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++)

ada-idna 0.1.0