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.
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.
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");- 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
Benchmarks comparing ada-idna with the popular idna crate (lower is better):
| Benchmark | ada-idna | idna crate | Ratio |
|---|---|---|---|
| Batch to_ascii conversion | 13.21 µs | 4.15 µs | 3.18x slower |
| Batch to_unicode conversion | 4.45 µs | 3.85 µs | 1.16x slower |
| Single ASCII domain | 11.48 ns | 17.60 ns | 1.53x faster |
| Single Unicode domain | 6.96 ns | 93.02 ns | 13.37x faster |
| Complex Unicode domain | 9.54 ns | 183.42 ns | 19.23x faster |
| Non-Latin scripts | 711.70 ns | 154.41 ns | 4.61x slower |
| CJK domains | 1.05 µs | 170.02 ns | 6.18x slower |
| Mixed scripts | 630.00 ns | 141.73 ns | 4.44x slower |
Ada-idna specific operations:
- Punycode encoding: 1.54 µs
- Punycode decoding: 517.16 ns
- Unicode normalization: 1.12 µs
Run cargo bench to reproduce these results on your system.
🚧 This implementation is incomplete and not ready for production use.
Known limitations:
- Performance is mixed compared to the mature
idnacrate - Ada-idna is significantly faster for single ASCII and Unicode domains ⚡
- 13.37x faster for simple Unicode domains, 19.23x faster for complex Unicode domains
- Some test cases fail due to expected value discrepancies
- Unicode table data may be incomplete
- Error handling needs refinement
- API is subject to change
# Build the library
cargo build
# Run tests
cargo test
# Run clippy
cargo clippy
# Format code
cargo fmt
# Run benchmarks (compares with idna crate)
cargo benchsrc/domain.rs- Main IDNA conversion functionssrc/punycode.rs- Punycode encoding/decodingsrc/mapping.rs- Character mapping and case foldingsrc/normalization.rs- Unicode NFC normalizationsrc/validation.rs- Character and domain validationsrc/unicode.rs- UTF-8 ↔ UTF-32 conversion utilitiessrc/unicode_tables.rs- Unicode lookup tablestests/- Comprehensive test suite
This project is part of the Ada URL family of libraries. Contributions are welcome!
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.
- 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++)