A pure Nim Domain Name System (DNS) client implemented with dnsprotocol.

This implementation has synchronous and asynchronous (async) procedures (procs) for transmitting data over the internet, using both UDP and TCP protocol.

Install

nimble install ndns

nimble install https://github.com/rockcavera/nim-ndns.git

Basic Use

Resolving IPv4 addresses for nim-lang.org (not async):

import ndns

let client = initDnsClient()

echo resolveIpv4(client, "nim-lang.org")

Resolving IPv4 addresses for nim-lang.org (async):

import asyncdispatch, ndns

let client = initDnsClient()

echo waitFor asyncResolveIpv4(client, "nim-lang.org")

For a "real-life" async example, see resolver.nim. In this example I have made as many comments as possible, even if they look silly. I think it might help someone, as a similar example I provided privately for a newcomer to Nim. It can also be compiled with -d:showLoopLog to show the async workflow.

Advanced Use

Creating a Message object with a QType.A query for the domain name nim-lang.org, transmitting the Message and receiving the response (not async):

import ndns

let header = initHeader(randId(), rd = true)

let question = initQuestion("nim-lang.org", QType.A, QClass.IN)
  # If the last character of "nim-lang.org" is not a '.', the initializer will
  # add, as it is called the DNS root.

let msg = initMessage(header, @[question])
  # The initializer automatically changes `header.qdcount` to `1'u16`

let client = initDnsClient()

var rmsg = dnsQuery(client, msg)

echo repr(rmsg)

Creating a Message object with a QType.A query for the domain name nim-lang.org, transmitting the Message and receiving the response (async):

import asyncdispatch, ndns

let header = initHeader(randId(), rd = true)

let question = initQuestion("nim-lang.org", QType.A, QClass.IN)
  # If the last character of "nim-lang.org" is not a '.', the initializer will
  # add, as it is called the DNS root.

let msg = initMessage(header, @[question])
  # The initializer automatically changes `header.qdcount` to `1'u16`

let client = initDnsClient()

var rmsg = waitFor dnsAsyncQuery(client, msg)

echo repr(rmsg)

Using System DNS Server

You can initialize the DNS client with the DNS resolver server used by the system. To do this, start the client with initSystemDnsClient.

import ndns

let client = initSystemDnsClient()

echo resolveIpv4(client, "nim-lang.org")

Documentation

https://rockcavera.github.io/nim-ndns/ndns.html