     1
     2
     3
     4
     5
     6
     7
     8
     9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73

    // Copyright 2016 The rust-url developers.
    //
    // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
    // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
    // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
    // option. This file may not be copied, modified, or distributed
    // except according to those terms.

    //! This Rust crate implements IDNA
    //! [per the WHATWG URL Standard](https://url.spec.whatwg.org/#idna).
    //!
    //! It also exposes the underlying algorithms from [*Unicode IDNA Compatibility Processing*
    //! (Unicode Technical Standard #46)](http://www.unicode.org/reports/tr46/)
    //! and [Punycode (RFC 3492)](https://tools.ietf.org/html/rfc3492).
    //!
    //! Quoting from [UTS #46’s introduction](http://www.unicode.org/reports/tr46/#Introduction):
    //!
    //! > Initially, domain names were restricted to ASCII characters.
    //! > A system was introduced in 2003 for internationalized domain names (IDN).
    //! > This system is called Internationalizing Domain Names for Applications,
    //! > or IDNA2003 for short.
    //! > This mechanism supports IDNs by means of a client software transformation
    //! > into a format known as Punycode.
    //! > A revision of IDNA was approved in 2010 (IDNA2008).
    //! > This revision has a number of incompatibilities with IDNA2003.
    //! >
    //! > The incompatibilities force implementers of client software,
    //! > such as browsers and emailers,
    //! > to face difficult choices during the transition period
    //! > as registries shift from IDNA2003 to IDNA2008.
    //! > This document specifies a mechanism
    //! > that minimizes the impact of this transition for client software,
    //! > allowing client software to access domains that are valid under either system.

    #[macro_use]
    extern crate matches;

    pub mod punycode;
    mod uts46;

    pub use crate::uts46::{Config, Errors, Idna};

    /// The [domain to ASCII](https://url.spec.whatwg.org/#concept-domain-to-ascii) algorithm.
    ///
    /// Return the ASCII representation a domain name,
    /// normalizing characters (upper-case to lower-case and other kinds of equivalence)
    /// and using Punycode as necessary.
    ///
    /// This process may fail.
    pub fn domain_to_ascii(domain: &str) -> Result<String, uts46::Errors> {
        Config::default().to_ascii(domain)
    }

    /// The [domain to ASCII](https://url.spec.whatwg.org/#concept-domain-to-ascii) algorithm,
    /// with the `beStrict` flag set.
    pub fn domain_to_ascii_strict(domain: &str) -> Result<String, uts46::Errors> {
        Config::default()
            .use_std3_ascii_rules(true)
            .verify_dns_length(true)
            .to_ascii(domain)
    }

    /// The [domain to Unicode](https://url.spec.whatwg.org/#concept-domain-to-unicode) algorithm.
    ///
    /// Return the Unicode representation of a domain name,
    /// normalizing characters (upper-case to lower-case and other kinds of equivalence)
    /// and decoding Punycode as necessary.
    ///
    /// This may indicate [syntax violations](https://url.spec.whatwg.org/#syntax-violation)
    /// but always returns a string for the mapped domain.
    pub fn domain_to_unicode(domain: &str) -> (String, Result<(), uts46::Errors>) {
        Config::default().to_unicode(domain)
    }