieStorage, shared with both Alamofire and Kingfisher sessions. Cookie changes are observed via NotificationCenter to reactively update the login state UI.

Tech Stack

Category	Technology
Language	Swift 5
Minimum Target	iOS 17.0
UI Framework	UIKit (programmatic)
Architecture	MVVM + Singleton Managers
Concurrency	Swift Actors + async/await + GCD
Reactive	Combine
Networking	Alamofire
Image Caching	Kingfisher
Persistence	CoreData
Authentication	WebKit + HTTPCookieStorage
Localization	NSLocalizedString + JSON tag database
Package Manager	Swift Package Manager

Architecture

graph TD
    subgraph UI["UI Layer (Programmatic UIKit)"]
        Root["RootViewController<br>(UITabBarController)"]
        BookList["BookListViewController<br>(Home / History / Download)"]
        Gallery[GalleryViewController]
        Search[SearchViewController]
        Setting[SettingViewController]
        Login[LoginViewController]
    end

    subgraph Logic["Business Logic (Singletons)"]
        VM[BookListViewModel]
        SM["SearchManager<br>(actor)"]
        DM["DownloadManager<br>(actor)"]
        DB[DBManager]
        SetM[SettingManager]
        TM[TranslateManager]
    end

    subgraph External["External"]
        API["E-Hentai / ExHentai API"]
        CD[(CoreData)]
        JSON["Tag Translation JSON"]
    end

    Root -->|"tab switch"| BookList
    Root -->|"tab switch"| Setting
    BookList -->|"push"| Gallery
    BookList -->|"push"| Search
    Setting -->|"push"| Login

    BookList <-->|"@Published / refresh"| VM
    VM <-->|"SearchInfo / SearchEvent"| SM
    VM <-->|"insert, query / dbChanged"| DB
    Gallery <-->|"download / progress"| DM
    Search -->|"SearchInfo"| SM
    Setting -->|"login / logout"| SetM
    Login -->|"WebKit cookie"| SetM

    SM -->|"gdata JSON + HTML scrape"| API
    DM -->|"HTML parse + image fetch"| API
    DB -->|"NSManagedObject CRUD"| CD
    SetM -.->|"HTTPCookie sync"| API
    TM -.->|"load at launch"| JSON
    TM -.->|"tag lookup"| BookList

Loading

• Main data flow — User browses the home tab → BookListViewModel triggers SearchManager → actor-isolated search sends an Alamofire request to E-Hentai's gdata API → parsed Book structs flow back via Combine's PassthroughSubject → ViewModel updates @Published books → DiffableDataSource animates the table view.
• Download pipeline — Tapping a gallery pushes GalleryViewController, which calls DownloadManager.download(). The actor splits pages into groups of 40 and fetches each group's HTML in parallel via TaskGroup. Image URLs are extracted by string parsing and downloaded concurrently, with per-page progress published via Combine. Completed images are persisted to Documents/<gid>/.
• Authentication boundary — SettingManager manages cookies across both HTTPCookieStorage (shared with Alamofire/Kingfisher) and WKWebsiteDataStore (used by the login WebView). Cookie changes trigger a NotificationCenter event, which SettingManager re-evaluates into a CurrentValueSubject<Bool> login state consumed by the Settings UI and search validation.
• Persistence layer — DBManager maintains an in-memory [DBType: [Book]] cache synchronized with a CoreData NSPersistentContainer background context. A concurrent DispatchQueue with .barrier flags ensures safe reads/writes without blocking the main thread.
• Tag translation — TranslateManager loads a bundled JSON database (from EhTagTranslation) at launch, building bidirectional English-Chinese lookup dictionaries for instant tag translation throughout the app.

Project Structure

EMHenTai/
|-- EMHenTai/
|   |-- Source/
|   |   |-- AppDelegate.swift              # App entry, Kingfisher & DB setup
|   |   |-- RootViewController.swift        # Tab bar with 4 tabs
|   |   |-- BookList/                       # Gallery list (home / history / download)
|   |   |-- Gallery/                        # Full-screen horizontal image viewer
|   |   |-- Search/                         # Advanced search filters UI
|   |   |-- Setting/                        # Login state & storage management
|   |   |-- Login/                          # WebKit-based E-Hentai login
|   |   |-- Tag/                            # Related tag browser with translation
|   |   |-- WebView/                        # In-app browser with share support
|   |   |-- Manager/                        # Core business logic
|   |   |   |-- SearchManager.swift         # Gallery search (actor)
|   |   |   |-- DownloadManager.swift       # Parallel image download (actor)
|   |   |   |-- DBManager.swift             # CoreData persistence
|   |   |   |-- SettingManager.swift        # Auth, cookies & preferences
|   |   |   `-- TranslateManager.swift      # Tag EN<>CN translation
|   |   |-- Model/                          # Book, SearchInfo data structs
|   |   `-- Tools/                          # Swift extensions & utilities
|   `-- Support/
|       |-- Assets.xcassets/                # App icon & image assets
|       |-- EMDB.xcdatamodeld/              # CoreData schema
|       |-- Info.plist
|       |-- tag-*.json                      # Bundled tag translation database
|       |-- en.lproj/                       # English localization strings
|       `-- zh-Hans.lproj/                  # Chinese localization strings
|-- EMHenTai.xcodeproj/                     # Xcode project with SPM dependencies
|-- Screenshots/                            # App screenshots
`-- LICENSE                                 # MIT License

FAQ

Q: I logged in on the website, but the app still shows "Not logged in"?

E-Hentai may temporarily block IPs that log in too frequently. Switch to a different VPN node (US or EU IPs are recommended) and try again.

Q: Why do downloads sometimes stall?

E-Hentai throttles IPs with excessive page loads. Wait a few minutes or switch your network, then resume the download.

Q: Why is there no IPA for direct installation?

Due to legal considerations around E-Hentai content, no pre-built binaries are distributed. Building from source ensures users make an informed choice.

Acknowledgments

• UI design inspired by @Dai-Hentai
• Tag translations powered by @EhTagTranslation

License

This project is licensed under the MIT License.