Nager.PublicSuffix

The TLD proliferation makes it difficult to check whether domain names are valid. This project uses the rules of publicsuffix.org, a list of known public domain suffixes (TLD) to validate and split domains into three the parts (TLD, domain, subdomain). The validation rules are loaded directly from https://publicsuffix.org.

A domain name has 3 major parts:

Example	TLD	Domain	Subdomain
blog.google.com	com	google	blog
www.wikipedia.org	org	wikipedia	www
mail.yandex.ru	ru	yandex	mail
www.amazon.co.uk	co.uk	amazon	www

nuget

The package is available on nuget

PM> install-package Nager.PublicSuffix

Online test tool

You can try the logic right here publicsuffix test tool

Benefits

• High performance
• FileTldRuleProvider or WebTldRuleProvider
• CacheProvider
• Async support

Examples

Loading data from web (publicsuffix.org)

Without any config the WebTldRuleProvider have a default cache live time of 1 day then you must refresh the cache with execute BuildAsync;

var domainParser = new DomainParser(new WebTldRuleProvider());

var domainName = domainParser.Get("sub.test.co.uk");
//domainName.Domain = "test";
//domainName.Hostname = "sub.test.co.uk";
//domainName.RegistrableDomain = "test.co.uk";
//domainName.SubDomain = "sub";
//domainName.TLD = "co.uk";

Loading data from web change cache config

//cache data for 10 hours
var cacheProvider = new FileCacheProvider(cacheTimeToLive: new TimeSpan(10, 0, 0));
var webTldRuleProvider = new WebTldRuleProvider(cacheProvider: cacheProvider);

var domainParser = new DomainParser(webTldRuleProvider);
for (var i = 0; i < 100; i++)
{
    var isValid = webTldRuleProvider.CacheProvider.IsCacheValid();
    if (!isValid)
    {
        webTldRuleProvider.BuildAsync().GetAwaiter().GetResult(); //Reload data
    }
	
    var domainInfo = domainParser.Get($"sub{i}.test.co.uk");
}

Loading data from file

var domainParser = new DomainParser(new FileTldRuleProvider("effective_tld_names.dat"));

var domainName = domainParser.Get("sub.test.co.uk");
//domainName.Domain = "test";
//domainName.Hostname = "sub.test.co.uk";
//domainName.RegistrableDomain = "test.co.uk";
//domainName.SubDomain = "sub";
//domainName.TLD = "co.uk";