YaWhois 1.0.1

YaWhois (dotnet) - Yet Another WHOIS Client Library

Description

This is a WHOIS client library written in .Net Standard 2.0 specification.

Why?

There are some WHOIS libraries were written in dotnet, but none of them satisfied of mine use cases. Previously, I have worked with whois program written by Marco d'Itri under Unix-like systems. And I like it.

YaWhois repeats logic done by whois program, specifically:

• Smart whois server selection for each query object.
• Server response processing (parsing) leaved to the application developer.

Usage

Hello, YaWhois!

var whois = new YaWhoisClient();
var response = whois.Query("github.com");
Console.WriteLine(response);

Using delegates

YaWhois is using delegates to be easy in use.

var whois = new YaWhoisClient();

// set delegate when responses received
whois.ResponseParsed += Whois_ResponseParsed;

// make request
whois.Query("github.com");


static void Whois_ResponseParsed(object sender, YaWhoisClientEventArgs e)
{
    YaWhoisClient whois = (YaWhoisClient)sender;

    Console.WriteLine($"[server: {e.Server}]");
    Console.WriteLine($"[query: {e.Query}]");
    Console.WriteLine(e.Response);
}

Async method

Same as above, but use QueryAsync method instead.

var whois = new YaWhoisClient();

whois.ResponseParsed += Whois_ResponseParsed;

// additional delegate for async queries
whois.ExceptionThrown += (o, e) =>
{
    Console.WriteLine(e.Exception.Message);
};

// use cancellation token if neccessary
var cts = new CancellationTokenSource();

whois.QueryAsync("github.com", token: cts.Token);

// ...

Using delegates

All delegates have only two arguments:

• object sender (YaWhoisClient)
• YaWhoisClientEventArgs args

The YaWhoisClientEventArgs contains all information about your query:

• object Value - user object per query
• IDataParser Parser - parser to get referral information, you can set to yours
• string Server - selected server (readonly)
• string Query - adopted query to the selected server (readonly)
• Encoding Encoding - server encoding (readonly)
• string Response - when query is completed, it contains server response (readonly)
• string Referral - referral server if server response contains this information (readonly)
• Exception Exception - used by QueryAsync(); contains exception if smth goes wrong (readonly)

General usage for user objects is passing them to Query() or QueryAsync():

// your object for the query below
var mydata = new MyData();

whois.Query("github.com", value: mydata);


// access your data in any delegate, for instance
static void Whois_Delegate(object sender, YaWhoisClientEventArgs e)
{
    var data = (MyData)e.Value;
    // ...
}

BeforeSendRequest

This delegate called before request to a server. Currently, this delegate has little purposes. You may change IDataParser Parser at this moment.

BeforeParseResponse

This one called after network request. You may observe the string Response value. You still may change IDataParser Parser at this moment.

ResponseParsed

This one called after parsing server response to find out the value of Referral.

This is last delegate to be called upon successful request.

Changing IDataParser Parser value will not give any results.

ExceptionThrown

This is used only by QueryAsync() method. When called the exception is set to Exception Exception property of the YaWhoisClientEventArgs arguments.

Recursive queries

YaWhoisClient does recursive queries when its find referral from the server response. If you wish disable this behaviour you may set your dummy IDataParser Parser.

An example to query IANA:

var whois = new YaWhoisClient();

// set delegate when responses received
whois.ResponseParsed += Whois_ResponseParsed;

// make request to IANA
whois.Query("github.com", "whois.iana.org");


// This delegate will be called for whois.iana.org response
// and a referral one (if it exists).
static void Whois_ResponseParsed(object sender, YaWhoisClientEventArgs e)
{
    Console.WriteLine($"[server: {e.Server}]");
    Console.WriteLine();
    Console.WriteLine(e.Response);
}

Exceptions

There are special exceptions which may be thrown by YaWhoisClient:

• NoServerException - when unable to find a server for this kind of object
• UnknownNetworkException - probably invalid AS number or IP address has been passed
• ExternalWhoisException - the server infromation is accessed by external resource

The Query() method throws exceptions.

The QueryAsync() method does not throws exceptions, instead it calls the ExceptionThrown delegate (see above for details).

See also

• RFC 3912 - WHOIS Protocol Specification
• github: rfc1036/whois - whois client written in C
• github: flipbit/whois - dotnet whois library

License

This software is released under BSD 2-clause "Simplified" License.