NSFW Image Checker (Rust)

A lightweight REST API server written in Rust that uses the nsfw crate and a pre-trained ONNX model to return scores in a json response.

This project is my first hands-on experience with Rust, built as a learning exercise and as a practical tool for image moderation. Feedback is very welcome!

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🚀 Features

• 🔍 Uses the nsfw crate and provided ONNX model to detect NSFW content in user-supplied images
• 🧠 Powered by ONNX Runtime and a robust pre-trained classifier
• ✅ Exposes simple /ping and /classify endpoints
• 🎯 Built-in integration tests

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📆 Categories Explained

The model classifies each image with scores across five categories

The higher the score, the more reliable the result.

Category	Description
porn_score	Highly explicit adult imagery including nudity and sexual acts
sexy_score	Provocative content such as lingerie, revealing clothing, or suggestive poses
hentai_score	Drawn or animated NSFW content (e.g anime or cartoons)
neutral_score	Safe-for-work content such as normal clothing, faces, objects, landscapes
drawing_score	Artistic or non-photographic images not intended to be sexual (e.g sketches)

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📁 Setup

1. Install Rust

If you don't already have Rust installed:

curl https://sh.rustup.rs -sSf | sh

More info at https://rustup.rs

2. Clone the Repository

git clone https://github.com/shane-chris-barker/rust-nsfw-image-checker.git

3. Download the Model

cd rust-nsfw-image-checker
sh download_model.sh

This script downloads the ONNX model into models/model.onnx.

The models/ folder is .gitignored but preserved via a .gitkeep file.

The model is approximately 85MB and may take a few seconds to download

🛠️Dependencies

Note: Ensure wget is installed on your system to run the model download script.

4. Run the Server

cargo run

Server will start at http://localhost:3000

🔮 API Endpoints

GET /ping

Returns a basic JSON response indicating that the server is up and running:

{"status":200,"result":true}

POST /classify

Accepts an image file using multipart/form-data. Example using curl:

curl -X POST http://localhost:3000/classify \
  -F image=@example.jpg

Response:

{
  "porn_score": 0.98313576,
  "sexy_score": 0.006444183,
  "hentai_score": 0.010374044,
  "neutral_score": 0.000044660992,
  "drawing_score": 0.0000013174929
}

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🔧 Testing

Run integration tests with:

cargo test

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😍 Thanks

• This project uses the nsfw crate by @fyko. Many thanks to Fyko for making this library and the ONNX file available!
• The Rust community and documentation for being excellent
• ChatGPT for helping me to learn the basics of Rust and how to translate my knowledge from PHP.

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📄 License

This project is licensed under the MIT License, which permits commercial and non-commercial use, modification, distribution, and private use.

See LICENSE for full details.

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🚫 Disclaimer

This project is provided as-is. Use responsibly. The model may not be 100% accurate and should not be relied upon for legal or high-stakes decisions.