IDNA for Rust

⚠️ This library is incomplete and under development ⚠️

This is a Rust implementation of the IDNA (Internationalized Domain Names in Applications) specification, based on the C++ implementation from ada-url/ada.

Fast and compliant IDNA conversion library for Rust with zero dependencies.

About

This library provides IDNA processing capabilities for converting between Unicode domain names and ASCII-compatible encoding (ACE) using Punycode. It implements the IDNA specification for internationalized domain name handling.

This is a Rust port of the IDNA functionality from github.com/ada-url/idna.

Usage

use ada_idna::domain::{to_ascii, to_unicode};

// Convert Unicode domain to ASCII
let ascii_domain = to_ascii("café.example").unwrap();
assert_eq!(ascii_domain, "xn--caf-dma.example");

// Convert ASCII back to Unicode
let unicode_domain = to_unicode("xn--caf-dma.example").unwrap();
assert_eq!(unicode_domain, "café.example");

Features

• Zero dependencies: No external crates required
• Complete IDNA support: Full to_ascii and to_unicode conversion
• RFC 3492 Punycode: Compliant Punycode encoding/decoding
• Unicode normalization: NFC normalization with composition tables
• Character mapping: Case folding, soft hyphen removal, format character handling
• Validation: Domain label and character validation
• High performance: Optimized UTF-8 ↔ UTF-32 transcoding

Current Status

🚧 This implementation is incomplete and not ready for production use.

Known limitations:

• Some test cases fail due to expected value discrepancies
• Unicode table data may be incomplete
• Error handling needs refinement
• API is subject to change

Development

Building and Testing

# Build the library
cargo build

# Run tests
cargo test

# Run clippy
cargo clippy

# Format code
cargo fmt

Project Structure

• src/domain.rs - Main IDNA conversion functions
• src/punycode.rs - Punycode encoding/decoding
• src/mapping.rs - Character mapping and case folding
• src/normalization.rs - Unicode NFC normalization
• src/validation.rs - Character and domain validation
• src/unicode.rs - UTF-8 ↔ UTF-32 conversion utilities
• src/unicode_tables.rs - Unicode lookup tables
• tests/ - Comprehensive test suite

Contributing

This project is part of the Ada URL family of libraries. Contributions are welcome!

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Related Projects

• ada-url/ada - Fast spec-compliant URL parser (C++)
• ada-url/rust - Rust bindings for Ada URL parser
• ada-url/idna - Original IDNA implementation (C++)