Unicode and Punycode Domain Name Processing

Provides high-performance functions for processing internationalized domain names, split across two tiers.

Details

The package exposes two distinct surfaces, deliberately kept separate:

• A low-level Punycode codec (puny_encode() / puny_decode()): the raw RFC 3492 transform with xn-- A-label framing (RFC 5890/5891) and letter-digit-hyphen checks. It performs no Unicode normalization.

• An IDNA/UTS-46 host-normalization surface (host_normalize()): Unicode NFC, UTS #46 mapping and validation, and conversion to a canonical lowercase ASCII comparison form under a pinned profile.

Use the codec when you need the literal ASCII-Compatible Encoding of a label; use host_normalize() when you need a standards-profiled comparison form for a host name.

See also

Useful links:

• https://bart-turczynski.github.io/punycoder/

• https://github.com/bart-turczynski/punycoder

• https://bart-turczynski.r-universe.dev/punycoder

• https://CRAN.R-project.org/package=punycoder

• Report bugs at https://github.com/bart-turczynski/punycoder/issues

Author

Maintainer: Bart Turczynski bartek@turczynski.pl (ORCID)

Authors:

• Bart Turczynski bartek@turczynski.pl (ORCID)

Examples

# Tier 1 - low-level codec: the raw RFC 3492 transform.
puny_encode("caf\u00E9.com")
#> [1] "xn--caf-dma.com"
puny_decode("xn--caf-dma.com")
#> [1] "café.com"

# Tier 2 - UTS #46: canonical lowercase ASCII comparison form.
host_normalize(c("Example.COM", "M\u00DCNCHEN.de"))
#> [1] "example.com"       "xn--mnchen-3ya.de"