Haskchan

A lightweight, self-hosted imageboard written in Haskell.

Simple to deploy. Easy to modify. Built for speed.

haskell · imageboard · chan · warp · sqlite · self-hosted · ffmpeg · imagemagick · tor · onion-service · captcha · image-upload · webm · mp4 · pdf-upload · moderation

Website · Source · Report a Bug

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Table of Contents

• Features
• Media Support
• Thumbnail Processing
• Requirements
• Installation
• Authentication and Security
• CAPTCHA
• Static File and MIME Type Support
• Configuration
• Production Deployment
• Tor Onion Service
• Updating Haskchan
• Development
• Contributing
• Reporting Bugs
• License

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Features

Category	Details
Core	Imageboard-style threads and replies
Uploads	Images, PDFs, WebM/MP4/MOV/M4V, and audio
Thumbnails	Automatic WebP and JPEG generation
Anti-spam	CAPTCHA support with click-to-refresh
Accounts	User registration, authentication, session management
Moderation	Moderator and administrator tooling
Storage	SQLite database
Backend	Haskell + Warp web server
Theming	Custom Haskchan theme with dark/light mode
Auth	Encrypted cookies with expiration; revoked on account deletion
Access control	Registration can be disabled; board creation is globally configurable
Deployment	Self-hosted, with optional Tor onion-service support

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Media Support

Haskchan detects uploaded files by inspecting their contents, not just the filename extension.

Type	Formats
Image	JPEG, PNG, GIF, WebP
Video	WebM, MP4, QuickTime/MOV, M4V
Audio	OGG, FLAC, M4A, AAC, MP3
Document	PDF
Text	TXT

Note: PDF files are detected via the %PDF- file signature and stored with the .pdf extension and application/pdf MIME type.

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Thumbnail Processing

Haskchan uses FFmpeg for media decoding and ImageMagick for thumbnail encoding.

Uploaded image
     │
     ▼
FFmpeg decoder
     │
     ▼
Haskell image frame
     │
     ▼
Temporary PNG
     │
     ├──► ImageMagick ──► WebP thumbnail
     │
     └──► ImageMagick ──► JPEG thumbnail

This avoids the older ffmpeg-light encoder path, which can fail with newer FFmpeg versions.

Verify ImageMagick is installed:

which convert

Expected output:

/usr/bin/convert

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Requirements

Haskchan currently works best on Linux (Ubuntu/Debian).

• GHC 8.10.7
• Stack
• SQLite
• ImageMagick
• FFmpeg 4.4.x libraries
• build-essential
• pkg-config
• zlib1g-dev

---

Installation

1. Clone Haskchan

git clone https://github.com/konamicode01/haskchan.git
cd haskchan

2. Install system dependencies

On Ubuntu/Debian:

sudo apt update
sudo apt install -y \
  build-essential \
  pkg-config \
  sqlite3 \
  imagemagick \
  zlib1g-dev

Verify ImageMagick:

convert -version

3. Install FFmpeg 4.4.4

Note: Haskchan uses the ffmpeg-light Haskell package, which relies on the older FFmpeg 4.x API/ABI. Newer FFmpeg versions may not be compatible.

Download and extract:

cd /root
wget https://ffmpeg.org/releases/ffmpeg-4.4.4.tar.xz
tar -xf ffmpeg-4.4.4.tar.xz
cd ffmpeg-4.4.4

Configure:

./configure \
  --prefix=/opt/ffmpeg4 \
  --libdir=/opt/ffmpeg4/lib \
  --enable-shared \
  --disable-static \
  --disable-asm \
  --disable-programs \
  --disable-doc

Build and install:

make -j"$(nproc)"
sudo make install

Register the libraries:

echo "/opt/ffmpeg4/lib" | sudo tee /etc/ld.so.conf.d/ffmpeg4.conf
sudo ldconfig

Set the library path:

export LD_LIBRARY_PATH=/opt/ffmpeg4/lib

To persist across sessions:

echo 'export LD_LIBRARY_PATH=/opt/ffmpeg4/lib' >> ~/.bashrc
source ~/.bashrc

4. Install Stack

curl -sSL https://get.haskellstack.org/ | sh

Verify:

stack --version

5. Build Haskchan

cd /root/haskchan
export LD_LIBRARY_PATH=/opt/ffmpeg4/lib
stack build

Note: The first build may take a while — Stack downloads GHC and all Haskell dependencies. The repo contains a manually maintained phi.cabal; Stack may report that it's ignoring package.yaml in favor of the Cabal file — this is expected.

6. Run Haskchan

export LD_LIBRARY_PATH=/opt/ffmpeg4/lib
stack run

The development server starts on the address configured by the application.

---

Authentication and Security

• Encrypted authentication cookies with expiration

• Authentication verifies the account still exists in the SQLite database

• Deleting a user account invalidates that user's existing session

• Registration can be fully disabled — when disabled, both the registration page and submission endpoint return:

  403 Registration is closed
  

• Board creation is controlled separately via the global board-creation setting. Administrators can still create boards even when ordinary user board creation is disabled.

---

CAPTCHA

• Included for account creation and posting
• Click-to-refresh — click the CAPTCHA image to get a fresh challenge without reloading the page
• Served with no-cache headers to prevent stale challenges from being reused by browsers or proxies

---

Static File and MIME Type Support

Uploaded file types are detected from content and served with the correct MIME type:

Extension	MIME Type
.webp	image/webp
.jpg / .jpeg	image/jpeg
.png	image/png
.gif	image/gif
.svg	image/svg+xml
.ico	image/x-icon
.css	text/css
.js	text/javascript
.mp4	video/mp4
.webm	video/webm
.mp3	audio/mpeg
.ogg	audio/ogg
.flac	audio/flac
.pdf	application/pdf
.txt	text/plain

---

Configuration

Project configuration lives in the Haskchan source tree. Before deploying publicly, configure:

• Database location
• Secret file
• Static file directories
• CAPTCHA directory
• Font path
• Server bind address
• Server ports
• Global site settings

Note: Make sure the user running Haskchan has write permission to the directories used for uploaded files and generated thumbnails.

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Production Deployment

Haskchan can run directly via Warp, or behind a reverse proxy such as nginx or Caddy.

Internet
   │
   ▼
nginx / Caddy
   │
   ▼
Haskchan

Or directly:

Internet
   │
   ▼
Haskchan

For production, use a service manager such as systemd rather than running stack run in an interactive terminal.

Example systemd unit:

[Unit]
Description=Haskchan Imageboard
After=network.target

[Service]
Type=simple
User=root
WorkingDirectory=/root/haskchan
Environment="LD_LIBRARY_PATH=/opt/ffmpeg4/lib"
ExecStart=/usr/local/bin/stack run
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target

Enable and start:

sudo systemctl daemon-reload
sudo systemctl enable haskchan
sudo systemctl start haskchan

Check status:

sudo systemctl status haskchan

View logs:

journalctl -u haskchan -f

---

Tor Onion Service

Haskchan can optionally expose a local HTTP listener for a Tor onion service:

Tor
 │
 ▼
127.0.0.1:7000
 │
 ▼
Haskchan

Example Tor configuration:

HiddenServiceDir /var/lib/tor/haskchan/
HiddenServicePort 80 127.0.0.1:7000

This allows Haskchan to be reached via a .onion address without requiring the onion service to use the public TLS certificate for the clearnet domain.

---

Updating Haskchan

Pull the latest source:

git pull origin main

Rebuild:

export LD_LIBRARY_PATH=/opt/ffmpeg4/lib
stack build

Restart the service:

sudo systemctl restart haskchan

Check status:

sudo systemctl status haskchan --no-pager

---

Development

stack build   # Build
stack run     # Run
stack test    # Run tests

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Contributing

Haskchan is open source and contributions are welcome, including:

• Bug fixes
• Security improvements
• Performance improvements
• New media formats
• UI improvements
• Documentation
• Deployment improvements
• Haskell code improvements
• Tests

Before submitting changes, build the project and confirm existing functionality still works.

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Reporting Bugs

When reporting a bug, please include:

• Operating system
• GHC version
• Stack version
• FFmpeg version
• Relevant Haskchan logs
• Steps to reproduce the problem

Note: Do not post private keys, authentication secrets, or other sensitive server configuration.

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License

See the repository for the project's current license.

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