public_suffix

pub package Build Status

A domain parser based on the Public Suffix List

public_suffix is a dart library for identifying the public suffixes (or TLDs), root domains and registrable parts of URLs.

Main features

  • Identify suffix, root domain, registrable domain (root + suffix) and subdomain from URLs.
  • Provide your own list of suffix rules to keep up to date with the rules you need.
  • Get results from matching with only ICANN/IANA rules or also include private ones.
    • For example, a private rule can see the full github.io as suffix while ICANN only recognises the io part.
  • Parse punycode encoded URLs and get both encoded and decoded results.
  • Check if URLs are subdomains, have valid domain parts, or end with known suffixes.

Usage

  1. Import public_suffix.dart.
  2. Initialise SuffixRules from a suffix rule list.
  3. Create instances of PublicSuffix to parse URLs.
  4. Access the different URL components through the PublicSuffix objects.

Short example

import 'package:public_suffix/public_suffix.dart';

main() {
  // Load a list of suffix rules from publicsuffix.org.
  String suffixListString = 'load the list into this string';
  SuffixRules.initFromString(suffixListString);
	  
  // Parse a URL.
  PublicSuffix parsedUrl =
      PublicSuffix.fromString('https://www.komposten.github.io');
	  
  // Obtain information using the many getters, for example:
  print(parsedUrl.suffix);      // github.io
  print(parsedUrl.root);        // komposten
  print(parsedUrl.domain);      // komposten.github.io
  print(parsedUrl.icannDomain); // github.io

  // public_suffix also supports punycoded URLs:
  parsedUrl = PublicSuffix.fromString('https://www.xn--6qq79v.cn');
  print(parsedUrl.domain);             // xn--6qq79v.cn
  print(parsedUrl.punyDecoded.domain); // 你好.cn
}

Initialising SuffixRules

public_suffix requires a list of suffix rules to work. There is no list bundled by default as these lists are updated frequently. Instead you'll have to load a list on your own and pass that list to SuffixRules. There are two ways of doing this:

  1. Load the list using your own code and pass it to SuffixRules.initFromString():
    //Example using Flutter
    import 'package:flutter/services.dart';
    import 'package:public_suffix/public_suffix.dart';
    
    main() {
        var suffixList = rootBundle.loadString('assets/public_suffix_list.dat');
        SuffixRules.initFromString(suffixList);
    }
    
  2. Import either the dart:io or the dart:html-based helper and load the list from a URI:
    //Example using dart:io; for dart:html use public_suffix_browser.dart instead.
    import 'package:public_suffix/public_suffix_io.dart';
    
    main() async {
      Uri uri = Uri.parse('https://publicsuffix.org/list/public_suffix_list.dat');
      await SuffixRulesHelper.initFromUri(listUri);
    }
    

Note: Don't overload publicsuffix.org's servers by repeatedly retrieving the suffix list from them. Cache a copy somewhere instead, and update that copy only when the master copy is updated.

Utility functions

Several utility functions can be found in the DomainUtils class (imported from public_suffix.dart). These currently include:

  • isSubdomainOf: Checks if a given URL is a subdomain of another domain.
  • isSubdomain: Checks if a given URL has a subdomain part.
  • isKnownSuffix: Checks if a given suffix (e.g. co.uk) is listed in the suffix rule list.
  • hasValidDomain: Checks if a given URL contains a registrable domain part.

Most of these create PublicSuffix objects internally. If you are already working with PublicSuffix objects, there are similar methods you can call directly on those to avoid creating new ones.

License

public_suffix is licensed under the MIT license. See LICENSE for the full license text.

Libraries

public_suffix
public_suffix_browser
public_suffix_io