proxyparser

A cross-platform Rust library and CLI for resolving the proxy that should be used for a URL. It supports environment variables, operating system proxy settings, PAC files, and normalized proxy result parsing.

Features

• Cross-platform system proxy detection
  • macOS: SystemConfiguration/CoreFoundation manual proxy and PAC settings
  • Windows: WinHTTP/IE proxy config, manual proxy lists, bypass rules, WPAD
  • Linux: GNOME gsettings and KDE kreadconfig5/kreadconfig6
• PAC support
  • Downloads http:// and https:// PAC files
  • Loads file:// and local PAC files
  • Executes FindProxyForURL with boa_engine
  • Implements common PAC helpers such as dnsResolve, myIpAddress, isInNet, shExpMatch, dnsDomainIs, localHostOrDomainIs, dnsDomainLevels, and weekdayRange
• Proxy parsing and post-processing
  • Normalizes manual and PAC proxy results to full URLs
  • Deduplicates proxy entries
  • Supports protocol filtering and maximum result limits
  • Converts SOCKS/SOCKS5 PAC directives to socks5://
  • Preserves DIRECT fallback semantics
• Priority order: environment variables -> system proxy/PAC -> DIRECT

Validation report

Latest local validation:

Check	Result	Notes
cargo fmt --check	PASS	Rust formatting is clean
cargo test	PASS	9 unit tests + 1 doctest passed
cargo package --allow-dirty	PASS	Crate packages and verifies successfully
Open-marker scan	PASS	No open implementation markers remain in source/config files

The repository CI runs the same Rust checks natively on Ubuntu, macOS, and Windows through GitHub Actions, so platform-specific system proxy modules are validated on their own operating systems instead of relying on fragile local cross-compilation.

Installation

cargo install proxyparser

Or build from source:

git clone https://github.com/zongyangbigpolo/rustproxyparser.git
cd rustproxyparser
cargo build --release

CLI usage

# Query the proxy for a specific URL
proxyparser https://httpbin.org/ip

# Use the default target (https://www.google.com)
proxyparser

Output is either DIRECT or a normalized proxy list, for example:

Proxy for https://example.com -> http://proxy.local:8080; socks5://backup.local:1080; DIRECT

Library usage

use proxyparser::find_proxy_for_url;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let proxy = find_proxy_for_url("https://example.com")?;
    println!("{proxy}");
    Ok(())
}

Proxy parser APIs are also public:

use proxyparser::proxy::{parse_proxy_result, ProxyParseOptions, ProxyScheme};

let options = ProxyParseOptions {
    allowed_schemes: Some(vec![ProxyScheme::Http, ProxyScheme::Socks5]),
    include_direct: true,
    max_proxies: 4,
};
let parsed = parse_proxy_result(
    "PROXY proxy.local:8080; SOCKS socks.local:1080; DIRECT",
    &options,
);

assert_eq!(
    parsed.to_proxy_string(),
    "http://proxy.local:8080; socks5://socks.local:1080; DIRECT"
);

License

This project is licensed under the MIT License.