faup-rs: Fast URL Parser for Rust

A high-performance, zero-allocation URL parser for Rust that handles:

• Hostnames (with subdomains, custom TLDs, and IDNs)
• IPv4/IPv6 addresses
• User credentials (username/password)
• Ports, paths, queries, and fragments
• UTF-8 and URL-encoded characters

Features

✅ Zero-allocation parsing: Borrows input strings where possible

✅ Public Suffix List (PSL): Correctly identifies domain suffixes

✅ Custom TLDs: Extendable via the CUSTOM_TLDS constant

✅ Comprehensive error handling: Clear, actionable error types

✅ UTF-8 support: Full Unicode handling for all URL components

Installation

Add to your Cargo.toml:

[dependencies]
faup-rs = "0.1"

Usage

Basic Parsing

use faup_rs::Url;

let url = Url::parse("https://user:[email protected]:8080/path?query=value#fragment").unwrap();
assert_eq!(url.scheme(), "https");
assert_eq!(url.host().to_string(), "sub.example.com");
assert_eq!(url.port(), Some(8080));
assert_eq!(url.path(), Some("/path"));
assert_eq!(url.query(), Some("query=value"));
assert_eq!(url.fragment(), Some("fragment"));

Hostname Components

use faup_rs::{Url, Host};

let url = Url::parse("https://sub.example.co.uk").unwrap();
if let Host::Hostname(hostname) = url.host() {
    assert_eq!(hostname.full_name(), "sub.example.co.uk");
    assert_eq!(hostname.suffix(), Some("co.uk"));
    assert_eq!(hostname.domain(), Some("example.co.uk"));
    assert_eq!(hostname.subdomain(), Some("sub"));
}

IP Addresses

use faup_rs::Url;

let url = Url::parse("http://[::1]").unwrap();
assert!(matches!(url.host(), faup_rs::Host::Ip(ip) if ip.is_loopback()));

User Info (UTF-8 Support)

use faup_rs::Url;

let url = Url::parse("https://用户:密码@example.com").unwrap();
let user_info = url.userinfo().unwrap();
assert_eq!(user_info.username(), "用户");
assert_eq!(user_info.password(), Some("密码"));

Custom TLDs

use faup_rs::Url;

let url = Url::parse("http://example.b32.i2p").unwrap();
assert_eq!(url.suffix(), Some("b32.i2p"));

Examples

Real-World URLs

use faup_rs::Url;

let urls = [
    "https://www.example.co.uk",
    "http://sub.domain.example.com/path/to/page",
    "https://例子.测试",
    "http://toaster.dyrøy.no",
    "http://full.custom-tld.test.b32.i2p",
];
for url_str in urls {
    let url = Url::parse(url_str).unwrap();
    println!("Parsed: {}", url);
}

License

This project is licensed under the GNU General Public License v3.0 (GPLv3)..

Acknowledgement

Thanks to Sebastien Tricaud for the original work on faup.

Funding

Faup-rs is co-funded by CIRCL and by the European Union under FETTA (Federated European Team for Threat Analysis) project.