utilvo-shield-filters

Zero-dependency JavaScript, TypeScript, Python, and Go parser for Adblock Plus 2.0 ([Adblock Plus 2.0]) and uBlock Origin static network filter rules.

Features

• Parse standard ||domain^$third-party,domain=~example.com network rules
• Extract target hostnames, $third-party modifiers, and excluded context domains
• Fast parent-domain suffix matching (Set-backed lookup) for hostname verification
• Built-in fetcher for the utilvo-shield-filters.txt blocklist

Installation

Node.js

npm install utilvo-shield-filters

const { parseAbpRule, isHostBlocked, fetchFilterHosts } = require("utilvo-shield-filters");

// Parse a single rule
const rule = parseAbpRule("||01counter.com^$third-party,domain=~youtube.com");
// => { domain: '01counter.com', thirdParty: true, excludedDomains: ['youtube.com'] }

// Match a hostname against a Set of rules
const blocked = new Set(["01counter.com"]);
console.log(isHostBlocked("tracker.01counter.com", blocked)); // true

Python

pip install utilvo-shield-filters

from utilvo_shield_filters import parse_abp_rule, is_host_blocked

rule = parse_abp_rule("||01counter.com^$third-party,domain=~youtube.com")
print(rule)
# {'domain': '01counter.com', 'third_party': True, 'excluded_domains': ['youtube.com']}

blocked = {"01counter.com"}
print(is_host_blocked("sub.01counter.com", blocked))  # True

Go

go get github.com/utilvo/utilvo-shield-filters@latest

package main

import (
	"fmt"
	shieldfilters "github.com/utilvo/utilvo-shield-filters"
)

func main() {
	domain, ok := shieldfilters.ParseAbpDomain("||01counter.com^$third-party")
	if ok {
		fmt.Println(domain) // 01counter.com
	}
}

API Reference

• parseAbpRule(line) / parse_abp_rule(line) / ParseAbpDomain(line): Parses a single ABP 2.0 rule line and returns the normalized lowercase domain and rule options. Returns null / None for comments (!), headers ([Adblock Plus 2.0]), or cosmetic filters.
• isHostBlocked(hostname, blockedSet) / is_host_blocked(hostname, blocked_set): Checks whether hostname or any of its parent registrable labels exist in blockedSet.
• fetchFilterHosts(url?) / fetch_filter_hosts(url?): Downloads and parses a remote ABP filter list into a Set of domain strings.

License

Code is licensed under the MIT License. Filter list rules are licensed under CC BY-SA 4.0.